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'CLDR' -- Possible downref: Non-RFC (?) normative reference: ref. 'COLORS' -- Possible downref: Non-RFC (?) normative reference: ref. 'TZDB' Summary: 0 errors (**), 0 flaws (~~), 11 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Calendaring extensions N. Jenkins 3 Internet-Draft R. Stepanek 4 Intended status: Standards Track Fastmail 5 Expires: April 19, 2021 October 16, 2020 7 JSCalendar: A JSON representation of calendar data 8 draft-ietf-calext-jscalendar-32 10 Abstract 12 This specification defines a data model and JSON representation of 13 calendar data that can be used for storage and data exchange in a 14 calendaring and scheduling environment. It aims to be an alternative 15 and, over time, successor to the widely deployed iCalendar data 16 format, and to be unambiguous, extendable, and simple to process. In 17 contrast to the jCal format, which is also JSON-based, JSCalendar is 18 not a direct mapping from iCalendar, but defines the data model 19 independently and expands semantics where appropriate. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on April 19, 2021. 38 Copyright Notice 40 Copyright (c) 2020 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (https://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 56 1.1. Motivation and Relation to iCalendar and jCal . . . . . . 5 57 1.2. Notational Conventions . . . . . . . . . . . . . . . . . 6 58 1.3. Type Signatures . . . . . . . . . . . . . . . . . . . . . 6 59 1.4. Data Types . . . . . . . . . . . . . . . . . . . . . . . 7 60 1.4.1. Id . . . . . . . . . . . . . . . . . . . . . . . . . 7 61 1.4.2. Int . . . . . . . . . . . . . . . . . . . . . . . . . 7 62 1.4.3. UnsignedInt . . . . . . . . . . . . . . . . . . . . . 8 63 1.4.4. UTCDateTime . . . . . . . . . . . . . . . . . . . . . 8 64 1.4.5. LocalDateTime . . . . . . . . . . . . . . . . . . . . 8 65 1.4.6. Duration . . . . . . . . . . . . . . . . . . . . . . 9 66 1.4.7. SignedDuration . . . . . . . . . . . . . . . . . . . 10 67 1.4.8. TimeZoneId . . . . . . . . . . . . . . . . . . . . . 10 68 1.4.9. PatchObject . . . . . . . . . . . . . . . . . . . . . 11 69 1.4.10. Relation . . . . . . . . . . . . . . . . . . . . . . 12 70 1.4.11. Link . . . . . . . . . . . . . . . . . . . . . . . . 12 71 2. JSCalendar Objects . . . . . . . . . . . . . . . . . . . . . 14 72 2.1. JSEvent . . . . . . . . . . . . . . . . . . . . . . . . . 14 73 2.2. JSTask . . . . . . . . . . . . . . . . . . . . . . . . . 14 74 2.3. JSGroup . . . . . . . . . . . . . . . . . . . . . . . . . 14 75 3. Structure of JSCalendar Objects . . . . . . . . . . . . . . . 15 76 3.1. Object Type . . . . . . . . . . . . . . . . . . . . . . . 15 77 3.2. Normalization and Equivalence . . . . . . . . . . . . . . 15 78 3.3. Vendor-specific Property Extensions, Values and Types . . 15 79 4. Common JSCalendar Properties . . . . . . . . . . . . . . . . 16 80 4.1. Metadata Properties . . . . . . . . . . . . . . . . . . . 16 81 4.1.1. @type . . . . . . . . . . . . . . . . . . . . . . . . 16 82 4.1.2. uid . . . . . . . . . . . . . . . . . . . . . . . . . 16 83 4.1.3. relatedTo . . . . . . . . . . . . . . . . . . . . . . 17 84 4.1.4. prodId . . . . . . . . . . . . . . . . . . . . . . . 17 85 4.1.5. created . . . . . . . . . . . . . . . . . . . . . . . 17 86 4.1.6. updated . . . . . . . . . . . . . . . . . . . . . . . 18 87 4.1.7. sequence . . . . . . . . . . . . . . . . . . . . . . 18 88 4.1.8. method . . . . . . . . . . . . . . . . . . . . . . . 18 89 4.2. What and Where Properties . . . . . . . . . . . . . . . . 18 90 4.2.1. title . . . . . . . . . . . . . . . . . . . . . . . . 18 91 4.2.2. description . . . . . . . . . . . . . . . . . . . . . 18 92 4.2.3. descriptionContentType . . . . . . . . . . . . . . . 18 93 4.2.4. showWithoutTime . . . . . . . . . . . . . . . . . . . 