rfc2445.txt (291838B)
1 2 3 4 5 6 7 Network Working Group F. Dawson 8 Request for Comments: 2445 Lotus 9 Category: Standards Track D. Stenerson 10 Microsoft 11 November 1998 12 13 14 Internet Calendaring and Scheduling Core Object Specification 15 (iCalendar) 16 17 Status of this Memo 18 19 This document specifies an Internet standards track protocol for the 20 Internet community, and requests discussion and suggestions for 21 improvements. Please refer to the current edition of the "Internet 22 Official Protocol Standards" (STD 1) for the standardization state 23 and status of this protocol. Distribution of this memo is unlimited. 24 25 Copyright Notice 26 27 Copyright (C) The Internet Society (1998). All Rights Reserved. 28 29 Abstract 30 31 There is a clear need to provide and deploy interoperable calendaring 32 and scheduling services for the Internet. Current group scheduling 33 and Personal Information Management (PIM) products are being extended 34 for use across the Internet, today, in proprietary ways. This memo 35 has been defined to provide the definition of a common format for 36 openly exchanging calendaring and scheduling information across the 37 Internet. 38 39 This memo is formatted as a registration for a MIME media type per 40 [RFC 2048]. However, the format in this memo is equally applicable 41 for use outside of a MIME message content type. 42 43 The proposed media type value is 'text/calendar'. This string would 44 label a media type containing calendaring and scheduling information 45 encoded as text characters formatted in a manner outlined below. 46 47 This MIME media type provides a standard content type for capturing 48 calendar event, to-do and journal entry information. It also can be 49 used to convey free/busy time information. The content type is 50 suitable as a MIME message entity that can be transferred over MIME 51 based email systems, using HTTP or some other Internet transport. In 52 53 54 55 56 57 58 Dawson & Stenerson Standards Track [Page 1] 59 60 RFC 2445 iCalendar November 1998 61 62 63 addition, the content type is useful as an object for interactions 64 between desktop applications using the operating system clipboard, 65 drag/drop or file systems capabilities. 66 67 This memo is based on the earlier work of the vCalendar specification 68 for the exchange of personal calendaring and scheduling information. 69 In order to avoid confusion with this referenced work, this memo is 70 to be known as the iCalendar specification. 71 72 This memo defines the format for specifying iCalendar object methods. 73 An iCalendar object method is a set of usage constraints for the 74 iCalendar object. For example, these methods might define scheduling 75 messages that request an event be scheduled, reply to an event 76 request, send a cancellation notice for an event, modify or replace 77 the definition of an event, provide a counter proposal for an 78 original event request, delegate an event request to another 79 individual, request free or busy time, reply to a free or busy time 80 request, or provide similar scheduling messages for a to-do or 81 journal entry calendar component. The iCalendar Transport-indendent 82 Interoperability Protocol (iTIP) defined in [ITIP] is one such 83 scheduling protocol. 84 85 Table of Contents 86 87 1 Introduction.....................................................5 88 2 Basic Grammar and Conventions....................................6 89 2.1 Formatting Conventions .......................................7 90 2.2 Related Memos ................................................8 91 2.3 International Considerations .................................8 92 3 Registration Information.........................................8 93 3.1 Content Type .................................................8 94 3.2 Parameters ...................................................9 95 3.3 Content Header Fields .......................................10 96 3.4 Encoding Considerations .....................................10 97 3.5 Security Considerations .....................................10 98 3.6 Interoperability Considerations .............................11 99 3.7 Applications Which Use This Media Type ......................11 100 3.8 Additional Information ......................................11 101 3.9 Magic Numbers ...............................................11 102 3.10 File Extensions ............................................11 103 3.11 Contact for Further Information: ...........................12 104 3.12 Intended Usage .............................................12 105 3.13 Authors/Change Controllers .................................12 106 4 iCalendar Object Specification..................................13 107 4.1 Content Lines ...............................................13 108 4.1.1 List and Field Separators ................................16 109 4.1.2 Multiple Values ..........................................16 110 4.1.3 Binary Content ...........................................16 111 112 113 114 Dawson & Stenerson Standards Track [Page 2] 115 116 RFC 2445 iCalendar November 1998 117 118 119 4.1.4 Character Set ............................................17 120 4.2 Property Parameters .........................................17 121 4.2.1 Alternate Text Representation ............................18 122 4.2.2 Common Name ..............................................19 123 4.2.3 Calendar User Type .......................................20 124 4.2.4 Delegators ...............................................20 125 4.2.5 Delegatees ...............................................21 126 4.2.6 Directory Entry Reference ................................21 127 4.2.7 Inline Encoding ..........................................22 128 4.2.8 Format Type ..............................................23 129 4.2.9 Free/Busy Time Type ......................................23 130 4.2.10 Language ................................................24 131 4.2.11 Group or List Membership ................................25 132 4.2.12 Participation Status ....................................25 133 4.2.13 Recurrence Identifier Range .............................27 134 4.2.14 Alarm Trigger Relationship ..............................27 135 4.2.15 Relationship Type .......................................28 136 4.2.16 Participation Role ......................................29 137 4.2.17 RSVP Expectation ........................................29 138 4.2.18 Sent By .................................................30 139 4.2.19 Time Zone Identifier ....................................30 140 4.2.20 Value Data Types ........................................32 141 4.3 Property Value Data Types ...................................32 142 4.3.1 Binary ...................................................33 143 4.3.2 Boolean ..................................................33 144 4.3.3 Calendar User Address ....................................34 145 4.3.4 Date .....................................................34 146 4.3.5 Date-Time ................................................35 147 4.3.6 Duration .................................................37 148 4.3.7 Float ....................................................38 149 4.3.8 Integer ..................................................38 150 4.3.9 Period of Time ...........................................39 151 4.3.10 Recurrence Rule .........................................40 152 4.3.11 Text ....................................................45 153 4.3.12 Time ....................................................47 154 4.3.13 URI .....................................................49 155 4.3.14 UTC Offset ..............................................49 156 4.4 iCalendar Object ............................................50 157 4.5 Property ....................................................51 158 4.6 Calendar Components .........................................51 159 4.6.1 Event Component ..........................................52 160 4.6.2 To-do Component ..........................................55 161 4.6.3 Journal Component ........................................56 162 4.6.4 Free/Busy Component ......................................58 163 4.6.5 Time Zone Component ......................................60 164 4.6.6 Alarm Component ..........................................67 165 4.7 Calendar Properties .........................................73 166 4.7.1 Calendar Scale ...........................................73 167 168 169 170 Dawson & Stenerson Standards Track [Page 3] 171 172 RFC 2445 iCalendar November 1998 173 174 175 4.7.2 Method ...................................................74 176 4.7.3 Product Identifier .......................................75 177 4.7.4 Version ..................................................76 178 4.8 Component Properties ........................................77 179 4.8.1 Descriptive Component Properties .........................77 180 4.8.1.1 Attachment ...........................................77 181 4.8.1.2 Categories ...........................................78 182 4.8.1.3 Classification .......................................79 183 4.8.1.4 Comment ..............................................80 184 4.8.1.5 Description ..........................................81 185 4.8.1.6 Geographic Position ..................................82 186 4.8.1.7 Location .............................................84 187 4.8.1.8 Percent Complete .....................................85 188 4.8.1.9 Priority .............................................85 189 4.8.1.10 Resources ...........................................87 190 4.8.1.11 Status ..............................................88 191 4.8.1.12 Summary .............................................89 192 4.8.2 Date and Time Component Properties .......................90 193 4.8.2.1 Date/Time Completed ..................................90 194 4.8.2.2 Date/Time End ........................................91 195 4.8.2.3 Date/Time Due ........................................92 196 4.8.2.4 Date/Time Start ......................................93 197 4.8.2.5 Duration .............................................94 198 4.8.2.6 Free/Busy Time .......................................95 199 4.8.2.7 Time Transparency ....................................96 200 4.8.3 Time Zone Component Properties ...........................97 201 4.8.3.1 Time Zone Identifier .................................97 202 4.8.3.2 Time Zone Name .......................................98 203 4.8.3.3 Time Zone Offset From ................................99 204 4.8.3.4 Time Zone Offset To .................................100 205 4.8.3.5 Time Zone URL .......................................101 206 4.8.4 Relationship Component Properties .......................102 207 4.8.4.1 Attendee ............................................102 208 4.8.4.2 Contact .............................................104 209 4.8.4.3 Organizer ...........................................106 210 4.8.4.4 Recurrence ID .......................................107 211 4.8.4.5 Related To ..........................................109 212 4.8.4.6 Uniform Resource Locator ............................110 213 4.8.4.7 Unique Identifier ...................................111 214 4.8.5 Recurrence Component Properties .........................112 215 4.8.5.1 Exception Date/Times ................................112 216 4.8.5.2 Exception Rule ......................................114 217 4.8.5.3 Recurrence Date/Times ...............................115 218 4.8.5.4 Recurrence Rule .....................................117 219 4.8.6 Alarm Component Properties ..............................126 220 4.8.6.1 Action ..............................................126 221 4.8.6.2 Repeat Count ........................................126 222 4.8.6.3 Trigger .............................................127 223 224 225 226 Dawson & Stenerson Standards Track [Page 4] 227 228 RFC 2445 iCalendar November 1998 229 230 231 4.8.7 Change Management Component Properties ..................129 232 4.8.7.1 Date/Time Created ...................................129 233 4.8.7.2 Date/Time Stamp .....................................130 234 4.8.7.3 Last Modified .......................................131 235 4.8.7.4 Sequence Number .....................................131 236 4.8.8 Miscellaneous Component Properties ......................133 237 4.8.8.1 Non-standard Properties .............................133 238 4.8.8.2 Request Status ......................................134 239 5 iCalendar Object Examples......................................136 240 6 Recommended Practices..........................................140 241 7 Registration of Content Type Elements..........................141 242 7.1 Registration of New and Modified iCalendar Object Methods ..141 243 7.2 Registration of New Properties .............................141 244 7.2.1 Define the property .....................................142 245 7.2.2 Post the Property definition ............................143 246 7.2.3 Allow a comment period ..................................143 247 7.2.4 Submit the property for approval ........................143 248 7.3 Property Change Control ....................................143 249 8 References.....................................................144 250 9 Acknowledgments................................................145 251 10 Authors' and Chairs' Addresses................................146 252 11 Full Copyright Statement......................................148 253 254 1 Introduction 255 256 The use of calendaring and scheduling has grown considerably in the 257 last decade. Enterprise and inter-enterprise business has become 258 dependent on rapid scheduling of events and actions using this 259 information technology. However, the longer term growth of 260 calendaring and scheduling, is currently limited by the lack of 261 Internet standards for the message content types that are central to 262 these knowledgeware applications. This memo is intended to progress 263 the level of interoperability possible between dissimilar calendaring 264 and scheduling applications. This memo defines a MIME content type 265 for exchanging electronic calendaring and scheduling information. The 266 Internet Calendaring and Scheduling Core Object Specification, or 267 iCalendar, allows for the capture and exchange of information 268 normally stored within a calendaring and scheduling application; such 269 as a Personal Information Manager (PIM) or a Group Scheduling 270 product. 271 272 The iCalendar format is suitable as an exchange format between 273 applications or systems. The format is defined in terms of a MIME 274 content type. This will enable the object to be exchanged using 275 several transports, including but not limited to SMTP, HTTP, a file 276 system, desktop interactive protocols such as the use of a memory- 277 based clipboard or drag/drop interactions, point-to-point 278 asynchronous communication, wired-network transport, or some form of 279 280 281 282 Dawson & Stenerson Standards Track [Page 5] 283 284 RFC 2445 iCalendar November 1998 285 286 287 unwired transport such as infrared might also be used. 288 289 The memo also provides for the definition of iCalendar object methods 290 that will map this content type to a set of messages for supporting 291 calendaring and scheduling operations such as requesting, replying 292 to, modifying, and canceling meetings or appointments, to-dos and 293 journal entries. The iCalendar object methods can be used to define 294 other calendaring and scheduling operations such a requesting for and 295 replying with free/busy time data. Such a scheduling protocol is 296 defined in the iCalendar Transport-independent Interoperability 297 Protocol (iTIP) defined in [ITIP]. 298 299 The memo also includes a formal grammar for the content type based on 300 the Internet ABNF defined in [RFC 2234]. This ABNF is required for 301 the implementation of parsers and to serve as the definitive 302 reference when ambiguities or questions arise in interpreting the 303 descriptive prose definition of the memo. 304 305 2 Basic Grammar and Conventions 306 307 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 308 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY" and 309 "OPTIONAL" in this document are to be interoperated as described in 310 [RFC 2119]. 311 312 This memo makes use of both a descriptive prose and a more formal 313 notation for defining the calendaring and scheduling format. 314 315 The notation used in this memo is the ABNF notation of [RFC 2234]. 316 Readers intending on implementing this format defined in this memo 317 should be familiar with this notation in order to properly interpret 318 the specifications of this memo. 319 320 All numeric and hexadecimal values used in this memo are given in 321 decimal notation. 322 323 All names of properties, property parameters, enumerated property 324 values and property parameter values are case-insensitive. However, 325 all other property values are case-sensitive, unless otherwise 326 stated. 327 328 Note: All indented editorial notes, such as this one, are 329 intended to provide the reader with additional information. The 330 information is not essential to the building of an 331 implementation conformant with this memo. The information is 332 provided to highlight a particular feature or characteristic of 333 the memo. 334 335 336 337 338 Dawson & Stenerson Standards Track [Page 6] 339 340 RFC 2445 iCalendar November 1998 341 342 343 The format for the iCalendar object is based on the syntax of the 344 [RFC 2425] content type. While the iCalendar object is not a profile 345 of the [RFC 2425] content type, it does reuse a number of the 346 elements from the [RFC 2425] specification. 347 348 2.1 Formatting Conventions 349 350 The mechanisms defined in this memo are defined in prose. Many of the 351 terms used to describe these have common usage that is different than 352 the standards usage of this memo. In order to reference within this 353 memo elements of the calendaring and scheduling model, core object 354 (this memo) or interoperability protocol [ITIP] some formatting 355 conventions have been used. Calendaring and scheduling roles are 356 referred to in quoted-strings of text with the first character of 357 each word in upper case. For example, "Organizer" refers to a role of 358 a "Calendar User" within the scheduling protocol defined by [ITIP]. 359 Calendar components defined by this memo are referred to with 360 capitalized, quoted-strings of text. All calendar components start 361 with the letter "V". For example, "VEVENT" refers to the event 362 calendar component, "VTODO" refers to the to-do calendar component 363 and "VJOURNAL" refers to the daily journal calendar component. 364 Scheduling methods defined by [ITIP] are referred to with 365 capitalized, quoted-strings of text. For example, "REQUEST" refers to 366 the method for requesting a scheduling calendar component be created 367 or modified, "REPLY" refers to the method a recipient of a request 368 uses to update their status with the "Organizer" of the calendar 369 component. 370 371 The properties defined by this memo are referred to with capitalized, 372 quoted-strings of text, followed by the word "property". For example, 373 "ATTENDEE" property refers to the iCalendar property used to convey 374 the calendar address of a calendar user. Property parameters defined 375 by this memo are referred to with lowercase, quoted-strings of text, 376 followed by the word "parameter". For example, "value" parameter 377 refers to the iCalendar property parameter used to override the 378 default data type for a property value. Enumerated values defined by 379 this memo are referred to with capitalized text, either alone or 380 followed by the word "value". For example, the "MINUTELY" value can 381 be used with the "FREQ" component of the "RECUR" data type to specify 382 repeating components based on an interval of one minute or more. 383 384 385 386 387 388 389 390 391 392 393 394 Dawson & Stenerson Standards Track [Page 7] 395 396 RFC 2445 iCalendar November 1998 397 398 399 2.2 Related Memos 400 401 Implementers will need to be familiar with several other memos that, 402 along with this memo, form a framework for Internet calendaring and 403 scheduling standards. This memo, [ICAL], specifies a core 404 specification of objects, data types, properties and property 405 parameters. 406 407 [ITIP] - specifies an interoperability protocol for scheduling 408 between different implementations; 409 410 [IMIP] specifies an Internet email binding for [ITIP]. 411 412 This memo does not attempt to repeat the specification of concepts or 413 definitions from these other memos. Where possible, references are 414 made to the memo that provides for the specification of these 415 concepts or definitions. 416 417 2.3 International Considerations 418 419 In the rest of this document, descriptions of characters are of the 420 form "character name (codepoint)", where "codepoint" is from the US- 421 ASCII character set. The "character name" is the authoritative 422 description; (codepoint) is a reference to that character in US-ASCII 423 or US-ASCII compatible sets (for example the ISO-8859-x family, UTF- 424 8, ISO-2022-xx, KOI8-R). If a non-US-ASCII compatible character set 425 is used, appropriate code-point from that character set MUST be 426 chosen instead. Use of non-US-ASCII-compatible character sets is NOT 427 recommended. 428 429 3 Registration Information 430 431 The Calendaring and Scheduling Core Object Specification is intended 432 for use as a MIME content type. However, the implementation of the 433 memo is in no way limited solely as a MIME content type. 434 435 3.1 Content Type 436 437 The following text is intended to register this memo as the MIME 438 content type "text/calendar". 439 440 To: ietf-types@uninett.no 441 442 Subject: Registration of MIME content type text/calendar. 443 444 MIME media type name: text 445 446 MIME subtype name: calendar 447 448 449 450 Dawson & Stenerson Standards Track [Page 8] 451 452 RFC 2445 iCalendar November 1998 453 454 455 3.2 Parameters 456 457 Required parameters: none 458 459 Optional parameters: charset, method, component and optinfo 460 461 The "charset" parameter is defined in [RFC 2046] for other body 462 parts. It is used to identify the default character set used within 463 the body part. 464 465 The "method" parameter is used to convey the iCalendar object method 466 or transaction semantics for the calendaring and scheduling 467 information. It also is an identifier for the restricted set of 468 properties and values that the iCalendar object consists of. The 469 parameter is to be used as a guide for applications interpreting the 470 information contained within the body part. It SHOULD NOT be used to 471 exclude or require particular pieces of information unless the 472 identified method definition specifically calls for this behavior. 473 Unless specifically forbidden by a particular method definition, a 474 text/calendar content type can contain any set of properties 475 permitted by the Calendaring and Scheduling Core Object 476 Specification. The "method" parameter MUST be the same value as that 477 specified in the "METHOD" component property in the iCalendar object. 478 If one is present, the other MUST also be present. 479 480 The value for the "method" parameter is defined as follows: 481 482 method = 1*(ALPHA / DIGIT / "-") 483 ; IANA registered iCalendar object method 484 485 The "component" parameter conveys the type of iCalendar calendar 486 component within the body part. If the iCalendar object contains more 487 than one calendar component type, then multiple component parameters 488 MUST be specified. 489 490 The value for the "component" parameter is defined as follows: 491 492 component = ("VEVENT" / "VTODO" / "VJOURNAL" / "VFREEBUSY" 493 / "VTIMEZONE" / x-name / iana-token) 494 495 The "optinfo" parameter conveys optional information about the 496 iCalendar object within the body part. This parameter can only 497 specify semantics already specified by the iCalendar object and that 498 can be otherwise determined by parsing the body part. In addition, 499 the optional information specified by this parameter MUST be 500 consistent with that information specified by the iCalendar object. 501 For example, it can be used to convey the "Attendee" response status 502 to a meeting request. The parameter value consists of a string value. 503 504 505 506 Dawson & Stenerson Standards Track [Page 9] 507 508 RFC 2445 iCalendar November 1998 509 510 511 The parameter can be specified multiple times. 512 513 This parameter MAY only specify semantics already specified by the 514 iCalendar object and that can be otherwise determined by parsing the 515 body part. 516 517 The value for the "optinfo" parameter is defined as follows: 518 519 optinfo = infovalue / qinfovalue 520 521 infovalue = iana-token / x-name 522 523 qinfovalue = DQUOTE (infovalue) DQUOTE 524 525 3.3 Content Header Fields 526 527 Optional content header fields: Any header fields defined by [RFC 528 2045]. 529 530 3.4 Encoding Considerations 531 532 This MIME content type can contain 8bit characters, so the use of 533 quoted-printable or BASE64 MIME content-transfer-encodings might be 534 necessary when iCalendar objects are transferred across protocols 535 restricted to the 7bit repertoire. Note that a text valued property 536 in the content entity can also have content encoding of special 537 characters using a BACKSLASH character (US-ASCII decimal 92) 538 escapement technique. This means that content values can end up 539 encoded twice. 540 541 3.5 Security Considerations 542 543 SPOOFING - - In this memo, the "Organizer" is the only person 544 authorized to make changes to an existing "VEVENT", "VTODO", 545 "VJOURNAL" calendar component and redistribute the updates to the 546 "Attendees". An iCalendar object that maliciously changes or cancels 547 an existing "VEVENT", "VTODO" or "VJOURNAL" or "VFREEBUSY" calendar 548 component might be constructed by someone other than the "Organizer" 549 and sent to the "Attendees". In addition in this memo, other than the 550 "Organizer", an "Attendee" of a "VEVENT", "VTODO", "VJOURNAL" 551 calendar component is the only other person authorized to update any 552 parameter associated with their "ATTENDEE" property and send it to 553 the "Organizer". An iCalendar object that maliciously changes the 554 "ATTENDEE" parameters can be constructed by someone other than the 555 real "Attendee" and sent to the "Organizer". 556 557 558 559 560 561 562 Dawson & Stenerson Standards Track [Page 10] 563 564 RFC 2445 iCalendar November 1998 565 566 567 PROCEDURAL ALARMS - - An iCalendar object can be created that 568 contains a "VEVENT" and "VTODO" calendar component with "VALARM" 569 calendar components. The "VALARM" calendar component can be of type 570 PROCEDURE and can have an attachment containing some sort of 571 executable program. Implementations that incorporate these types of 572 alarms are subject to any virus or malicious attack that might occur 573 as a result of executing the attachment. 574 575 ATTACHMENTS - - An iCalendar object can include references to Uniform 576 Resource Locators that can be programmed resources. 577 578 Implementers and users of this memo should be aware of the network 579 security implications of accepting and parsing such information. In 580 addition, the security considerations observed by implementations of 581 electronic mail systems should be followed for this memo. 582 583 3.6 Interoperability Considerations 584 585 This MIME content type is intended to define a common format for 586 conveying calendaring and scheduling information between different 587 systems. It is heavily based on the earlier [VCAL] industry 588 specification. 589 590 3.7 Applications Which Use This Media Type 591 592 This content-type is designed for widespread use by Internet 593 calendaring and scheduling applications. In addition, applications in 594 the workflow and document management area might find this content- 595 type applicable. The [ITIP] and [IMIP] Internet protocols directly 596 use this content-type also. Future work on an Internet calendar 597 access protocol will utilize this content-type too. 598 599 3.8 Additional Information 600 601 This memo defines this content-type. 602 603 3.9 Magic Numbers 604 605 None. 606 607 3.10 File Extensions 608 609 The file extension of "ics" is to be used to designate a file 610 containing (an arbitrary set of) calendaring and scheduling 611 information consistent with this MIME content type. 612 613 614 615 616 617 618 Dawson & Stenerson Standards Track [Page 11] 619 620 RFC 2445 iCalendar November 1998 621 622 623 The file extension of "ifb" is to be used to designate a file 624 containing free or busy time information consistent with this MIME 625 content type. 626 627 Macintosh file type codes: The file type code of "iCal" is to be used 628 in Apple MacIntosh operating system environments to designate a file 629 containing calendaring and scheduling information consistent with 630 this MIME media type. 631 632 The file type code of "iFBf" is to be used in Apple MacIntosh 633 operating system environments to designate a file containing free or 634 busy time information consistent with this MIME media type. 635 636 3.11 Contact for Further Information: 637 638 Frank Dawson 639 6544 Battleford Drive 640 Raleigh, NC 27613-3502 641 919-676-9515 (Telephone) 642 919-676-9564 (Data/Facsimile) 643 Frank_Dawson@Lotus.com (Internet Mail) 644 645 Derik Stenerson 646 One Microsoft Way 647 Redmond, WA 98052-6399 648 425-936-5522 (Telephone) 649 425-936-7329 (Facsimile) 650 deriks@microsoft.com (Internet Mail) 651 652 3.12 Intended Usage 653 654 COMMON 655 656 3.13 Authors/Change Controllers 657 658 Frank Dawson 659 6544 Battleford Drive 660 Raleigh, NC 27613-3502 661 919-676-9515 (Telephone) 662 919-676-9564 (Data/Facsimile) 663 Frank_Dawson@Lotus.com (Internet Mail) 664 665 Derik Stenerson 666 One Microsoft Way 667 Redmond, WA 98052-6399 668 425-936-5522 (Telephone) 669 425-936-7329 (Facsimile) 670 deriks@microsoft.com (Internet Mail) 671 672 673 674 Dawson & Stenerson Standards Track [Page 12] 675 676 RFC 2445 iCalendar November 1998 677 678 679 4 iCalendar Object Specification 680 681 The following sections define the details of a Calendaring and 682 Scheduling Core Object Specification. This information is intended to 683 be an integral part of the MIME content type registration. In 684 addition, this information can be used independent of such content 685 registration. In particular, this memo has direct applicability for 686 use as a calendaring and scheduling exchange format in file-, memory- 687 or network-based transport mechanisms. 688 689 4.1 Content Lines 690 691 The iCalendar object is organized into individual lines of text, 692 called content lines. Content lines are delimited by a line break, 693 which is a CRLF sequence (US-ASCII decimal 13, followed by US-ASCII 694 decimal 10). 695 696 Lines of text SHOULD NOT be longer than 75 octets, excluding the line 697 break. Long content lines SHOULD be split into a multiple line 698 representations using a line "folding" technique. That is, a long 699 line can be split between any two characters by inserting a CRLF 700 immediately followed by a single linear white space character (i.e., 701 SPACE, US-ASCII decimal 32 or HTAB, US-ASCII decimal 9). Any sequence 702 of CRLF followed immediately by a single linear white space character 703 is ignored (i.e., removed) when processing the content type. 704 705 For example the line: 706 707 DESCRIPTION:This is a long description that exists on a long line. 708 709 Can be represented as: 710 711 DESCRIPTION:This is a lo 712 ng description 713 that exists on a long line. 714 715 The process of moving from this folded multiple line representation 716 to its single line representation is called "unfolding". Unfolding is 717 accomplished by removing the CRLF character and the linear white 718 space character that immediately follows. 719 720 When parsing a content line, folded lines MUST first be unfolded 721 according to the unfolding procedure described above. When generating 722 a content line, lines longer than 75 octets SHOULD be folded 723 according to the folding procedure described above. 724 725 726 727 728 729 730 Dawson & Stenerson Standards Track [Page 13] 731 732 RFC 2445 iCalendar November 1998 733 734 735 The content information associated with an iCalendar object is 736 formatted using a syntax similar to that defined by [RFC 2425]. That 737 is, the content information consists of CRLF-separated content lines. 738 739 The following notation defines the lines of content in an iCalendar 740 object: 741 742 contentline = name *(";" param ) ":" value CRLF 743 ; This ABNF is just a general definition for an initial parsing 744 ; of the content line into its property name, parameter list, 745 ; and value string 746 747 ; When parsing a content line, folded lines MUST first 748 ; be unfolded according to the unfolding procedure 749 ; described above. When generating a content line, lines 750 ; longer than 75 octets SHOULD be folded according to 751 ; the folding procedure described above. 752 753 name = x-name / iana-token 754 755 iana-token = 1*(ALPHA / DIGIT / "-") 756 ; iCalendar identifier registered with IANA 757 758 x-name = "X-" [vendorid "-"] 1*(ALPHA / DIGIT / "-") 759 ; Reservered for experimental use. Not intended for use in 760 ; released products. 761 762 vendorid = 3*(ALPHA / DIGIT) ;Vendor identification 763 764 param = param-name "=" param-value 765 *("," param-value) 766 ; Each property defines the specific ABNF for the parameters 767 ; allowed on the property. Refer to specific properties for 768 ; precise parameter ABNF. 769 770 param-name = iana-token / x-token 771 772 param-value = paramtext / quoted-string 773 774 paramtext = *SAFE-CHAR 775 776 value = *VALUE-CHAR 777 778 quoted-string = DQUOTE *QSAFE-CHAR DQUOTE 779 780 NON-US-ASCII = %x80-F8 781 ; Use restricted by charset parameter 782 ; on outer MIME object (UTF-8 preferred) 783 784 785 786 Dawson & Stenerson Standards Track [Page 14] 787 788 RFC 2445 iCalendar November 1998 789 790 791 QSAFE-CHAR = WSP / %x21 / %x23-7E / NON-US-ASCII 792 ; Any character except CTLs and DQUOTE 793 794 SAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E 795 / NON-US-ASCII 796 ; Any character except CTLs, DQUOTE, ";", ":", "," 797 798 VALUE-CHAR = WSP / %x21-7E / NON-US-ASCII 799 ; Any textual character 800 801 CR = %x0D 802 ; carriage return 803 804 LF = %x0A 805 ; line feed 806 807 CRLF = CR LF 808 ; Internet standard newline 809 810 CTL = %x00-08 / %x0A-1F / %x7F 811 ; Controls 812 813 ALPHA = %x41-5A / %x61-7A ; A-Z / a-z 814 815 DIGIT = %x30-39 816 ; 0-9 817 818 DQUOTE = %x22 819 ; Quotation Mark 820 821 WSP = SPACE / HTAB 822 823 SPACE = %x20 824 825 HTAB = %x09 826 827 The property value component of a content line has a format that is 828 property specific. Refer to the section describing each property for 829 a definition of this format. 830 831 All names of properties, property parameters, enumerated property 832 values and property parameter values are case-insensitive. However, 833 all other property values are case-sensitive, unless otherwise 834 stated. 835 836 837 838 839 840 841 842 Dawson & Stenerson Standards Track [Page 15] 843 844 RFC 2445 iCalendar November 1998 845 846 847 4.1.1 List and Field Separators 848 849 Some properties and parameters allow a list of values. Values in a 850 list of values MUST be separated by a COMMA character (US-ASCII 851 decimal 44). There is no significance to the order of values in a 852 list. For those parameter values (such as those that specify URI 853 values) that are specified in quoted-strings, the individual quoted- 854 strings are separated by a COMMA character (US-ASCII decimal 44). 855 856 Some property values are defined in terms of multiple parts. These 857 structured property values MUST have their value parts separated by a 858 SEMICOLON character (US-ASCII decimal 59). 859 860 Some properties allow a list of parameters. Each property parameter 861 in a list of property parameters MUST be separated by a SEMICOLON 862 character (US-ASCII decimal 59). 863 864 Property parameters with values containing a COLON, a SEMICOLON or a 865 COMMA character MUST be placed in quoted text. 866 867 For example, in the following properties a SEMICOLON is used to 868 separate property parameters from each other, and a COMMA is used to 869 separate property values in a value list. 870 871 ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT:MAILTO: 872 jsmith@host.com 873 874 RDATE;VALUE=DATE:19970304,19970504,19970704,19970904 875 876 4.1.2 Multiple Values 877 878 Some properties defined in the iCalendar object can have multiple 879 values. The general rule for encoding multi-valued items is to simply 880 create a new content line for each value, including the property 881 name. However, it should be noted that some properties support 882 encoding multiple values in a single property by separating the 883 values with a COMMA character (US-ASCII decimal 44). Individual 884 property definitions should be consulted for determining whether a 885 specific property allows multiple values and in which of these two 886 forms. 887 888 4.1.3 Binary Content 889 890 Binary content information in an iCalendar object SHOULD be 891 referenced using a URI within a property value. That is the binary 892 content information SHOULD be placed in an external MIME entity that 893 can be referenced by a URI from within the iCalendar object. In 894 applications where this is not feasible, binary content information 895 896 897 898 Dawson & Stenerson Standards Track [Page 16] 899 900 RFC 2445 iCalendar November 1998 901 902 903 can be included within an iCalendar object, but only after first 904 encoding it into text using the "BASE64" encoding method defined in 905 [RFC 2045]. Inline binary contact SHOULD only be used in applications 906 whose special circumstances demand that an iCalendar object be 907 expressed as a single entity. A property containing inline binary 908 content information MUST specify the "ENCODING" property parameter. 909 Binary content information placed external to the iCalendar object 910 MUST be referenced by a uniform resource identifier (URI). 911 912 The following example specifies an "ATTACH" property that references 913 an attachment external to the iCalendar object with a URI reference: 914 915 ATTACH:http://xyz.com/public/quarterly-report.doc 916 917 The following example specifies an "ATTACH" property with inline 918 binary encoded content information: 919 920 ATTACH;FMTTYPE=image/basic;ENCODING=BASE64;VALUE=BINARY: 921 MIICajCCAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQAwdzELMAkGA1U 922 EBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb25zIE 923 <...remainder of "BASE64" encoded binary data...> 924 925 4.1.4 Character Set 926 927 There is not a property parameter to declare the character set used 928 in a property value. The default character set for an iCalendar 929 object is UTF-8 as defined in [RFC 2279]. 930 931 The "charset" Content-Type parameter can be used in MIME transports 932 to specify any other IANA registered character set. 933 934 4.2 Property Parameters 935 936 A property can have attributes associated with it. These "property 937 parameters" contain meta-information about the property or the 938 property value. Property parameters are provided to specify such 939 information as the location of an alternate text representation for a 940 property value, the language of a text property value, the data type 941 of the property value and other attributes. 942 943 Property parameter values that contain the COLON (US-ASCII decimal 944 58), SEMICOLON (US-ASCII decimal 59) or COMMA (US-ASCII decimal 44) 945 character separators MUST be specified as quoted-string text values. 946 Property parameter values MUST NOT contain the DOUBLE-QUOTE (US-ASCII 947 decimal 22) character. The DOUBLE-QUOTE (US-ASCII decimal 22) 948 character is used as a delimiter for parameter values that contain 949 restricted characters or URI text. For example: 950 951 952 953 954 Dawson & Stenerson Standards Track [Page 17] 955 956 RFC 2445 iCalendar November 1998 957 958 959 DESCRIPTION;ALTREP="http://www.wiz.org":The Fall'98 Wild Wizards 960 Conference - - Las Vegas, NV, USA 961 962 Property parameter values that are not in quoted strings are case 963 insensitive. 964 965 The general property parameters defined by this memo are defined by 966 the following notation: 967 968 parameter = altrepparam ; Alternate text representation 969 / cnparam ; Common name 970 / cutypeparam ; Calendar user type 971 / delfromparam ; Delegator 972 / deltoparam ; Delegatee 973 / dirparam ; Directory entry 974 / encodingparam ; Inline encoding 975 / fmttypeparam ; Format type 976 / fbtypeparam ; Free/busy time type 977 / languageparam ; Language for text 978 / memberparam ; Group or list membership 979 / partstatparam ; Participation status 980 / rangeparam ; Recurrence identifier range 981 / trigrelparam ; Alarm trigger relationship 982 / reltypeparam ; Relationship type 983 / roleparam ; Participation role 984 / rsvpparam ; RSVP expectation 985 / sentbyparam ; Sent by 986 / tzidparam ; Reference to time zone object 987 / valuetypeparam ; Property value data type 988 / ianaparam 989 ; Some other IANA registered iCalendar parameter. 990 / xparam 991 ; A non-standard, experimental parameter. 992 993 ianaparam = iana-token "=" param-value *("," param-value) 994 995 xparam =x-name "=" param-value *("," param-value) 996 997 4.2.1 Alternate Text Representation 998 999 Parameter Name: ALTREP 1000 1001 Purpose: To specify an alternate text representation for the property 1002 value. 1003 1004 Format Definition: The property parameter is defined by the following 1005 notation: 1006 1007 1008 1009 1010 Dawson & Stenerson Standards Track [Page 18] 1011 1012 RFC 2445 iCalendar November 1998 1013 1014 1015 altrepparam = "ALTREP" "=" DQUOTE uri DQUOTE 1016 1017 Description: The parameter specifies a URI that points to an 1018 alternate representation for a textual property value. A property 1019 specifying this parameter MUST also include a value that reflects the 1020 default representation of the text value. The individual URI 1021 parameter values MUST each be specified in a quoted-string. 1022 1023 Example: 1024 1025 DESCRIPTION;ALTREP="CID:<part3.msg.970415T083000@host.com>":Project 1026 XYZ Review Meeting will include the following agenda items: (a) 1027 Market Overview, (b) Finances, (c) Project Management 1028 1029 The "ALTREP" property parameter value might point to a "text/html" 1030 content portion. 1031 1032 Content-Type:text/html 1033 Content-Id:<part3.msg.970415T083000@host.com> 1034 1035 <html><body> 1036 <p><b>Project XYZ Review Meeting</b> will include the following 1037 agenda items:<ol><li>Market 1038 Overview</li><li>Finances</li><li>Project Management</li></ol></p> 1039 </body></html> 1040 1041 4.2.2 Common Name 1042 1043 Parameter Name: CN 1044 1045 Purpose: To specify the common name to be associated with the 1046 calendar user specified by the property. 1047 1048 Format Definition: The property parameter is defined by the following 1049 notation: 1050 1051 cnparam = "CN" "=" param-value 1052 1053 Description: This parameter can be specified on properties with a 1054 CAL-ADDRESS value type. The parameter specifies the common name to be 1055 associated with the calendar user specified by the property. The 1056 parameter value is text. The parameter value can be used for display 1057 text to be associated with the calendar address specified by the 1058 property. 1059 1060 1061 1062 1063 1064 1065 1066 Dawson & Stenerson Standards Track [Page 19] 1067 1068 RFC 2445 iCalendar November 1998 1069 1070 1071 Example: 1072 1073 ORGANIZER;CN="John Smith":MAILTO:jsmith@host.com 1074 1075 4.2.3 Calendar User Type 1076 1077 Parameter Name: CUTYPE 1078 1079 Purpose: To specify the type of calendar user specified by the 1080 property. 1081 1082 Format Definition: The property parameter is defined by the following 1083 notation: 1084 1085 cutypeparam = "CUTYPE" "=" 1086 ("INDIVIDUAL" ; An individual 1087 / "GROUP" ; A group of individuals 1088 / "RESOURCE" ; A physical resource 1089 / "ROOM" ; A room resource 1090 / "UNKNOWN" ; Otherwise not known 1091 / x-name ; Experimental type 1092 / iana-token) ; Other IANA registered 1093 ; type 1094 ; Default is INDIVIDUAL 1095 1096 Description: This parameter can be specified on properties with a 1097 CAL-ADDRESS value type. The parameter identifies the type of calendar 1098 user specified by the property. If not specified on a property that 1099 allows this parameter, the default is INDIVIDUAL. 1100 1101 Example: 1102 1103 ATTENDEE;CUTYPE=GROUP:MAILTO:ietf-calsch@imc.org 1104 1105 4.2.4 Delegators 1106 1107 Parameter Name: DELEGATED-FROM 1108 1109 Purpose: To specify the calendar users that have delegated their 1110 participation to the calendar user specified by the property. 1111 1112 Format Definition: The property parameter is defined by the following 1113 notation: 1114 1115 delfromparam = "DELEGATED-FROM" "=" DQUOTE cal-address DQUOTE 1116 *("," DQUOTE cal-address DQUOTE) 1117 1118 1119 1120 1121 1122 Dawson & Stenerson Standards Track [Page 20] 1123 1124 RFC 2445 iCalendar November 1998 1125 1126 1127 Description: This parameter can be specified on properties with a 1128 CAL-ADDRESS value type. This parameter can be specified on a property 1129 that has a value type of calendar address. This parameter specifies 1130 those calendar uses that have delegated their participation in a 1131 group scheduled event or to-do to the calendar user specified by the 1132 property. The value MUST be a MAILTO URI as defined in [RFC 1738]. 1133 The individual calendar address parameter values MUST each be 1134 specified in a quoted-string. 1135 1136 Example: 1137 1138 ATTENDEE;DELEGATED-FROM="MAILTO:jsmith@host.com":MAILTO: 1139 jdoe@host.com 1140 1141 4.2.5 Delegatees 1142 1143 Parameter Name: DELEGATED-TO 1144 1145 Purpose: To specify the calendar users to whom the calendar user 1146 specified by the property has delegated participation. 1147 1148 Format Definition: The property parameter is defined by the following 1149 notation: 1150 1151 deltoparam = "DELEGATED-TO" "=" DQUOTE cal-address DQUOTE 1152 *("," DQUOTE cal-address DQUOTE) 1153 1154 Description: This parameter can be specified on properties with a 1155 CAL-ADDRESS value type. This parameter specifies those calendar users 1156 whom have been delegated participation in a group scheduled event or 1157 to-do by the calendar user specified by the property. The value MUST 1158 be a MAILTO URI as defined in [RFC 1738]. The individual calendar 1159 address parameter values MUST each be specified in a quoted-string. 1160 1161 Example: 1162 1163 ATTENDEE;DELEGATED-TO="MAILTO:jdoe@host.com","MAILTO:jqpublic@ 1164 host.com":MAILTO:jsmith@host.com 1165 1166 4.2.6 Directory Entry Reference 1167 1168 Parameter Name: DIR 1169 1170 Purpose: To specify reference to a directory entry associated with 1171 the calendar user specified by the property. 1172 1173 Format Definition: The property parameter is defined by the following 1174 notation: 1175 1176 1177 1178 Dawson & Stenerson Standards Track [Page 21] 1179 1180 RFC 2445 iCalendar November 1998 1181 1182 1183 dirparam = "DIR" "=" DQUOTE uri DQUOTE 1184 1185 Description: This parameter can be specified on properties with a 1186 CAL-ADDRESS value type. The parameter specifies a reference to the 1187 directory entry associated with the calendar user specified by the 1188 property. The parameter value is a URI. The individual URI parameter 1189 values MUST each be specified in a quoted-string. 1190 1191 Example: 1192 1193 ORGANIZER;DIR="ldap://host.com:6666/o=eDABC%20Industries,c=3DUS?? 1194 (cn=3DBJim%20Dolittle)":MAILTO:jimdo@host1.com 1195 1196 4.2.7 Inline Encoding 1197 1198 Parameter Name: ENCODING 1199 1200 Purpose: To specify an alternate inline encoding for the property 1201 value. 1202 1203 Format Definition: The property parameter is defined by the following 1204 notation: 1205 1206 encodingparam = "ENCODING" "=" 1207 ("8BIT" 1208 ; "8bit" text encoding is defined in [RFC 2045] 1209 / "BASE64" 1210 ; "BASE64" binary encoding format is defined in [RFC 2045] 1211 / iana-token 1212 ; Some other IANA registered iCalendar encoding type 1213 / x-name) 1214 ; A non-standard, experimental encoding type 1215 1216 Description: The property parameter identifies the inline encoding 1217 used in a property value. The default encoding is "8BIT", 1218 corresponding to a property value consisting of text. The "BASE64" 1219 encoding type corresponds to a property value encoded using the 1220 "BASE64" encoding defined in [RFC 2045]. 1221 1222 If the value type parameter is ";VALUE=BINARY", then the inline 1223 encoding parameter MUST be specified with the value 1224 ";ENCODING=BASE64". 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 Dawson & Stenerson Standards Track [Page 22] 1235 1236 RFC 2445 iCalendar November 1998 1237 1238 1239 Example: 1240 1241 ATTACH;FMTYPE=IMAGE/JPEG;ENCODING=BASE64;VALUE=BINARY:MIICajC 1242 CAdOgAwIBAgICBEUwDQYJKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDA 1243 qBgNVBAoTI05ldHNjYXBlIENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRw 1244 <...remainder of "BASE64" encoded binary data...> 1245 1246 4.2.8 Format Type 1247 1248 Parameter Name: FMTTYPE 1249 1250 Purpose: To specify the content type of a referenced object. 1251 1252 Format Definition: The property parameter is defined by the following 1253 notation: 1254 1255 fmttypeparam = "FMTTYPE" "=" iana-token 1256 ; A IANA registered content type 1257 / x-name 1258 ; A non-standard content type 1259 1260 Description: This parameter can be specified on properties that are 1261 used to reference an object. The parameter specifies the content type 1262 of the referenced object. For example, on the "ATTACH" property, a 1263 FTP type URI value does not, by itself, necessarily convey the type 1264 of content associated with the resource. The parameter value MUST be 1265 the TEXT for either an IANA registered content type or a non-standard 1266 content type. 1267 1268 Example: 1269 1270 ATTACH;FMTTYPE=application/binary:ftp://domain.com/pub/docs/ 1271 agenda.doc 1272 1273 4.2.9 Free/Busy Time Type 1274 1275 Parameter Name: FBTYPE 1276 1277 Purpose: To specify the free or busy time type. 1278 1279 Format Definition: The property parameter is defined by the following 1280 notation: 1281 1282 fbtypeparam = "FBTYPE" "=" ("FREE" / "BUSY" 1283 / "BUSY-UNAVAILABLE" / "BUSY-TENTATIVE" 1284 / x-name 1285 ; Some experimental iCalendar data type. 1286 / iana-token) 1287 1288 1289 1290 Dawson & Stenerson Standards Track [Page 23] 1291 1292 RFC 2445 iCalendar November 1998 1293 1294 1295 ; Some other IANA registered iCalendar data type. 1296 1297 Description: The parameter specifies the free or busy time type. The 1298 value FREE indicates that the time interval is free for scheduling. 1299 The value BUSY indicates that the time interval is busy because one 1300 or more events have been scheduled for that interval. The value 1301 BUSY-UNAVAILABLE indicates that the time interval is busy and that 1302 the interval can not be scheduled. The value BUSY-TENTATIVE indicates 1303 that the time interval is busy because one or more events have been 1304 tentatively scheduled for that interval. If not specified on a 1305 property that allows this parameter, the default is BUSY. 1306 1307 Example: The following is an example of this parameter on a FREEBUSY 1308 property. 1309 1310 FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z 1311 1312 4.2.10 Language 1313 1314 Parameter Name: LANGUAGE 1315 1316 Purpose: To specify the language for text values in a property or 1317 property parameter. 1318 1319 Format Definition: The property parameter is defined by the following 1320 notation: 1321 1322 languageparam = "LANGUAGE" "=" language 1323 1324 language = <Text identifying a language, as defined in [RFC 1766]> 1325 1326 Description: This parameter can be specified on properties with a 1327 text value type. The parameter identifies the language of the text in 1328 the property or property parameter value. The value of the "language" 1329 property parameter is that defined in [RFC 1766]. 1330 1331 For transport in a MIME entity, the Content-Language header field can 1332 be used to set the default language for the entire body part. 1333 Otherwise, no default language is assumed. 1334 1335 Example: 1336 1337 SUMMARY;LANGUAGE=us-EN:Company Holiday Party 1338 1339 LOCATION;LANGUAGE=en:Germany 1340 LOCATION;LANGUAGE=no:Tyskland 1341 1342 1343 1344 1345 1346 Dawson & Stenerson Standards Track [Page 24] 1347 1348 RFC 2445 iCalendar November 1998 1349 1350 1351 The following example makes use of the Quoted-Printable encoding in 1352 order to represent non-ASCII characters. 1353 1354 LOCATION;LANGUAGE=da:K=F8benhavn 1355 LOCATION;LANGUAGE=en:Copenhagen 1356 1357 4.2.11 Group or List Membership 1358 1359 Parameter Name: MEMBER 1360 1361 Purpose: To specify the group or list membership of the calendar user 1362 specified by the property. 1363 1364 Format Definition: The property parameter is defined by the following 1365 notation: 1366 1367 memberparam = "MEMBER" "=" DQUOTE cal-address DQUOTE 1368 *("," DQUOTE cal-address DQUOTE) 1369 1370 Description: This parameter can be specified on properties with a 1371 CAL-ADDRESS value type. The parameter identifies the groups or list 1372 membership for the calendar user specified by the property. The 1373 parameter value either a single calendar address in a quoted-string 1374 or a COMMA character (US-ASCII decimal 44) list of calendar 1375 addresses, each in a quoted-string. The individual calendar address 1376 parameter values MUST each be specified in a quoted-string. 1377 1378 Example: 1379 1380 ATTENDEE;MEMBER="MAILTO:ietf-calsch@imc.org":MAILTO:jsmith@host.com 1381 1382 ATTENDEE;MEMBER="MAILTO:projectA@host.com","MAILTO:projectB@host. 1383 com":MAILTO:janedoe@host.com 1384 1385 4.2.12 Participation Status 1386 1387 Parameter Name: PARTSTAT 1388 1389 Purpose: To specify the participation status for the calendar user 1390 specified by the property. 1391 1392 Format Definition: The property parameter is defined by the following 1393 notation: 1394 1395 partstatparam = "PARTSTAT" "=" 1396 ("NEEDS-ACTION" ; Event needs action 1397 / "ACCEPTED" ; Event accepted 1398 / "DECLINED" ; Event declined 1399 1400 1401 1402 Dawson & Stenerson Standards Track [Page 25] 1403 1404 RFC 2445 iCalendar November 1998 1405 1406 1407 / "TENTATIVE" ; Event tentatively 1408 ; accepted 1409 / "DELEGATED" ; Event delegated 1410 / x-name ; Experimental status 1411 / iana-token) ; Other IANA registered 1412 ; status 1413 ; These are the participation statuses for a "VEVENT". Default is 1414 ; NEEDS-ACTION 1415 partstatparam /= "PARTSTAT" "=" 1416 ("NEEDS-ACTION" ; To-do needs action 1417 / "ACCEPTED" ; To-do accepted 1418 / "DECLINED" ; To-do declined 1419 / "TENTATIVE" ; To-do tentatively 1420 ; accepted 1421 / "DELEGATED" ; To-do delegated 1422 / "COMPLETED" ; To-do completed. 1423 ; COMPLETED property has 1424 ;date/time completed. 1425 / "IN-PROCESS" ; To-do in process of 1426 ; being completed 1427 / x-name ; Experimental status 1428 / iana-token) ; Other IANA registered 1429 ; status 1430 ; These are the participation statuses for a "VTODO". Default is 1431 ; NEEDS-ACTION 1432 1433 partstatparam /= "PARTSTAT" "=" 1434 ("NEEDS-ACTION" ; Journal needs action 1435 / "ACCEPTED" ; Journal accepted 1436 / "DECLINED" ; Journal declined 1437 / x-name ; Experimental status 1438 / iana-token) ; Other IANA registered 1439 ; status 1440 ; These are the participation statuses for a "VJOURNAL". Default is 1441 ; NEEDS-ACTION 1442 1443 Description: This parameter can be specified on properties with a 1444 CAL-ADDRESS value type. The parameter identifies the participation 1445 status for the calendar user specified by the property value. The 1446 parameter values differ depending on whether they are associated with 1447 a group scheduled "VEVENT", "VTODO" or "VJOURNAL". The values MUST 1448 match one of the values allowed for the given calendar component. If 1449 not specified on a property that allows this parameter, the default 1450 value is NEEDS-ACTION. 1451 1452 Example: 1453 1454 ATTENDEE;PARTSTAT=DECLINED:MAILTO:jsmith@host.com 1455 1456 1457 1458 Dawson & Stenerson Standards Track [Page 26] 1459 1460 RFC 2445 iCalendar November 1998 1461 1462 1463 4.2.13 Recurrence Identifier Range 1464 1465 Parameter Name: RANGE 1466 1467 Purpose: To specify the effective range of recurrence instances from 1468 the instance specified by the recurrence identifier specified by the 1469 property. 1470 1471 Format Definition: The property parameter is defined by the following 1472 notation: 1473 1474 rangeparam = "RANGE" "=" ("THISANDPRIOR" 1475 ; To specify all instances prior to the recurrence identifier 1476 / "THISANDFUTURE") 1477 ; To specify the instance specified by the recurrence identifier 1478 ; and all subsequent recurrence instances 1479 1480 Description: The parameter can be specified on a property that 1481 specifies a recurrence identifier. The parameter specifies the 1482 effective range of recurrence instances that is specified by the 1483 property. The effective range is from the recurrence identified 1484 specified by the property. If this parameter is not specified an 1485 allowed property, then the default range is the single instance 1486 specified by the recurrence identifier value of the property. The 1487 parameter value can be "THISANDPRIOR" to indicate a range defined by 1488 the recurrence identified value of the property and all prior 1489 instances. The parameter value can also be "THISANDFUTURE" to 1490 indicate a range defined by the recurrence identifier and all 1491 subsequent instances. 1492 1493 Example: 1494 1495 RECURRENCE-ID;RANGE=THISANDPRIOR:19980401T133000Z 1496 1497 4.2.14 Alarm Trigger Relationship 1498 1499 Parameter Name: RELATED 1500 1501 Purpose: To specify the relationship of the alarm trigger with 1502 respect to the start or end of the calendar component. 1503 1504 Format Definition: The property parameter is defined by the following 1505 notation: 1506 1507 trigrelparam = "RELATED" "=" 1508 ("START" ; Trigger off of start 1509 / "END") ; Trigger off of end 1510 1511 1512 1513 1514 Dawson & Stenerson Standards Track [Page 27] 1515 1516 RFC 2445 iCalendar November 1998 1517 1518 1519 Description: The parameter can be specified on properties that 1520 specify an alarm trigger with a DURATION value type. The parameter 1521 specifies whether the alarm will trigger relative to the start or end 1522 of the calendar component. The parameter value START will set the 1523 alarm to trigger off the start of the calendar component; the 1524 parameter value END will set the alarm to trigger off the end of the 1525 calendar component. If the parameter is not specified on an allowable 1526 property, then the default is START. 1527 1528 Example: 1529 1530 TRIGGER;RELATED=END:PT5M 1531 1532 4.2.15 Relationship Type 1533 1534 Parameter Name: RELTYPE 1535 1536 Purpose: To specify the type of hierarchical relationship associated 1537 with the calendar component specified by the property. 1538 1539 Format Definition: The property parameter is defined by the following 1540 notation: 1541 1542 reltypeparam = "RELTYPE" "=" 1543 ("PARENT" ; Parent relationship. Default. 1544 / "CHILD" ; Child relationship 1545 / "SIBLING ; Sibling relationship 1546 / iana-token ; Some other IANA registered 1547 ; iCalendar relationship type 1548 / x-name) ; A non-standard, experimental 1549 ; relationship type 1550 1551 Description: This parameter can be specified on a property that 1552 references another related calendar. The parameter specifies the 1553 hierarchical relationship type of the calendar component referenced 1554 by the property. The parameter value can be PARENT, to indicate that 1555 the referenced calendar component is a superior of calendar 1556 component; CHILD to indicate that the referenced calendar component 1557 is a subordinate of the calendar component; SIBLING to indicate that 1558 the referenced calendar component is a peer of the calendar 1559 component. If this parameter is not specified on an allowable 1560 property, the default relationship type is PARENT. 1561 1562 Example: 1563 1564 RELATED-TO;RELTYPE=SIBLING:<19960401-080045-4000F192713@host.com> 1565 1566 1567 1568 1569 1570 Dawson & Stenerson Standards Track [Page 28] 1571 1572 RFC 2445 iCalendar November 1998 1573 1574 1575 4.2.16 Participation Role 1576 1577 Parameter Name: ROLE 1578 1579 Purpose: To specify the participation role for the calendar user 1580 specified by the property. 1581 1582 Format Definition: The property parameter is defined by the following 1583 notation: 1584 1585 roleparam = "ROLE" "=" 1586 ("CHAIR" ; Indicates chair of the 1587 ; calendar entity 1588 / "REQ-PARTICIPANT" ; Indicates a participant whose 1589 ; participation is required 1590 / "OPT-PARTICIPANT" ; Indicates a participant whose 1591 ; participation is optional 1592 / "NON-PARTICIPANT" ; Indicates a participant who is 1593 ; copied for information 1594 ; purposes only 1595 / x-name ; Experimental role 1596 / iana-token) ; Other IANA role 1597 ; Default is REQ-PARTICIPANT 1598 1599 Description: This parameter can be specified on properties with a 1600 CAL-ADDRESS value type. The parameter specifies the participation 1601 role for the calendar user specified by the property in the group 1602 schedule calendar component. If not specified on a property that 1603 allows this parameter, the default value is REQ-PARTICIPANT. 1604 1605 Example: 1606 1607 ATTENDEE;ROLE=CHAIR:MAILTO:mrbig@host.com 1608 1609 4.2.17 RSVP Expectation 1610 1611 Parameter Name: RSVP 1612 1613 Purpose: To specify whether there is an expectation of a favor of a 1614 reply from the calendar user specified by the property value. 1615 1616 Format Definition: The property parameter is defined by the following 1617 notation: 1618 1619 rsvpparam = "RSVP" "=" ("TRUE" / "FALSE") 1620 ; Default is FALSE 1621 1622 1623 1624 1625 1626 Dawson & Stenerson Standards Track [Page 29] 1627 1628 RFC 2445 iCalendar November 1998 1629 1630 1631 Description: This parameter can be specified on properties with a 1632 CAL-ADDRESS value type. The parameter identifies the expectation of a 1633 reply from the calendar user specified by the property value. This 1634 parameter is used by the "Organizer" to request a participation 1635 status reply from an "Attendee" of a group scheduled event or to-do. 1636 If not specified on a property that allows this parameter, the 1637 default value is FALSE. 1638 1639 Example: 1640 1641 ATTENDEE;RSVP=TRUE:MAILTO:jsmith@host.com 1642 1643 4.2.18 Sent By 1644 1645 Parameter Name: SENT-BY 1646 1647 Purpose: To specify the calendar user that is acting on behalf of the 1648 calendar user specified by the property. 1649 1650 Format Definition: The property parameter is defined by the following 1651 notation: 1652 1653 sentbyparam = "SENT-BY" "=" DQUOTE cal-address DQUOTE 1654 1655 Description: This parameter can be specified on properties with a 1656 CAL-ADDRESS value type. The parameter specifies the calendar user 1657 that is acting on behalf of the calendar user specified by the 1658 property. The parameter value MUST be a MAILTO URI as defined in [RFC 1659 1738]. The individual calendar address parameter values MUST each be 1660 specified in a quoted-string. 1661 1662 Example: 1663 1664 ORGANIZER;SENT-BY:"MAILTO:sray@host.com":MAILTO:jsmith@host.com 1665 1666 4.2.19 Time Zone Identifier 1667 1668 Parameter Name: TZID 1669 1670 Purpose: To specify the identifier for the time zone definition for a 1671 time component in the property value. 1672 1673 Format Definition: This property parameter is defined by the 1674 following notation: 1675 1676 tzidparam = "TZID" "=" [tzidprefix] paramtext CRLF 1677 1678 tzidprefix = "/" 1679 1680 1681 1682 Dawson & Stenerson Standards Track [Page 30] 1683 1684 RFC 2445 iCalendar November 1998 1685 1686 1687 Description: The parameter MUST be specified on the "DTSTART", 1688 "DTEND", "DUE", "EXDATE" and "RDATE" properties when either a DATE- 1689 TIME or TIME value type is specified and when the value is not either 1690 a UTC or a "floating" time. Refer to the DATE-TIME or TIME value type 1691 definition for a description of UTC and "floating time" formats. This 1692 property parameter specifies a text value which uniquely identifies 1693 the "VTIMEZONE" calendar component to be used when evaluating the 1694 time portion of the property. The value of the TZID property 1695 parameter will be equal to the value of the TZID property for the 1696 matching time zone definition. An individual "VTIMEZONE" calendar 1697 component MUST be specified for each unique "TZID" parameter value 1698 specified in the iCalendar object. 1699 1700 The parameter MUST be specified on properties with a DATE-TIME value 1701 if the DATE-TIME is not either a UTC or a "floating" time. 1702 1703 The presence of the SOLIDUS character (US-ASCII decimal 47) as a 1704 prefix, indicates that this TZID represents a unique ID in a globally 1705 defined time zone registry (when such registry is defined). 1706 1707 Note: This document does not define a naming convention for time 1708 zone identifiers. Implementers may want to use the naming 1709 conventions defined in existing time zone specifications such as 1710 the public-domain Olson database [TZ]. The specification of 1711 globally unique time zone identifiers is not addressed by this 1712 document and is left for future study. 1713 1714 The following are examples of this property parameter: 1715 1716 DTSTART;TZID=US-Eastern:19980119T020000 1717 1718 DTEND;TZID=US-Eastern:19980119T030000 1719 1720 The TZID property parameter MUST NOT be applied to DATE-TIME or TIME 1721 properties whose time values are specified in UTC. 1722 1723 The use of local time in a DATE-TIME or TIME value without the TZID 1724 property parameter is to be interpreted as a local time value, 1725 regardless of the existence of "VTIMEZONE" calendar components in the 1726 iCalendar object. 1727 1728 For more information see the sections on the data types DATE-TIME and 1729 TIME. 1730 1731 1732 1733 1734 1735 1736 1737 1738 Dawson & Stenerson Standards Track [Page 31] 1739 1740 RFC 2445 iCalendar November 1998 1741 1742 1743 4.2.20 Value Data Types 1744 1745 Parameter Name: VALUE 1746 1747 Purpose: To explicitly specify the data type format for a property 1748 value. 1749 1750 Format Definition: The "VALUE" property parameter is defined by the 1751 following notation: 1752 1753 valuetypeparam = "VALUE" "=" valuetype 1754 1755 valuetype = ("BINARY" 1756 / "BOOLEAN" 1757 / "CAL-ADDRESS" 1758 / "DATE" 1759 / "DATE-TIME" 1760 / "DURATION" 1761 / "FLOAT" 1762 / "INTEGER" 1763 / "PERIOD" 1764 / "RECUR" 1765 / "TEXT" 1766 / "TIME" 1767 / "URI" 1768 / "UTC-OFFSET" 1769 / x-name 1770 ; Some experimental iCalendar data type. 1771 / iana-token) 1772 ; Some other IANA registered iCalendar data type. 1773 1774 Description: The parameter specifies the data type and format of the 1775 property value. The property values MUST be of a single value type. 1776 For example, a "RDATE" property cannot have a combination of DATE- 1777 TIME and TIME value types. 1778 1779 If the property's value is the default value type, then this 1780 parameter need not be specified. However, if the property's default 1781 value type is overridden by some other allowable value type, then 1782 this parameter MUST be specified. 1783 1784 4.3 Property Value Data Types 1785 1786 The properties in an iCalendar object are strongly typed. The 1787 definition of each property restricts the value to be one of the 1788 value data types, or simply value types, defined in this section. The 1789 value type for a property will either be specified implicitly as the 1790 default value type or will be explicitly specified with the "VALUE" 1791 1792 1793 1794 Dawson & Stenerson Standards Track [Page 32] 1795 1796 RFC 2445 iCalendar November 1998 1797 1798 1799 parameter. If the value type of a property is one of the alternate 1800 valid types, then it MUST be explicitly specified with the "VALUE" 1801 parameter. 1802 1803 4.3.1 Binary 1804 1805 Value Name: BINARY 1806 1807 Purpose: This value type is used to identify properties that contain 1808 a character encoding of inline binary data. For example, an inline 1809 attachment of an object code might be included in an iCalendar 1810 object. 1811 1812 Formal Definition: The value type is defined by the following 1813 notation: 1814 1815 binary = *(4b-char) [b-end] 1816 ; A "BASE64" encoded character string, as defined by [RFC 2045]. 1817 1818 b-end = (2b-char "==") / (3b-char "=") 1819 1820 b-char = ALPHA / DIGIT / "+" / "/" 1821 1822 Description: Property values with this value type MUST also include 1823 the inline encoding parameter sequence of ";ENCODING=BASE64". That 1824 is, all inline binary data MUST first be character encoded using the 1825 "BASE64" encoding method defined in [RFC 2045]. No additional content 1826 value encoding (i.e., BACKSLASH character encoding) is defined for 1827 this value type. 1828 1829 Example: The following is an abridged example of a "BASE64" encoded 1830 binary value data. 1831 1832 ATTACH;VALUE=BINARY;ENCODING=BASE64:MIICajCCAdOgAwIBAgICBEUwDQY 1833 JKoZIhvcNAQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlI 1834 ENvbW11bmljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZv 1835 <...remainder of "BASE64" encoded binary data...> 1836 1837 4.3.2 Boolean 1838 1839 Value Name: BOOLEAN 1840 1841 Purpose: This value type is used to identify properties that contain 1842 either a "TRUE" or "FALSE" Boolean value. 1843 1844 Formal Definition: The value type is defined by the following 1845 notation: 1846 1847 1848 1849 1850 Dawson & Stenerson Standards Track [Page 33] 1851 1852 RFC 2445 iCalendar November 1998 1853 1854 1855 boolean = "TRUE" / "FALSE" 1856 1857 Description: These values are case insensitive text. No additional 1858 content value encoding (i.e., BACKSLASH character encoding) is 1859 defined for this value type. 1860 1861 Example: The following is an example of a hypothetical property that 1862 has a BOOLEAN value type: 1863 1864 GIBBERISH:TRUE 1865 1866 4.3.3 Calendar User Address 1867 1868 Value Name: CAL-ADDRESS 1869 1870 Purpose: This value type is used to identify properties that contain 1871 a calendar user address. 