19 94 4.2.5. locations . . . . . . . . . . . . . . . . . . . . . . 19 95 4.2.6. virtualLocations . . . . . . . . . . . . . . . . . . 20 96 4.2.7. links . . . . . . . . . . . . . . . . . . . . . . . . 21 97 4.2.8. locale . . . . . . . . . . . . . . . . . . . . . . . 21 98 4.2.9. keywords . . . . . . . . . . . . . . . . . . . . . . 22 99 4.2.10. categories . . . . . . . . . . . . . . . . . . . . . 22 100 4.2.11. color . . . . . . . . . . . . . . . . . . . . . . . . 22 101 4.3. Recurrence Properties . . . . . . . . . . . . . . . . . . 22 102 4.3.1. recurrenceId . . . . . . . . . . . . . . . . . . . . 23 103 4.3.2. recurrenceRules . . . . . . . . . . . . . . . . . . . 23 104 4.3.3. excludedRecurrenceRules . . . . . . . . . . . . . . . 31 105 4.3.4. recurrenceOverrides . . . . . . . . . . . . . . . . . 32 106 4.3.5. excluded . . . . . . . . . . . . . . . . . . . . . . 33 107 4.4. Sharing and Scheduling Properties . . . . . . . . . . . . 33 108 4.4.1. priority . . . . . . . . . . . . . . . . . . . . . . 33 109 4.4.2. freeBusyStatus . . . . . . . . . . . . . . . . . . . 33 110 4.4.3. privacy . . . . . . . . . . . . . . . . . . . . . . . 34 111 4.4.4. replyTo . . . . . . . . . . . . . . . . . . . . . . . 35 112 4.4.5. participants . . . . . . . . . . . . . . . . . . . . 35 113 4.5. Alerts Properties . . . . . . . . . . . . . . . . . . . . 41 114 4.5.1. useDefaultAlerts . . . . . . . . . . . . . . . . . . 41 115 4.5.2. alerts . . . . . . . . . . . . . . . . . . . . . . . 41 116 4.6. Multilingual Properties . . . . . . . . . . . . . . . . . 43 117 4.6.1. localizations . . . . . . . . . . . . . . . . . . . . 43 118 4.7. Time Zone Properties . . . . . . . . . . . . . . . . . . 44 119 4.7.1. timeZone . . . . . . . . . . . . . . . . . . . . . . 44 120 4.7.2. timeZones . . . . . . . . . . . . . . . . . . . . . . 44 121 5. Type-specific JSCalendar Properties . . . . . . . . . . . . . 47 122 5.1. JSEvent Properties . . . . . . . . . . . . . . . . . . . 47 123 5.1.1. start . . . . . . . . . . . . . . . . . . . . . . . . 47 124 5.1.2. duration . . . . . . . . . . . . . . . . . . . . . . 47 125 5.1.3. status . . . . . . . . . . . . . . . . . . . . . . . 47 126 5.2. JSTask Properties . . . . . . . . . . . . . . . . . . . . 48 127 5.2.1. due . . . . . . . . . . . . . . . . . . . . . . . . . 48 128 5.2.2. start . . . . . . . . . . . . . . . . . . . . . . . . 48 129 5.2.3. estimatedDuration . . . . . . . . . . . . . . . . . . 48 130 5.2.4. percentComplete . . . . . . . . . . . . . . . . . . . 48 131 5.2.5. progress . . . . . . . . . . . . . . . . . . . . . . 48 132 5.2.6. progressUpdated . . . . . . . . . . . . . . . . . . . 49 133 5.3. JSGroup Properties . . . . . . . . . . . . . . . . . . . 49 134 5.3.1. entries . . . . . . . . . . . . . . . . . . . . . . . 50 135 5.3.2. source . . . . . . . . . . . . . . . . . . . . . . . 50 136 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 50 137 6.1. Simple event . . . . . . . . . . . . . . . . . . . . . . 51 138 6.2. Simple task . . . . . . . . . . . . . . . . . . . . . . . 51 139 6.3. Simple group . . . . . . . . . . . . . . . . . . . . . . 51 140 6.4. All-day event . . . . . . . . . . . . . . . . . . . . . . 52 141 6.5. Task with a due date . . . . . . . . . . . . . . . . . . 52 142 6.6. Event with end time zone . . . . . . . . . . . . . . . . 53 143 6.7. Floating-time event (with recurrence) . . . . . . . . . . 53 144 6.8. Event with multiple locations and localization . . . . . 54 145 6.9. Recurring event with overrides . . . . . . . . . . . . . 55 146 6.10. Recurring event with participants . . . . . . . . . . . . 56 147 7. Security Considerations . . . . . . . . . . . . . . . . . . . 58 148 7.1. Expanding Recurrences . . . . . . . . . . . . . . . . . . 58 149 7.2. JSON Parsing . . . . . . . . . . . . . . . . . . . . . . 59 150 7.3. URI Values . . . . . . . . . . . . . . . . . . . . . . . 