1872 1873 Formal Definition: The value type is as defined by the following 1874 notation: 1875 1876 cal-address = uri 1877 1878 Description: The value is a URI as defined by [RFC 1738] or any other 1879 IANA registered form for a URI. When used to address an Internet 1880 email transport address for a calendar user, the value MUST be a 1881 MAILTO URI, as defined by [RFC 1738]. No additional content value 1882 encoding (i.e., BACKSLASH character encoding) is defined for this 1883 value type. 1884 1885 Example: 1886 1887 ATTENDEE:MAILTO:jane_doe@host.com 1888 1889 4.3.4 Date 1890 1891 Value Name: DATE 1892 1893 Purpose: This value type is used to identify values that contain a 1894 calendar date. 1895 1896 Formal Definition: The value type is defined by the following 1897 notation: 1898 1899 date = date-value 1900 1901 date-value = date-fullyear date-month date-mday 1902 date-fullyear = 4DIGIT 1903 1904 1905 1906 Dawson & Stenerson Standards Track [Page 34] 1907 1908 RFC 2445 iCalendar November 1998 1909 1910 1911 date-month = 2DIGIT ;01-12 1912 date-mday = 2DIGIT ;01-28, 01-29, 01-30, 01-31 1913 ;based on month/year 1914 1915 Description: If the property permits, multiple "date" values are 1916 specified as a COMMA character (US-ASCII decimal 44) separated list 1917 of values. The format for the value type is expressed as the [ISO 1918 8601] complete representation, basic format for a calendar date. The 1919 textual format specifies a four-digit year, two-digit month, and 1920 two-digit day of the month. There are no separator characters between 1921 the year, month and day component text. 1922 1923 No additional content value encoding (i.e., BACKSLASH character 1924 encoding) is defined for this value type. 1925 1926 Example: The following represents July 14, 1997: 1927 1928 19970714 1929 1930 4.3.5 Date-Time 1931 1932 Value Name: DATE-TIME 1933 1934 Purpose: This value type is used to identify values that specify a 1935 precise calendar date and time of day. 1936 1937 Formal Definition: The value type is defined by the following 1938 notation: 1939 1940 date-time = date "T" time ;As specified in the date and time 1941 ;value definitions 1942 1943 Description: If the property permits, multiple "date-time" values are 1944 specified as a COMMA character (US-ASCII decimal 44) separated list 1945 of values. No additional content value encoding (i.e., BACKSLASH 1946 character encoding) is defined for this value type. 1947 1948 The "DATE-TIME" data type is used to identify values that contain a 1949 precise calendar date and time of day. The format is based on the 1950 [ISO 8601] complete representation, basic format for a calendar date 1951 and time of day. The text format is a concatenation of the "date", 1952 followed by the LATIN CAPITAL LETTER T character (US-ASCII decimal 1953 84) time designator, followed by the "time" format. 1954 1955 The "DATE-TIME" data type expresses time values in three forms: 1956 1957 The form of date and time with UTC offset MUST NOT be used. For 1958 example, the following is not valid for a date-time value: 1959 1960 1961 1962 Dawson & Stenerson Standards Track [Page 35] 1963 1964 RFC 2445 iCalendar November 1998 1965 1966 1967 DTSTART:19980119T230000-0800 ;Invalid time format 1968 1969 FORM #1: DATE WITH LOCAL TIME 1970 1971 The date with local time form is simply a date-time value that does 1972 not contain the UTC designator nor does it reference a time zone. For 1973 example, the following represents Janurary 18, 1998, at 11 PM: 1974 1975 DTSTART:19980118T230000 1976 1977 Date-time values of this type are said to be "floating" and are not 1978 bound to any time zone in particular. They are used to represent the 1979 same hour, minute, and second value regardless of which time zone is 1980 currently being observed. For example, an event can be defined that 1981 indicates that an individual will be busy from 11:00 AM to 1:00 PM 1982 every day, no matter which time zone the person is in. In these 1983 cases, a local time can be specified. The recipient of an iCalendar 1984 object with a property value consisting of a local time, without any 1985 relative time zone information, SHOULD interpret the value as being 1986 fixed to whatever time zone the ATTENDEE is in at any given moment. 1987 This means that two ATTENDEEs, in different time zones, receiving the 1988 same event definition as a floating time, may be participating in the 1989 event at different actual times. Floating time SHOULD only be used 1990 where that is the reasonable behavior. 1991 1992 In most cases, a fixed time is desired. To properly communicate a 1993 fixed time in a property value, either UTC time or local time with 1994 time zone reference MUST be specified. 1995 1996 The use of local time in a DATE-TIME value without the TZID property 1997 parameter is to be interpreted as floating time, regardless of the 1998 existence of "VTIMEZONE" calendar components in the iCalendar object. 1999 2000 FORM #2: DATE WITH UTC TIME 2001 2002 The date with UTC time, or absolute time, is identified by a LATIN 2003 CAPITAL LETTER Z suffix character (US-ASCII decimal 90), the UTC 2004 designator, appended to the time value. For example, the following 2005 represents January 19, 1998, at 0700 UTC: 2006 2007 DTSTART:19980119T070000Z 2008 2009 The TZID property parameter MUST NOT be applied to DATE-TIME 2010 properties whose time values are specified in UTC. 2011 2012 FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE 2013 2014 2015 2016 2017 2018 Dawson & Stenerson Standards Track [Page 36] 2019 2020 RFC 2445 iCalendar November 1998 2021 2022 2023 The date and local time with reference to time zone information is 2024 identified by the use the TZID property parameter to reference the 2025 appropriate time zone definition. TZID is discussed in detail in the 2026 section on Time Zone. For example, the following represents 2 AM in 2027 New York on Janurary 19, 1998: 2028 2029 DTSTART;TZID=US-Eastern:19980119T020000 2030 2031 Example: The following represents July 14, 1997, at 1:30 PM in New 2032 York City in each of the three time formats, using the "DTSTART" 2033 property. 2034 2035 DTSTART:19970714T133000 ;Local time 2036 DTSTART:19970714T173000Z ;UTC time 2037 DTSTART;TZID=US-Eastern:19970714T133000 ;Local time and time 2038 ; zone reference 2039 2040 A time value MUST ONLY specify 60 seconds when specifying the 2041 periodic "leap second" in the time value. For example: 2042 2043 COMPLETED:19970630T235960Z 2044 2045 4.3.6 Duration 2046 2047 Value Name: DURATION 2048 2049 Purpose: This value type is used to identify properties that contain 2050 a duration of time. 2051 2052 Formal Definition: The value type is defined by the following 2053 notation: 2054 2055 dur-value = (["+"] / "-") "P" (dur-date / dur-time / dur-week) 2056 2057 dur-date = dur-day [dur-time] 2058 dur-time = "T" (dur-hour / dur-minute / dur-second) 2059 dur-week = 1*DIGIT "W" 2060 dur-hour = 1*DIGIT "H" [dur-minute] 2061 dur-minute = 1*DIGIT "M" [dur-second] 2062 dur-second = 1*DIGIT "S" 2063 dur-day = 1*DIGIT "D" 2064 2065 Description: If the property permits, multiple "duration" values are 2066 specified by a COMMA character (US-ASCII decimal 44) separated list 2067 of values. The format is expressed as the [ISO 8601] basic format for 2068 the duration of time. The format can represent durations in terms of 2069 weeks, days, hours, minutes, and seconds. 2070 2071 2072 2073 2074 Dawson & Stenerson Standards Track [Page 37] 2075 2076 RFC 2445 iCalendar November 1998 2077 2078 2079 No additional content value encoding (i.e., BACKSLASH character 2080 encoding) are defined for this value type. 2081 2082 Example: A duration of 15 days, 5 hours and 20 seconds would be: 2083 2084 P15DT5H0M20S 2085 2086 A duration of 7 weeks would be: 2087 2088 P7W 2089 2090 4.3.7 Float 2091 2092 Value Name: FLOAT 2093 2094 Purpose: This value type is used to identify properties that contain 2095 a real number value. 2096 2097 Formal Definition: The value type is defined by the following 2098 notation: 2099 2100 float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT] 2101 2102 Description: If the property permits, multiple "float" values are 2103 specified by a COMMA character (US-ASCII decimal 44) separated list 2104 of values. 2105 2106 No additional content value encoding (i.e., BACKSLASH character 2107 encoding) is defined for this value type. 2108 2109 Example: 2110 2111 1000000.0000001 2112 1.333 2113 -3.14 2114 2115 4.3.8 Integer 2116 2117 Value Name:INTEGER 2118 2119 Purpose: This value type is used to identify properties that contain 2120 a signed integer value. 2121 2122 Formal Definition: The value type is defined by the following 2123 notation: 2124 2125 integer = (["+"] / "-") 1*DIGIT 2126 2127 2128 2129 2130 Dawson & Stenerson Standards Track [Page 38] 2131 2132 RFC 2445 iCalendar November 1998 2133 2134 2135 Description: If the property permits, multiple "integer" values are 2136 specified by a COMMA character (US-ASCII decimal 44) separated list 2137 of values. The valid range for "integer" is -2147483648 to 2138 2147483647. If the sign is not specified, then the value is assumed 2139 to be positive. 2140 2141 No additional content value encoding (i.e., BACKSLASH character 2142 encoding) is defined for this value type. 2143 2144 Example: 2145 2146 1234567890 2147 -1234567890 2148 +1234567890 2149 432109876 2150 2151 4.3.9 Period of Time 2152 2153 Value Name: PERIOD 2154 2155 Purpose: This value type is used to identify values that contain a 2156 precise period of time. 2157 2158 Formal Definition: The data type is defined by the following 2159 notation: 2160 2161 period = period-explicit / period-start 2162 2163 period-explicit = date-time "/" date-time 2164 ; [ISO 8601] complete representation basic format for a period of 2165 ; time consisting of a start and end. The start MUST be before the 2166 ; end. 2167 2168 period-start = date-time "/" dur-value 2169 ; [ISO 8601] complete representation basic format for a period of 2170 ; time consisting of a start and positive duration of time. 2171 2172 Description: If the property permits, multiple "period" values are 2173 specified by a COMMA character (US-ASCII decimal 44) separated list 2174 of values. There are two forms of a period of time. First, a period 2175 of time is identified by its start and its end. This format is 2176 expressed as the [ISO 8601] complete representation, basic format for 2177 "DATE-TIME" start of the period, followed by a SOLIDUS character 2178 (US-ASCII decimal 47), followed by the "DATE-TIME" of the end of the 2179 period. The start of the period MUST be before the end of the period. 2180 Second, a period of time can also be defined by a start and a 2181 positive duration of time. The format is expressed as the [ISO 8601] 2182 complete representation, basic format for the "DATE-TIME" start of 2183 2184 2185 2186 Dawson & Stenerson Standards Track [Page 39] 2187 2188 RFC 2445 iCalendar November 1998 2189 2190 2191 the period, followed by a SOLIDUS character (US-ASCII decimal 47), 2192 followed by the [ISO 8601] basic format for "DURATION" of the period. 2193 2194 Example: The period starting at 18:00:00 UTC, on January 1, 1997 and 2195 ending at 07:00:00 UTC on January 2, 1997 would be: 2196 2197 19970101T180000Z/19970102T070000Z 2198 2199 The period start at 18:00:00 on January 1, 1997 and lasting 5 hours 2200 and 30 minutes would be: 2201 2202 19970101T180000Z/PT5H30M 2203 2204 No additional content value encoding (i.e., BACKSLASH character 2205 encoding) is defined for this value type. 2206 2207 4.3.10 Recurrence Rule 2208 2209 Value Name: RECUR 2210 2211 Purpose: This value type is used to identify properties that contain 2212 a recurrence rule specification. 2213 2214 Formal Definition: The value type is defined by the following 2215 notation: 2216 2217 recur = "FREQ"=freq *( 2218 2219 ; either UNTIL or COUNT may appear in a 'recur', 2220 ; but UNTIL and COUNT MUST NOT occur in the same 'recur' 2221 2222 ( ";" "UNTIL" "=" enddate ) / 2223 ( ";" "COUNT" "=" 1*DIGIT ) / 2224 2225 ; the rest of these keywords are optional, 2226 ; but MUST NOT occur more than once 2227 2228 ( ";" "INTERVAL" "=" 1*DIGIT ) / 2229 ( ";" "BYSECOND" "=" byseclist ) / 2230 ( ";" "BYMINUTE" "=" byminlist ) / 2231 ( ";" "BYHOUR" "=" byhrlist ) / 2232 ( ";" "BYDAY" "=" bywdaylist ) / 2233 ( ";" "BYMONTHDAY" "=" bymodaylist ) / 2234 ( ";" "BYYEARDAY" "=" byyrdaylist ) / 2235 ( ";" "BYWEEKNO" "=" bywknolist ) / 2236 ( ";" "BYMONTH" "=" bymolist ) / 2237 ( ";" "BYSETPOS" "=" bysplist ) / 2238 ( ";" "WKST" "=" weekday ) / 2239 2240 2241 2242 Dawson & Stenerson Standards Track [Page 40] 2243 2244 RFC 2445 iCalendar November 1998 2245 2246 2247 ( ";" x-name "=" text ) 2248 ) 2249 2250 freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY" 2251 / "WEEKLY" / "MONTHLY" / "YEARLY" 2252 2253 enddate = date 2254 enddate =/ date-time ;An UTC value 2255 2256 byseclist = seconds / ( seconds *("," seconds) ) 2257 2258 seconds = 1DIGIT / 2DIGIT ;0 to 59 2259 2260 byminlist = minutes / ( minutes *("," minutes) ) 2261 2262 minutes = 1DIGIT / 2DIGIT ;0 to 59 2263 2264 byhrlist = hour / ( hour *("," hour) ) 2265 2266 hour = 1DIGIT / 2DIGIT ;0 to 23 2267 2268 bywdaylist = weekdaynum / ( weekdaynum *("," weekdaynum) ) 2269 2270 weekdaynum = [([plus] ordwk / minus ordwk)] weekday 2271 2272 plus = "+" 2273 2274 minus = "-" 2275 2276 ordwk = 1DIGIT / 2DIGIT ;1 to 53 2277 2278 weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA" 2279 ;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, 2280 ;FRIDAY, SATURDAY and SUNDAY days of the week. 2281 2282 bymodaylist = monthdaynum / ( monthdaynum *("," monthdaynum) ) 2283 2284 monthdaynum = ([plus] ordmoday) / (minus ordmoday) 2285 2286 ordmoday = 1DIGIT / 2DIGIT ;1 to 31 2287 2288 byyrdaylist = yeardaynum / ( yeardaynum *("," yeardaynum) ) 2289 2290 yeardaynum = ([plus] ordyrday) / (minus ordyrday) 2291 2292 ordyrday = 1DIGIT / 2DIGIT / 3DIGIT ;1 to 366 2293 2294 bywknolist = weeknum / ( weeknum *("," weeknum) ) 2295 2296 2297 2298 Dawson & Stenerson Standards Track [Page 41] 2299 2300 RFC 2445 iCalendar November 1998 2301 2302 2303 weeknum = ([plus] ordwk) / (minus ordwk) 2304 2305 bymolist = monthnum / ( monthnum *("," monthnum) ) 2306 2307 monthnum = 1DIGIT / 2DIGIT ;1 to 12 2308 2309 bysplist = setposday / ( setposday *("," setposday) ) 2310 2311 setposday = yeardaynum 2312 2313 Description: If the property permits, multiple "recur" values are 2314 specified by a COMMA character (US-ASCII decimal 44) separated list 2315 of values. The value type is a structured value consisting of a list 2316 of one or more recurrence grammar parts. Each rule part is defined by 2317 a NAME=VALUE pair. The rule parts are separated from each other by 2318 the SEMICOLON character (US-ASCII decimal 59). The rule parts are not 2319 ordered in any particular sequence. Individual rule parts MUST only 2320 be specified once. 2321 2322 The FREQ rule part identifies the type of recurrence rule. This rule 2323 part MUST be specified in the recurrence rule. Valid values include 2324 SECONDLY, to specify repeating events based on an interval of a 2325 second or more; MINUTELY, to specify repeating events based on an 2326 interval of a minute or more; HOURLY, to specify repeating events 2327 based on an interval of an hour or more; DAILY, to specify repeating 2328 events based on an interval of a day or more; WEEKLY, to specify 2329 repeating events based on an interval of a week or more; MONTHLY, to 2330 specify repeating events based on an interval of a month or more; and 2331 YEARLY, to specify repeating events based on an interval of a year or 2332 more. 2333 2334 The INTERVAL rule part contains a positive integer representing how 2335 often the recurrence rule repeats. The default value is "1", meaning 2336 every second for a SECONDLY rule, or every minute for a MINUTELY 2337 rule, every hour for an HOURLY rule, every day for a DAILY rule, 2338 every week for a WEEKLY rule, every month for a MONTHLY rule and 2339 every year for a YEARLY rule. 2340 2341 The UNTIL rule part defines a date-time value which bounds the 2342 recurrence rule in an inclusive manner. If the value specified by 2343 UNTIL is synchronized with the specified recurrence, this date or 2344 date-time becomes the last instance of the recurrence. If specified 2345 as a date-time value, then it MUST be specified in an UTC time 2346 format. If not present, and the COUNT rule part is also not present, 2347 the RRULE is considered to repeat forever. 2348 2349 The COUNT rule part defines the number of occurrences at which to 2350 range-bound the recurrence. The "DTSTART" property value, if 2351 2352 2353 2354 Dawson & Stenerson Standards Track [Page 42] 2355 2356 RFC 2445 iCalendar November 1998 2357 2358 2359 specified, counts as the first occurrence. 2360 2361 The BYSECOND rule part specifies a COMMA character (US-ASCII decimal 2362 44) separated list of seconds within a minute. Valid values are 0 to 2363 59. The BYMINUTE rule part specifies a COMMA character (US-ASCII 2364 decimal 44) separated list of minutes within an hour. Valid values 2365 are 0 to 59. The BYHOUR rule part specifies a COMMA character (US- 2366 ASCII decimal 44) separated list of hours of the day. Valid values 2367 are 0 to 23. 2368 2369 The BYDAY rule part specifies a COMMA character (US-ASCII decimal 44) 2370 separated list of days of the week; MO indicates Monday; TU indicates 2371 Tuesday; WE indicates Wednesday; TH indicates Thursday; FR indicates 2372 Friday; SA indicates Saturday; SU indicates Sunday. 2373 2374 Each BYDAY value can also be preceded by a positive (+n) or negative 2375 (-n) integer. If present, this indicates the nth occurrence of the 2376 specific day within the MONTHLY or YEARLY RRULE. For example, within 2377 a MONTHLY rule, +1MO (or simply 1MO) represents the first Monday 2378 within the month, whereas -1MO represents the last Monday of the 2379 month. If an integer modifier is not present, it means all days of 2380 this type within the specified frequency. For example, within a 2381 MONTHLY rule, MO represents all Mondays within the month. 2382 2383 The BYMONTHDAY rule part specifies a COMMA character (ASCII decimal 2384 44) separated list of days of the month. Valid values are 1 to 31 or 2385 -31 to -1. For example, -10 represents the tenth to the last day of 2386 the month. 2387 2388 The BYYEARDAY rule part specifies a COMMA character (US-ASCII decimal 2389 44) separated list of days of the year. Valid values are 1 to 366 or 2390 -366 to -1. For example, -1 represents the last day of the year 2391 (December 31st) and -306 represents the 306th to the last day of the 2392 year (March 1st). 2393 2394 The BYWEEKNO rule part specifies a COMMA character (US-ASCII decimal 2395 44) separated list of ordinals specifying weeks of the year. Valid 2396 values are 1 to 53 or -53 to -1. This corresponds to weeks according 2397 to week numbering as defined in [ISO 8601]. A week is defined as a 2398 seven day period, starting on the day of the week defined to be the 2399 week start (see WKST). Week number one of the calendar year is the 2400 first week which contains at least four (4) days in that calendar 2401 year. This rule part is only valid for YEARLY rules. For example, 3 2402 represents the third week of the year. 2403 2404 Note: Assuming a Monday week start, week 53 can only occur when 2405 Thursday is January 1 or if it is a leap year and Wednesday is 2406 January 1. 2407 2408 2409 2410 Dawson & Stenerson Standards Track [Page 43] 2411 2412 RFC 2445 iCalendar November 1998 2413 2414 2415 The BYMONTH rule part specifies a COMMA character (US-ASCII decimal 2416 44) separated list of months of the year. Valid values are 1 to 12. 2417 2418 The WKST rule part specifies the day on which the workweek starts. 2419 Valid values are MO, TU, WE, TH, FR, SA and SU. This is significant 2420 when a WEEKLY RRULE has an interval greater than 1, and a BYDAY rule 2421 part is specified. This is also significant when in a YEARLY RRULE 2422 when a BYWEEKNO rule part is specified. The default value is MO. 2423 2424 The BYSETPOS rule part specifies a COMMA character (US-ASCII decimal 2425 44) separated list of values which corresponds to the nth occurrence 2426 within the set of events specified by the rule. Valid values are 1 to 2427 366 or -366 to -1. It MUST only be used in conjunction with another 2428 BYxxx rule part. For example "the last work day of the month" could 2429 be represented as: 2430 2431 RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1 2432 2433 Each BYSETPOS value can include a positive (+n) or negative (-n) 2434 integer. If present, this indicates the nth occurrence of the 2435 specific occurrence within the set of events specified by the rule. 2436 2437 If BYxxx rule part values are found which are beyond the available 2438 scope (ie, BYMONTHDAY=30 in February), they are simply ignored. 2439 2440 Information, not contained in the rule, necessary to determine the 2441 various recurrence instance start time and dates are derived from the 2442 Start Time (DTSTART) entry attribute. For example, 2443 "FREQ=YEARLY;BYMONTH=1" doesn't specify a specific day within the 2444 month or a time. This information would be the same as what is 2445 specified for DTSTART. 2446 2447 BYxxx rule parts modify the recurrence in some manner. BYxxx rule 2448 parts for a period of time which is the same or greater than the 2449 frequency generally reduce or limit the number of occurrences of the 2450 recurrence generated. For example, "FREQ=DAILY;BYMONTH=1" reduces the 2451 number of recurrence instances from all days (if BYMONTH tag is not 2452 present) to all days in January. BYxxx rule parts for a period of 2453 time less than the frequency generally increase or expand the number 2454 of occurrences of the recurrence. For example, 2455 "FREQ=YEARLY;BYMONTH=1,2" increases the number of days within the 2456 yearly recurrence set from 1 (if BYMONTH tag is not present) to 2. 2457 2458 If multiple BYxxx rule parts are specified, then after evaluating the 2459 specified FREQ and INTERVAL rule parts, the BYxxx rule parts are 2460 applied to the current set of evaluated occurrences in the following 2461 order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY, BYHOUR, 2462 BYMINUTE, BYSECOND and BYSETPOS; then COUNT and UNTIL are evaluated. 2463 2464 2465 2466 Dawson & Stenerson Standards Track [Page 44] 2467 2468 RFC 2445 iCalendar November 1998 2469 2470 2471 Here is an example of evaluating multiple BYxxx rule parts. 2472 2473 DTSTART;TZID=US-Eastern:19970105T083000 2474 RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9; 2475 BYMINUTE=30 2476 2477 First, the "INTERVAL=2" would be applied to "FREQ=YEARLY" to arrive 2478 at "every other year". Then, "BYMONTH=1" would be applied to arrive 2479 at "every January, every other year". Then, "BYDAY=SU" would be 2480 applied to arrive at "every Sunday in January, every other year". 2481 Then, "BYHOUR=8,9" would be applied to arrive at "every Sunday in 2482 January at 8 AM and 9 AM, every other year". Then, "BYMINUTE=30" 2483 would be applied to arrive at "every Sunday in January at 8:30 AM and 2484 9:30 AM, every other year". Then, lacking information from RRULE, the 2485 second is derived from DTSTART, to end up in "every Sunday in January 2486 at 8:30:00 AM and 9:30:00 AM, every other year". Similarly, if the 2487 BYMINUTE, BYHOUR, BYDAY, BYMONTHDAY or BYMONTH rule part were 2488 missing, the appropriate minute, hour, day or month would have been 2489 retrieved from the "DTSTART" property. 2490 2491 No additional content value encoding (i.e., BACKSLASH character 2492 encoding) is defined for this value type. 2493 2494 Example: The following is a rule which specifies 10 meetings which 2495 occur every other day: 2496 2497 FREQ=DAILY;COUNT=10;INTERVAL=2 2498 2499 There are other examples specified in the "RRULE" specification. 2500 2501 4.3.11 Text 2502 2503 Value Name: TEXT 2504 2505 Purpose This value type is used to identify values that contain human 2506 readable text. 2507 2508 Formal Definition: The character sets supported by this revision of 2509 iCalendar are UTF-8 and US ASCII thereof. The applicability to other 2510 character sets is for future work. The value type is defined by the 2511 following notation. 2512 2513 text = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR) 2514 ; Folded according to description above 2515 2516 ESCAPED-CHAR = "\\" / "\;" / "\," / "\N" / "\n") 2517 ; \\ encodes \, \N or \n encodes newline 2518 ; \; encodes ;, \, encodes , 2519 2520 2521 2522 Dawson & Stenerson Standards Track [Page 45] 2523 2524 RFC 2445 iCalendar November 1998 2525 2526 2527 TSAFE-CHAR = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B 2528 %x5D-7E / NON-US-ASCII 2529 ; Any character except CTLs not needed by the current 2530 ; character set, DQUOTE, ";", ":", "\", "," 2531 2532 Note: Certain other character sets may require modification of the 2533 above definitions, but this is beyond the scope of this document. 2534 2535 Description: If the property permits, multiple "text" values are 2536 specified by a COMMA character (US-ASCII decimal 44) separated list 2537 of values. 2538 2539 The language in which the text is represented can be controlled by 2540 the "LANGUAGE" property parameter. 2541 2542 An intentional formatted text line break MUST only be included in a 2543 "TEXT" property value by representing the line break with the 2544 character sequence of BACKSLASH (US-ASCII decimal 92), followed by a 2545 LATIN SMALL LETTER N (US-ASCII decimal 110) or a LATIN CAPITAL LETTER 2546 N (US-ASCII decimal 78), that is "\n" or "\N". 2547 2548 The "TEXT" property values may also contain special characters that 2549 are used to signify delimiters, such as a COMMA character for lists 2550 of values or a SEMICOLON character for structured values. In order to 2551 support the inclusion of these special characters in "TEXT" property 2552 values, they MUST be escaped with a BACKSLASH character. A BACKSLASH 2553 character (US-ASCII decimal 92) in a "TEXT" property value MUST be 2554 escaped with another BACKSLASH character. A COMMA character in a 2555 "TEXT" property value MUST be escaped with a BACKSLASH character 2556 (US-ASCII decimal 92). A SEMICOLON character in a "TEXT" property 2557 value MUST be escaped with a BACKSLASH character (US-ASCII decimal 2558 92). However, a COLON character in a "TEXT" property value SHALL NOT 2559 be escaped with a BACKSLASH character.Example: A multiple line value 2560 of: 2561 2562 Project XYZ Final Review 2563 Conference Room - 3B 2564 Come Prepared. 2565 2566 would be represented as: 2567 2568 Project XYZ Final Review\nConference Room - 3B\nCome Prepared. 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 Dawson & Stenerson Standards Track [Page 46] 2579 2580 RFC 2445 iCalendar November 1998 2581 2582 2583 4.3.12 Time 2584 2585 Value Name: TIME 2586 2587 Purpose: This value type is used to identify values that contain a 2588 time of day. 2589 2590 Formal Definition: The data type is defined by the following 2591 notation: 2592 2593 time = time-hour time-minute time-second [time-utc] 2594 2595 time-hour = 2DIGIT ;00-23 2596 time-minute = 2DIGIT ;00-59 2597 time-second = 2DIGIT ;00-60 2598 ;The "60" value is used to account for "leap" seconds. 2599 2600 time-utc = "Z" 2601 2602 Description: If the property permits, multiple "time" values are 2603 specified by a COMMA character (US-ASCII decimal 44) separated list 2604 of values. No additional content value encoding (i.e., BACKSLASH 2605 character encoding) is defined for this value type. 2606 2607 The "TIME" data type is used to identify values that contain a time 2608 of day. The format is based on the [ISO 8601] complete 2609 representation, basic format for a time of day. The text format 2610 consists of a two-digit 24-hour of the day (i.e., values 0-23), two- 2611 digit minute in the hour (i.e., values 0-59), and two-digit seconds 2612 in the minute (i.e., values 0-60). The seconds value of 60 MUST only 2613 to be used to account for "leap" seconds. Fractions of a second are 2614 not supported by this format. 2615 2616 In parallel to the "DATE-TIME" definition above, the "TIME" data type 2617 expresses time values in three forms: 2618 2619 The form of time with UTC offset MUST NOT be used. For example, the 2620 following is NOT VALID for a time value: 2621 2622 230000-0800 ;Invalid time format 2623 2624 FORM #1 LOCAL TIME 2625 2626 The local time form is simply a time value that does not contain the 2627 UTC designator nor does it reference a time zone. For example, 11:00 2628 PM: 2629 2630 230000 2631 2632 2633 2634 Dawson & Stenerson Standards Track [Page 47] 2635 2636 RFC 2445 iCalendar November 1998 2637 2638 2639 Time values of this type are said to be "floating" and are not bound 2640 to any time zone in particular. They are used to represent the same 2641 hour, minute, and second value regardless of which time zone is 2642 currently being observed. For example, an event can be defined that 2643 indicates that an individual will be busy from 11:00 AM to 1:00 PM 2644 every day, no matter which time zone the person is in. In these 2645 cases, a local time can be specified. The recipient of an iCalendar 2646 object with a property value consisting of a local time, without any 2647 relative time zone information, SHOULD interpret the value as being 2648 fixed to whatever time zone the ATTENDEE is in at any given moment. 2649 This means that two ATTENDEEs may participate in the same event at 2650 different UTC times; floating time SHOULD only be used where that is 2651 reasonable behavior. 2652 2653 In most cases, a fixed time is desired. To properly communicate a 2654 fixed time in a property value, either UTC time or local time with 2655 time zone reference MUST be specified. 2656 2657 The use of local time in a TIME value without the TZID property 2658 parameter is to be interpreted as a local time value, regardless of 2659 the existence of "VTIMEZONE" calendar components in the iCalendar 2660 object. 2661 2662 FORM #2: UTC TIME 2663 2664 UTC time, or absolute time, is identified by a LATIN CAPITAL LETTER Z 2665 suffix character (US-ASCII decimal 90), the UTC designator, appended 2666 to the time value. For example, the following represents 07:00 AM 2667 UTC: 2668 2669 070000Z 2670 2671 The TZID property parameter MUST NOT be applied to TIME properties 2672 whose time values are specified in UTC. 2673 2674 FORM #3: LOCAL TIME AND TIME ZONE REFERENCE 2675 2676 The local time with reference to time zone information form is 2677 identified by the use the TZID property parameter to reference the 2678 appropriate time zone definition. TZID is discussed in detail in the 2679 section on Time Zone. 2680 2681 Example: The following represents 8:30 AM in New York in Winter, five 2682 hours behind UTC, in each of the three formats using the "X- 2683 TIMEOFDAY" non-standard property: 2684 2685 2686 2687 2688 2689 2690 Dawson & Stenerson Standards Track [Page 48] 2691 2692 RFC 2445 iCalendar November 1998 2693 2694 2695 X-TIMEOFDAY:083000 2696 2697 X-TIMEOFDAY:133000Z 2698 2699 X-TIMEOFDAY;TZID=US-Eastern:083000 2700 2701 4.3.13 URI 2702 2703 Value Name: URI 2704 2705 Purpose: This value type is used to identify values that contain a 2706 uniform resource identifier (URI) type of reference to the property 2707 value. 2708 2709 Formal Definition: The data type is defined by the following 2710 notation: 2711 2712 uri = <As defined by any IETF RFC> 2713 2714 Description: This data type might be used to reference binary 2715 information, for values that are large, or otherwise undesirable to 2716 include directly in the iCalendar object. 2717 2718 The URI value formats in RFC 1738, RFC 2111 and any other IETF 2719 registered value format can be specified. 2720 2721 Any IANA registered URI format can be used. These include, but are 2722 not limited to, those defined in RFC 1738 and RFC 2111. 2723 2724 When a property parameter value is a URI value type, the URI MUST be 2725 specified as a quoted-string value. 2726 2727 No additional content value encoding (i.e., BACKSLASH character 2728 encoding) is defined for this value type. 2729 2730 Example: The following is a URI for a network file: 2731 2732 http://host1.com/my-report.txt 2733 2734 4.3.14 UTC Offset 2735 2736 Value Name: UTC-OFFSET 2737 2738 Purpose: This value type is used to identify properties that contain 2739 an offset from UTC to local time. 2740 2741 Formal Definition: The data type is defined by the following 2742 notation: 2743 2744 2745 2746 Dawson & Stenerson Standards Track [Page 49] 2747 2748 RFC 2445 iCalendar November 1998 2749 2750 2751 utc-offset = time-numzone ;As defined above in time data type 2752 2753 time-numzone = ("+" / "-") time-hour time-minute [time- 2754 second] 2755 2756 Description: The PLUS SIGN character MUST be specified for positive 2757 UTC offsets (i.e., ahead of UTC). The value of "-0000" and "-000000" 2758 are not allowed. The time-second, if present, may not be 60; if 2759 absent, it defaults to zero. 2760 2761 No additional content value encoding (i.e., BACKSLASH character 2762 encoding) is defined for this value type. 2763 2764 Example: The following UTC offsets are given for standard time for 2765 New York (five hours behind UTC) and Geneva (one hour ahead of UTC): 2766 2767 -0500 2768 2769 +0100 2770 2771 4.4 iCalendar Object 2772 2773 The Calendaring and Scheduling Core Object is a collection of 2774 calendaring and scheduling information. Typically, this information 2775 will consist of a single iCalendar object. However, multiple 2776 iCalendar objects can be sequentially grouped together. The first 2777 line and last line of the iCalendar object MUST contain a pair of 2778 iCalendar object delimiter strings. The syntax for an iCalendar 2779 object is as follows: 2780 2781 icalobject = 1*("BEGIN" ":" "VCALENDAR" CRLF 2782 icalbody 2783 "END" ":" "VCALENDAR" CRLF) 2784 2785 The following is a simple example of an iCalendar object: 2786 2787 BEGIN:VCALENDAR 2788 VERSION:2.0 2789 PRODID:-//hacksw/handcal//NONSGML v1.0//EN 2790 BEGIN:VEVENT 2791 DTSTART:19970714T170000Z 2792 DTEND:19970715T035959Z 2793 SUMMARY:Bastille Day Party 2794 END:VEVENT 2795 END:VCALENDAR 2796 2797 2798 2799 2800 2801 2802 Dawson & Stenerson Standards Track [Page 50] 2803 2804 RFC 2445 iCalendar November 1998 2805 2806 2807 4.5 Property 2808 2809 A property is the definition of an individual attribute describing a 2810 calendar or a calendar component. A property takes the form defined 2811 by the "contentline" notation defined in section 4.1.1. 2812 2813 The following is an example of a property: 2814 2815 DTSTART:19960415T133000Z 2816 2817 This memo imposes no ordering of properties within an iCalendar 2818 object. 2819 2820 Property names, parameter names and enumerated parameter values are 2821 case insensitive. For example, the property name "DUE" is the same as 2822 "due" and "Due", DTSTART;TZID=US-Eastern:19980714T120000 is the same 2823 as DtStart;TzID=US-Eastern:19980714T120000. 2824 2825 4.6 Calendar Components 2826 2827 The body of the iCalendar object consists of a sequence of calendar 2828 properties and one or more calendar components. The calendar 2829 properties are attributes that apply to the calendar as a whole. The 2830 calendar components are collections of properties that express a 2831 particular calendar semantic. For example, the calendar component can 2832 specify an event, a to-do, a journal entry, time zone information, or 2833 free/busy time information, or an alarm. 2834 2835 The body of the iCalendar object is defined by the following 2836 notation: 2837 2838 icalbody = calprops component 2839 2840 calprops = 2*( 2841 2842 ; 'prodid' and 'version' are both REQUIRED, 2843 ; but MUST NOT occur more than once 2844 2845 prodid /version / 2846 2847 ; 'calscale' and 'method' are optional, 2848 ; but MUST NOT occur more than once 2849 2850 calscale / 2851 method / 2852 2853 x-prop 2854 2855 2856 2857 2858 Dawson & Stenerson Standards Track [Page 51] 2859 2860 RFC 2445 iCalendar November 1998 2861 2862 2863 ) 2864 2865 component = 1*(eventc / todoc / journalc / freebusyc / 2866 / timezonec / iana-comp / x-comp) 2867 2868 iana-comp = "BEGIN" ":" iana-token CRLF 2869 2870 1*contentline 2871 2872 "END" ":" iana-token CRLF 2873 2874 x-comp = "BEGIN" ":" x-name CRLF 2875 2876 1*contentline 2877 2878 "END" ":" x-name CRLF 2879 2880 An iCalendar object MUST include the "PRODID" and "VERSION" calendar 2881 properties. In addition, it MUST include at least one calendar 2882 component. Special forms of iCalendar objects are possible to publish 2883 just busy time (i.e., only a "VFREEBUSY" calendar component) or time 2884 zone (i.e., only a "VTIMEZONE" calendar component) information. In 2885 addition, a complex iCalendar object is possible that is used to 2886 capture a complete snapshot of the contents of a calendar (e.g., 2887 composite of many different calendar components). More commonly, an 2888 iCalendar object will consist of just a single "VEVENT", "VTODO" or 2889 "VJOURNAL" calendar component. 2890 2891 4.6.1 Event Component 2892 2893 Component Name: "VEVENT" 2894 2895 Purpose: Provide a grouping of component properties that describe an 2896 event. 2897 2898 Format Definition: A "VEVENT" calendar component is defined by the 2899 following notation: 2900 2901 eventc = "BEGIN" ":" "VEVENT" CRLF 2902 eventprop *alarmc 2903 "END" ":" "VEVENT" CRLF 2904 2905 eventprop = *( 2906 2907 ; the following are optional, 2908 ; but MUST NOT occur more than once 2909 2910 class / created / description / dtstart / geo / 2911 2912 2913 2914 Dawson & Stenerson Standards Track [Page 52] 2915 2916 RFC 2445 iCalendar November 1998 2917 2918 2919 last-mod / location / organizer / priority / 2920 dtstamp / seq / status / summary / transp / 2921 uid / url / recurid / 2922 2923 ; either 'dtend' or 'duration' may appear in 2924 ; a 'eventprop', but 'dtend' and 'duration' 2925 ; MUST NOT occur in the same 'eventprop' 2926 2927 dtend / duration / 2928 2929 ; the following are optional, 2930 ; and MAY occur more than once 2931 2932 attach / attendee / categories / comment / 2933 contact / exdate / exrule / rstatus / related / 2934 resources / rdate / rrule / x-prop 2935 2936 ) 2937 2938 Description: A "VEVENT" calendar component is a grouping of component 2939 properties, and possibly including "VALARM" calendar components, that 2940 represents a scheduled amount of time on a calendar. For example, it 2941 can be an activity; such as a one-hour long, department meeting from 2942 8:00 AM to 9:00 AM, tomorrow. Generally, an event will take up time 2943 on an individual calendar. Hence, the event will appear as an opaque 2944 interval in a search for busy time. Alternately, the event can have 2945 its Time Transparency set to "TRANSPARENT" in order to prevent 2946 blocking of the event in searches for busy time. 2947 2948 The "VEVENT" is also the calendar component used to specify an 2949 anniversary or daily reminder within a calendar. These events have a 2950 DATE value type for the "DTSTART" property instead of the default 2951 data type of DATE-TIME. If such a "VEVENT" has a "DTEND" property, it 2952 MUST be specified as a DATE value also. The anniversary type of 2953 "VEVENT" can span more than one date (i.e, "DTEND" property value is 2954 set to a calendar date after the "DTSTART" property value). 2955 2956 The "DTSTART" property for a "VEVENT" specifies the inclusive start 2957 of the event. For recurring events, it also specifies the very first 2958 instance in the recurrence set. The "DTEND" property for a "VEVENT" 2959 calendar component specifies the non-inclusive end of the event. For 2960 cases where a "VEVENT" calendar component specifies a "DTSTART" 2961 property with a DATE data type but no "DTEND" property, the events 2962 non-inclusive end is the end of the calendar date specified by the 2963 "DTSTART" property. For cases where a "VEVENT" calendar component 2964 specifies a "DTSTART" property with a DATE-TIME data type but no 2965 "DTEND" property, the event ends on the same calendar date and time 2966 of day specified by the "DTSTART" property. 2967 2968 2969 2970 Dawson & Stenerson Standards Track [Page 53] 2971 2972 RFC 2445 iCalendar November 1998 2973 2974 2975 The "VEVENT" calendar component cannot be nested within another 2976 calendar component. However, "VEVENT" calendar components can be 2977 related to each other or to a "VTODO" or to a "VJOURNAL" calendar 2978 component with the "RELATED-TO" property. 2979 2980 Example: The following is an example of the "VEVENT" calendar 2981 component used to represent a meeting that will also be opaque to 2982 searches for busy time: 2983 2984 BEGIN:VEVENT 2985 UID:19970901T130000Z-123401@host.com 2986 DTSTAMP:19970901T1300Z 2987 DTSTART:19970903T163000Z 2988 DTEND:19970903T190000Z 2989 SUMMARY:Annual Employee Review 2990 CLASS:PRIVATE 2991 CATEGORIES:BUSINESS,HUMAN RESOURCES 2992 END:VEVENT 2993 2994 The following is an example of the "VEVENT" calendar component used 2995 to represent a reminder that will not be opaque, but rather 2996 transparent, to searches for busy time: 2997 2998 BEGIN:VEVENT 2999 UID:19970901T130000Z-123402@host.com 3000 DTSTAMP:19970901T1300Z 3001 DTSTART:19970401T163000Z 3002 DTEND:19970402T010000Z 3003 SUMMARY:Laurel is in sensitivity awareness class. 3004 CLASS:PUBLIC 3005 CATEGORIES:BUSINESS,HUMAN RESOURCES 3006 TRANSP:TRANSPARENT 3007 END:VEVENT 3008 3009 The following is an example of the "VEVENT" calendar component used 3010 to represent an anniversary that will occur annually. Since it takes 3011 up no time, it will not appear as opaque in a search for busy time; 3012 no matter what the value of the "TRANSP" property indicates: 3013 3014 BEGIN:VEVENT 3015 UID:19970901T130000Z-123403@host.com 3016 DTSTAMP:19970901T1300Z 3017 DTSTART:19971102 3018 SUMMARY:Our Blissful Anniversary 3019 CLASS:CONFIDENTIAL 3020 CATEGORIES:ANNIVERSARY,PERSONAL,SPECIAL OCCASION 3021 RRULE:FREQ=YEARLY 3022 END:VEVENT 3023 3024 3025 3026 Dawson & Stenerson Standards Track [Page 54] 3027 3028 RFC 2445 iCalendar November 1998 3029 3030 3031 4.6.2 To-do Component 3032 3033 Component Name: VTODO 3034 3035 Purpose: Provide a grouping of calendar properties that describe a 3036 to-do. 3037 3038 Formal Definition: A "VTODO" calendar component is defined by the 3039 following notation: 3040 3041 todoc = "BEGIN" ":" "VTODO" CRLF 3042 todoprop *alarmc 3043 "END" ":" "VTODO" CRLF 3044 3045 todoprop = *( 3046 3047 ; the following are optional, 3048 ; but MUST NOT occur more than once 3049 3050 class / completed / created / description / dtstamp / 3051 dtstart / geo / last-mod / location / organizer / 3052 percent / priority / recurid / seq / status / 3053 summary / uid / url / 3054 3055 ; either 'due' or 'duration' may appear in 3056 ; a 'todoprop', but 'due' and 'duration' 3057 ; MUST NOT occur in the same 'todoprop' 3058 3059 due / duration / 3060 3061 ; the following are optional, 3062 ; and MAY occur more than once 3063 attach / attendee / categories / comment / contact / 3064 exdate / exrule / rstatus / related / resources / 3065 rdate / rrule / x-prop 3066 3067 ) 3068 3069 Description: A "VTODO" calendar component is a grouping of component 3070 properties and possibly "VALARM" calendar components that represent 3071 an action-item or assignment. For example, it can be used to 3072 represent an item of work assigned to an individual; such as "turn in 3073 travel expense today". 3074 3075 The "VTODO" calendar component cannot be nested within another 3076 calendar component. However, "VTODO" calendar components can be 3077 related to each other or to a "VTODO" or to a "VJOURNAL" calendar 3078 component with the "RELATED-TO" property. 3079 3080 3081 3082 Dawson & Stenerson Standards Track [Page 55] 3083 3084 RFC 2445 iCalendar November 1998 3085 3086 3087 A "VTODO" calendar component without the "DTSTART" and "DUE" (or 3088 "DURATION") properties specifies a to-do that will be associated with 3089 each successive calendar date, until it is completed. 3090 3091 Example: The following is an example of a "VTODO" calendar component: 3092 3093 BEGIN:VTODO 3094 UID:19970901T130000Z-123404@host.com 3095 DTSTAMP:19970901T1300Z 3096 DTSTART:19970415T133000Z 3097 DUE:19970416T045959Z 3098 SUMMARY:1996 Income Tax Preparation 3099 CLASS:CONFIDENTIAL 3100 CATEGORIES:FAMILY,FINANCE 3101 PRIORITY:1 3102 STATUS:NEEDS-ACTION 3103 END:VTODO 3104 3105 4.6.3 Journal Component 3106 3107 Component Name: VJOURNAL 3108 3109 Purpose: Provide a grouping of component properties that describe a 3110 journal entry. 3111 3112 Formal Definition: A "VJOURNAL" calendar component is defined by the 3113 following notation: 3114 3115 journalc = "BEGIN" ":" "VJOURNAL" CRLF 3116 jourprop 3117 "END" ":" "VJOURNAL" CRLF 3118 3119 jourprop = *( 3120 3121 ; the following are optional, 3122 ; but MUST NOT occur more than once 3123 3124 class / created / description / dtstart / dtstamp / 3125 last-mod / organizer / recurid / seq / status / 3126 summary / uid / url / 3127 3128 ; the following are optional, 3129 ; and MAY occur more than once 3130 3131 attach / attendee / categories / comment / 3132 contact / exdate / exrule / related / rdate / 3133 rrule / rstatus / x-prop 3134 3135 3136 3137 3138 Dawson & Stenerson Standards Track [Page 56] 3139 3140 RFC 2445 iCalendar November 1998 3141 3142 3143 ) 3144 3145 Description: A "VJOURNAL" calendar component is a grouping of 3146 component properties that represent one or more descriptive text 3147 notes associated with a particular calendar date. The "DTSTART" 3148 property is used to specify the calendar date that the journal entry 3149 is associated with. Generally, it will have a DATE value data type, 3150 but it can also be used to specify a DATE-TIME value data type. 3151 Examples of a journal entry include a daily record of a legislative 3152 body or a journal entry of individual telephone contacts for the day 3153 or an ordered list of accomplishments for the day. The "VJOURNAL" 3154 calendar component can also be used to associate a document with a 3155 calendar date. 3156 3157 The "VJOURNAL" calendar component does not take up time on a 3158 calendar. Hence, it does not play a role in free or busy time 3159 searches - - it is as though it has a time transparency value of 3160 TRANSPARENT. It is transparent to any such searches. 3161 3162 The "VJOURNAL" calendar component cannot be nested within another 3163 calendar component. However, "VJOURNAL" calendar components can be 3164 related to each other or to a "VEVENT" or to a "VTODO" calendar 3165 component, with the "RELATED-TO" property. 3166 3167 Example: The following is an example of the "VJOURNAL" calendar 3168 component: 3169 3170 BEGIN:VJOURNAL 3171 UID:19970901T130000Z-123405@host.com 3172 DTSTAMP:19970901T1300Z 3173 DTSTART;VALUE=DATE:19970317 3174 SUMMARY:Staff meeting minutes 3175 DESCRIPTION:1. Staff meeting: Participants include Joe\, Lisa 3176 and Bob. Aurora project plans were reviewed. There is currently 3177 no budget reserves for this project. Lisa will escalate to 3178 management. Next meeting on Tuesday.\n 3179 2. Telephone Conference: ABC Corp. sales representative called 3180 to discuss new printer. Promised to get us a demo by Friday.\n 3181 3. Henry Miller (Handsoff Insurance): Car was totaled by tree. 3182 Is looking into a loaner car. 654-2323 (tel). 3183 END:VJOURNAL 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 Dawson & Stenerson Standards Track [Page 57] 3195 3196 RFC 2445 iCalendar November 1998 3197 3198 3199 4.6.4 Free/Busy Component 3200 3201 Component Name: VFREEBUSY 3202 3203 Purpose: Provide a grouping of component properties that describe 3204 either a request for free/busy time, describe a response to a request 3205 for free/busy time or describe a published set of busy time. 3206 3207 Formal Definition: A "VFREEBUSY" calendar component is defined by the 3208 following notation: 3209 3210 freebusyc = "BEGIN" ":" "VFREEBUSY" CRLF 3211 fbprop 3212 "END" ":" "VFREEBUSY" CRLF 3213 3214 fbprop = *( 3215 3216 ; the following are optional, 3217 ; but MUST NOT occur more than once 3218 3219 contact / dtstart / dtend / duration / dtstamp / 3220 organizer / uid / url / 3221 3222 ; the following are optional, 3223 ; and MAY occur more than once 3224 3225 attendee / comment / freebusy / rstatus / x-prop 3226 3227 ) 3228 3229 Description: A "VFREEBUSY" calendar component is a grouping of 3230 component properties that represents either a request for, a reply to 3231 a request for free or busy time information or a published set of 3232 busy time information. 3233 3234 When used to request free/busy time information, the "ATTENDEE" 3235 property specifies the calendar users whose free/busy time is being 3236 requested; the "ORGANIZER" property specifies the calendar user who 3237 is requesting the free/busy time; the "DTSTART" and "DTEND" 3238 properties specify the window of time for which the free/busy time is 3239 being requested; the "UID" and "DTSTAMP" properties are specified to 3240 assist in proper sequencing of multiple free/busy time requests. 3241 3242 When used to reply to a request for free/busy time, the "ATTENDEE" 3243 property specifies the calendar user responding to the free/busy time 3244 request; the "ORGANIZER" property specifies the calendar user that 3245 originally requested the free/busy time; the "FREEBUSY" property 3246 specifies the free/busy time information (if it exists); and the 3247 3248 3249 3250 Dawson & Stenerson Standards Track [Page 58] 3251 3252 RFC 2445 iCalendar November 1998 3253 3254 3255 "UID" and "DTSTAMP" properties are specified to assist in proper 3256 sequencing of multiple free/busy time replies. 3257 3258 When used to publish busy time, the "ORGANIZER" property specifies 3259 the calendar user associated with the published busy time; the 3260 "DTSTART" and "DTEND" properties specify an inclusive time window 3261 that surrounds the busy time information; the "FREEBUSY" property 3262 specifies the published busy time information; and the "DTSTAMP" 3263 property specifies the date/time that iCalendar object was created. 3264 3265 The "VFREEBUSY" calendar component cannot be nested within another 3266 calendar component. Multiple "VFREEBUSY" calendar components can be 3267 specified within an iCalendar object. This permits the grouping of 3268 Free/Busy information into logical collections, such as monthly 3269 groups of busy time information. 3270 3271 The "VFREEBUSY" calendar component is intended for use in iCalendar 3272 object methods involving requests for free time, requests for busy 3273 time, requests for both free and busy, and the associated replies. 3274 3275 Free/Busy information is represented with the "FREEBUSY" property. 3276 This property provides a terse representation of time periods. One or 3277 more "FREEBUSY" properties can be specified in the "VFREEBUSY" 3278 calendar component. 3279 3280 When present in a "VFREEBUSY" calendar component, the "DTSTART" and 3281 "DTEND" properties SHOULD be specified prior to any "FREEBUSY" 3282 properties. In a free time request, these properties can be used in 3283 combination with the "DURATION" property to represent a request for a 3284 duration of free time within a specified window of time. 3285 3286 The recurrence properties ("RRULE", "EXRULE", "RDATE", "EXDATE") are 3287 not permitted within a "VFREEBUSY" calendar component. Any recurring 3288 events are resolved into their individual busy time periods using the 3289 "FREEBUSY" property. 3290 3291 Example: The following is an example of a "VFREEBUSY" calendar 3292 component used to request free or busy time information: 3293 3294 BEGIN:VFREEBUSY 3295 ORGANIZER:MAILTO:jane_doe@host1.com 3296 ATTENDEE:MAILTO:john_public@host2.com 3297 DTSTART:19971015T050000Z 3298 DTEND:19971016T050000Z 3299 DTSTAMP:19970901T083000Z 3300 END:VFREEBUSY 3301 3302 3303 3304 3305 3306 Dawson & Stenerson Standards Track [Page 59] 3307 3308 RFC 2445 iCalendar November 1998 3309 3310 3311 The following is an example of a "VFREEBUSY" calendar component used 3312 to reply to the request with busy time information: 3313 3314 BEGIN:VFREEBUSY 3315 ORGANIZER:MAILTO:jane_doe@host1.com 3316 ATTENDEE:MAILTO:john_public@host2.com 3317 DTSTAMP:19970901T100000Z 3318 FREEBUSY;VALUE=PERIOD:19971015T050000Z/PT8H30M, 3319 19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M 3320 URL:http://host2.com/pub/busy/jpublic-01.ifb 3321 COMMENT:This iCalendar file contains busy time information for 3322 the next three months. 3323 END:VFREEBUSY 3324 3325 The following is an example of a "VFREEBUSY" calendar component used 3326 to publish busy time information. 3327 3328 BEGIN:VFREEBUSY 3329 ORGANIZER:jsmith@host.com 3330 DTSTART:19980313T141711Z 3331 DTEND:19980410T141711Z 3332 FREEBUSY:19980314T233000Z/19980315T003000Z 3333 FREEBUSY:19980316T153000Z/19980316T163000Z 3334 FREEBUSY:19980318T030000Z/19980318T040000Z 3335 URL:http://www.host.com/calendar/busytime/jsmith.ifb 3336 END:VFREEBUSY 3337 3338 4.6.5 Time Zone Component 3339 3340 Component Name: VTIMEZONE 3341 3342 Purpose: Provide a grouping of component properties that defines a 3343 time zone. 3344 3345 Formal Definition: A "VTIMEZONE" calendar component is defined by the 3346 following notation: 3347 3348 timezonec = "BEGIN" ":" "VTIMEZONE" CRLF 3349 3350 2*( 3351 3352 ; 'tzid' is required, but MUST NOT occur more 3353 ; than once 3354 3355 tzid / 3356 3357 ; 'last-mod' and 'tzurl' are optional, 3358 but MUST NOT occur more than once 3359 3360 3361 3362 Dawson & Stenerson Standards Track [Page 60] 3363 3364 RFC 2445 iCalendar November 1998 3365 3366 3367 last-mod / tzurl / 3368 3369 ; one of 'standardc' or 'daylightc' MUST occur 3370 ..; and each MAY occur more than once. 3371 3372 standardc / daylightc / 3373 3374 ; the following is optional, 3375 ; and MAY occur more than once 3376 3377 x-prop 3378 3379 ) 3380 3381 "END" ":" "VTIMEZONE" CRLF 3382 3383 standardc = "BEGIN" ":" "STANDARD" CRLF 3384 3385 tzprop 3386 3387 "END" ":" "STANDARD" CRLF 3388 3389 daylightc = "BEGIN" ":" "DAYLIGHT" CRLF 3390 3391 tzprop 3392 3393 "END" ":" "DAYLIGHT" CRLF 3394 3395 tzprop = 3*( 3396 3397 ; the following are each REQUIRED, 3398 ; but MUST NOT occur more than once 3399 3400 dtstart / tzoffsetto / tzoffsetfrom / 3401 3402 ; the following are optional, 3403 ; and MAY occur more than once 3404 3405 comment / rdate / rrule / tzname / x-prop 3406 3407 ) 3408 3409 Description: A time zone is unambiguously defined by the set of time 3410 measurement rules determined by the governing body for a given 3411 geographic area. These rules describe at a minimum the base offset 3412 from UTC for the time zone, often referred to as the Standard Time 3413 offset. Many locations adjust their Standard Time forward or backward 3414 by one hour, in order to accommodate seasonal changes in number of 3415 3416 3417 3418 Dawson & Stenerson Standards Track [Page 61] 3419 3420 RFC 2445 iCalendar November 1998 3421 3422 3423 daylight hours, often referred to as Daylight Saving Time. Some 3424 locations adjust their time by a fraction of an hour. Standard Time 3425 is also known as Winter Time. Daylight Saving Time is also known as 3426 Advanced Time, Summer Time, or Legal Time in certain countries. The 3427 following table shows the changes in time zone rules in effect for 3428 New York City starting from 1967. Each line represents a description 3429 or rule for a particular observance. 3430 3431 Effective Observance Rule 3432 3433 Date (Date/Time) Offset Abbreviation 3434 3435 1967-* last Sun in Oct, 02:00 -0500 EST 3436 3437 1967-1973 last Sun in Apr, 02:00 -0400 EDT 3438 3439 1974-1974 Jan 6, 02:00 -0400 EDT 3440 3441 1975-1975 Feb 23, 02:00 -0400 EDT 3442 3443 1976-1986 last Sun in Apr, 02:00 -0400 EDT 3444 3445 1987-* first Sun in Apr, 02:00 -0400 EDT 3446 3447 Note: The specification of a global time zone registry is not 3448 addressed by this document and is left for future study. 3449 However, implementers may find the Olson time zone database [TZ] 3450 a useful reference. It is an informal, public-domain collection 3451 of time zone information, which is currently being maintained by 3452 volunteer Internet participants, and is used in several 3453 operating systems. This database contains current and historical 3454 time zone information for a wide variety of locations around the 3455 globe; it provides a time zone identifier for every unique time 3456 zone rule set in actual use since 1970, with historical data 3457 going back to the introduction of standard time. 3458 3459 Interoperability between two calendaring and scheduling applications, 3460 especially for recurring events, to-dos or journal entries, is 3461 dependent on the ability to capture and convey date and time 3462 information in an unambiguous format. The specification of current 3463 time zone information is integral to this behavior. 3464 3465 If present, the "VTIMEZONE" calendar component defines the set of 3466 Standard Time and Daylight Saving Time observances (or rules) for a 3467 particular time zone for a given interval of time. The "VTIMEZONE" 3468 calendar component cannot be nested within other calendar components. 3469 Multiple "VTIMEZONE" calendar components can exist in an iCalendar 3470 object. In this situation, each "VTIMEZONE" MUST represent a unique 3471 3472 3473 3474 Dawson & Stenerson Standards Track [Page 62] 3475 3476 RFC 2445 iCalendar November 1998 3477 3478 3479 time zone definition. This is necessary for some classes of events, 3480 such as airline flights, that start in one time zone and end in 3481 another. 3482 3483 The "VTIMEZONE" calendar component MUST be present if the iCalendar 3484 object contains an RRULE that generates dates on both sides of a time 3485 zone shift (e.g. both in Standard Time and Daylight Saving Time) 3486 unless the iCalendar object intends to convey a floating time (See 3487 the section "4.1.10.11 Time" for proper interpretation of floating 3488 time). It can be present if the iCalendar object does not contain 3489 such a RRULE. In addition, if a RRULE is present, there MUST be valid 3490 time zone information for all recurrence instances. 3491 3492 The "VTIMEZONE" calendar component MUST include the "TZID" property 3493 and at least one definition of a standard or daylight component. The 3494 standard or daylight component MUST include the "DTSTART", 3495 "TZOFFSETFROM" and "TZOFFSETTO" properties. 3496 3497 An individual "VTIMEZONE" calendar component MUST be specified for 3498 each unique "TZID" parameter value specified in the iCalendar object. 3499 3500 Each "VTIMEZONE" calendar component consists of a collection of one 3501 or more sub-components that describe the rule for a particular 3502 observance (either a Standard Time or a Daylight Saving Time 3503 observance). The "STANDARD" sub-component consists of a collection of 3504 properties that describe Standard Time. The "DAYLIGHT" sub-component 3505 consists of a collection of properties that describe Daylight Saving 3506 Time. In general this collection of properties consists of: 3507 3508 - the first onset date-time for the observance 3509 3510 - the last onset date-time for the observance, if a last onset 3511 is known. 3512 3513 - the offset to be applied for the observance 3514 3515 - a rule that describes the day and time when the observance 3516 takes effect 3517 3518 - an optional name for the observance 3519 3520 For a given time zone, there may be multiple unique definitions of 3521 the observances over a period of time. Each observance is described 3522 using either a "STANDARD" or "DAYLIGHT" sub-component. The collection 3523 of these sub-components is used to describe the time zone for a given 3524 period of time. The offset to apply at any given time is found by 3525 locating the observance that has the last onset date and time before 3526 the time in question, and using the offset value from that 3527 3528 3529 3530 Dawson & Stenerson Standards Track [Page 63] 3531 3532 RFC 2445 iCalendar November 1998 3533 3534 3535 observance. 3536 3537 The top-level properties in a "VTIMEZONE" calendar component are: 3538 3539 The mandatory "TZID" property is a text value that uniquely 3540 identifies the VTIMZONE calendar component within the scope of an 3541 iCalendar object. 3542 3543 The optional "LAST-MODIFIED" property is a UTC value that specifies 3544 the date and time that this time zone definition was last updated. 3545 3546 The optional "TZURL" property is url value that points to a published 3547 VTIMEZONE definition. TZURL SHOULD refer to a resource that is 3548 accessible by anyone who might need to interpret the object. This 3549 SHOULD NOT normally be a file: URL or other URL that is not widely- 3550 accessible. 3551 3552 The collection of properties that are used to define the STANDARD and 3553 DAYLIGHT sub-components include: 3554 3555 The mandatory "DTSTART" property gives the effective onset date and 3556 local time for the time zone sub-component definition. "DTSTART" in 3557 this usage MUST be specified as a local DATE-TIME value. 3558 3559 The mandatory "TZOFFSETFROM" property gives the UTC offset which is 3560 in use when the onset of this time zone observance begins. 3561 "TZOFFSETFROM" is combined with "DTSTART" to define the effective 3562 onset for the time zone sub-component definition. For example, the 3563 following represents the time at which the observance of Standard 3564 Time took effect in Fall 1967 for New York City: 3565 3566 DTSTART:19671029T020000 3567 3568 TZOFFSETFROM:-0400 3569 3570 The mandatory "TZOFFSETTO " property gives the UTC offset for the 3571 time zone sub-component (Standard Time or Daylight Saving Time) when 3572 this observance is in use. 3573 3574 The optional "TZNAME" property is the customary name for the time 3575 zone. It may be specified multiple times, to allow for specifying 3576 multiple language variants of the time zone names. This could be used 3577 for displaying dates. 3578 3579 If specified, the onset for the observance defined by the time zone 3580 sub-component is defined by either the "RRULE" or "RDATE" property. 3581 If neither is specified, only one sub-component can be specified in 3582 the "VTIMEZONE" calendar component and it is assumed that the single 3583 3584 3585 3586 Dawson & Stenerson Standards Track [Page 64] 3587 3588 RFC 2445 iCalendar November 1998 3589 3590 3591 observance specified is always in effect. 3592 3593 The "RRULE" property defines the recurrence rule for the onset of the 3594 observance defined by this time zone sub-component. Some specific 3595 requirements for the usage of RRULE for this purpose include: 3596 3597 - If observance is known to have an effective end date, the 3598 "UNTIL" recurrence rule parameter MUST be used to specify the 3599 last valid onset of this observance (i.e., the UNTIL date-time 3600 will be equal to the last instance generated by the recurrence 3601 pattern). It MUST be specified in UTC time. 3602 3603 - The "DTSTART" and the "TZOFFSETTO" properties MUST be used 3604 when generating the onset date-time values (instances) from the 3605 RRULE. 3606 3607 Alternatively, the "RDATE" property can be used to define the onset 3608 of the observance by giving the individual onset date and times. 3609 "RDATE" in this usage MUST be specified as a local DATE-TIME value in 3610 UTC time. 3611 3612 The optional "COMMENT" property is also allowed for descriptive 3613 explanatory text. 3614 3615 Example: The following are examples of the "VTIMEZONE" calendar 3616 component: 3617 3618 This is an example showing time zone information for the Eastern 3619 United States using "RDATE" property. Note that this is only suitable 3620 for a recurring event that starts on or later than April 6, 1997 at 3621 03:00:00 EDT (i.e., the earliest effective transition date and time) 3622 and ends no later than April 7, 1998 02:00:00 EST (i.e., latest valid 3623 date and time for EST in this scenario). For example, this can be 3624 used for a recurring event that occurs every Friday, 8am-9:00 AM, 3625 starting June 1, 1997, ending December 31, 1997. 3626 3627 BEGIN:VTIMEZONE 3628 TZID:US-Eastern 3629 LAST-MODIFIED:19870101T000000Z 3630 BEGIN:STANDARD 3631 DTSTART:19971026T020000 3632 RDATE:19971026T020000 3633 TZOFFSETFROM:-0400 3634 TZOFFSETTO:-0500 3635 TZNAME:EST 3636 END:STANDARD 3637 BEGIN:DAYLIGHT 3638 DTSTART:19971026T020000 3639 3640 3641 3642 Dawson & Stenerson Standards Track [Page 65] 3643 3644 RFC 2445 iCalendar November 1998 3645 3646 3647 RDATE:19970406T020000 3648 TZOFFSETFROM:-0500 3649 TZOFFSETTO:-0400 3650 TZNAME:EDT 3651 END:DAYLIGHT 3652 END:VTIMEZONE 3653 3654 This is a simple example showing the current time zone rules for the 3655 Eastern United States using a RRULE recurrence pattern. Note that 3656 there is no effective end date to either of the Standard Time or 3657 Daylight Time rules. This information would be valid for a recurring 3658 event starting today and continuing indefinitely. 3659 3660 BEGIN:VTIMEZONE 3661 TZID:US-Eastern 3662 LAST-MODIFIED:19870101T000000Z 3663 TZURL:http://zones.stds_r_us.net/tz/US-Eastern 3664 BEGIN:STANDARD 3665 DTSTART:19671029T020000 3666 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 3667 TZOFFSETFROM:-0400 3668 TZOFFSETTO:-0500 3669 TZNAME:EST 3670 END:STANDARD 3671 BEGIN:DAYLIGHT 3672 DTSTART:19870405T020000 3673 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4 3674 TZOFFSETFROM:-0500 3675 TZOFFSETTO:-0400 3676 TZNAME:EDT 3677 END:DAYLIGHT 3678 END:VTIMEZONE 3679 3680 This is an example showing a fictitious set of rules for the Eastern 3681 United States, where the Daylight Time rule has an effective end date 3682 (i.e., after that date, Daylight Time is no longer observed). 3683 3684 BEGIN:VTIMEZONE 3685 TZID:US--Fictitious-Eastern 3686 LAST-MODIFIED:19870101T000000Z 3687 BEGIN:STANDARD 3688 DTSTART:19671029T020000 3689 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 3690 TZOFFSETFROM:-0400 3691 TZOFFSETTO:-0500 3692 TZNAME:EST 3693 END:STANDARD 3694 3695 3696 3697 3698 Dawson & Stenerson Standards Track [Page 66] 3699 3700 RFC 2445 iCalendar November 1998 3701 3702 3703 BEGIN:DAYLIGHT 3704 DTSTART:19870405T020000 3705 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z 3706 TZOFFSETFROM:-0500 3707 TZOFFSETTO:-0400 3708 TZNAME:EDT 3709 END:DAYLIGHT 3710 END:VTIMEZONE 3711 3712 This is an example showing a fictitious set of rules for the Eastern 3713 United States, where the first Daylight Time rule has an effective 3714 end date. There is a second Daylight Time rule that picks up where 3715 the other left off. 3716 3717 BEGIN:VTIMEZONE 3718 TZID:US--Fictitious-Eastern 3719 LAST-MODIFIED:19870101T000000Z 3720 BEGIN:STANDARD 3721 DTSTART:19671029T020000 3722 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 3723 TZOFFSETFROM:-0400 3724 TZOFFSETTO:-0500 3725 TZNAME:EST 3726 END:STANDARD 3727 BEGIN:DAYLIGHT 3728 DTSTART:19870405T020000 3729 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z 3730 TZOFFSETFROM:-0500 3731 TZOFFSETTO:-0400 3732 TZNAME:EDT 3733 END:DAYLIGHT 3734 BEGIN:DAYLIGHT 3735 DTSTART:19990424T020000 3736 RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=4 3737 TZOFFSETFROM:-0500 3738 TZOFFSETTO:-0400 3739 TZNAME:EDT 3740 END:DAYLIGHT 3741 END:VTIMEZONE 3742 3743 4.6.6 Alarm Component 3744 3745 Component Name: VALARM 3746 3747 Purpose: Provide a grouping of component properties that define an 3748 alarm. 3749 3750 3751 3752 3753 3754 Dawson & Stenerson Standards Track [Page 67] 3755 3756 RFC 2445 iCalendar November 1998 3757 3758 3759 Formal Definition: A "VALARM" calendar component is defined by the 3760 following notation: 3761 3762 alarmc = "BEGIN" ":" "VALARM" CRLF 3763 (audioprop / dispprop / emailprop / procprop) 3764 "END" ":" "VALARM" CRLF 3765 3766 audioprop = 2*( 3767 3768 ; 'action' and 'trigger' are both REQUIRED, 3769 ; but MUST NOT occur more than once 3770 3771 action / trigger / 3772 3773 ; 'duration' and 'repeat' are both optional, 3774 ; and MUST NOT occur more than once each, 3775 ; but if one occurs, so MUST the other 3776 3777 duration / repeat / 3778 3779 ; the following is optional, 3780 ; but MUST NOT occur more than once 3781 3782 attach / 3783 3784 ; the following is optional, 3785 ; and MAY occur more than once 3786 3787 x-prop 3788 3789 ) 3790 3791 3792 3793 dispprop = 3*( 3794 3795 ; the following are all REQUIRED, 3796 ; but MUST NOT occur more than once 3797 3798 action / description / trigger / 3799 3800 ; 'duration' and 'repeat' are both optional, 3801 ; and MUST NOT occur more than once each, 3802 ; but if one occurs, so MUST the other 3803 3804 duration / repeat / 3805 3806 ; the following is optional, 3807 3808 3809 3810 Dawson & Stenerson Standards Track [Page 68] 3811 3812 RFC 2445 iCalendar November 1998 3813 3814 3815 ; and MAY occur more than once 3816 3817 *x-prop 3818 3819 ) 3820 3821 3822 3823 emailprop = 5*( 3824 3825 ; the following are all REQUIRED, 3826 ; but MUST NOT occur more than once 3827 3828 action / description / trigger / summary 3829 3830 ; the following is REQUIRED, 3831 ; and MAY occur more than once 3832 3833 attendee / 3834 3835 ; 'duration' and 'repeat' are both optional, 3836 ; and MUST NOT occur more than once each, 3837 ; but if one occurs, so MUST the other 3838 3839 duration / repeat / 3840 3841 ; the following are optional, 3842 ; and MAY occur more than once 3843 3844 attach / x-prop 3845 3846 ) 3847 3848 3849 3850 procprop = 3*( 3851 3852 ; the following are all REQUIRED, 3853 ; but MUST NOT occur more than once 3854 3855 action / attach / trigger / 3856 3857 ; 'duration' and 'repeat' are both optional, 3858 ; and MUST NOT occur more than once each, 3859 ; but if one occurs, so MUST the other 3860 3861 duration / repeat / 3862 3863 3864 3865 3866 Dawson & Stenerson Standards Track [Page 69] 3867 3868 RFC 2445 iCalendar November 1998 3869 3870 3871 ; 'description' is optional, 3872 ; and MUST NOT occur more than once 3873 3874 description / 3875 3876 ; the following is optional, 3877 ; and MAY occur more than once 3878 3879 x-prop 3880 3881 ) 3882 3883 Description: A "VALARM" calendar component is a grouping of component 3884 properties that is a reminder or alarm for an event or a to-do. For 3885 example, it may be used to define a reminder for a pending event or 3886 an overdue to-do. 3887 3888 The "VALARM" calendar component MUST include the "ACTION" and 3889 "TRIGGER" properties. The "ACTION" property further constrains the 3890 "VALARM" calendar component in the following ways: 3891 3892 When the action is "AUDIO", the alarm can also include one and only 3893 one "ATTACH" property, which MUST point to a sound resource, which is 3894 rendered when the alarm is triggered. 3895 3896 When the action is "DISPLAY", the alarm MUST also include a 3897 "DESCRIPTION" property, which contains the text to be displayed when 3898 the alarm is triggered. 3899 3900 When the action is "EMAIL", the alarm MUST include a "DESCRIPTION" 3901 property, which contains the text to be used as the message body, a 3902 "SUMMARY" property, which contains the text to be used as the message 3903 subject, and one or more "ATTENDEE" properties, which contain the 3904 email address of attendees to receive the message. It can also 3905 include one or more "ATTACH" properties, which are intended to be 3906 sent as message attachments. When the alarm is triggered, the email 3907 message is sent. 3908 3909 When the action is "PROCEDURE", the alarm MUST include one and only 3910 one "ATTACH" property, which MUST point to a procedure resource, 3911 which is invoked when the alarm is triggered. 3912 3913 The "VALARM" calendar component MUST only appear within either a 3914 "VEVENT" or "VTODO" calendar component. "VALARM" calendar components 3915 cannot be nested. Multiple mutually independent "VALARM" calendar 3916 components can be specified for a single "VEVENT" or "VTODO" calendar 3917 component. 3918 3919 3920 3921 3922 Dawson & Stenerson Standards Track [Page 70] 3923 3924 RFC 2445 iCalendar November 1998 3925 3926 3927 The "TRIGGER" property specifies when the alarm will be triggered. 3928 The "TRIGGER" property specifies a duration prior to the start of an 3929 event or a to-do. The "TRIGGER" edge may be explicitly set to be 3930 relative to the "START" or "END" of the event or to-do with the 3931 "RELATED" parameter of the "TRIGGER" property. The "TRIGGER" property 3932 value type can alternatively be set to an absolute calendar date and 3933 time of day value. 3934 3935 In an alarm set to trigger on the "START" of an event or to-do, the 3936 "DTSTART" property MUST be present in the associated event or to-do. 3937 In an alarm in a "VEVENT" calendar component set to trigger on the 3938 "END" of the event, either the "DTEND" property MUST be present, or 3939 the "DTSTART" and "DURATION" properties MUST both be present. In an 3940 alarm in a "VTODO" calendar component set to trigger on the "END" of 3941 the to-do, either the "DUE" property MUST be present, or the 3942 "DTSTART" and "DURATION" properties MUST both be present. 3943 3944 The alarm can be defined such that it triggers repeatedly. A 3945 definition of an alarm with a repeating trigger MUST include both the 3946 "DURATION" and "REPEAT" properties. The "DURATION" property specifies 3947 the delay period, after which the alarm will repeat. The "REPEAT" 3948 property specifies the number of additional repetitions that the 3949 alarm will triggered. This repitition count is in addition to the 3950 initial triggering of the alarm. Both of these properties MUST be 3951 present in order to specify a repeating alarm. If one of these two 3952 properties is absent, then the alarm will not repeat beyond the 3953 initial trigger. 