59 151 7.4. Spam . . . . . . . . . . . . . . . . . . . . . . . . . . 60 152 7.5. Duplication . . . . . . . . . . . . . . . . . . . . . . . 60 153 7.6. Time Zones . . . . . . . . . . . . . . . . . . . . . . . 60 154 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 61 155 8.1. Media Type Registration . . . . . . . . . . . . . . . . . 61 156 8.2. Creation of "JSCalendar Properties" Registry . . . . . . 62 157 8.2.1. Preliminary Community Review . . . . . . . . . . . . 63 158 8.2.2. Submit Request to IANA . . . . . . . . . . . . . . . 63 159 8.2.3. Designated Expert Review . . . . . . . . . . . . . . 63 160 8.2.4. Change Procedures . . . . . . . . . . . . . . . . . . 63 161 8.2.5. JSCalendar Properties Registry Template . . . . . . . 64 162 8.2.6. Initial Contents for the JSCalendar Properties 163 Registry . . . . . . . . . . . . . . . . . . . . . . 64 164 8.3. Creation of "JSCalendar Types" Registry . . . . . . . . . 73 165 8.3.1. JSCalendar Types Registry Template . . . . . . . . . 73 166 8.3.2. Initial Contents for the JSCalendar Types Registry . 73 167 8.4. Creation of "JSCalendar Enum Values" Registry . . . . . . 74 168 8.4.1. JSCalendar Enum Property Template . . . . . . . . . . 74 169 8.4.2. JSCalendar Enum Value Template . . . . . . . . . . . 75 170 8.4.3. Initial Contents for the JSCalendar Enum Values 171 registry . . . . . . . . . . . . . . . . . . . . . . 75 172 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 81 173 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 81 174 10.1. Normative References . . . . . . . . . . . . . . . . . . 82 175 10.2. Informative References . . . . . . . . . . . . . . . . . 84 176 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 85 178 1. Introduction 180 This document defines a data model for calendar event and task 181 objects, or groups of such objects, in electronic calendar 182 applications and systems. The format aims to be unambiguous, 183 extendable and simple to process. 185 The key design considerations for this data model are as follows: 187 o The attributes of the calendar entry represented must be described 188 as simple key-value pairs. Simple events are simple to represent; 189 complex events can be modelled accurately. 191 o Wherever possible, there should be only one way to express the 192 desired semantics, reducing complexity. 194 o The data model should avoid ambiguities, which often lead to 195 interoperability issues between implementations. 197 o The data model should be generally compatible with the iCalendar 198 data format [RFC5545] [RFC7986] and extensions, but the 199 specification should add new attributes where the iCalendar format 200 currently lacks expressivity, and drop seldom-used, obsolete, or 201 redundant properties. This means translation with no loss of 202 semantics should be easy with most common iCalendar files. 204 o Extensions, such as new properties and components, should not 205 require updates to this document. 207 The representation of this data model is defined in the I-JSON format 208 [RFC7493], which is a strict subset of the JavaScript Object Notation 209 (JSON) Data Interchange Format [RFC8259]. Using JSON is mostly a 210 pragmatic choice: its widespread use makes JSCalendar easier to 211 adopt, and the ready availability of production-ready JSON 212 implementations eliminates a whole category of parser-related 213 interoperability issues, which iCalendar has often suffered from. 215 1.1. Motivation and Relation to iCalendar and jCal 217 The iCalendar data format [RFC5545], a widely deployed interchange 218 format for calendaring and scheduling data, has served calendaring 219 vendors for a long while, but contains some ambiguities and pitfalls 220 that can not be overcome without backward-incompatible changes. 222 Sources of implementation errors include the following: 224 o iCalendar defines various formats for local times, UTC time, and 225 dates. 