3954 3955 The "ACTION" property is used within the "VALARM" calendar component 3956 to specify the type of action invoked when the alarm is triggered. 3957 The "VALARM" properties provide enough information for a specific 3958 action to be invoked. It is typically the responsibility of a 3959 "Calendar User Agent" (CUA) to deliver the alarm in the specified 3960 fashion. An "ACTION" property value of AUDIO specifies an alarm that 3961 causes a sound to be played to alert the user; DISPLAY specifies an 3962 alarm that causes a text message to be displayed to the user; EMAIL 3963 specifies an alarm that causes an electronic email message to be 3964 delivered to one or more email addresses; and PROCEDURE specifies an 3965 alarm that causes a procedure to be executed. The "ACTION" property 3966 MUST specify one and only one of these values. 3967 3968 In an AUDIO alarm, if the optional "ATTACH" property is included, it 3969 MUST specify an audio sound resource. The intention is that the sound 3970 will be played as the alarm effect. If an "ATTACH" property is 3971 specified that does not refer to a sound resource, or if the 3972 specified sound resource cannot be rendered (because its format is 3973 unsupported, or because it cannot be retrieved), then the CUA or 3974 other entity responsible for playing the sound may choose a fallback 3975 3976 3977 3978 Dawson & Stenerson Standards Track [Page 71] 3979 3980 RFC 2445 iCalendar November 1998 3981 3982 3983 action, such as playing a built-in default sound, or playing no sound 3984 at all. 3985 3986 In a DISPLAY alarm, the intended alarm effect is for the text value 3987 of the "DESCRIPTION" property to be displayed to the user. 3988 3989 In an EMAIL alarm, the intended alarm effect is for an email message 3990 to be composed and delivered to all the addresses specified by the 3991 "ATTENDEE" properties in the "VALARM" calendar component. The 3992 "DESCRIPTION" property of the "VALARM" calendar component MUST be 3993 used as the body text of the message, and the "SUMMARY" property MUST 3994 be used as the subject text. Any "ATTACH" properties in the "VALARM" 3995 calendar component SHOULD be sent as attachments to the message. 3996 3997 In a PROCEDURE alarm, the "ATTACH" property in the "VALARM" calendar 3998 component MUST specify a procedure or program that is intended to be 3999 invoked as the alarm effect. If the procedure or program is in a 4000 format that cannot be rendered, then no procedure alarm will be 4001 invoked. If the "DESCRIPTION" property is present, its value 4002 specifies the argument string to be passed to the procedure or 4003 program. "Calendar User Agents" that receive an iCalendar object with 4004 this category of alarm, can disable or allow the "Calendar User" to 4005 disable, or otherwise ignore this type of alarm. While a very useful 4006 alarm capability, the PROCEDURE type of alarm SHOULD be treated by 4007 the "Calendar User Agent" as a potential security risk. 4008 4009 Example: The following example is for a "VALARM" calendar component 4010 that specifies an audio alarm that will sound at a precise time and 4011 repeat 4 more times at 15 minute intervals: 4012 4013 BEGIN:VALARM 4014 TRIGGER;VALUE=DATE-TIME:19970317T133000Z 4015 REPEAT:4 4016 DURATION:PT15M 4017 ACTION:AUDIO 4018 ATTACH;FMTTYPE=audio/basic:ftp://host.com/pub/sounds/bell-01.aud 4019 END:VALARM 4020 4021 The following example is for a "VALARM" calendar component that 4022 specifies a display alarm that will trigger 30 minutes before the 4023 scheduled start of the event or the due date/time of the to-do it is 4024 associated with and will repeat 2 more times at 15 minute intervals: 4025 4026 BEGIN:VALARM 4027 TRIGGER:-PT30M 4028 REPEAT:2 4029 DURATION:PT15M 4030 ACTION:DISPLAY 4031 4032 4033 4034 Dawson & Stenerson Standards Track [Page 72] 4035 4036 RFC 2445 iCalendar November 1998 4037 4038 4039 DESCRIPTION:Breakfast meeting with executive\n 4040 team at 8:30 AM EST. 4041 END:VALARM 4042 4043 The following example is for a "VALARM" calendar component that 4044 specifies an email alarm that will trigger 2 days before the 4045 scheduled due date/time of a to-do it is associated with. It does not 4046 repeat. The email has a subject, body and attachment link. 4047 4048 BEGIN:VALARM 4049 TRIGGER:-P2D 4050 ACTION:EMAIL 4051 ATTENDEE:MAILTO:john_doe@host.com 4052 SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING *** 4053 DESCRIPTION:A draft agenda needs to be sent out to the attendees 4054 to the weekly managers meeting (MGR-LIST). Attached is a 4055 pointer the document template for the agenda file. 4056 ATTACH;FMTTYPE=application/binary:http://host.com/templates/agen 4057 da.doc 4058 END:VALARM 4059 4060 The following example is for a "VALARM" calendar component that 4061 specifies a procedural alarm that will trigger at a precise date/time 4062 and will repeat 23 more times at one hour intervals. The alarm will 4063 invoke a procedure file. 4064 4065 BEGIN:VALARM 4066 TRIGGER;VALUE=DATE-TIME:19980101T050000Z 4067 REPEAT:23 4068 DURATION:PT1H 4069 ACTION:PROCEDURE 4070 ATTACH;FMTTYPE=application/binary:ftp://host.com/novo- 4071 procs/felizano.exe 4072 END:VALARM 4073 4074 4.7 Calendar Properties 4075 4076 The Calendar Properties are attributes that apply to the iCalendar 4077 object, as a whole. These properties do not appear within a calendar 4078 component. They SHOULD be specified after the "BEGIN:VCALENDAR" 4079 property and prior to any calendar component. 4080 4081 4.7.1 Calendar Scale 4082 4083 Property Name: CALSCALE 4084 4085 Purpose: This property defines the calendar scale used for the 4086 calendar information specified in the iCalendar object. 4087 4088 4089 4090 Dawson & Stenerson Standards Track [Page 73] 4091 4092 RFC 2445 iCalendar November 1998 4093 4094 4095 Value Type: TEXT 4096 4097 Property Parameters: Non-standard property parameters can be 4098 specified on this property. 4099 4100 Conformance: Property can be specified in an iCalendar object. The 4101 default value is "GREGORIAN". 4102 4103 Description: This memo is based on the Gregorian calendar scale. The 4104 Gregorian calendar scale is assumed if this property is not specified 4105 in the iCalendar object. It is expected that other calendar scales 4106 will be defined in other specifications or by future versions of this 4107 memo. 4108 4109 Format Definition: The property is defined by the following notation: 4110 4111 calscale = "CALSCALE" calparam ":" calvalue CRLF 4112 4113 calparam = *(";" xparam) 4114 4115 calvalue = "GREGORIAN" / iana-token 4116 4117 Example: The following is an example of this property: 4118 4119 CALSCALE:GREGORIAN 4120 4121 4.7.2 Method 4122 4123 Property Name: METHOD 4124 4125 Purpose: This property defines the iCalendar object method associated 4126 with the calendar object. 4127 4128 Value Type: TEXT 4129 4130 Property Parameters: Non-standard property parameters can be 4131 specified on this property. 4132 4133 Conformance: The property can be specified in an iCalendar object. 4134 4135 Description: When used in a MIME message entity, the value of this 4136 property MUST be the same as the Content-Type "method" parameter 4137 value. This property can only appear once within the iCalendar 4138 object. If either the "METHOD" property or the Content-Type "method" 4139 parameter is specified, then the other MUST also be specified. 4140 4141 No methods are defined by this specification. This is the subject of 4142 other specifications, such as the iCalendar Transport-independent 4143 4144 4145 4146 Dawson & Stenerson Standards Track [Page 74] 4147 4148 RFC 2445 iCalendar November 1998 4149 4150 4151 Interoperability Protocol (iTIP) defined by [ITIP]. 4152 4153 If this property is not present in the iCalendar object, then a 4154 scheduling transaction MUST NOT be assumed. In such cases, the 4155 iCalendar object is merely being used to transport a snapshot of some 4156 calendar information; without the intention of conveying a scheduling 4157 semantic. 4158 4159 Format Definition: The property is defined by the following notation: 4160 4161 method = "METHOD" metparam ":" metvalue CRLF 4162 4163 metparam = *(";" xparam) 4164 4165 metvalue = iana-token 4166 4167 Example: The following is a hypothetical example of this property to 4168 convey that the iCalendar object is a request for a meeting: 4169 4170 METHOD:REQUEST 4171 4172 4.7.3 Product Identifier 4173 4174 Property Name: PRODID 4175 4176 Purpose: This property specifies the identifier for the product that 4177 created the iCalendar object. 4178 4179 Value Type: TEXT 4180 4181 Property Parameters: Non-standard property parameters can be 4182 specified on this property. 4183 4184 Conformance: The property MUST be specified once in an iCalendar 4185 object. 4186 4187 Description: The vendor of the implementation SHOULD assure that this 4188 is a globally unique identifier; using some technique such as an FPI 4189 value, as defined in [ISO 9070]. 4190 4191 This property SHOULD not be used to alter the interpretation of an 4192 iCalendar object beyond the semantics specified in this memo. For 4193 example, it is not to be used to further the understanding of non- 4194 standard properties. 4195 4196 Format Definition: The property is defined by the following notation: 4197 4198 prodid = "PRODID" pidparam ":" pidvalue CRLF 4199 4200 4201 4202 Dawson & Stenerson Standards Track [Page 75] 4203 4204 RFC 2445 iCalendar November 1998 4205 4206 4207 pidparam = *(";" xparam) 4208 4209 pidvalue = text 4210 ;Any text that describes the product and version 4211 ;and that is generally assured of being unique. 4212 4213 Example: The following is an example of this property. It does not 4214 imply that English is the default language. 4215 4216 PRODID:-//ABC Corporation//NONSGML My Product//EN 4217 4218 4.7.4 Version 4219 4220 Property Name: VERSION 4221 4222 Purpose: This property specifies the identifier corresponding to the 4223 highest version number or the minimum and maximum range of the 4224 iCalendar specification that is required in order to interpret the 4225 iCalendar object. 4226 4227 Value Type: TEXT 4228 4229 Property Parameters: Non-standard property parameters can be 4230 specified on this property. 4231 4232 Conformance: This property MUST be specified by an iCalendar object, 4233 but MUST only be specified once. 4234 4235 Description: A value of "2.0" corresponds to this memo. 4236 4237 Format Definition: The property is defined by the following notation: 4238 4239 version = "VERSION" verparam ":" vervalue CRLF 4240 4241 verparam = *(";" xparam) 4242 4243 vervalue = "2.0" ;This memo 4244 / maxver 4245 / (minver ";" maxver) 4246 4247 minver = <A IANA registered iCalendar version identifier> 4248 ;Minimum iCalendar version needed to parse the iCalendar object 4249 4250 maxver = <A IANA registered iCalendar version identifier> 4251 ;Maximum iCalendar version needed to parse the iCalendar object 4252 4253 Example: The following is an example of this property: 4254 4255 4256 4257 4258 Dawson & Stenerson Standards Track [Page 76] 4259 4260 RFC 2445 iCalendar November 1998 4261 4262 4263 VERSION:2.0 4264 4265 4.8 Component Properties 4266 4267 The following properties can appear within calendar components, as 4268 specified by each component property definition. 4269 4270 4.8.1 Descriptive Component Properties 4271 4272 The following properties specify descriptive information about 4273 calendar components. 4274 4275 4.8.1.1 Attachment 4276 4277 Property Name: ATTACH 4278 4279 Purpose: The property provides the capability to associate a document 4280 object with a calendar component. 4281 4282 Value Type: The default value type for this property is URI. The 4283 value type can also be set to BINARY to indicate inline binary 4284 encoded content information. 4285 4286 Property Parameters: Non-standard, inline encoding, format type and 4287 value data type property parameters can be specified on this 4288 property. 4289 4290 Conformance: The property can be specified in a "VEVENT", "VTODO", 4291 "VJOURNAL" or "VALARM" calendar components. 4292 4293 Description: The property can be specified within "VEVENT", "VTODO", 4294 "VJOURNAL", or "VALARM" calendar components. This property can be 4295 specified multiple times within an iCalendar object. 4296 4297 Format Definition: The property is defined by the following notation: 4298 4299 attach = "ATTACH" attparam ":" uri CRLF 4300 4301 attach =/ "ATTACH" attparam ";" "ENCODING" "=" "BASE64" 4302 ";" "VALUE" "=" "BINARY" ":" binary 4303 4304 attparam = *( 4305 4306 ; the following is optional, 4307 ; but MUST NOT occur more than once 4308 4309 (";" fmttypeparam) / 4310 4311 4312 4313 4314 Dawson & Stenerson Standards Track [Page 77] 4315 4316 RFC 2445 iCalendar November 1998 4317 4318 4319 ; the following is optional, 4320 ; and MAY occur more than once 4321 4322 (";" xparam) 4323 4324 ) 4325 4326 Example: The following are examples of this property: 4327 4328 ATTACH:CID:jsmith.part3.960817T083000.xyzMail@host1.com 4329 4330 ATTACH;FMTTYPE=application/postscript:ftp://xyzCorp.com/pub/ 4331 reports/r-960812.ps 4332 4333 4.8.1.2 Categories 4334 4335 Property Name: CATEGORIES 4336 4337 Purpose: This property defines the categories for a calendar 4338 component. 4339 4340 Value Type: TEXT 4341 4342 Property Parameters: Non-standard and language property parameters 4343 can be specified on this property. 4344 4345 Conformance: The property can be specified within "VEVENT", "VTODO" 4346 or "VJOURNAL" calendar components. 4347 4348 Description: This property is used to specify categories or subtypes 4349 of the calendar component. The categories are useful in searching for 4350 a calendar component of a particular type and category. Within the 4351 "VEVENT", "VTODO" or "VJOURNAL" calendar components, more than one 4352 category can be specified as a list of categories separated by the 4353 COMMA character (US-ASCII decimal 44). 4354 4355 Format Definition: The property is defined by the following notation: 4356 4357 categories = "CATEGORIES" catparam ":" text *("," text) 4358 CRLF 4359 4360 catparam = *( 4361 4362 ; the following is optional, 4363 ; but MUST NOT occur more than once 4364 4365 (";" languageparam ) / 4366 4367 4368 4369 4370 Dawson & Stenerson Standards Track [Page 78] 4371 4372 RFC 2445 iCalendar November 1998 4373 4374 4375 ; the following is optional, 4376 ; and MAY occur more than once 4377 4378 (";" xparam) 4379 4380 ) 4381 4382 Example: The following are examples of this property: 4383 4384 CATEGORIES:APPOINTMENT,EDUCATION 4385 4386 CATEGORIES:MEETING 4387 4388 4.8.1.3 Classification 4389 4390 Property Name: CLASS 4391 4392 Purpose: This property defines the access classification for a 4393 calendar component. 4394 4395 Value Type: TEXT 4396 4397 Property Parameters: Non-standard property parameters can be 4398 specified on this property. 4399 4400 Conformance: The property can be specified once in a "VEVENT", 4401 "VTODO" or "VJOURNAL" calendar components. 4402 4403 Description: An access classification is only one component of the 4404 general security system within a calendar application. It provides a 4405 method of capturing the scope of the access the calendar owner 4406 intends for information within an individual calendar entry. The 4407 access classification of an individual iCalendar component is useful 4408 when measured along with the other security components of a calendar 4409 system (e.g., calendar user authentication, authorization, access 4410 rights, access role, etc.). Hence, the semantics of the individual 4411 access classifications cannot be completely defined by this memo 4412 alone. Additionally, due to the "blind" nature of most exchange 4413 processes using this memo, these access classifications cannot serve 4414 as an enforcement statement for a system receiving an iCalendar 4415 object. Rather, they provide a method for capturing the intention of 4416 the calendar owner for the access to the calendar component. 4417 4418 Format Definition: The property is defined by the following notation: 4419 4420 class = "CLASS" classparam ":" classvalue CRLF 4421 4422 classparam = *(";" xparam) 4423 4424 4425 4426 Dawson & Stenerson Standards Track [Page 79] 4427 4428 RFC 2445 iCalendar November 1998 4429 4430 4431 classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token 4432 / x-name 4433 ;Default is PUBLIC 4434 4435 Example: The following is an example of this property: 4436 4437 CLASS:PUBLIC 4438 4439 4.8.1.4 Comment 4440 4441 Property Name: COMMENT 4442 4443 Purpose: This property specifies non-processing information intended 4444 to provide a comment to the calendar user. 4445 4446 Value Type: TEXT 4447 4448 Property Parameters: Non-standard, alternate text representation and 4449 language property parameters can be specified on this property. 4450 4451 Conformance: This property can be specified in "VEVENT", "VTODO", 4452 "VJOURNAL", "VTIMEZONE" or "VFREEBUSY" calendar components. 4453 4454 Description: The property can be specified multiple times. 4455 4456 Format Definition: The property is defined by the following notation: 4457 4458 comment = "COMMENT" commparam ":" text CRLF 4459 4460 commparam = *( 4461 4462 ; the following are optional, 4463 ; but MUST NOT occur more than once 4464 4465 (";" altrepparam) / (";" languageparam) / 4466 4467 ; the following is optional, 4468 ; and MAY occur more than once 4469 4470 (";" xparam) 4471 4472 ) 4473 4474 Example: The following is an example of this property: 4475 4476 COMMENT:The meeting really needs to include both ourselves 4477 and the customer. We can't hold this meeting without them. 4478 As a matter of fact\, the venue for the meeting ought to be at 4479 4480 4481 4482 Dawson & Stenerson Standards Track [Page 80] 4483 4484 RFC 2445 iCalendar November 1998 4485 4486 4487 their site. - - John 4488 4489 The data type for this property is TEXT. 4490 4491 4.8.1.5 Description 4492 4493 Property Name: DESCRIPTION 4494 4495 Purpose: This property provides a more complete description of the 4496 calendar component, than that provided by the "SUMMARY" property. 4497 4498 Value Type: TEXT 4499 4500 Property Parameters: Non-standard, alternate text representation and 4501 language property parameters can be specified on this property. 4502 4503 Conformance: The property can be specified in the "VEVENT", "VTODO", 4504 "VJOURNAL" or "VALARM" calendar components. The property can be 4505 specified multiple times only within a "VJOURNAL" calendar component. 4506 4507 Description: This property is used in the "VEVENT" and "VTODO" to 4508 capture lengthy textual decriptions associated with the activity. 4509 4510 This property is used in the "VJOURNAL" calendar component to capture 4511 one more textual journal entries. 4512 4513 This property is used in the "VALARM" calendar component to capture 4514 the display text for a DISPLAY category of alarm, to capture the body 4515 text for an EMAIL category of alarm and to capture the argument 4516 string for a PROCEDURE category of alarm. 4517 4518 Format Definition: The property is defined by the following notation: 4519 4520 description = "DESCRIPTION" descparam ":" text CRLF 4521 4522 descparam = *( 4523 4524 ; the following are optional, 4525 ; but MUST NOT occur more than once 4526 4527 (";" altrepparam) / (";" languageparam) / 4528 4529 ; the following is optional, 4530 ; and MAY occur more than once 4531 4532 (";" xparam) 4533 4534 ) 4535 4536 4537 4538 Dawson & Stenerson Standards Track [Page 81] 4539 4540 RFC 2445 iCalendar November 1998 4541 4542 4543 Example: The following is an example of the property with formatted 4544 line breaks in the property value: 4545 4546 DESCRIPTION:Meeting to provide technical review for "Phoenix" 4547 design.\n Happy Face Conference Room. Phoenix design team 4548 MUST attend this meeting.\n RSVP to team leader. 4549 4550 The following is an example of the property with folding of long 4551 lines: 4552 4553 DESCRIPTION:Last draft of the new novel is to be completed 4554 for the editor's proof today. 4555 4556 4.8.1.6 Geographic Position 4557 4558 Property Name: GEO 4559 4560 Purpose: This property specifies information related to the global 4561 position for the activity specified by a calendar component. 4562 4563 Value Type: FLOAT. The value MUST be two SEMICOLON separated FLOAT 4564 values. 4565 4566 Property Parameters: Non-standard property parameters can be 4567 specified on this property. 4568 4569 Conformance: This property can be specified in "VEVENT" or "VTODO" 4570 calendar components. 4571 4572 Description: The property value specifies latitude and longitude, in 4573 that order (i.e., "LAT LON" ordering). The longitude represents the 4574 location east or west of the prime meridian as a positive or negative 4575 real number, respectively. The longitude and latitude values MAY be 4576 specified up to six decimal places, which will allow for accuracy to 4577 within one meter of geographical position. Receiving applications 4578 MUST accept values of this precision and MAY truncate values of 4579 greater precision. 4580 4581 Values for latitude and longitude shall be expressed as decimal 4582 fractions of degrees. Whole degrees of latitude shall be represented 4583 by a two-digit decimal number ranging from 0 through 90. Whole 4584 degrees of longitude shall be represented by a decimal number ranging 4585 from 0 through 180. When a decimal fraction of a degree is specified, 4586 it shall be separated from the whole number of degrees by a decimal 4587 point. 4588 4589 4590 4591 4592 4593 4594 Dawson & Stenerson Standards Track [Page 82] 4595 4596 RFC 2445 iCalendar November 1998 4597 4598 4599 Latitudes north of the equator shall be specified by a plus sign (+), 4600 or by the absence of a minus sign (-), preceding the digits 4601 designating degrees. Latitudes south of the Equator shall be 4602 designated by a minus sign (-) preceding the digits designating 4603 degrees. A point on the Equator shall be assigned to the Northern 4604 Hemisphere. 4605 4606 Longitudes east of the prime meridian shall be specified by a plus 4607 sign (+), or by the absence of a minus sign (-), preceding the digits 4608 designating degrees. Longitudes west of the meridian shall be 4609 designated by minus sign (-) preceding the digits designating 4610 degrees. A point on the prime meridian shall be assigned to the 4611 Eastern Hemisphere. A point on the 180th meridian shall be assigned 4612 to the Western Hemisphere. One exception to this last convention is 4613 permitted. For the special condition of describing a band of latitude 4614 around the earth, the East Bounding Coordinate data element shall be 4615 assigned the value +180 (180) degrees. 4616 4617 Any spatial address with a latitude of +90 (90) or -90 degrees will 4618 specify the position at the North or South Pole, respectively. The 4619 component for longitude may have any legal value. 4620 4621 With the exception of the special condition described above, this 4622 form is specified in Department of Commerce, 1986, Representation of 4623 geographic point locations for information interchange (Federal 4624 Information Processing Standard 70-1): Washington, Department of 4625 Commerce, National Institute of Standards and Technology. 4626 4627 The simple formula for converting degrees-minutes-seconds into 4628 decimal degrees is: 4629 4630 decimal = degrees + minutes/60 + seconds/3600. 4631 4632 Format Definition: The property is defined by the following notation: 4633 4634 geo = "GEO" geoparam ":" geovalue CRLF 4635 4636 geoparam = *(";" xparam) 4637 4638 geovalue = float ";" float 4639 ;Latitude and Longitude components 4640 4641 Example: The following is an example of this property: 4642 4643 GEO:37.386013;-122.082932 4644 4645 4646 4647 4648 4649 4650 Dawson & Stenerson Standards Track [Page 83] 4651 4652 RFC 2445 iCalendar November 1998 4653 4654 4655 4.8.1.7 Location 4656 4657 Property Name: LOCATION 4658 4659 Purpose: The property defines the intended venue for the activity 4660 defined by a calendar component. 4661 4662 Value Type: TEXT 4663 4664 Property Parameters: Non-standard, alternate text representation and 4665 language property parameters can be specified on this property. 4666 4667 Conformance: This property can be specified in "VEVENT" or "VTODO" 4668 calendar component. 4669 4670 Description: Specific venues such as conference or meeting rooms may 4671 be explicitly specified using this property. An alternate 4672 representation may be specified that is a URI that points to 4673 directory information with more structured specification of the 4674 location. For example, the alternate representation may specify 4675 either an LDAP URI pointing to an LDAP server entry or a CID URI 4676 pointing to a MIME body part containing a vCard [RFC 2426] for the 4677 location. 4678 4679 Format Definition: The property is defined by the following notation: 4680 4681 location = "LOCATION locparam ":" text CRLF 4682 4683 locparam = *( 4684 4685 ; the following are optional, 4686 ; but MUST NOT occur more than once 4687 4688 (";" altrepparam) / (";" languageparam) / 4689 4690 ; the following is optional, 4691 ; and MAY occur more than once 4692 4693 (";" xparam) 4694 4695 ) 4696 4697 Example: The following are some examples of this property: 4698 4699 LOCATION:Conference Room - F123, Bldg. 002 4700 4701 LOCATION;ALTREP="http://xyzcorp.com/conf-rooms/f123.vcf": 4702 Conference Room - F123, Bldg. 002 4703 4704 4705 4706 Dawson & Stenerson Standards Track [Page 84] 4707 4708 RFC 2445 iCalendar November 1998 4709 4710 4711 4.8.1.8 Percent Complete 4712 4713 Property Name: PERCENT-COMPLETE 4714 4715 Purpose: This property is used by an assignee or delegatee of a to-do 4716 to convey the percent completion of a to-do to the Organizer. 4717 4718 Value Type: INTEGER 4719 4720 Property Parameters: Non-standard property parameters can be 4721 specified on this property. 4722 4723 Conformance: This property can be specified in a "VTODO" calendar 4724 component. 4725 4726 Description: The property value is a positive integer between zero 4727 and one hundred. A value of "0" indicates the to-do has not yet been 4728 started. A value of "100" indicates that the to-do has been 4729 completed. Integer values in between indicate the percent partially 4730 complete. 4731 4732 When a to-do is assigned to multiple individuals, the property value 4733 indicates the percent complete for that portion of the to-do assigned 4734 to the assignee or delegatee. For example, if a to-do is assigned to 4735 both individuals "A" and "B". A reply from "A" with a percent 4736 complete of "70" indicates that "A" has completed 70% of the to-do 4737 assigned to them. A reply from "B" with a percent complete of "50" 4738 indicates "B" has completed 50% of the to-do assigned to them. 4739 4740 Format Definition: The property is defined by the following notation: 4741 4742 percent = "PERCENT-COMPLETE" pctparam ":" integer CRLF 4743 4744 pctparam = *(";" xparam) 4745 4746 Example: The following is an example of this property to show 39% 4747 completion: 4748 4749 PERCENT-COMPLETE:39 4750 4751 4.8.1.9 Priority 4752 4753 Property Name: PRIORITY 4754 4755 Purpose: The property defines the relative priority for a calendar 4756 component. 4757 4758 Value Type: INTEGER 4759 4760 4761 4762 Dawson & Stenerson Standards Track [Page 85] 4763 4764 RFC 2445 iCalendar November 1998 4765 4766 4767 Property Parameters: Non-standard property parameters can be 4768 specified on this property. 4769 4770 Conformance: The property can be specified in a "VEVENT" or "VTODO" 4771 calendar component. 4772 4773 Description: The priority is specified as an integer in the range 4774 zero to nine. A value of zero (US-ASCII decimal 48) specifies an 4775 undefined priority. A value of one (US-ASCII decimal 49) is the 4776 highest priority. A value of two (US-ASCII decimal 50) is the second 4777 highest priority. Subsequent numbers specify a decreasing ordinal 4778 priority. A value of nine (US-ASCII decimal 58) is the lowest 4779 priority. 4780 4781 A CUA with a three-level priority scheme of "HIGH", "MEDIUM" and 4782 "LOW" is mapped into this property such that a property value in the 4783 range of one (US-ASCII decimal 49) to four (US-ASCII decimal 52) 4784 specifies "HIGH" priority. A value of five (US-ASCII decimal 53) is 4785 the normal or "MEDIUM" priority. A value in the range of six (US- 4786 ASCII decimal 54) to nine (US-ASCII decimal 58) is "LOW" priority. 4787 4788 A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ..., 4789 "C3" is mapped into this property such that a property value of one 4790 (US-ASCII decimal 49) specifies "A1", a property value of two (US- 4791 ASCII decimal 50) specifies "A2", a property value of three (US-ASCII 4792 decimal 51) specifies "A3", and so forth up to a property value of 9 4793 (US-ASCII decimal 58) specifies "C3". 4794 4795 Other integer values are reserved for future use. 4796 4797 Within a "VEVENT" calendar component, this property specifies a 4798 priority for the event. This property may be useful when more than 4799 one event is scheduled for a given time period. 4800 4801 Within a "VTODO" calendar component, this property specified a 4802 priority for the to-do. This property is useful in prioritizing 4803 multiple action items for a given time period. 4804 4805 Format Definition: The property is specified by the following 4806 notation: 4807 4808 priority = "PRIORITY" prioparam ":" privalue CRLF 4809 ;Default is zero 4810 4811 prioparam = *(";" xparam) 4812 4813 privalue = integer ;Must be in the range [0..9] 4814 ; All other values are reserved for future use 4815 4816 4817 4818 Dawson & Stenerson Standards Track [Page 86] 4819 4820 RFC 2445 iCalendar November 1998 4821 4822 4823 The following is an example of a property with the highest priority: 4824 4825 PRIORITY:1 4826 4827 The following is an example of a property with a next highest 4828 priority: 4829 4830 PRIORITY:2 4831 4832 Example: The following is an example of a property with no priority. 4833 This is equivalent to not specifying the "PRIORITY" property: 4834 4835 PRIORITY:0 4836 4837 4.8.1.10 Resources 4838 4839 Property Name: RESOURCES 4840 4841 Purpose: This property defines the equipment or resources anticipated 4842 for an activity specified by a calendar entity.. 4843 4844 Value Type: TEXT 4845 4846 Property Parameters: Non-standard, alternate text representation and 4847 language property parameters can be specified on this property. 4848 4849 Conformance: This property can be specified in "VEVENT" or "VTODO" 4850 calendar component. 4851 4852 Description: The property value is an arbitrary text. More than one 4853 resource can be specified as a list of resources separated by the 4854 COMMA character (US-ASCII decimal 44). 4855 4856 Format Definition: The property is defined by the following notation: 4857 4858 resources = "RESOURCES" resrcparam ":" text *("," text) CRLF 4859 4860 resrcparam = *( 4861 4862 ; the following are optional, 4863 ; but MUST NOT occur more than once 4864 4865 (";" altrepparam) / (";" languageparam) / 4866 4867 ; the following is optional, 4868 ; and MAY occur more than once 4869 4870 4871 4872 4873 4874 Dawson & Stenerson Standards Track [Page 87] 4875 4876 RFC 2445 iCalendar November 1998 4877 4878 4879 (";" xparam) 4880 4881 ) 4882 4883 Example: The following is an example of this property: 4884 4885 RESOURCES:EASEL,PROJECTOR,VCR 4886 4887 RESOURCES;LANGUAGE=fr:1 raton-laveur 4888 4889 4.8.1.11 Status 4890 4891 Property Name: STATUS 4892 4893 Purpose: This property defines the overall status or confirmation for 4894 the calendar component. 4895 4896 Value Type: TEXT 4897 4898 Property Parameters: Non-standard property parameters can be 4899 specified on this property. 4900 4901 Conformance: This property can be specified in "VEVENT", "VTODO" or 4902 "VJOURNAL" calendar components. 4903 4904 Description: In a group scheduled calendar component, the property is 4905 used by the "Organizer" to provide a confirmation of the event to the 4906 "Attendees". For example in a "VEVENT" calendar component, the 4907 "Organizer" can indicate that a meeting is tentative, confirmed or 4908 cancelled. In a "VTODO" calendar component, the "Organizer" can 4909 indicate that an action item needs action, is completed, is in 4910 process or being worked on, or has been cancelled. In a "VJOURNAL" 4911 calendar component, the "Organizer" can indicate that a journal entry 4912 is draft, final or has been cancelled or removed. 4913 4914 Format Definition: The property is defined by the following notation: 4915 4916 status = "STATUS" statparam] ":" statvalue CRLF 4917 4918 statparam = *(";" xparam) 4919 4920 statvalue = "TENTATIVE" ;Indicates event is 4921 ;tentative. 4922 / "CONFIRMED" ;Indicates event is 4923 ;definite. 4924 / "CANCELLED" ;Indicates event was 4925 ;cancelled. 4926 ;Status values for a "VEVENT" 4927 4928 4929 4930 Dawson & Stenerson Standards Track [Page 88] 4931 4932 RFC 2445 iCalendar November 1998 4933 4934 4935 statvalue =/ "NEEDS-ACTION" ;Indicates to-do needs action. 4936 / "COMPLETED" ;Indicates to-do completed. 4937 / "IN-PROCESS" ;Indicates to-do in process of 4938 / "CANCELLED" ;Indicates to-do was cancelled. 4939 ;Status values for "VTODO". 4940 4941 statvalue =/ "DRAFT" ;Indicates journal is draft. 4942 / "FINAL" ;Indicates journal is final. 4943 / "CANCELLED" ;Indicates journal is removed. 4944 ;Status values for "VJOURNAL". 4945 4946 Example: The following is an example of this property for a "VEVENT" 4947 calendar component: 4948 4949 STATUS:TENTATIVE 4950 4951 The following is an example of this property for a "VTODO" calendar 4952 component: 4953 4954 STATUS:NEEDS-ACTION 4955 4956 The following is an example of this property for a "VJOURNAL" 4957 calendar component: 4958 4959 STATUS:DRAFT 4960 4961 4.8.1.12 Summary 4962 4963 Property Name: SUMMARY 4964 4965 Purpose: This property defines a short summary or subject for the 4966 calendar component. 4967 4968 Value Type: TEXT 4969 4970 Property Parameters: Non-standard, alternate text representation and 4971 language property parameters can be specified on this property. 4972 4973 Conformance: The property can be specified in "VEVENT", "VTODO", 4974 "VJOURNAL" or "VALARM" calendar components. 4975 4976 Description: This property is used in the "VEVENT", "VTODO" and 4977 "VJOURNAL" calendar components to capture a short, one line summary 4978 about the activity or journal entry. 4979 4980 This property is used in the "VALARM" calendar component to capture 4981 the subject of an EMAIL category of alarm. 4982 4983 4984 4985 4986 Dawson & Stenerson Standards Track [Page 89] 4987 4988 RFC 2445 iCalendar November 1998 4989 4990 4991 Format Definition: The property is defined by the following notation: 4992 4993 summary = "SUMMARY" summparam ":" text CRLF 4994 4995 summparam = *( 4996 4997 ; the following are optional, 4998 ; but MUST NOT occur more than once 4999 5000 (";" altrepparam) / (";" languageparam) / 5001 5002 ; the following is optional, 5003 ; and MAY occur more than once 5004 5005 (";" xparam) 5006 5007 ) 5008 5009 Example: The following is an example of this property: 5010 5011 SUMMARY:Department Party 5012 5013 4.8.2 Date and Time Component Properties 5014 5015 The following properties specify date and time related information in 5016 calendar components. 5017 5018 4.8.2.1 Date/Time Completed 5019 5020 Property Name: COMPLETED 5021 5022 Purpose: This property defines the date and time that a to-do was 5023 actually completed. 5024 5025 Value Type: DATE-TIME 5026 5027 Property Parameters: Non-standard property parameters can be 5028 specified on this property. 5029 5030 Conformance: The property can be specified in a "VTODO" calendar 5031 component. 5032 5033 Description: The date and time MUST be in a UTC format. 5034 5035 Format Definition: The property is defined by the following notation: 5036 5037 completed = "COMPLETED" compparam ":" date-time CRLF 5038 5039 5040 5041 5042 Dawson & Stenerson Standards Track [Page 90] 5043 5044 RFC 2445 iCalendar November 1998 5045 5046 5047 compparam = *(";" xparam) 5048 5049 Example: The following is an example of this property: 5050 5051 COMPLETED:19960401T235959Z 5052 5053 4.8.2.2 Date/Time End 5054 5055 Property Name: DTEND 5056 5057 Purpose: This property specifies the date and time that a calendar 5058 component ends. 5059 5060 Value Type: The default value type is DATE-TIME. The value type can 5061 be set to a DATE value type. 5062 5063 Property Parameters: Non-standard, value data type, time zone 5064 identifier property parameters can be specified on this property. 5065 5066 Conformance: This property can be specified in "VEVENT" or 5067 "VFREEBUSY" calendar components. 5068 5069 Description: Within the "VEVENT" calendar component, this property 5070 defines the date and time by which the event ends. The value MUST be 5071 later in time than the value of the "DTSTART" property. 5072 5073 Within the "VFREEBUSY" calendar component, this property defines the 5074 end date and time for the free or busy time information. The time 5075 MUST be specified in the UTC time format. The value MUST be later in 5076 time than the value of the "DTSTART" property. 5077 5078 Format Definition: The property is defined by the following notation: 5079 5080 dtend = "DTEND" dtendparam":" dtendval CRLF 5081 5082 dtendparam = *( 5083 5084 ; the following are optional, 5085 ; but MUST NOT occur more than once 5086 5087 (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / 5088 (";" tzidparam) / 5089 5090 ; the following is optional, 5091 ; and MAY occur more than once 5092 5093 5094 5095 5096 5097 5098 Dawson & Stenerson Standards Track [Page 91] 5099 5100 RFC 2445 iCalendar November 1998 5101 5102 5103 (";" xparam) 5104 5105 ) 5106 5107 5108 5109 dtendval = date-time / date 5110 ;Value MUST match value type 5111 5112 Example: The following is an example of this property: 5113 5114 DTEND:19960401T235959Z 5115 5116 DTEND;VALUE=DATE:19980704 5117 5118 4.8.2.3 Date/Time Due 5119 5120 Property Name: DUE 5121 5122 Purpose: This property defines the date and time that a to-do is 5123 expected to be completed. 5124 5125 Value Type: The default value type is DATE-TIME. The value type can 5126 be set to a DATE value type. 5127 5128 Property Parameters: Non-standard, value data type, time zone 5129 identifier property parameters can be specified on this property. 5130 5131 Conformance: The property can be specified once in a "VTODO" calendar 5132 component. 5133 5134 Description: The value MUST be a date/time equal to or after the 5135 DTSTART value, if specified. 5136 5137 Format Definition: The property is defined by the following notation: 5138 5139 due = "DUE" dueparam":" dueval CRLF 5140 5141 dueparam = *( 5142 ; the following are optional, 5143 ; but MUST NOT occur more than once 5144 5145 (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / 5146 (";" tzidparam) / 5147 5148 ; the following is optional, 5149 ; and MAY occur more than once 5150 5151 5152 5153 5154 Dawson & Stenerson Standards Track [Page 92] 5155 5156 RFC 2445 iCalendar November 1998 5157 5158 5159 *(";" xparam) 5160 5161 ) 5162 5163 5164 5165 dueval = date-time / date 5166 ;Value MUST match value type 5167 5168 Example: The following is an example of this property: 5169 5170 DUE:19980430T235959Z 5171 5172 4.8.2.4 Date/Time Start 5173 5174 Property Name: DTSTART 5175 5176 Purpose: This property specifies when the calendar component begins. 5177 5178 Value Type: The default value type is DATE-TIME. The time value MUST 5179 be one of the forms defined for the DATE-TIME value type. The value 5180 type can be set to a DATE value type. 5181 5182 Property Parameters: Non-standard, value data type, time zone 5183 identifier property parameters can be specified on this property. 5184 5185 Conformance: This property can be specified in the "VEVENT", "VTODO", 5186 "VFREEBUSY", or "VTIMEZONE" calendar components. 5187 5188 Description: Within the "VEVENT" calendar component, this property 5189 defines the start date and time for the event. The property is 5190 REQUIRED in "VEVENT" calendar components. Events can have a start 5191 date/time but no end date/time. In that case, the event does not take 5192 up any time. 5193 5194 Within the "VFREEBUSY" calendar component, this property defines the 5195 start date and time for the free or busy time information. The time 5196 MUST be specified in UTC time. 5197 5198 Within the "VTIMEZONE" calendar component, this property defines the 5199 effective start date and time for a time zone specification. This 5200 property is REQUIRED within each STANDARD and DAYLIGHT part included 5201 in "VTIMEZONE" calendar components and MUST be specified as a local 5202 DATE-TIME without the "TZID" property parameter. 5203 5204 Format Definition: The property is defined by the following notation: 5205 5206 dtstart = "DTSTART" dtstparam ":" dtstval CRLF 5207 5208 5209 5210 Dawson & Stenerson Standards Track [Page 93] 5211 5212 RFC 2445 iCalendar November 1998 5213 5214 5215 dtstparam = *( 5216 5217 ; the following are optional, 5218 ; but MUST NOT occur more than once 5219 5220 (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / 5221 (";" tzidparam) / 5222 5223 ; the following is optional, 5224 ; and MAY occur more than once 5225 5226 *(";" xparam) 5227 5228 ) 5229 5230 5231 5232 dtstval = date-time / date 5233 ;Value MUST match value type 5234 5235 Example: The following is an example of this property: 5236 5237 DTSTART:19980118T073000Z 5238 5239 4.8.2.5 Duration 5240 5241 Property Name: DURATION 5242 5243 Purpose: The property specifies a positive duration of time. 5244 5245 Value Type: DURATION 5246 5247 Property Parameters: Non-standard property parameters can be 5248 specified on this property. 5249 5250 Conformance: The property can be specified in "VEVENT", "VTODO", 5251 "VFREEBUSY" or "VALARM" calendar components. 5252 5253 Description: In a "VEVENT" calendar component the property may be 5254 used to specify a duration of the event, instead of an explicit end 5255 date/time. In a "VTODO" calendar component the property may be used 5256 to specify a duration for the to-do, instead of an explicit due 5257 date/time. In a "VFREEBUSY" calendar component the property may be 5258 used to specify the interval of free time being requested. In a 5259 "VALARM" calendar component the property may be used to specify the 5260 delay period prior to repeating an alarm. 5261 5262 Format Definition: The property is defined by the following notation: 5263 5264 5265 5266 Dawson & Stenerson Standards Track [Page 94] 5267 5268 RFC 2445 iCalendar November 1998 5269 5270 5271 duration = "DURATION" durparam ":" dur-value CRLF 5272 ;consisting of a positive duration of time. 5273 5274 durparam = *(";" xparam) 5275 5276 Example: The following is an example of this property that specifies 5277 an interval of time of 1 hour and zero minutes and zero seconds: 5278 5279 DURATION:PT1H0M0S 5280 5281 The following is an example of this property that specifies an 5282 interval of time of 15 minutes. 5283 5284 DURATION:PT15M 5285 5286 4.8.2.6 Free/Busy Time 5287 5288 Property Name: FREEBUSY 5289 5290 Purpose: The property defines one or more free or busy time 5291 intervals. 5292 5293 Value Type: PERIOD. The date and time values MUST be in an UTC time 5294 format. 5295 5296 Property Parameters: Non-standard or free/busy time type property 5297 parameters can be specified on this property. 5298 5299 Conformance: The property can be specified in a "VFREEBUSY" calendar 5300 component. 5301 5302 Property Parameter: "FBTYPE" and non-standard parameters can be 5303 specified on this property. 5304 5305 Description: These time periods can be specified as either a start 5306 and end date-time or a start date-time and duration. The date and 5307 time MUST be a UTC time format. 5308 5309 "FREEBUSY" properties within the "VFREEBUSY" calendar component 5310 SHOULD be sorted in ascending order, based on start time and then end 5311 time, with the earliest periods first. 5312 5313 The "FREEBUSY" property can specify more than one value, separated by 5314 the COMMA character (US-ASCII decimal 44). In such cases, the 5315 "FREEBUSY" property values SHOULD all be of the same "FBTYPE" 5316 property parameter type (e.g., all values of a particular "FBTYPE" 5317 listed together in a single property). 5318 5319 5320 5321 5322 Dawson & Stenerson Standards Track [Page 95] 5323 5324 RFC 2445 iCalendar November 1998 5325 5326 5327 Format Definition: The property is defined by the following notation: 5328 5329 freebusy = "FREEBUSY" fbparam ":" fbvalue 5330 CRLF 5331 5332 fbparam = *( 5333 ; the following is optional, 5334 ; but MUST NOT occur more than once 5335 5336 (";" fbtypeparam) / 5337 5338 ; the following is optional, 5339 ; and MAY occur more than once 5340 5341 (";" xparam) 5342 5343 ) 5344 5345 fbvalue = period *["," period] 5346 ;Time value MUST be in the UTC time format. 5347 5348 Example: The following are some examples of this property: 5349 5350 FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:19970308T160000Z/PT8H30M 5351 5352 FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H 5353 5354 FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H, 5355 19970308T230000Z/19970309T000000Z 5356 5357 4.8.2.7 Time Transparency 5358 5359 Property Name: TRANSP 5360 5361 Purpose: This property defines whether an event is transparent or not 5362 to busy time searches. 5363 5364 Value Type: TEXT 5365 5366 Property Parameters: Non-standard property parameters can be 5367 specified on this property. 5368 5369 Conformance: This property can be specified once in a "VEVENT" 5370 calendar component. 5371 5372 Description: Time Transparency is the characteristic of an event that 5373 determines whether it appears to consume time on a calendar. Events 5374 that consume actual time for the individual or resource associated 5375 5376 5377 5378 Dawson & Stenerson Standards Track [Page 96] 5379 5380 RFC 2445 iCalendar November 1998 5381 5382 5383 with the calendar SHOULD be recorded as OPAQUE, allowing them to be 5384 detected by free-busy time searches. Other events, which do not take 5385 up the individual's (or resource's) time SHOULD be recorded as 5386 TRANSPARENT, making them invisible to free-busy time searches. 5387 5388 Format Definition: The property is specified by the following 5389 notation: 5390 5391 transp = "TRANSP" tranparam ":" transvalue CRLF 5392 5393 tranparam = *(";" xparam) 5394 5395 transvalue = "OPAQUE" ;Blocks or opaque on busy time searches. 5396 / "TRANSPARENT" ;Transparent on busy time searches. 5397 ;Default value is OPAQUE 5398 5399 Example: The following is an example of this property for an event 5400 that is transparent or does not block on free/busy time searches: 5401 5402 TRANSP:TRANSPARENT 5403 5404 The following is an example of this property for an event that is 5405 opaque or blocks on free/busy time searches: 5406 5407 TRANSP:OPAQUE 5408 5409 4.8.3 Time Zone Component Properties 5410 5411 The following properties specify time zone information in calendar 5412 components. 5413 5414 4.8.3.1 Time Zone Identifier 5415 5416 Property Name: TZID 5417 5418 Purpose: This property specifies the text value that uniquely 5419 identifies the "VTIMEZONE" calendar component. 5420 5421 Value Type: TEXT 5422 5423 Property Parameters: Non-standard property parameters can be 5424 specified on this property. 5425 5426 Conformance: This property MUST be specified in a "VTIMEZONE" 5427 calendar component. 5428 5429 5430 5431 5432 5433 5434 Dawson & Stenerson Standards Track [Page 97] 5435 5436 RFC 2445 iCalendar November 1998 5437 5438 5439 Description: This is the label by which a time zone calendar 5440 component is referenced by any iCalendar properties whose data type 5441 is either DATE-TIME or TIME and not intended to specify a UTC or a 5442 "floating" time. The presence of the SOLIDUS character (US-ASCII 5443 decimal 47) as a prefix, indicates that this TZID represents an 5444 unique ID in a globally defined time zone registry (when such 5445 registry is defined). 5446 5447 Note: This document does not define a naming convention for time 5448 zone identifiers. Implementers may want to use the naming 5449 conventions defined in existing time zone specifications such as 5450 the public-domain Olson database [TZ]. The specification of 5451 globally unique time zone identifiers is not addressed by this 5452 document and is left for future study. 5453 5454 Format Definition: This property is defined by the following 5455 notation: 5456 5457 tzid = "TZID" tzidpropparam ":" [tzidprefix] text CRLF 5458 5459 tzidpropparam = *(";" xparam) 5460 5461 ;tzidprefix = "/" 5462 ; Defined previously. Just listed here for reader convenience. 5463 5464 Example: The following are examples of non-globally unique time zone 5465 identifiers: 5466 5467 TZID:US-Eastern 5468 5469 TZID:California-Los_Angeles 5470 5471 The following is an example of a fictitious globally unique time zone 5472 identifier: 5473 5474 TZID:/US-New_York-New_York 5475 5476 4.8.3.2 Time Zone Name 5477 5478 Property Name: TZNAME 5479 5480 Purpose: This property specifies the customary designation for a time 5481 zone description. 5482 5483 Value Type: TEXT 5484 5485 Property Parameters: Non-standard and language property parameters 5486 can be specified on this property. 5487 5488 5489 5490 Dawson & Stenerson Standards Track [Page 98] 5491 5492 RFC 2445 iCalendar November 1998 5493 5494 5495 Conformance: This property can be specified in a "VTIMEZONE" calendar 5496 component. 5497 5498 Description: This property may be specified in multiple languages; in 5499 order to provide for different language requirements. 5500 5501 Format Definition: This property is defined by the following 5502 notation: 5503 5504 tzname = "TZNAME" tznparam ":" text CRLF 5505 5506 tznparam = *( 5507 5508 ; the following is optional, 5509 ; but MUST NOT occur more than once 5510 5511 (";" languageparam) / 5512 5513 ; the following is optional, 5514 ; and MAY occur more than once 5515 5516 (";" xparam) 5517 5518 ) 5519 5520 Example: The following are example of this property: 5521 5522 TZNAME:EST 5523 5524 The following is an example of this property when two different 5525 languages for the time zone name are specified: 5526 5527 TZNAME;LANGUAGE=en:EST 5528 TZNAME;LANGUAGE=fr-CA:HNE 5529 5530 4.8.3.3 Time Zone Offset From 5531 5532 Property Name: TZOFFSETFROM 5533 5534 Purpose: This property specifies the offset which is in use prior to 5535 this time zone observance. 5536 5537 Value Type: UTC-OFFSET 5538 5539 Property Parameters: Non-standard property parameters can be 5540 specified on this property. 5541 5542 5543 5544 5545 5546 Dawson & Stenerson Standards Track [Page 99] 5547 5548 RFC 2445 iCalendar November 1998 5549 5550 5551 Conformance: This property MUST be specified in a "VTIMEZONE" 5552 calendar component. 5553 5554 Description: This property specifies the offset which is in use prior 5555 to this time observance. It is used to calculate the absolute time at 5556 which the transition to a given observance takes place. This property 5557 MUST only be specified in a "VTIMEZONE" calendar component. A 5558 "VTIMEZONE" calendar component MUST include this property. The 5559 property value is a signed numeric indicating the number of hours and 5560 possibly minutes from UTC. Positive numbers represent time zones east 5561 of the prime meridian, or ahead of UTC. Negative numbers represent 5562 time zones west of the prime meridian, or behind UTC. 5563 5564 Format Definition: The property is defined by the following notation: 5565 5566 tzoffsetfrom = "TZOFFSETFROM" frmparam ":" utc-offset 5567 CRLF 5568 5569 frmparam = *(";" xparam) 5570 5571 Example: The following are examples of this property: 5572 5573 TZOFFSETFROM:-0500 5574 5575 TZOFFSETFROM:+1345 5576 5577 4.8.3.4 Time Zone Offset To 5578 5579 Property Name: TZOFFSETTO 5580 5581 Purpose: This property specifies the offset which is in use in this 5582 time zone observance. 5583 5584 Value Type: UTC-OFFSET 5585 5586 Property Parameters: Non-standard property parameters can be 5587 specified on this property. 5588 5589 Conformance: This property MUST be specified in a "VTIMEZONE" 5590 calendar component. 5591 5592 Description: This property specifies the offset which is in use in 5593 this time zone observance. It is used to calculate the absolute time 5594 for the new observance. The property value is a signed numeric 5595 indicating the number of hours and possibly minutes from UTC. 5596 Positive numbers represent time zones east of the prime meridian, or 5597 ahead of UTC. Negative numbers represent time zones west of the prime 5598 meridian, or behind UTC. 5599 5600 5601 5602 Dawson & Stenerson Standards Track [Page 100] 5603 5604 RFC 2445 iCalendar November 1998 5605 5606 5607 Format Definition: The property is defined by the following notation: 5608 5609 tzoffsetto = "TZOFFSETTO" toparam ":" utc-offset CRLF 5610 5611 toparam = *(";" xparam) 5612 5613 Example: The following are examples of this property: 5614 5615 TZOFFSETTO:-0400 5616 5617 TZOFFSETTO:+1245 5618 5619 4.8.3.5 Time Zone URL 5620 5621 Property Name: TZURL 5622 5623 Purpose: The TZURL provides a means for a VTIMEZONE component to 5624 point to a network location that can be used to retrieve an up-to- 5625 date version of itself. 5626 5627 Value Type: URI 5628 5629 Property Parameters: Non-standard property parameters can be 5630 specified on this property. 5631 5632 Conformance: This property can be specified in a "VTIMEZONE" calendar 5633 component. 5634 5635 Description: The TZURL provides a means for a VTIMEZONE component to 5636 point to a network location that can be used to retrieve an up-to- 5637 date version of itself. This provides a hook to handle changes 5638 government bodies impose upon time zone definitions. Retrieval of 5639 this resource results in an iCalendar object containing a single 5640 VTIMEZONE component and a METHOD property set to PUBLISH. 5641 5642 Format Definition: The property is defined by the following notation: 5643 5644 tzurl = "TZURL" tzurlparam ":" uri CRLF 5645 5646 tzurlparam = *(";" xparam) 5647 5648 Example: The following is an example of this property: 5649 5650 TZURL:http://timezones.r.us.net/tz/US-California-Los_Angeles 5651 5652 5653 5654 5655 5656 5657 5658 Dawson & Stenerson Standards Track [Page 101] 5659 5660 RFC 2445 iCalendar November 1998 5661 5662 5663 4.8.4 Relationship Component Properties 5664 5665 The following properties specify relationship information in calendar 5666 components. 5667 5668 4.8.4.1 Attendee 5669 5670 Property Name: ATTENDEE 5671 5672 Purpose: The property defines an "Attendee" within a calendar 5673 component. 5674 5675 Value Type: CAL-ADDRESS 5676 5677 Property Parameters: Non-standard, language, calendar user type, 5678 group or list membership, participation role, participation status, 5679 RSVP expectation, delegatee, delegator, sent by, common name or 5680 directory entry reference property parameters can be specified on 5681 this property. 5682 5683 Conformance: This property MUST be specified in an iCalendar object 5684 that specifies a group scheduled calendar entity. This property MUST 5685 NOT be specified in an iCalendar object when publishing the calendar 5686 information (e.g., NOT in an iCalendar object that specifies the 5687 publication of a calendar user's busy time, event, to-do or journal). 5688 This property is not specified in an iCalendar object that specifies 5689 only a time zone definition or that defines calendar entities that 5690 are not group scheduled entities, but are entities only on a single 5691 user's calendar. 5692 5693 Description: The property MUST only be specified within calendar 5694 components to specify participants, non-participants and the chair of 5695 a group scheduled calendar entity. The property is specified within 5696 an "EMAIL" category of the "VALARM" calendar component to specify an 5697 email address that is to receive the email type of iCalendar alarm. 5698 5699 The property parameter CN is for the common or displayable name 5700 associated with the calendar address; ROLE, for the intended role 5701 that the attendee will have in the calendar component; PARTSTAT, for 5702 the status of the attendee's participation; RSVP, for indicating 5703 whether the favor of a reply is requested; CUTYPE, to indicate the 5704 type of calendar user; MEMBER, to indicate the groups that the 5705 attendee belongs to; DELEGATED-TO, to indicate the calendar users 5706 that the original request was delegated to; and DELEGATED-FROM, to 5707 indicate whom the request was delegated from; SENT-BY, to indicate 5708 whom is acting on behalf of the ATTENDEE; and DIR, to indicate the 5709 URI that points to the directory information corresponding to the 5710 attendee. These property parameters can be specified on an "ATTENDEE" 5711 5712 5713 5714 Dawson & Stenerson Standards Track [Page 102] 5715 5716 RFC 2445 iCalendar November 1998 5717 5718 5719 property in either a "VEVENT", "VTODO" or "VJOURNAL" calendar 5720 component. They MUST not be specified in an "ATTENDEE" property in a 5721 "VFREEBUSY" or "VALARM" calendar component. If the LANGUAGE property 5722 parameter is specified, the identified language applies to the CN 5723 parameter. 5724 5725 A recipient delegated a request MUST inherit the RSVP and ROLE values 5726 from the attendee that delegated the request to them. 5727 5728 Multiple attendees can be specified by including multiple "ATTENDEE" 5729 properties within the calendar component. 5730 5731 Format Definition: The property is defined by the following notation: 5732 5733 attendee = "ATTENDEE" attparam ":" cal-address CRLF 5734 5735 attparam = *( 5736 5737 ; the following are optional, 5738 ; but MUST NOT occur more than once 5739 5740 (";" cutypeparam) / (";"memberparam) / 5741 (";" roleparam) / (";" partstatparam) / 5742 (";" rsvpparam) / (";" deltoparam) / 5743 (";" delfromparam) / (";" sentbyparam) / 5744 (";"cnparam) / (";" dirparam) / 5745 (";" languageparam) / 5746 5747 ; the following is optional, 5748 ; and MAY occur more than once 5749 5750 (";" xparam) 5751 5752 ) 5753 5754 Example: The following are examples of this property's use for a to- 5755 do: 5756 5757 ORGANIZER:MAILTO:jsmith@host1.com 5758 ATTENDEE;MEMBER="MAILTO:DEV-GROUP@host2.com": 5759 MAILTO:joecool@host2.com 5760 ATTENDEE;DELEGATED-FROM="MAILTO:immud@host3.com": 5761 MAILTO:ildoit@host1.com 5762 5763 The following is an example of this property used for specifying 5764 multiple attendees to an event: 5765 5766 5767 5768 5769 5770 Dawson & Stenerson Standards Track [Page 103] 5771 5772 RFC 2445 iCalendar November 1998 5773 5774 5775 ORGANIZER:MAILTO:jsmith@host1.com 5776 ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;CN=Henry Cabot 5777 :MAILTO:hcabot@host2.com 5778 ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM="MAILTO:bob@host.com" 5779 ;PARTSTAT=ACCEPTED;CN=Jane Doe:MAILTO:jdoe@host1.com 5780 5781 The following is an example of this property with a URI to the 5782 directory information associated with the attendee: 5783 5784 ATTENDEE;CN=John Smith;DIR="ldap://host.com:6666/o=eDABC% 5785 20Industries,c=3DUS??(cn=3DBJim%20Dolittle)":MAILTO:jimdo@ 5786 host1.com 5787 5788 The following is an example of this property with "delegatee" and 5789 "delegator" information for an event: 5790 5791 ORGANIZER;CN=John Smith:MAILTO:jsmith@host.com 5792 ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;DELEGATED-FROM= 5793 "MAILTO:iamboss@host2.com";CN=Henry Cabot:MAILTO:hcabot@ 5794 host2.com 5795 ATTENDEE;ROLE=NON-PARTICIPANT;PARTSTAT=DELEGATED;DELEGATED-TO= 5796 "MAILTO:hcabot@host2.com";CN=The Big Cheese:MAILTO:iamboss 5797 @host2.com 5798 ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=Jane Doe 5799 :MAILTO:jdoe@host1.com 5800 5801 Example: The following is an example of this property's use when 5802 another calendar user is acting on behalf of the "Attendee": 5803 5804 ATTENDEE;SENT-BY=MAILTO:jan_doe@host1.com;CN=John Smith:MAILTO: 5805 jsmith@host1.com 5806 5807 4.8.4.2 Contact 5808 5809 Property Name: CONTACT 5810 5811 Purpose: The property is used to represent contact information or 5812 alternately a reference to contact information associated with the 5813 calendar component. 5814 5815 Value Type: TEXT 5816 5817 Property Parameters: Non-standard, alternate text representation and 5818 language property parameters can be specified on this property. 5819 5820 Conformance: The property can be specified in a "VEVENT", "VTODO", 5821 "VJOURNAL" or "VFREEBUSY" calendar component. 5822 5823 5824 5825 5826 Dawson & Stenerson Standards Track [Page 104] 5827 5828 RFC 2445 iCalendar November 1998 5829 5830 5831 Description: The property value consists of textual contact 5832 information. An alternative representation for the property value can 5833 also be specified that refers to a URI pointing to an alternate form, 5834 such as a vCard [RFC 2426], for the contact information. 5835 5836 Format Definition: The property is defined by the following notation: 5837 5838 contact = "CONTACT" contparam ":" text CRLF 5839 5840 contparam = *( 5841 ; the following are optional, 5842 ; but MUST NOT occur more than once 5843 5844 (";" altrepparam) / (";" languageparam) / 5845 5846 ; the following is optional, 5847 ; and MAY occur more than once 5848 5849 (";" xparam) 5850 5851 ) 5852 5853 Example: The following is an example of this property referencing 5854 textual contact information: 5855 5856 CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234 5857 5858 The following is an example of this property with an alternate 5859 representation of a LDAP URI to a directory entry containing the 5860 contact information: 5861 5862 CONTACT;ALTREP="ldap://host.com:6666/o=3DABC%20Industries\, 5863 c=3DUS??(cn=3DBJim%20Dolittle)":Jim Dolittle\, ABC Industries\, 5864 +1-919-555-1234 5865 5866 The following is an example of this property with an alternate 5867 representation of a MIME body part containing the contact 5868 information, such as a vCard [RFC 2426] embedded in a [MIME-DIR] 5869 content-type: 5870 5871 CONTACT;ALTREP="CID=<part3.msg970930T083000SILVER@host.com>":Jim 5872 Dolittle\, ABC Industries\, +1-919-555-1234 5873 5874 The following is an example of this property referencing a network 5875 resource, such as a vCard [RFC 2426] object containing the contact 5876 information: 5877 5878 5879 5880 5881 5882 Dawson & Stenerson Standards Track [Page 105] 5883 5884 RFC 2445 iCalendar November 1998 5885 5886 5887 CONTACT;ALTREP="http://host.com/pdi/jdoe.vcf":Jim 5888 Dolittle\, ABC Industries\, +1-919-555-1234 5889 5890 4.8.4.3 Organizer 5891 5892 Property Name: ORGANIZER 5893 5894 Purpose: The property defines the organizer for a calendar component. 5895 5896 Value Type: CAL-ADDRESS 5897 5898 Property Parameters: Non-standard, language, common name, directory 5899 entry reference, sent by property parameters can be specified on this 5900 property. 5901 5902 Conformance: This property MUST be specified in an iCalendar object 5903 that specifies a group scheduled calendar entity. This property MUST 5904 be specified in an iCalendar object that specifies the publication of 5905 a calendar user's busy time. This property MUST NOT be specified in 5906 an iCalendar object that specifies only a time zone definition or 5907 that defines calendar entities that are not group scheduled entities, 5908 but are entities only on a single user's calendar. 5909 5910 Description: The property is specified within the "VEVENT", "VTODO", 5911 "VJOURNAL calendar components to specify the organizer of a group 5912 scheduled calendar entity. The property is specified within the 5913 "VFREEBUSY" calendar component to specify the calendar user 5914 requesting the free or busy time. When publishing a "VFREEBUSY" 5915 calendar component, the property is used to specify the calendar that 5916 the published busy time came from. 5917 5918 The property has the property parameters CN, for specifying the 5919 common or display name associated with the "Organizer", DIR, for 5920 specifying a pointer to the directory information associated with the 5921 "Organizer", SENT-BY, for specifying another calendar user that is 5922 acting on behalf of the "Organizer". The non-standard parameters may 5923 also be specified on this property. If the LANGUAGE property 5924 parameter is specified, the identified language applies to the CN 5925 parameter value. 5926 5927 Format Definition: The property is defined by the following notation: 5928 5929 organizer = "ORGANIZER" orgparam ":" 5930 cal-address CRLF 5931 5932 orgparam = *( 5933 5934 ; the following are optional, 5935 5936 5937 5938 Dawson & Stenerson Standards Track [Page 106] 5939 5940 RFC 2445 iCalendar November 1998 5941 5942 5943 ; but MUST NOT occur more than once 5944 5945 (";" cnparam) / (";" dirparam) / (";" sentbyparam) / 5946 (";" languageparam) / 5947 5948 ; the following is optional, 5949 ; and MAY occur more than once 5950 5951 (";" xparam) 5952 5953 ) 5954 5955 Example: The following is an example of this property: 5956 5957 ORGANIZER;CN=John Smith:MAILTO:jsmith@host1.com 5958 5959 The following is an example of this property with a pointer to the 5960 directory information associated with the organizer: 5961 5962 ORGANIZER;CN=JohnSmith;DIR="ldap://host.com:6666/o=3DDC%20Associ 5963 ates,c=3DUS??(cn=3DJohn%20Smith)":MAILTO:jsmith@host1.com 5964 5965 The following is an example of this property used by another calendar 5966 user who is acting on behalf of the organizer, with responses 5967 intended to be sent back to the organizer, not the other calendar 5968 user: 5969 5970 ORGANIZER;SENT-BY="MAILTO:jane_doe@host.com": 5971 MAILTO:jsmith@host1.com 5972 5973 4.8.4.4 Recurrence ID 5974 5975 Property Name: RECURRENCE-ID 5976 5977 Purpose: This property is used in conjunction with the "UID" and 5978 "SEQUENCE" property to identify a specific instance of a recurring 5979 "VEVENT", "VTODO" or "VJOURNAL" calendar component. The property 5980 value is the effective value of the "DTSTART" property of the 5981 recurrence instance. 5982 5983 Value Type: The default value type for this property is DATE-TIME. 5984 The time format can be any of the valid forms defined for a DATE-TIME 5985 value type. See DATE-TIME value type definition for specific 5986 interpretations of the various forms. The value type can be set to 5987 DATE. 5988 5989 5990 5991 5992 5993 5994 Dawson & Stenerson Standards Track [Page 107] 5995 5996 RFC 2445 iCalendar November 1998 5997 5998 5999 Property Parameters: Non-standard property, value data type, time 6000 zone identifier and recurrence identifier range parameters can be 6001 specified on this property. 6002 6003 Conformance: This property can be specified in an iCalendar object 6004 containing a recurring calendar component. 6005 6006 Description: The full range of calendar components specified by a 6007 recurrence set is referenced by referring to just the "UID" property 6008 value corresponding to the calendar component. The "RECURRENCE-ID" 6009 property allows the reference to an individual instance within the 6010 recurrence set. 6011 6012 If the value of the "DTSTART" property is a DATE type value, then the 6013 value MUST be the calendar date for the recurrence instance. 6014 6015 The date/time value is set to the time when the original recurrence 6016 instance would occur; meaning that if the intent is to change a 6017 Friday meeting to Thursday, the date/time is still set to the 6018 original Friday meeting. 6019 6020 The "RECURRENCE-ID" property is used in conjunction with the "UID" 6021 and "SEQUENCE" property to identify a particular instance of a 6022 recurring event, to-do or journal. For a given pair of "UID" and 6023 "SEQUENCE" property values, the "RECURRENCE-ID" value for a 6024 recurrence instance is fixed. When the definition of the recurrence 6025 set for a calendar component changes, and hence the "SEQUENCE" 6026 property value changes, the "RECURRENCE-ID" for a given recurrence 6027 instance might also change.The "RANGE" parameter is used to specify 6028 the effective range of recurrence instances from the instance 6029 specified by the "RECURRENCE-ID" property value. The default value 6030 for the range parameter is the single recurrence instance only. The 6031 value can also be "THISANDPRIOR" to indicate a range defined by the 6032 given recurrence instance and all prior instances or the value can be 6033 "THISANDFUTURE" to indicate a range defined by the given recurrence 6034 instance and all subsequent instances. 6035 6036 Format Definition: The property is defined by the following notation: 6037 6038 recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF 6039 6040 ridparam = *( 6041 6042 ; the following are optional, 6043 ; but MUST NOT occur more than once 6044 6045 (";" "VALUE" "=" ("DATE-TIME" / "DATE)) / 6046 (";" tzidparam) / (";" rangeparam) / 6047 6048 6049 6050 Dawson & Stenerson Standards Track [Page 108] 6051 6052 RFC 2445 iCalendar November 1998 6053 6054 6055 ; the following is optional, 6056 ; and MAY occur more than once 6057 6058 (";" xparam) 6059 6060 ) 6061 6062 ridval = date-time / date 6063 ;Value MUST match value type 6064 6065 Example: The following are examples of this property: 6066 6067 RECURRENCE-ID;VALUE=DATE:19960401 6068 6069 RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z 6070 6071 4.8.4.5 Related To 6072 6073 Property Name: RELATED-TO 6074 6075 Purpose: The property is used to represent a relationship or 6076 reference between one calendar component and another. 6077 6078 Value Type: TEXT 6079 6080 Property Parameters: Non-standard and relationship type property 6081 parameters can be specified on this property. 6082 6083 Conformance: The property can be specified one or more times in the 6084 "VEVENT", "VTODO" or "VJOURNAL" calendar components. 6085 6086 Description: The property value consists of the persistent, globally 6087 unique identifier of another calendar component. This value would be 6088 represented in a calendar component by the "UID" property. 6089 6090 By default, the property value points to another calendar component 6091 that has a PARENT relationship to the referencing object. The 6092 "RELTYPE" property parameter is used to either explicitly state the 6093 default PARENT relationship type to the referenced calendar component 6094 or to override the default PARENT relationship type and specify 6095 either a CHILD or SIBLING relationship. The PARENT relationship 6096 indicates that the calendar component is a subordinate of the 6097 referenced calendar component. The CHILD relationship indicates that 6098 the calendar component is a superior of the referenced calendar 6099 component. The SIBLING relationship indicates that the calendar 6100 component is a peer of the referenced calendar component. 6101 6102 6103 6104 6105 6106 Dawson & Stenerson Standards Track [Page 109] 6107 6108 RFC 2445 iCalendar November 1998 6109 6110 6111 Changes to a calendar component referenced by this property can have 6112 an implicit impact on the related calendar component. For example, if 6113 a group event changes its start or end date or time, then the 6114 related, dependent events will need to have their start and end dates 6115 changed in a corresponding way. Similarly, if a PARENT calendar 6116 component is canceled or deleted, then there is an implied impact to 6117 the related CHILD calendar components. This property is intended only 6118 to provide information on the relationship of calendar components. It 6119 is up to the target calendar system to maintain any property 6120 implications of this relationship. 