227 o iCalendar requires custom time zone definitions within a single 228 calendar component. 230 o iCalendar's definition of recurrence rules is ambiguous and has 231 resulted in differing understandings even between experienced 232 calendar developers. 234 o The iCalendar format itself causes interoperability issues due to 235 misuse of CRLF-terminated strings, line continuations, and subtle 236 differences among iCalendar parsers. 238 In recent years, many new products and services have appeared that 239 wish to use a JSON representation of calendar data within their APIs. 240 The JSON format for iCalendar data, jCal [RFC7265], is a direct 241 mapping between iCalendar and JSON. In its effort to represent full 242 iCalendar semantics, it inherits all the same pitfalls and uses a 243 complicated JSON structure. 245 As a consequence, since the standardization of jCal, the majority of 246 implementations and service providers either kept using iCalendar, or 247 came up with their own proprietary JSON representations, which are 248 incompatible with each other and often suffer from common pitfalls, 249 such as storing event start times in UTC (which become incorrect if 250 the timezone's rules change in the future). JSCalendar meets the 251 demand for JSON-formatted calendar data that is free of such known 252 problems and provides a standard representation as an alternative to 253 the proprietary formats. 255 1.2. Notational Conventions 257 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 258 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 259 "OPTIONAL" in this document are to be interpreted as described in BCP 260 14 [RFC2119] [RFC8174] when, and only when, they appear in all 261 capitals, as shown here. 263 The underlying format used for this specification is JSON. 264 Consequently, the terms "object" and "array" as well as the four 265 primitive types (strings, numbers, booleans, and null) are to be 266 interpreted as described in Section 1 of [RFC8259]. 268 Some examples in this document contain "partial" JSON documents used 269 for illustrative purposes. In these examples, three periods "..." 270 are used to indicate a portion of the document that has been removed 271 for compactness. 273 1.3. Type Signatures 275 Type signatures are given for all JSON values in this document. The 276 following conventions are used: 278 o "*" - The type is undefined (the value could be any type, although 279 permitted values may be constrained by the context of this value). 281 o "String" - The JSON string type. 283 o "Number" - The JSON number type. 285 o "Boolean" - The JSON boolean type. 287 o "A[B]" - A JSON object where the keys are all of type "A", and the 288 values are all of type "B". 290 o "A[]" - An array of values of type "A". 292 o "A|B" - The value is either of type "A" or of type "B". 294 Other types may also be given, with their representations defined 295 elsewhere in this document. 297 1.4. Data Types 299 In addition to the standard JSON data types, the following data types 300 are used in this specification: 302 1.4.1. Id 304 Where "Id" is given as a data type, it means a "String" of at least 1 305 and a maximum of 255 octets in size, and it MUST only contain 306 characters from the "URL and Filename Safe" base64url alphabet, as 307 defined in Section 5 of [RFC4648], excluding the pad character ("="). 308 This means the allowed characters are the ASCII alphanumeric 309 characters ("A-Za-z0-9"), hyphen ("-"), and underscore ("_"). 311 In many places in JSCalendar a JSON map is used where the map keys 312 are of type Id and the map values are all the same type of object. 313 This construction represents an unordered set of objects, with the 314 added advantage that each entry has a name (the corresponding map 315 key). This allows for more concise patching of objects, and, when 316 applicable, for the objects in question to be referenced from other 317 objects within the JSCalendar object. 