6121 6122 Format Definition: The property is defined by the following notation: 6123 6124 related = "RELATED-TO" [relparam] ":" text CRLF 6125 6126 relparam = *( 6127 6128 ; the following is optional, 6129 ; but MUST NOT occur more than once 6130 6131 (";" reltypeparam) / 6132 6133 ; the following is optional, 6134 ; and MAY occur more than once 6135 6136 (";" xparm) 6137 6138 ) 6139 6140 The following is an example of this property: 6141 6142 RELATED-TO:<jsmith.part7.19960817T083000.xyzMail@host3.com> 6143 6144 RELATED-TO:<19960401-080045-4000F192713-0052@host1.com> 6145 6146 4.8.4.6 Uniform Resource Locator 6147 6148 Property Name: URL 6149 6150 Purpose: This property defines a Uniform Resource Locator (URL) 6151 associated with the iCalendar object. 6152 6153 Value Type: URI 6154 6155 Property Parameters: Non-standard property parameters can be 6156 specified on this property. 6157 6158 6159 6160 6161 6162 Dawson & Stenerson Standards Track [Page 110] 6163 6164 RFC 2445 iCalendar November 1998 6165 6166 6167 Conformance: This property can be specified once in the "VEVENT", 6168 "VTODO", "VJOURNAL" or "VFREEBUSY" calendar components. 6169 6170 Description: This property may be used in a calendar component to 6171 convey a location where a more dynamic rendition of the calendar 6172 information associated with the calendar component can be found. This 6173 memo does not attempt to standardize the form of the URI, nor the 6174 format of the resource pointed to by the property value. If the URL 6175 property and Content-Location MIME header are both specified, they 6176 MUST point to the same resource. 6177 6178 Format Definition: The property is defined by the following notation: 6179 6180 url = "URL" urlparam ":" uri CRLF 6181 6182 urlparam = *(";" xparam) 6183 6184 Example: The following is an example of this property: 6185 6186 URL:http://abc.com/pub/calendars/jsmith/mytime.ics 6187 6188 4.8.4.7 Unique Identifier 6189 6190 Property Name: UID 6191 6192 Purpose: This property defines the persistent, globally unique 6193 identifier for the calendar component. 6194 6195 Value Type: TEXT 6196 6197 Property Parameters: Non-standard property parameters can be 6198 specified on this property. 6199 6200 Conformance: The property MUST be specified in the "VEVENT", "VTODO", 6201 "VJOURNAL" or "VFREEBUSY" calendar components. 6202 6203 Description: The UID itself MUST be a globally unique identifier. The 6204 generator of the identifier MUST guarantee that the identifier is 6205 unique. There are several algorithms that can be used to accomplish 6206 this. The identifier is RECOMMENDED to be the identical syntax to the 6207 [RFC 822] addr-spec. A good method to assure uniqueness is to put the 6208 domain name or a domain literal IP address of the host on which the 6209 identifier was created on the right hand side of the "@", and on the 6210 left hand side, put a combination of the current calendar date and 6211 time of day (i.e., formatted in as a DATE-TIME value) along with some 6212 other currently unique (perhaps sequential) identifier available on 6213 the system (for example, a process id number). Using a date/time 6214 value on the left hand side and a domain name or domain literal on 6215 6216 6217 6218 Dawson & Stenerson Standards Track [Page 111] 6219 6220 RFC 2445 iCalendar November 1998 6221 6222 6223 the right hand side makes it possible to guarantee uniqueness since 6224 no two hosts should be using the same domain name or IP address at 6225 the same time. Though other algorithms will work, it is RECOMMENDED 6226 that the right hand side contain some domain identifier (either of 6227 the host itself or otherwise) such that the generator of the message 6228 identifier can guarantee the uniqueness of the left hand side within 6229 the scope of that domain. 6230 6231 This is the method for correlating scheduling messages with the 6232 referenced "VEVENT", "VTODO", or "VJOURNAL" calendar component. 6233 6234 The full range of calendar components specified by a recurrence set 6235 is referenced by referring to just the "UID" property value 6236 corresponding to the calendar component. The "RECURRENCE-ID" property 6237 allows the reference to an individual instance within the recurrence 6238 set. 6239 6240 This property is an important method for group scheduling 6241 applications to match requests with later replies, modifications or 6242 deletion requests. Calendaring and scheduling applications MUST 6243 generate this property in "VEVENT", "VTODO" and "VJOURNAL" calendar 6244 components to assure interoperability with other group scheduling 6245 applications. This identifier is created by the calendar system that 6246 generates an iCalendar object. 6247 6248 Implementations MUST be able to receive and persist values of at 6249 least 255 characters for this property. 6250 6251 Format Definition: The property is defined by the following notation: 6252 6253 uid = "UID" uidparam ":" text CRLF 6254 6255 uidparam = *(";" xparam) 6256 6257 Example: The following is an example of this property: 6258 6259 UID:19960401T080045Z-4000F192713-0052@host1.com 6260 6261 4.8.5 Recurrence Component Properties 6262 6263 The following properties specify recurrence information in calendar 6264 components. 6265 6266 4.8.5.1 Exception Date/Times 6267 6268 Property Name: EXDATE 6269 6270 6271 6272 6273 6274 Dawson & Stenerson Standards Track [Page 112] 6275 6276 RFC 2445 iCalendar November 1998 6277 6278 6279 Purpose: This property defines the list of date/time exceptions for a 6280 recurring calendar component. 6281 6282 Value Type: The default value type for this property is DATE-TIME. 6283 The value type can be set to DATE. 6284 6285 Property Parameters: Non-standard, value data type and time zone 6286 identifier property parameters can be specified on this property. 6287 6288 Conformance: This property can be specified in an iCalendar object 6289 that includes a recurring calendar component. 6290 6291 Description: The exception dates, if specified, are used in computing 6292 the recurrence set. The recurrence set is the complete set of 6293 recurrence instances for a calendar component. The recurrence set is 6294 generated by considering the initial "DTSTART" property along with 6295 the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained 6296 within the iCalendar object. The "DTSTART" property defines the first 6297 instance in the recurrence set. Multiple instances of the "RRULE" and 6298 "EXRULE" properties can also be specified to define more 6299 sophisticated recurrence sets. The final recurrence set is generated 6300 by gathering all of the start date-times generated by any of the 6301 specified "RRULE" and "RDATE" properties, and then excluding any 6302 start date and times which fall within the union of start date and 6303 times generated by any specified "EXRULE" and "EXDATE" properties. 6304 This implies that start date and times within exclusion related 6305 properties (i.e., "EXDATE" and "EXRULE") take precedence over those 6306 specified by inclusion properties (i.e., "RDATE" and "RRULE"). Where 6307 duplicate instances are generated by the "RRULE" and "RDATE" 6308 properties, only one recurrence is considered. Duplicate instances 6309 are ignored. 6310 6311 The "EXDATE" property can be used to exclude the value specified in 6312 "DTSTART". However, in such cases the original "DTSTART" date MUST 6313 still be maintained by the calendaring and scheduling system because 6314 the original "DTSTART" value has inherent usage dependencies by other 6315 properties such as the "RECURRENCE-ID". 6316 6317 Format Definition: The property is defined by the following notation: 6318 6319 exdate = "EXDATE" exdtparam ":" exdtval *("," exdtval) CRLF 6320 6321 exdtparam = *( 6322 6323 ; the following are optional, 6324 ; but MUST NOT occur more than once 6325 6326 (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / 6327 6328 6329 6330 Dawson & Stenerson Standards Track [Page 113] 6331 6332 RFC 2445 iCalendar November 1998 6333 6334 6335 (";" tzidparam) / 6336 6337 ; the following is optional, 6338 ; and MAY occur more than once 6339 6340 (";" xparam) 6341 6342 ) 6343 6344 exdtval = date-time / date 6345 ;Value MUST match value type 6346 6347 Example: The following is an example of this property: 6348 6349 EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z 6350 6351 4.8.5.2 Exception Rule 6352 6353 Property Name: EXRULE 6354 6355 Purpose: This property defines a rule or repeating pattern for an 6356 exception to a recurrence set. 6357 6358 Value Type: RECUR 6359 6360 Property Parameters: Non-standard property parameters can be 6361 specified on this property. 6362 6363 Conformance: This property can be specified in "VEVENT", "VTODO" or 6364 "VJOURNAL" calendar components. 6365 6366 Description: The exception rule, if specified, is used in computing 6367 the recurrence set. The recurrence set is the complete set of 6368 recurrence instances for a calendar component. The recurrence set is 6369 generated by considering the initial "DTSTART" property along with 6370 the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained 6371 within the iCalendar object. The "DTSTART" defines the first instance 6372 in the recurrence set. Multiple instances of the "RRULE" and "EXRULE" 6373 properties can also be specified to define more sophisticated 6374 recurrence sets. The final recurrence set is generated by gathering 6375 all of the start date-times generated by any of the specified "RRULE" 6376 and "RDATE" properties, and excluding any start date and times which 6377 fall within the union of start date and times generated by any 6378 specified "EXRULE" and "EXDATE" properties. This implies that start 6379 date and times within exclusion related properties (i.e., "EXDATE" 6380 and "EXRULE") take precedence over those specified by inclusion 6381 6382 6383 6384 6385 6386 Dawson & Stenerson Standards Track [Page 114] 6387 6388 RFC 2445 iCalendar November 1998 6389 6390 6391 properties (i.e., "RDATE" and "RRULE"). Where duplicate instances are 6392 generated by the "RRULE" and "RDATE" properties, only one recurrence 6393 is considered. Duplicate instances are ignored. 6394 6395 The "EXRULE" property can be used to exclude the value specified in 6396 "DTSTART". However, in such cases the original "DTSTART" date MUST 6397 still be maintained by the calendaring and scheduling system because 6398 the original "DTSTART" value has inherent usage dependencies by other 6399 properties such as the "RECURRENCE-ID". 6400 6401 Format Definition: The property is defined by the following notation: 6402 6403 exrule = "EXRULE" exrparam ":" recur CRLF 6404 6405 exrparam = *(";" xparam) 6406 6407 Example: The following are examples of this property. Except every 6408 other week, on Tuesday and Thursday for 4 occurrences: 6409 6410 EXRULE:FREQ=WEEKLY;COUNT=4;INTERVAL=2;BYDAY=TU,TH 6411 6412 Except daily for 10 occurrences: 6413 6414 EXRULE:FREQ=DAILY;COUNT=10 6415 6416 Except yearly in June and July for 8 occurrences: 6417 6418 EXRULE:FREQ=YEARLY;COUNT=8;BYMONTH=6,7 6419 6420 4.8.5.3 Recurrence Date/Times 6421 6422 Property Name: RDATE 6423 6424 Purpose: This property defines the list of date/times for a 6425 recurrence set. 6426 6427 Value Type: The default value type for this property is DATE-TIME. 6428 The value type can be set to DATE or PERIOD. 6429 6430 Property Parameters: Non-standard, value data type and time zone 6431 identifier property parameters can be specified on this property. 6432 6433 Conformance: The property can be specified in "VEVENT", "VTODO", 6434 "VJOURNAL" or "VTIMEZONE" calendar components. 6435 6436 6437 6438 6439 6440 6441 6442 Dawson & Stenerson Standards Track [Page 115] 6443 6444 RFC 2445 iCalendar November 1998 6445 6446 6447 Description: This property can appear along with the "RRULE" property 6448 to define an aggregate set of repeating occurrences. When they both 6449 appear in an iCalendar object, the recurring events are defined by 6450 the union of occurrences defined by both the "RDATE" and "RRULE". 6451 6452 The recurrence dates, if specified, are used in computing the 6453 recurrence set. The recurrence set is the complete set of recurrence 6454 instances for a calendar component. The recurrence set is generated 6455 by considering the initial "DTSTART" property along with the "RRULE", 6456 "RDATE", "EXDATE" and "EXRULE" properties contained within the 6457 iCalendar object. The "DTSTART" property defines the first instance 6458 in the recurrence set. Multiple instances of the "RRULE" and "EXRULE" 6459 properties can also be specified to define more sophisticated 6460 recurrence sets. The final recurrence set is generated by gathering 6461 all of the start date/times generated by any of the specified "RRULE" 6462 and "RDATE" properties, and excluding any start date/times which fall 6463 within the union of start date/times generated by any specified 6464 "EXRULE" and "EXDATE" properties. This implies that start date/times 6465 within exclusion related properties (i.e., "EXDATE" and "EXRULE") 6466 take precedence over those specified by inclusion properties (i.e., 6467 "RDATE" and "RRULE"). Where duplicate instances are generated by the 6468 "RRULE" and "RDATE" properties, only one recurrence is considered. 6469 Duplicate instances are ignored. 6470 6471 Format Definition: The property is defined by the following notation: 6472 6473 rdate = "RDATE" rdtparam ":" rdtval *("," rdtval) CRLF 6474 6475 rdtparam = *( 6476 6477 ; the following are optional, 6478 ; but MUST NOT occur more than once 6479 6480 (";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) / 6481 (";" tzidparam) / 6482 6483 ; the following is optional, 6484 ; and MAY occur more than once 6485 6486 (";" xparam) 6487 6488 ) 6489 6490 rdtval = date-time / date / period 6491 ;Value MUST match value type 6492 6493 Example: The following are examples of this property: 6494 6495 6496 6497 6498 Dawson & Stenerson Standards Track [Page 116] 6499 6500 RFC 2445 iCalendar November 1998 6501 6502 6503 RDATE:19970714T123000Z 6504 6505 RDATE;TZID=US-EASTERN:19970714T083000 6506 6507 RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z, 6508 19960404T010000Z/PT3H 6509 6510 RDATE;VALUE=DATE:19970101,19970120,19970217,19970421 6511 19970526,19970704,19970901,19971014,19971128,19971129,19971225 6512 6513 4.8.5.4 Recurrence Rule 6514 6515 Property Name: RRULE 6516 6517 Purpose: This property defines a rule or repeating pattern for 6518 recurring events, to-dos, or time zone definitions. 6519 6520 Value Type: RECUR 6521 6522 Property Parameters: Non-standard property parameters can be 6523 specified on this property. 6524 6525 Conformance: This property can be specified one or more times in 6526 recurring "VEVENT", "VTODO" and "VJOURNAL" calendar components. It 6527 can also be specified once in each STANDARD or DAYLIGHT sub-component 6528 of the "VTIMEZONE" calendar component. 6529 6530 Description: The recurrence rule, if specified, is used in computing 6531 the recurrence set. The recurrence set is the complete set of 6532 recurrence instances for a calendar component. The recurrence set is 6533 generated by considering the initial "DTSTART" property along with 6534 the "RRULE", "RDATE", "EXDATE" and "EXRULE" properties contained 6535 within the iCalendar object. The "DTSTART" property defines the first 6536 instance in the recurrence set. Multiple instances of the "RRULE" and 6537 "EXRULE" properties can also be specified to define more 6538 sophisticated recurrence sets. The final recurrence set is generated 6539 by gathering all of the start date/times generated by any of the 6540 specified "RRULE" and "RDATE" properties, and excluding any start 6541 date/times which fall within the union of start date/times generated 6542 by any specified "EXRULE" and "EXDATE" properties. This implies that 6543 start date/times within exclusion related properties (i.e., "EXDATE" 6544 and "EXRULE") take precedence over those specified by inclusion 6545 properties (i.e., "RDATE" and "RRULE"). Where duplicate instances are 6546 generated by the "RRULE" and "RDATE" properties, only one recurrence 6547 is considered. Duplicate instances are ignored. 6548 6549 6550 6551 6552 6553 6554 Dawson & Stenerson Standards Track [Page 117] 6555 6556 RFC 2445 iCalendar November 1998 6557 6558 6559 The "DTSTART" and "DTEND" property pair or "DTSTART" and "DURATION" 6560 property pair, specified within the iCalendar object defines the 6561 first instance of the recurrence. When used with a recurrence rule, 6562 the "DTSTART" and "DTEND" properties MUST be specified in local time 6563 and the appropriate set of "VTIMEZONE" calendar components MUST be 6564 included. For detail on the usage of the "VTIMEZONE" calendar 6565 component, see the "VTIMEZONE" calendar component definition. 6566 6567 Any duration associated with the iCalendar object applies to all 6568 members of the generated recurrence set. Any modified duration for 6569 specific recurrences MUST be explicitly specified using the "RDATE" 6570 property. 6571 6572 Format Definition: This property is defined by the following 6573 notation: 6574 6575 rrule = "RRULE" rrulparam ":" recur CRLF 6576 6577 rrulparam = *(";" xparam) 6578 6579 Example: All examples assume the Eastern United States time zone. 6580 6581 Daily for 10 occurrences: 6582 6583 DTSTART;TZID=US-Eastern:19970902T090000 6584 RRULE:FREQ=DAILY;COUNT=10 6585 6586 ==> (1997 9:00 AM EDT)September 2-11 6587 6588 Daily until December 24, 1997: 6589 6590 DTSTART;TZID=US-Eastern:19970902T090000 6591 RRULE:FREQ=DAILY;UNTIL=19971224T000000Z 6592 6593 ==> (1997 9:00 AM EDT)September 2-30;October 1-25 6594 (1997 9:00 AM EST)October 26-31;November 1-30;December 1-23 6595 6596 Every other day - forever: 6597 6598 DTSTART;TZID=US-Eastern:19970902T090000 6599 RRULE:FREQ=DAILY;INTERVAL=2 6600 ==> (1997 9:00 AM EDT)September2,4,6,8...24,26,28,30; 6601 October 2,4,6...20,22,24 6602 (1997 9:00 AM EST)October 26,28,30;November 1,3,5,7...25,27,29; 6603 Dec 1,3,... 6604 6605 Every 10 days, 5 occurrences: 6606 6607 6608 6609 6610 Dawson & Stenerson Standards Track [Page 118] 6611 6612 RFC 2445 iCalendar November 1998 6613 6614 6615 DTSTART;TZID=US-Eastern:19970902T090000 6616 RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5 6617 6618 ==> (1997 9:00 AM EDT)September 2,12,22;October 2,12 6619 6620 Everyday in January, for 3 years: 6621 6622 DTSTART;TZID=US-Eastern:19980101T090000 6623 RRULE:FREQ=YEARLY;UNTIL=20000131T090000Z; 6624 BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA 6625 or 6626 RRULE:FREQ=DAILY;UNTIL=20000131T090000Z;BYMONTH=1 6627 6628 ==> (1998 9:00 AM EDT)January 1-31 6629 (1999 9:00 AM EDT)January 1-31 6630 (2000 9:00 AM EDT)January 1-31 6631 6632 Weekly for 10 occurrences 6633 6634 DTSTART;TZID=US-Eastern:19970902T090000 6635 RRULE:FREQ=WEEKLY;COUNT=10 6636 6637 ==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21 6638 (1997 9:00 AM EST)October 28;November 4 6639 6640 Weekly until December 24, 1997 6641 6642 DTSTART;TZID=US-Eastern:19970902T090000 6643 RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z 6644 6645 ==> (1997 9:00 AM EDT)September 2,9,16,23,30;October 7,14,21 6646 (1997 9:00 AM EST)October 28;November 4,11,18,25; 6647 December 2,9,16,23 6648 Every other week - forever: 6649 6650 DTSTART;TZID=US-Eastern:19970902T090000 6651 RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU 6652 6653 ==> (1997 9:00 AM EDT)September 2,16,30;October 14 6654 (1997 9:00 AM EST)October 28;November 11,25;December 9,23 6655 (1998 9:00 AM EST)January 6,20;February 6656 ... 6657 6658 Weekly on Tuesday and Thursday for 5 weeks: 6659 6660 DTSTART;TZID=US-Eastern:19970902T090000 6661 RRULE:FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH 6662 or 6663 6664 6665 6666 Dawson & Stenerson Standards Track [Page 119] 6667 6668 RFC 2445 iCalendar November 1998 6669 6670 6671 RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH 6672 6673 ==> (1997 9:00 AM EDT)September 2,4,9,11,16,18,23,25,30;October 2 6674 6675 Every other week on Monday, Wednesday and Friday until December 24, 6676 1997, but starting on Tuesday, September 2, 1997: 6677 6678 DTSTART;TZID=US-Eastern:19970902T090000 6679 RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU; 6680 BYDAY=MO,WE,FR 6681 ==> (1997 9:00 AM EDT)September 2,3,5,15,17,19,29;October 6682 1,3,13,15,17 6683 (1997 9:00 AM EST)October 27,29,31;November 10,12,14,24,26,28; 6684 December 8,10,12,22 6685 6686 Every other week on Tuesday and Thursday, for 8 occurrences: 6687 6688 DTSTART;TZID=US-Eastern:19970902T090000 6689 RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH 6690 6691 ==> (1997 9:00 AM EDT)September 2,4,16,18,30;October 2,14,16 6692 6693 Monthly on the 1st Friday for ten occurrences: 6694 6695 DTSTART;TZID=US-Eastern:19970905T090000 6696 RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR 6697 6698 ==> (1997 9:00 AM EDT)September 5;October 3 6699 (1997 9:00 AM EST)November 7;Dec 5 6700 (1998 9:00 AM EST)January 2;February 6;March 6;April 3 6701 (1998 9:00 AM EDT)May 1;June 5 6702 6703 Monthly on the 1st Friday until December 24, 1997: 6704 6705 DTSTART;TZID=US-Eastern:19970905T090000 6706 RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR 6707 6708 ==> (1997 9:00 AM EDT)September 5;October 3 6709 (1997 9:00 AM EST)November 7;December 5 6710 6711 Every other month on the 1st and last Sunday of the month for 10 6712 occurrences: 6713 6714 DTSTART;TZID=US-Eastern:19970907T090000 6715 RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU 6716 6717 ==> (1997 9:00 AM EDT)September 7,28 6718 (1997 9:00 AM EST)November 2,30 6719 6720 6721 6722 Dawson & Stenerson Standards Track [Page 120] 6723 6724 RFC 2445 iCalendar November 1998 6725 6726 6727 (1998 9:00 AM EST)January 4,25;March 1,29 6728 (1998 9:00 AM EDT)May 3,31 6729 6730 Monthly on the second to last Monday of the month for 6 months: 6731 6732 DTSTART;TZID=US-Eastern:19970922T090000 6733 RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO 6734 6735 ==> (1997 9:00 AM EDT)September 22;October 20 6736 (1997 9:00 AM EST)November 17;December 22 6737 (1998 9:00 AM EST)January 19;February 16 6738 6739 Monthly on the third to the last day of the month, forever: 6740 6741 DTSTART;TZID=US-Eastern:19970928T090000 6742 RRULE:FREQ=MONTHLY;BYMONTHDAY=-3 6743 6744 ==> (1997 9:00 AM EDT)September 28 6745 (1997 9:00 AM EST)October 29;November 28;December 29 6746 (1998 9:00 AM EST)January 29;February 26 6747 ... 6748 6749 Monthly on the 2nd and 15th of the month for 10 occurrences: 6750 6751 DTSTART;TZID=US-Eastern:19970902T090000 6752 RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15 6753 6754 ==> (1997 9:00 AM EDT)September 2,15;October 2,15 6755 (1997 9:00 AM EST)November 2,15;December 2,15 6756 (1998 9:00 AM EST)January 2,15 6757 6758 Monthly on the first and last day of the month for 10 occurrences: 6759 6760 DTSTART;TZID=US-Eastern:19970930T090000 6761 RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1 6762 6763 ==> (1997 9:00 AM EDT)September 30;October 1 6764 (1997 9:00 AM EST)October 31;November 1,30;December 1,31 6765 (1998 9:00 AM EST)January 1,31;February 1 6766 6767 Every 18 months on the 10th thru 15th of the month for 10 6768 occurrences: 6769 6770 DTSTART;TZID=US-Eastern:19970910T090000 6771 RRULE:FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12,13,14, 6772 15 6773 6774 ==> (1997 9:00 AM EDT)September 10,11,12,13,14,15 6775 6776 6777 6778 Dawson & Stenerson Standards Track [Page 121] 6779 6780 RFC 2445 iCalendar November 1998 6781 6782 6783 (1999 9:00 AM EST)March 10,11,12,13 6784 6785 Every Tuesday, every other month: 6786 6787 DTSTART;TZID=US-Eastern:19970902T090000 6788 RRULE:FREQ=MONTHLY;INTERVAL=2;BYDAY=TU 6789 6790 ==> (1997 9:00 AM EDT)September 2,9,16,23,30 6791 (1997 9:00 AM EST)November 4,11,18,25 6792 (1998 9:00 AM EST)January 6,13,20,27;March 3,10,17,24,31 6793 ... 6794 6795 Yearly in June and July for 10 occurrences: 6796 6797 DTSTART;TZID=US-Eastern:19970610T090000 6798 RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7 6799 ==> (1997 9:00 AM EDT)June 10;July 10 6800 (1998 9:00 AM EDT)June 10;July 10 6801 (1999 9:00 AM EDT)June 10;July 10 6802 (2000 9:00 AM EDT)June 10;July 10 6803 (2001 9:00 AM EDT)June 10;July 10 6804 Note: Since none of the BYDAY, BYMONTHDAY or BYYEARDAY components 6805 are specified, the day is gotten from DTSTART 6806 6807 Every other year on January, February, and March for 10 occurrences: 6808 6809 DTSTART;TZID=US-Eastern:19970310T090000 6810 RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3 6811 6812 ==> (1997 9:00 AM EST)March 10 6813 (1999 9:00 AM EST)January 10;February 10;March 10 6814 (2001 9:00 AM EST)January 10;February 10;March 10 6815 (2003 9:00 AM EST)January 10;February 10;March 10 6816 6817 Every 3rd year on the 1st, 100th and 200th day for 10 occurrences: 6818 6819 DTSTART;TZID=US-Eastern:19970101T090000 6820 RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200 6821 6822 ==> (1997 9:00 AM EST)January 1 6823 (1997 9:00 AM EDT)April 10;July 19 6824 (2000 9:00 AM EST)January 1 6825 (2000 9:00 AM EDT)April 9;July 18 6826 (2003 9:00 AM EST)January 1 6827 (2003 9:00 AM EDT)April 10;July 19 6828 (2006 9:00 AM EST)January 1 6829 6830 Every 20th Monday of the year, forever: 6831 6832 6833 6834 Dawson & Stenerson Standards Track [Page 122] 6835 6836 RFC 2445 iCalendar November 1998 6837 6838 6839 DTSTART;TZID=US-Eastern:19970519T090000 6840 RRULE:FREQ=YEARLY;BYDAY=20MO 6841 6842 ==> (1997 9:00 AM EDT)May 19 6843 (1998 9:00 AM EDT)May 18 6844 (1999 9:00 AM EDT)May 17 6845 ... 6846 6847 Monday of week number 20 (where the default start of the week is 6848 Monday), forever: 6849 6850 DTSTART;TZID=US-Eastern:19970512T090000 6851 RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO 6852 6853 ==> (1997 9:00 AM EDT)May 12 6854 (1998 9:00 AM EDT)May 11 6855 (1999 9:00 AM EDT)May 17 6856 ... 6857 6858 Every Thursday in March, forever: 6859 6860 DTSTART;TZID=US-Eastern:19970313T090000 6861 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH 6862 6863 ==> (1997 9:00 AM EST)March 13,20,27 6864 (1998 9:00 AM EST)March 5,12,19,26 6865 (1999 9:00 AM EST)March 4,11,18,25 6866 ... 6867 6868 Every Thursday, but only during June, July, and August, forever: 6869 6870 DTSTART;TZID=US-Eastern:19970605T090000 6871 RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8 6872 6873 ==> (1997 9:00 AM EDT)June 5,12,19,26;July 3,10,17,24,31; 6874 August 7,14,21,28 6875 (1998 9:00 AM EDT)June 4,11,18,25;July 2,9,16,23,30; 6876 August 6,13,20,27 6877 (1999 9:00 AM EDT)June 3,10,17,24;July 1,8,15,22,29; 6878 August 5,12,19,26 6879 ... 6880 6881 Every Friday the 13th, forever: 6882 6883 DTSTART;TZID=US-Eastern:19970902T090000 6884 EXDATE;TZID=US-Eastern:19970902T090000 6885 RRULE:FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13 6886 6887 6888 6889 6890 Dawson & Stenerson Standards Track [Page 123] 6891 6892 RFC 2445 iCalendar November 1998 6893 6894 6895 ==> (1998 9:00 AM EST)February 13;March 13;November 13 6896 (1999 9:00 AM EDT)August 13 6897 (2000 9:00 AM EDT)October 13 6898 ... 6899 6900 The first Saturday that follows the first Sunday of the month, 6901 forever: 6902 6903 DTSTART;TZID=US-Eastern:19970913T090000 6904 RRULE:FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13 6905 6906 ==> (1997 9:00 AM EDT)September 13;October 11 6907 (1997 9:00 AM EST)November 8;December 13 6908 (1998 9:00 AM EST)January 10;February 7;March 7 6909 (1998 9:00 AM EDT)April 11;May 9;June 13... 6910 ... 6911 6912 Every four years, the first Tuesday after a Monday in November, 6913 forever (U.S. Presidential Election day): 6914 6915 DTSTART;TZID=US-Eastern:19961105T090000 6916 RRULE:FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU;BYMONTHDAY=2,3,4, 6917 5,6,7,8 6918 6919 ==> (1996 9:00 AM EST)November 5 6920 (2000 9:00 AM EST)November 7 6921 (2004 9:00 AM EST)November 2 6922 ... 6923 6924 The 3rd instance into the month of one of Tuesday, Wednesday or 6925 Thursday, for the next 3 months: 6926 6927 DTSTART;TZID=US-Eastern:19970904T090000 6928 RRULE:FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3 6929 6930 ==> (1997 9:00 AM EDT)September 4;October 7 6931 (1997 9:00 AM EST)November 6 6932 6933 The 2nd to last weekday of the month: 6934 6935 DTSTART;TZID=US-Eastern:19970929T090000 6936 RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2 6937 6938 ==> (1997 9:00 AM EDT)September 29 6939 (1997 9:00 AM EST)October 30;November 27;December 30 6940 (1998 9:00 AM EST)January 29;February 26;March 30 6941 ... 6942 6943 6944 6945 6946 Dawson & Stenerson Standards Track [Page 124] 6947 6948 RFC 2445 iCalendar November 1998 6949 6950 6951 Every 3 hours from 9:00 AM to 5:00 PM on a specific day: 6952 6953 DTSTART;TZID=US-Eastern:19970902T090000 6954 RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z 6955 6956 ==> (September 2, 1997 EDT)09:00,12:00,15:00 6957 6958 Every 15 minutes for 6 occurrences: 6959 6960 DTSTART;TZID=US-Eastern:19970902T090000 6961 RRULE:FREQ=MINUTELY;INTERVAL=15;COUNT=6 6962 6963 ==> (September 2, 1997 EDT)09:00,09:15,09:30,09:45,10:00,10:15 6964 6965 Every hour and a half for 4 occurrences: 6966 6967 DTSTART;TZID=US-Eastern:19970902T090000 6968 RRULE:FREQ=MINUTELY;INTERVAL=90;COUNT=4 6969 6970 ==> (September 2, 1997 EDT)09:00,10:30;12:00;13:30 6971 6972 Every 20 minutes from 9:00 AM to 4:40 PM every day: 6973 6974 DTSTART;TZID=US-Eastern:19970902T090000 6975 RRULE:FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40 6976 or 6977 RRULE:FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16 6978 6979 ==> (September 2, 1997 EDT)9:00,9:20,9:40,10:00,10:20, 6980 ... 16:00,16:20,16:40 6981 (September 3, 1997 EDT)9:00,9:20,9:40,10:00,10:20, 6982 ...16:00,16:20,16:40 6983 ... 6984 6985 An example where the days generated makes a difference because of 6986 WKST: 6987 6988 DTSTART;TZID=US-Eastern:19970805T090000 6989 RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO 6990 6991 ==> (1997 EDT)Aug 5,10,19,24 6992 6993 changing only WKST from MO to SU, yields different results... 6994 6995 DTSTART;TZID=US-Eastern:19970805T090000 6996 RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU 6997 ==> (1997 EDT)August 5,17,19,31 6998 6999 7000 7001 7002 Dawson & Stenerson Standards Track [Page 125] 7003 7004 RFC 2445 iCalendar November 1998 7005 7006 7007 4.8.6 Alarm Component Properties 7008 7009 The following properties specify alarm information in calendar 7010 components. 7011 7012 4.8.6.1 Action 7013 7014 Property Name: ACTION 7015 7016 Purpose: This property defines the action to be invoked when an alarm 7017 is triggered. 7018 7019 Value Type: TEXT 7020 7021 Property Parameters: Non-standard property parameters can be 7022 specified on this property. 7023 7024 Conformance: This property MUST be specified once in a "VALARM" 7025 calendar component. 7026 7027 Description: Each "VALARM" calendar component has a particular type 7028 of action associated with it. This property specifies the type of 7029 action 7030 7031 Format Definition: The property is defined by the following notation: 7032 7033 action = "ACTION" actionparam ":" actionvalue CRLF 7034 7035 actionparam = *(";" xparam) 7036 7037 actionvalue = "AUDIO" / "DISPLAY" / "EMAIL" / "PROCEDURE" 7038 / iana-token / x-name 7039 7040 Example: The following are examples of this property in a "VALARM" 7041 calendar component: 7042 7043 ACTION:AUDIO 7044 7045 ACTION:DISPLAY 7046 7047 ACTION:PROCEDURE 7048 7049 4.8.6.2 Repeat Count 7050 7051 Property Name: REPEAT 7052 7053 Purpose: This property defines the number of time the alarm should be 7054 repeated, after the initial trigger. 7055 7056 7057 7058 Dawson & Stenerson Standards Track [Page 126] 7059 7060 RFC 2445 iCalendar November 1998 7061 7062 7063 Value Type: INTEGER 7064 7065 Property Parameters: Non-standard property parameters can be 7066 specified on this property. 7067 7068 Conformance: This property can be specified in a "VALARM" calendar 7069 component. 7070 7071 Description: If the alarm triggers more than once, then this property 7072 MUST be specified along with the "DURATION" property. 7073 7074 Format Definition: The property is defined by the following notation: 7075 7076 repeatcnt = "REPEAT" repparam ":" integer CRLF 7077 ;Default is "0", zero. 7078 7079 repparam = *(";" xparam) 7080 7081 Example: The following is an example of this property for an alarm 7082 that repeats 4 additional times with a 5 minute delay after the 7083 initial triggering of the alarm: 7084 7085 REPEAT:4 7086 DURATION:PT5M 7087 7088 4.8.6.3 Trigger 7089 7090 Property Name: TRIGGER 7091 7092 Purpose: This property specifies when an alarm will trigger. 7093 7094 Value Type: The default value type is DURATION. The value type can be 7095 set to a DATE-TIME value type, in which case the value MUST specify a 7096 UTC formatted DATE-TIME value. 7097 7098 Property Parameters: Non-standard, value data type, time zone 7099 identifier or trigger relationship property parameters can be 7100 specified on this property. The trigger relationship property 7101 parameter MUST only be specified when the value type is DURATION. 7102 7103 Conformance: This property MUST be specified in the "VALARM" calendar 7104 component. 7105 7106 Description: Within the "VALARM" calendar component, this property 7107 defines when the alarm will trigger. The default value type is 7108 DURATION, specifying a relative time for the trigger of the alarm. 7109 The default duration is relative to the start of an event or to-do 7110 that the alarm is associated with. The duration can be explicitly set 7111 7112 7113 7114 Dawson & Stenerson Standards Track [Page 127] 7115 7116 RFC 2445 iCalendar November 1998 7117 7118 7119 to trigger from either the end or the start of the associated event 7120 or to-do with the "RELATED" parameter. A value of START will set the 7121 alarm to trigger off the start of the associated event or to-do. A 7122 value of END will set the alarm to trigger off the end of the 7123 associated event or to-do. 7124 7125 Either a positive or negative duration may be specified for the 7126 "TRIGGER" property. An alarm with a positive duration is triggered 7127 after the associated start or end of the event or to-do. An alarm 7128 with a negative duration is triggered before the associated start or 7129 end of the event or to-do. 7130 7131 The "RELATED" property parameter is not valid if the value type of 7132 the property is set to DATE-TIME (i.e., for an absolute date and time 7133 alarm trigger). If a value type of DATE-TIME is specified, then the 7134 property value MUST be specified in the UTC time format. If an 7135 absolute trigger is specified on an alarm for a recurring event or 7136 to-do, then the alarm will only trigger for the specified absolute 7137 date/time, along with any specified repeating instances. 7138 7139 If the trigger is set relative to START, then the "DTSTART" property 7140 MUST be present in the associated "VEVENT" or "VTODO" calendar 7141 component. If an alarm is specified for an event with the trigger set 7142 relative to the END, then the "DTEND" property or the "DSTART" and 7143 "DURATION' properties MUST be present in the associated "VEVENT" 7144 calendar component. If the alarm is specified for a to-do with a 7145 trigger set relative to the END, then either the "DUE" property or 7146 the "DSTART" and "DURATION' properties MUST be present in the 7147 associated "VTODO" calendar component. 7148 7149 Alarms specified in an event or to-do which is defined in terms of a 7150 DATE value type will be triggered relative to 00:00:00 UTC on the 7151 specified date. For example, if "DTSTART:19980205, then the duration 7152 trigger will be relative to19980205T000000Z. 7153 7154 Format Definition: The property is defined by the following notation: 7155 7156 trigger = "TRIGGER" (trigrel / trigabs) 7157 7158 trigrel = *( 7159 7160 ; the following are optional, 7161 ; but MUST NOT occur more than once 7162 7163 (";" "VALUE" "=" "DURATION") / 7164 (";" trigrelparam) / 7165 7166 ; the following is optional, 7167 7168 7169 7170 Dawson & Stenerson Standards Track [Page 128] 7171 7172 RFC 2445 iCalendar November 1998 7173 7174 7175 ; and MAY occur more than once 7176 7177 (";" xparam) 7178 ) ":" dur-value 7179 7180 trigabs = 1*( 7181 7182 ; the following is REQUIRED, 7183 ; but MUST NOT occur more than once 7184 7185 (";" "VALUE" "=" "DATE-TIME") / 7186 7187 ; the following is optional, 7188 ; and MAY occur more than once 7189 7190 (";" xparam) 7191 7192 ) ":" date-time 7193 7194 Example: A trigger set 15 minutes prior to the start of the event or 7195 to-do. 7196 7197 TRIGGER:-P15M 7198 7199 A trigger set 5 minutes after the end of the event or to-do. 7200 7201 TRIGGER;RELATED=END:P5M 7202 7203 A trigger set to an absolute date/time. 7204 7205 TRIGGER;VALUE=DATE-TIME:19980101T050000Z 7206 7207 4.8.7 Change Management Component Properties 7208 7209 The following properties specify change management information in 7210 calendar components. 7211 7212 4.8.7.1 Date/Time Created 7213 7214 Property Name: CREATED 7215 7216 Purpose: This property specifies the date and time that the calendar 7217 information was created by the calendar user agent in the calendar 7218 store. 7219 7220 Note: This is analogous to the creation date and time for a file 7221 in the file system. 7222 7223 7224 7225 7226 Dawson & Stenerson Standards Track [Page 129] 7227 7228 RFC 2445 iCalendar November 1998 7229 7230 7231 Value Type: DATE-TIME 7232 7233 Property Parameters: Non-standard property parameters can be 7234 specified on this property. 7235 7236 Conformance: The property can be specified once in "VEVENT", "VTODO" 7237 or "VJOURNAL" calendar components. 7238 7239 Description: The date and time is a UTC value. 7240 7241 Format Definition: The property is defined by the following notation: 7242 7243 created = "CREATED" creaparam ":" date-time CRLF 7244 7245 creaparam = *(";" xparam) 7246 7247 Example: The following is an example of this property: 7248 7249 CREATED:19960329T133000Z 7250 7251 4.8.7.2 Date/Time Stamp 7252 7253 Property Name: DTSTAMP 7254 7255 Purpose: The property indicates the date/time that the instance of 7256 the iCalendar object was created. 7257 7258 Value Type: DATE-TIME 7259 7260 Property Parameters: Non-standard property parameters can be 7261 specified on this property. 7262 7263 Conformance: This property MUST be included in the "VEVENT", "VTODO", 7264 "VJOURNAL" or "VFREEBUSY" calendar components. 7265 7266 Description: The value MUST be specified in the UTC time format. 7267 7268 This property is also useful to protocols such as [IMIP] that have 7269 inherent latency issues with the delivery of content. This property 7270 will assist in the proper sequencing of messages containing iCalendar 7271 objects. 7272 7273 This property is different than the "CREATED" and "LAST-MODIFIED" 7274 properties. These two properties are used to specify when the 7275 particular calendar data in the calendar store was created and last 7276 modified. This is different than when the iCalendar object 7277 representation of the calendar service information was created or 7278 last modified. 7279 7280 7281 7282 Dawson & Stenerson Standards Track [Page 130] 7283 7284 RFC 2445 iCalendar November 1998 7285 7286 7287 Format Definition: The property is defined by the following notation: 7288 7289 dtstamp = "DTSTAMP" stmparam ":" date-time CRLF 7290 7291 stmparam = *(";" xparam) 7292 7293 Example: 7294 7295 DTSTAMP:19971210T080000Z 7296 7297 4.8.7.3 Last Modified 7298 7299 Property Name: LAST-MODIFIED 7300 7301 Purpose: The property specifies the date and time that the 7302 information associated with the calendar component was last revised 7303 in the calendar store. 7304 7305 Note: This is analogous to the modification date and time for a 7306 file in the file system. 7307 7308 Value Type: DATE-TIME 7309 7310 Property Parameters: Non-standard property parameters can be 7311 specified on this property. 7312 7313 Conformance: This property can be specified in the "EVENT", "VTODO", 7314 "VJOURNAL" or "VTIMEZONE" calendar components. 7315 7316 Description: The property value MUST be specified in the UTC time 7317 format. 7318 7319 Format Definition: The property is defined by the following notation: 7320 7321 last-mod = "LAST-MODIFIED" lstparam ":" date-time CRLF 7322 7323 lstparam = *(";" xparam) 7324 7325 Example: The following is are examples of this property: 7326 7327 LAST-MODIFIED:19960817T133000Z 7328 7329 4.8.7.4 Sequence Number 7330 7331 Property Name: SEQUENCE 7332 7333 Purpose: This property defines the revision sequence number of the 7334 calendar component within a sequence of revisions. 7335 7336 7337 7338 Dawson & Stenerson Standards Track [Page 131] 7339 7340 RFC 2445 iCalendar November 1998 7341 7342 7343 Value Type: integer 7344 7345 Property Parameters: Non-standard property parameters can be 7346 specified on this property. 7347 7348 Conformance: The property can be specified in "VEVENT", "VTODO" or 7349 "VJOURNAL" calendar component. 7350 7351 Description: When a calendar component is created, its sequence 7352 number is zero (US-ASCII decimal 48). It is monotonically incremented 7353 by the "Organizer's" CUA each time the "Organizer" makes a 7354 significant revision to the calendar component. When the "Organizer" 7355 makes changes to one of the following properties, the sequence number 7356 MUST be incremented: 7357 7358 . "DTSTART" 7359 7360 . "DTEND" 7361 7362 . "DUE" 7363 7364 . "RDATE" 7365 7366 . "RRULE" 7367 7368 . "EXDATE" 7369 7370 . "EXRULE" 7371 7372 . "STATUS" 7373 7374 In addition, changes made by the "Organizer" to other properties can 7375 also force the sequence number to be incremented. The "Organizer" CUA 7376 MUST increment the sequence number when ever it makes changes to 7377 properties in the calendar component that the "Organizer" deems will 7378 jeopardize the validity of the participation status of the 7379 "Attendees". For example, changing the location of a meeting from one 7380 locale to another distant locale could effectively impact the 7381 participation status of the "Attendees". 7382 7383 The "Organizer" includes this property in an iCalendar object that it 7384 sends to an "Attendee" to specify the current version of the calendar 7385 component. 7386 7387 The "Attendee" includes this property in an iCalendar object that it 7388 sends to the "Organizer" to specify the version of the calendar 7389 component that the "Attendee" is referring to. 7390 7391 7392 7393 7394 Dawson & Stenerson Standards Track [Page 132] 7395 7396 RFC 2445 iCalendar November 1998 7397 7398 7399 A change to the sequence number is not the mechanism that an 7400 "Organizer" uses to request a response from the "Attendees". The 7401 "RSVP" parameter on the "ATTENDEE" property is used by the 7402 "Organizer" to indicate that a response from the "Attendees" is 7403 requested. 7404 7405 Format Definition: This property is defined by the following 7406 notation: 7407 7408 seq = "SEQUENCE" seqparam ":" integer CRLF 7409 ; Default is "0" 7410 7411 seqparam = *(";" xparam) 7412 7413 Example: The following is an example of this property for a calendar 7414 component that was just created by the "Organizer". 7415 7416 SEQUENCE:0 7417 7418 The following is an example of this property for a calendar component 7419 that has been revised two different times by the "Organizer". 7420 7421 SEQUENCE:2 7422 7423 4.8.8 Miscellaneous Component Properties 7424 7425 The following properties specify information about a number of 7426 miscellaneous features of calendar components. 7427 7428 4.8.8.1 Non-standard Properties 7429 7430 Property Name: Any property name with a "X-" prefix 7431 7432 Purpose: This class of property provides a framework for defining 7433 non-standard properties. 7434 7435 Value Type: TEXT 7436 7437 Property Parameters: Non-standard and language property parameters 7438 can be specified on this property. 7439 7440 Conformance: This property can be specified in any calendar 7441 component. 7442 7443 Description: The MIME Calendaring and Scheduling Content Type 7444 provides a "standard mechanism for doing non-standard things". This 7445 extension support is provided for implementers to "push the envelope" 7446 on the existing version of the memo. Extension properties are 7447 7448 7449 7450 Dawson & Stenerson Standards Track [Page 133] 7451 7452 RFC 2445 iCalendar November 1998 7453 7454 7455 specified by property and/or property parameter names that have the 7456 prefix text of "X-" (the two character sequence: LATIN CAPITAL LETTER 7457 X character followed by the HYPEN-MINUS character). It is recommended 7458 that vendors concatenate onto this sentinel another short prefix text 7459 to identify the vendor. This will facilitate readability of the 7460 extensions and minimize possible collision of names between different 7461 vendors. User agents that support this content type are expected to 7462 be able to parse the extension properties and property parameters but 7463 can ignore them. 7464 7465 At present, there is no registration authority for names of extension 7466 properties and property parameters. The data type for this property 7467 is TEXT. Optionally, the data type can be any of the other valid data 7468 types. 7469 7470 Format Definition: The property is defined by the following notation: 7471 7472 x-prop = x-name *(";" xparam) [";" languageparam] ":" text CRLF 7473 ; Lines longer than 75 octets should be folded 7474 7475 Example: The following might be the ABC vendor's extension for an 7476 audio-clip form of subject property: 7477 7478 X-ABC-MMSUBJ;X-ABC-MMSUBJTYPE=wave:http://load.noise.org/mysubj.wav 7479 7480 4.8.8.2 Request Status 7481 7482 Property Name: REQUEST-STATUS 7483 7484 Purpose: This property defines the status code returned for a 7485 scheduling request. 7486 7487 Value Type: TEXT 7488 7489 Property Parameters: Non-standard and language property parameters 7490 can be specified on this property. 7491 7492 Conformance: The property can be specified in "VEVENT", "VTODO", 7493 "VJOURNAL" or "VFREEBUSY" calendar component. 7494 7495 Description: This property is used to return status code information 7496 related to the processing of an associated iCalendar object. The data 7497 type for this property is TEXT. 7498 7499 The value consists of a short return status component, a longer 7500 return status description component, and optionally a status-specific 7501 data component. The components of the value are separated by the 7502 SEMICOLON character (US-ASCII decimal 59). 7503 7504 7505 7506 Dawson & Stenerson Standards Track [Page 134] 7507 7508 RFC 2445 iCalendar November 1998 7509 7510 7511 The short return status is a PERIOD character (US-ASCII decimal 46) 7512 separated 3-tuple of integers. For example, "3.1.1". The successive 7513 levels of integers provide for a successive level of status code 7514 granularity. 7515 7516 The following are initial classes for the return status code. 7517 Individual iCalendar object methods will define specific return 7518 status codes for these classes. In addition, other classes for the 7519 return status code may be defined using the registration process 7520 defined later in this memo. 7521 7522 |==============+===============================================| 7523 | Short Return | Longer Return Status Description | 7524 | Status Code | | 7525 |==============+===============================================| 7526 | 1.xx | Preliminary success. This class of status | 7527 | | of status code indicates that the request has | 7528 | | request has been initially processed but that | 7529 | | completion is pending. | 7530 |==============+===============================================| 7531 | 2.xx | Successful. This class of status code | 7532 | | indicates that the request was completed | 7533 | | successfuly. However, the exact status code | 7534 | | can indicate that a fallback has been taken. | 7535 |==============+===============================================| 7536 | 3.xx | Client Error. This class of status code | 7537 | | indicates that the request was not successful.| 7538 | | The error is the result of either a syntax or | 7539 | | a semantic error in the client formatted | 7540 | | request. Request should not be retried until | 7541 | | the condition in the request is corrected. | 7542 |==============+===============================================| 7543 | 4.xx | Scheduling Error. This class of status code | 7544 | | indicates that the request was not successful.| 7545 | | Some sort of error occurred within the | 7546 | | calendaring and scheduling service, not | 7547 | | directly related to the request itself. | 7548 |==============+===============================================| 7549 7550 Format Definition: The property is defined by the following notation: 7551 7552 rstatus = "REQUEST-STATUS" rstatparam ":" 7553 statcode ";" statdesc [";" extdata] 7554 7555 rstatparam = *( 7556 7557 ; the following is optional, 7558 ; but MUST NOT occur more than once 7559 7560 7561 7562 Dawson & Stenerson Standards Track [Page 135] 7563 7564 RFC 2445 iCalendar November 1998 7565 7566 7567 (";" languageparm) / 7568 7569 ; the following is optional, 7570 ; and MAY occur more than once 7571 7572 (";" xparam) 7573 7574 ) 7575 7576 statcode = 1*DIGIT *("." 1*DIGIT) 7577 ;Hierarchical, numeric return status code 7578 7579 statdesc = text 7580 ;Textual status description 7581 7582 extdata = text 7583 ;Textual exception data. For example, the offending property 7584 ;name and value or complete property line. 7585 7586 Example: The following are some possible examples of this property. 7587 The COMMA and SEMICOLON separator characters in the property value 7588 are BACKSLASH character escaped because they appear in a text value. 7589 7590 REQUEST-STATUS:2.0;Success 7591 7592 REQUEST-STATUS:3.1;Invalid property value;DTSTART:96-Apr-01 7593 7594 REQUEST-STATUS:2.8; Success\, repeating event ignored. Scheduled 7595 as a single event.;RRULE:FREQ=WEEKLY\;INTERVAL=2 7596 7597 REQUEST-STATUS:4.1;Event conflict. Date/time is busy. 7598 7599 REQUEST-STATUS:3.7;Invalid calendar user;ATTENDEE: 7600 MAILTO:jsmith@host.com 7601 7602 5 iCalendar Object Examples 7603 7604 The following examples are provided as an informational source of 7605 illustrative iCalendar objects consistent with this content type. 7606 7607 The following example specifies a three-day conference that begins at 7608 8:00 AM EDT, September 18, 1996 and end at 6:00 PM EDT, September 20, 7609 1996. 7610 7611 BEGIN:VCALENDAR PRODID:-//xyz Corp//NONSGML PDA Calendar Verson 7612 1.0//EN VERSION:2.0 BEGIN:VEVENT DTSTAMP:19960704T120000Z 7613 UID:uid1@host.com ORGANIZER:MAILTO:jsmith@host.com 7614 DTSTART:19960918T143000Z DTEND:19960920T220000Z STATUS:CONFIRMED 7615 7616 7617 7618 Dawson & Stenerson Standards Track [Page 136] 7619 7620 RFC 2445 iCalendar November 1998 7621 7622 7623 CATEGORIES:CONFERENCE SUMMARY:Networld+Interop Conference 7624 DESCRIPTION:Networld+Interop Conference 7625 and Exhibit\nAtlanta World Congress Center\n 7626 Atlanta, Georgia END:VEVENT END:VCALENDAR 7627 7628 The following example specifies a group scheduled meeting that begin 7629 at 8:30 AM EST on March 12, 1998 and end at 9:30 AM EST on March 12, 7630 1998. The "Organizer" has scheduled the meeting with one or more 7631 calendar users in a group. A time zone specification for Eastern 7632 United States has been specified. 7633 7634 BEGIN:VCALENDAR 7635 PRODID:-//RDU Software//NONSGML HandCal//EN 7636 VERSION:2.0 7637 BEGIN:VTIMEZONE 7638 TZID:US-Eastern 7639 BEGIN:STANDARD 7640 DTSTART:19981025T020000 7641 RDATE:19981025T020000 7642 TZOFFSETFROM:-0400 7643 TZOFFSETTO:-0500 7644 TZNAME:EST 7645 END:STANDARD 7646 BEGIN:DAYLIGHT 7647 DTSTART:19990404T020000 7648 RDATE:19990404T020000 7649 TZOFFSETFROM:-0500 7650 TZOFFSETTO:-0400 7651 TZNAME:EDT 7652 END:DAYLIGHT 7653 END:VTIMEZONE 7654 BEGIN:VEVENT 7655 DTSTAMP:19980309T231000Z 7656 UID:guid-1.host1.com 7657 ORGANIZER;ROLE=CHAIR:MAILTO:mrbig@host.com 7658 ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT;CUTYPE=GROUP: 7659 MAILTO:employee-A@host.com 7660 DESCRIPTION:Project XYZ Review Meeting 7661 CATEGORIES:MEETING 7662 CLASS:PUBLIC 7663 CREATED:19980309T130000Z 7664 SUMMARY:XYZ Project Review 7665 DTSTART;TZID=US-Eastern:19980312T083000 7666 DTEND;TZID=US-Eastern:19980312T093000 7667 LOCATION:1CP Conference Room 4350 7668 END:VEVENT 7669 END:VCALENDAR 7670 7671 7672 7673 7674 Dawson & Stenerson Standards Track [Page 137] 7675 7676 RFC 2445 iCalendar November 1998 7677 7678 7679 The following is an example of an iCalendar object passed in a MIME 7680 message with a single body part consisting of a "text/calendar" 7681 Content Type. 7682 7683 TO:jsmith@host1.com 7684 FROM:jdoe@host1.com 7685 MIME-VERSION:1.0 7686 MESSAGE-ID:<id3@host1.com> 7687 CONTENT-TYPE:text/calendar 7688 7689 BEGIN:VCALENDAR 7690 METHOD:xyz 7691 VERSION:2.0 7692 PRODID:-//ABC Corporation//NONSGML My Product//EN 7693 BEGIN:VEVENT 7694 DTSTAMP:19970324T1200Z 7695 SEQUENCE:0 7696 UID:uid3@host1.com 7697 ORGANIZER:MAILTO:jdoe@host1.com 7698 ATTENDEE;RSVP=TRUE:MAILTO:jsmith@host1.com 7699 DTSTART:19970324T123000Z 7700 DTEND:19970324T210000Z 7701 CATEGORIES:MEETING,PROJECT 7702 CLASS:PUBLIC 7703 SUMMARY:Calendaring Interoperability Planning Meeting 7704 DESCRIPTION:Discuss how we can test c&s interoperability\n 7705 using iCalendar and other IETF standards. 7706 LOCATION:LDB Lobby 7707 ATTACH;FMTTYPE=application/postscript:ftp://xyzCorp.com/pub/ 7708 conf/bkgrnd.ps 7709 END:VEVENT 7710 END:VCALENDAR 7711 7712 The following is an example of a to-do due on April 15, 1998. An 7713 audio alarm has been specified to remind the calendar user at noon, 7714 the day before the to-do is expected to be completed and repeat 7715 hourly, four additional times. The to-do definition has been modified 7716 twice since it was initially created. 7717 7718 BEGIN:VCALENDAR 7719 VERSION:2.0 7720 PRODID:-//ABC Corporation//NONSGML My Product//EN 7721 BEGIN:VTODO 7722 DTSTAMP:19980130T134500Z 7723 SEQUENCE:2 7724 UID:uid4@host1.com 7725 ORGANIZER:MAILTO:unclesam@us.gov 7726 ATTENDEE;PARTSTAT=ACCEPTED:MAILTO:jqpublic@host.com 7727 7728 7729 7730 Dawson & Stenerson Standards Track [Page 138] 7731 7732 RFC 2445 iCalendar November 1998 7733 7734 7735 DUE:19980415T235959 7736 STATUS:NEEDS-ACTION 7737 SUMMARY:Submit Income Taxes 7738 BEGIN:VALARM 7739 ACTION:AUDIO 7740 TRIGGER:19980403T120000 7741 ATTACH;FMTTYPE=audio/basic:http://host.com/pub/audio- 7742 files/ssbanner.aud 7743 REPEAT:4 7744 DURATION:PT1H 7745 END:VALARM 7746 END:VTODO 7747 END:VCALENDAR 7748 7749 The following is an example of a journal entry. 7750 7751 BEGIN:VCALENDAR 7752 VERSION:2.0 7753 PRODID:-//ABC Corporation//NONSGML My Product//EN 7754 BEGIN:VJOURNAL 7755 DTSTAMP:19970324T120000Z 7756 UID:uid5@host1.com 7757 ORGANIZER:MAILTO:jsmith@host.com 7758 STATUS:DRAFT 7759 CLASS:PUBLIC 7760 CATEGORY:Project Report, XYZ, Weekly Meeting 7761 DESCRIPTION:Project xyz Review Meeting Minutes\n 7762 Agenda\n1. Review of project version 1.0 requirements.\n2. 7763 Definition 7764 of project processes.\n3. Review of project schedule.\n 7765 Participants: John Smith, Jane Doe, Jim Dandy\n-It was 7766 decided that the requirements need to be signed off by 7767 product marketing.\n-Project processes were accepted.\n 7768 -Project schedule needs to account for scheduled holidays 7769 and employee vacation time. Check with HR for specific 7770 dates.\n-New schedule will be distributed by Friday.\n- 7771 Next weeks meeting is cancelled. No meeting until 3/23. 7772 END:VJOURNAL 7773 END:VCALENDAR 7774 7775 The following is an example of published busy time information. The 7776 iCalendar object might be placed in the network resource 7777 www.host.com/calendar/busytime/jsmith.ifb. 7778 7779 BEGIN:VCALENDAR 7780 VERSION:2.0 7781 PRODID:-//RDU Software//NONSGML HandCal//EN 7782 BEGIN:VFREEBUSY 7783 7784 7785 7786 Dawson & Stenerson Standards Track [Page 139] 7787 7788 RFC 2445 iCalendar November 1998 7789 7790 7791 ORGANIZER:MAILTO:jsmith@host.com 7792 DTSTART:19980313T141711Z 7793 DTEND:19980410T141711Z 7794 FREEBUSY:19980314T233000Z/19980315T003000Z 7795 FREEBUSY:19980316T153000Z/19980316T163000Z 7796 FREEBUSY:19980318T030000Z/19980318T040000Z 7797 URL:http://www.host.com/calendar/busytime/jsmith.ifb 7798 END:VFREEBUSY 7799 END:VCALENDAR 7800 7801 6 Recommended Practices 7802 7803 These recommended practices should be followed in order to assure 7804 consistent handling of the following cases for an iCalendar object. 7805 7806 1. Content lines longer than 75 octets SHOULD be folded. 7807 7808 2. A calendar entry with a "DTSTART" property but no "DTEND" 7809 property does not take up any time. It is intended to represent 7810 an event that is associated with a given calendar date and time 7811 of day, such as an anniversary. Since the event does not take up 7812 any time, it MUST NOT be used to record busy time no matter what 7813 the value for the "TRANSP" property. 7814 7815 3. When the "DTSTART" and "DTEND", for "VEVENT", "VJOURNAL" and 7816 "VFREEBUSY" calendar components, and "DTSTART" and "DUE", for 7817 "VTODO" calendar components, have the same value data type (e.g., 7818 DATE-TIME), they SHOULD specify values in the same time format 7819 (e.g., UTC time format). 7820 7821 4. When the combination of the "RRULE" and "RDATE" properties on an 7822 iCalendar object produces multiple instances having the same 7823 start date/time, they should be collapsed to, and considered as, 7824 a single instance. 7825 7826 5. When a calendar user receives multiple requests for the same 7827 calendar component (e.g., REQUEST for a "VEVENT" calendar 7828 component) as a result of being on multiple mailing lists 7829 specified by "ATTENDEE" properties in the request, they SHOULD 7830 respond to only one of the requests. The calendar user SHOULD 7831 also specify (using the "MEMBER" parameter of the "ATTENDEE" 7832 property) which mailing list they are a member of. 7833 7834 6. An implementation can truncate a "SUMMARY" property value to 255 7835 characters. 7836 7837 7838 7839 7840 7841 7842 Dawson & Stenerson Standards Track [Page 140] 7843 7844 RFC 2445 iCalendar November 1998 7845 7846 7847 7. If seconds of the minute are not supported by an implementation, 7848 then a value of "00" SHOULD be specified for the seconds 7849 component in a time value. 7850 7851 8. If the value type parameter (VALUE=) contains an unknown value 7852 type, it SHOULD be treated as TEXT. 7853 7854 9. TZURL values SHOULD NOT be specified as a FILE URI type. This URI 7855 form can be useful within an organization, but is problematic in 7856 the Internet. 7857 7858 10. Some possible English values for CATEGORIES property include 7859 "ANNIVERSARY", "APPOINTMENT", "BUSINESS", "EDUCATION", 7860 "HOLIDAY", "MEETING", "MISCELLANEOUS", "NON-WORKING HOURS", "NOT 7861 IN OFFICE", "PERSONAL", "PHONE CALL", "SICK DAY", "SPECIAL 7862 OCCASION", "TRAVEL", "VACATION". Categories can be specified in 7863 any registered language. 7864 7865 11. Some possible English values for RESOURCES property include 7866 "CATERING", "CHAIRS", "COMPUTER PROJECTOR", "EASEL", "OVERHEAD 7867 PROJECTOR", "SPEAKER PHONE", "TABLE", "TV", "VCR", "VIDEO 7868 PHONE", "VEHICLE". Resources can be specified in any registered 7869 language. 7870 7871 7 Registration of Content Type Elements 7872 7873 This section provides the process for registration of MIME 7874 Calendaring and Scheduling Content Type iCalendar object methods and 7875 new or modified properties. 7876 7877 7.1 Registration of New and Modified iCalendar Object Methods 7878 7879 New MIME Calendaring and Scheduling Content Type iCalendar object 7880 methods are registered by the publication of an IETF Request for 7881 Comments (RFC). Changes to an iCalendar object method are registered 7882 by the publication of a revision of the RFC defining the method. 7883 7884 7.2 Registration of New Properties 7885 7886 This section defines procedures by which new properties or enumerated 7887 property values for the MIME Calendaring and Scheduling Content Type 7888 can be registered with the IANA. Non-IANA properties can be used by 7889 bilateral agreement, provided the associated properties names follow 7890 the "X-" convention. 7891 7892 The procedures defined here are designed to allow public comment and 7893 review of new properties, while posing only a small impediment to the 7894 definition of new properties. 7895 7896 7897 7898 Dawson & Stenerson Standards Track [Page 141] 7899 7900 RFC 2445 iCalendar November 1998 7901 7902 7903 Registration of a new property is accomplished by the following 7904 steps. 7905 7906 7.2.1 Define the property 7907 7908 A property is defined by completing the following template. 7909 7910 To: ietf-calendar@imc.org 7911 7912 Subject: Registration of text/calendar MIME property XXX 7913 7914 Property name: 7915 7916 Property purpose: 7917 7918 Property value type(s): 7919 7920 Property parameter (s): 7921 7922 Conformance: 7923 7924 Description: 7925 7926 Format definition: 7927 7928 Examples: 7929 7930 The meaning of each field in the template is as follows. 7931 7932 Property name: The name of the property, as it will appear in the 7933 body of an text/calendar MIME Content-Type "property: value" line to 7934 the left of the colon ":". 7935 7936 Property purpose: The purpose of the property (e.g., to indicate a 7937 delegate for the event or to-do, etc.). Give a short but clear 7938 description. 7939 7940 Property value type (s): Any of the valid value types for the 7941 property value needs to be specified. The default value type also 7942 needs to be specified. If a new value type is specified, it needs to 7943 be declared in this section. 7944 7945 Property parameter (s): Any of the valid property parameters for the 7946 property needs to be specified. 7947 7948 Conformance: The calendar components that the property can appear in 7949 needs to be specified. 7950 7951 7952 7953 7954 Dawson & Stenerson Standards Track [Page 142] 7955 7956 RFC 2445 iCalendar November 1998 7957 7958 7959 Description: Any special notes about the property, how it is to be 7960 used, etc. 7961 7962 Format definition: The ABNF for the property definition needs to be 7963 specified. 7964 7965 Examples: One or more examples of instances of the property needs to 7966 be specified. 7967 7968 7.2.2 Post the Property definition 7969 7970 The property description MUST be posted to the new property 7971 discussion list, ietf-calendar@imc.org. 7972 7973 7.2.3 Allow a comment period 7974 7975 Discussion on the new property MUST be allowed to take place on the 7976 list for a minimum of two weeks. Consensus MUST be reached on the 7977 property before proceeding to the next step. 7978 7979 7.2.4 Submit the property for approval 7980 7981 Once the two-week comment period has elapsed, and the proposer is 7982 convinced consensus has been reached on the property, the 7983 registration application should be submitted to the Method Reviewer 7984 for approval. The Method Reviewer is appointed to the Application 7985 Area Directors and can either accept or reject the property 7986 registration. An accepted registration should be passed on by the 7987 Method Reviewer to the IANA for inclusion in the official IANA method 7988 registry. The registration can be rejected for any of the following 7989 reasons. 1) Insufficient comment period; 2) Consensus not reached; 3) 7990 Technical deficiencies raised on the list or elsewhere have not been 7991 addressed. The Method Reviewer's decision to reject a property can be 7992 appealed by the proposer to the IESG, or the objections raised can be 7993 addressed by the proposer and the property resubmitted. 7994 7995 7.3 Property Change Control 7996 7997 Existing properties can be changed using the same process by which 7998 they were registered. 7999 8000 1. Define the change 8001 8002 2. Post the change 8003 8004 3. Allow a comment period 8005 8006 4. Submit the property for approval 8007 8008 8009 8010 Dawson & Stenerson Standards Track [Page 143] 8011 8012 RFC 2445 iCalendar November 1998 8013 8014 8015 Note that the original author or any other interested party can 8016 propose a change to an existing property, but that such changes 8017 should only be proposed when there are serious omissions or errors in 8018 the published memo. The Method Reviewer can object to a change if it 8019 is not backward compatible, but is not required to do so. 8020 8021 Property definitions can never be deleted from the IANA registry, but 8022 properties which are no longer believed to be useful can be declared 8023 OBSOLETE by a change to their "intended use" field. 8024 8025 8 References 8026 8027 [IMIP] Dawson, F., Mansour, S. and S. Silverberg, "iCalendar 8028 Message-based Interoperability Protocol (IMIP)", RFC 2447, 8029 November 1998. 8030 8031 [ITIP] Silverberg, S., Mansour, S., Dawson, F. and R. Hopson, 8032 "iCalendar Transport-Independent Interoperability Protocol 8033 (iTIP) : Scheduling Events, Busy Time, To-dos and Journal 8034 Entries", RFC 2446, November 1998. 8035 8036 [ISO 8601] ISO 8601, "Data elements and interchange formats- 8037 Information interchange--Representation of dates and 8038 times", International Organization for Standardization, 8039 June, 1988. 8040 8041 [ISO 9070] ISO/IEC 9070, "Information Technology_SGML Support 8042 Facilities--Registration Procedures for Public Text Owner 8043 Identifiers", Second Edition, International Organization 8044 for Standardization, April 1991. 8045 8046 [RFC 822] Crocker, D., "Standard for the Format of ARPA Internet 8047 Text Messages", STD 11, RFC 822, August 1982. 8048 8049 [RFC 1738] Berners-Lee, T., Masinter, L. and M. McCahill, "Uniform 8050 Resource Locators (URL)", RFC 1738, December 1994. 8051 8052 [RFC 1766] Alvestrand, H., "Tags for the Identification of 8053 Languages", RFC 1766, March 1995. 8054 8055 [RFC 2045] Freed, N. and N. Borenstein, " Multipurpose Internet Mail 8056 Extensions (MIME) - Part One: Format of Internet Message 8057 Bodies", RFC 2045, November 1996. 8058 8059 [RFC 2046] Freed, N. and N. Borenstein, " Multipurpose Internet Mail 8060 Extensions (MIME) - Part Two: Media Types", RFC 2046, 8061 November 1996. 8062 8063 8064 8065 8066 Dawson & Stenerson Standards Track [Page 144] 8067 8068 RFC 2445 iCalendar November 1998 8069 8070 8071 [RFC 2048] Freed, N., Klensin, J. and J. Postel, "Multipurpose 8072 Internet Mail Extensions (MIME) - Part Four: Registration 8073 Procedures", RFC 2048, January 1997. 8074 8075 [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate 8076 Requirement Levels", BCP 14, RFC 2119, March 1997. 8077 8078 [RFC 2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 8079 Specifications: ABNF", RFC 2234, November 1997. 8080 8081 [RFC 2279] Yergeau, F., "UTF-8, a transformation format of ISO 8082 10646", RFC 2279, January 1998. 8083 8084 [RFC 2425] Howes, T., Smith, M. and F. Dawson, "A MIME Content-Type 8085 for Directory Information", RFC 2425, September 1998. 8086 8087 [RFC 2426] Dawson, F. and T. Howes, "vCard MIME Directory Profile", 8088 RFC 2426, September 1998. 8089 8090 [TZ] Olson, A.D., et al, Time zone code and data, 8091 ftp://elsie.nci.nih.gov/pub/, updated periodically. 8092 8093 [VCAL] Internet Mail Consortium, "vCalendar - The Electronic 8094 Calendaring and Scheduling Exchange Format", 8095 http://www.imc.org/pdi/vcal-10.txt, September 18, 1996. 8096 8097 9 Acknowledgments 8098 8099 A hearty thanks to the IETF Calendaring and Scheduling Working Group 8100 and also the following individuals who have participated in the 8101 drafting, review and discussion of this memo: 8102 8103 Roland Alden, Harald T. Alvestrand, Eric Berman, Denis Bigorgne, John 8104 Binici, Bill Bliss, Philippe Boucher, Steve Carter, Andre 8105 Courtemanche, Dave Crocker, David Curley, Alec Dun, John Evans, Ross 8106 Finlayson, Randell Flint, Ned Freed, Patrik Faltstrom, Chuck 8107 Grandgent, Mark Handley, Steve Hanna, Paul B. Hill, Paul Hoffman, 8108 Ross Hopson, Mark Horton, Daryl Huff, Bruce Kahn, C. Harald Koch, 8109 Ryan Jansen, Don Lavange, Antoine Leca, Theodore Lorek, Steve 8110 Mansour, Skip Montanaro, Keith Moore, Cecil Murray, Chris Newman, 8111 John Noerenberg, Ralph Patterson, Pete Resnick, Keith Rhodes, Robert 8112 Ripberger, John Rose, Doug Royer, Andras Salamar, Ted Schuh, Vinod 8113 Seraphin, Derrick Shadel, Ken Shan, Andrew Shuman, Steve Silverberg, 8114 William P. Spencer, John Sun, Mark Towfiq, Yvonne Tso, Robert Visnov, 8115 James L. Weiner, Mike Weston, William Wyatt. 8116 8117 8118 8119 8120 8121 8122 Dawson & Stenerson Standards Track [Page 145] 8123 8124 RFC 2445 iCalendar November 1998 8125 8126 8127 10 Authors' and Chairs' Addresses 8128 8129 The following address information is provided in a MIME-VCARD, 8130 Electronic Business Card, format. 8131 8132 The authors of this memo are: 8133 8134 BEGIN:VCARD 8135 VERSION:3.0 8136 N:Dawson;Frank 8137 FN:Frank Dawson 8138 ORG:Lotus Development Corporation 8139 ADR;TYPE=WORK,POSTAL,PARCEL:;;6544 Battleford Drive; 8140 Raleigh;NC;27613-3502;USA 8141 TEL;TYPE=WORK,MSG:+1-919-676-9515 8142 TEL;TYPE=WORK,FAX:+1-919-676-9564 8143 EMAIL;TYPE=PREF,INTERNET:Frank_Dawson@Lotus.com 8144 EMAIL;TYPE=INTERNET:fdawson@earthlink.net 8145 URL:http://home.earthlink.net/~fdawson 8146 END:VCARD 8147 8148 BEGIN:VCARD 8149 VERSION:3.0 8150 N:Stenerson;Derik 8151 FN:Derik Stenerson 8152 ORG:Microsoft Corporation 8153 ADR;TYPE=WORK,POSTAL,PARCEL:;;One Microsoft Way; 8154 Redmond;WA;98052-6399;USA 8155 TEL;TYPE=WORK,MSG:+1-425-936-5522 8156 TEL;TYPE=WORK,FAX:+1-425-936-7329 8157 EMAIL;TYPE=INTERNET:deriks@Microsoft.com 8158 END:VCARD 8159 8160 The iCalendar object is a result of the work of the Internet 8161 Engineering Task Force Calendaring and Scheduling Working Group. The 8162 chairmen of that working group are: 8163 8164 BEGIN:VCARD 8165 VERSION:3.0 8166 N:Ganguly;Anik 8167 FN:Anik Ganguly 8168 ORG: Open Text Inc. 8169 ADR;TYPE=WORK,POSTAL,PARCEL:;Suite 101;38777 West Six Mile Road; 8170 Livonia;MI;48152;USA 8171 TEL;TYPE=WORK,MSG:+1-734-542-5955 8172 EMAIL;TYPE=INTERNET:ganguly@acm.org 8173 END:VCARD 8174 8175 8176 8177 8178 Dawson & Stenerson Standards Track [Page 146] 8179 8180 RFC 2445 iCalendar November 1998 8181 8182 8183 The co-chairman of that working group is: 8184 8185 BEGIN:VCARD 8186 VERSION:3.0 8187 N:Moskowitz;Robert 8188 FN:Robert Moskowitz 8189 EMAIL;TYPE=INTERNET:rgm-ietf@htt-consult.com 8190 END:VCARD 8191 8192 8193 8194 8195 8196 8197 8198 8199 8200 8201 8202 8203 8204 8205 8206 8207 8208 8209 8210 8211 8212 8213 8214 8215 8216 8217 8218 8219 8220 8221 8222 8223 8224 8225 8226 8227 8228 8229 8230 8231 8232 8233 8234 Dawson & Stenerson Standards Track [Page 147] 8235 8236 RFC 2445 iCalendar November 1998 8237 8238 8239 11. Full Copyright Statement 8240 8241 Copyright (C) The Internet Society (1998). All Rights Reserved. 8242 8243 This document and translations of it may be copied and furnished to 8244 others, and derivative works that comment on or otherwise explain it 8245 or assist in its implementation may be prepared, copied, published 8246 and distributed, in whole or in part, without restriction of any 8247 kind, provided that the above copyright notice and this paragraph are 8248 included on all such copies and derivative works. However, this 8249 document itself may not be modified in any way, such as by removing 8250 the copyright notice or references to the Internet Society or other 8251 Internet organizations, except as needed for the purpose of 8252 developing Internet standards in which case the procedures for 8253 copyrights defined in the Internet Standards process must be 8254 followed, or as required to translate it into languages other than 8255 English. 8256 8257 The limited permissions granted above are perpetual and will not be 8258 revoked by the Internet Society or its successors or assigns. 8259 8260 This document and the information contained herein is provided on an 8261 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 8262 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 8263 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 8264 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 8265 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 8266 8267 8268 8269 8270 8271 8272 8273 8274 8275 8276 8277 8278 8279 8280 8281 8282 8283 8284 8285 8286 8287 8288 8289 8290 Dawson & Stenerson Standards Track [Page 148] 8291