319 Unless otherwise specified for a particular property, there are no 320 uniqueness constraints on an Id value (other than, of course, the 321 requirement that you cannot have two values with the same key within 322 a single JSON map). For example, two JSEvent objects might use the 323 same Ids in their respective "links" properties. Or within the same 324 JSEvent object the same Id could appear in the "participants" and 325 "alerts" properties. These situations do not imply any semantic 326 connections among the objects. 328 Nevertheless, a UUID [RFC4122] is typically a good choice. 330 1.4.2. Int 332 Where "Int" is given as a data type, it means an integer in the range 333 -2^53+1 <= value <= 2^53-1, the safe range for integers stored in a 334 floating-point double, represented as a JSON "Number". 336 1.4.3. UnsignedInt 338 Where "UnsignedInt" is given as a data type, it means an integer in 339 the range 0 <= value <= 2^53-1, represented as a JSON "Number". 341 1.4.4. UTCDateTime 343 This is a string in [RFC3339] "date-time" format, with the further 344 restrictions that any letters MUST be in uppercase, and the time 345 offset MUST be the character "Z". Fractional second values MUST NOT 346 be included unless non-zero and MUST NOT have trailing zeros, to 347 ensure there is only a single representation for each date-time. 349 For example "2010-10-10T10:10:10.003Z" is conformant, but 350 "2010-10-10T10:10:10.000Z" is invalid and is correctly encoded as 351 "2010-10-10T10:10:10Z". 353 1.4.5. LocalDateTime 355 This is a date-time string with no time zone/offset information. It 356 is otherwise in the same format as UTCDateTime, including fractional 357 seconds. For example "2006-01-02T15:04:05" and 358 "2006-01-02T15:04:05.003" are both valid. The time zone to associate 359 with the LocalDateTime comes from the "timeZone" property of the 360 JSCalendar object (see Section 4.7.1). If no time zone is specified, 361 the LocalDateTime is "floating". Floating date-times are not tied to 362 any specific time zone. Instead, they occur in each time zone at the 363 given wall-clock time (as opposed to the same instant point in time). 365 A time zone may have a period of discontinuity, for example a change 366 from standard time to daylight-savings time. When converting local 367 date-times that fall in the discontinuity to UTC, the offset before 368 the transition MUST be used. 370 For example, in the America/Los_Angeles time zone, the date-time 371 2020-11-01T01:30:00 occurs twice: before the DST transition with a 372 UTC offset of -07:00, and again after the transition with an offset 373 of -08:00. When converting to UTC, we therefore use the offset 374 before the transition (-07:00) and so it becomes 375 2020-11-01T08:30:00Z. 377 Similarly, in the Australia/Melbourne time zone, the date-time 378 2020-10-04T02:30:00 does not exist: the clocks are moved forward one 379 hour for DST on that day at 02:00. However, such a value may appear 380 during calculations (see duration semantics in Section 1.4.6), or due 381 to a change in time zone rules (so it was valid when the event was 382 first created). Again, it is interpreted as though the offset before 383 the transition is in effect (+10:00), therefore when converted to UTC 384 we get 2020-10-03T16:30:00Z. 386 1.4.6. Duration 388 Where Duration is given as a type, it means a length of time 389 represented by a subset of ISO8601 duration format, as specified by 390 the following ABNF [RFC5234]: 392 dur-secfrac = "." 1*DIGIT 393 dur-second = 1*DIGIT [dur-secfrac] "S" 394 dur-minute = 1*DIGIT "M" [dur-second] 395 dur-hour = 1*DIGIT "H" [dur-minute] 396 dur-time = "T" (dur-hour / dur-minute / dur-second) 397 dur-day = 1*DIGIT "D" 398 dur-week = 1*DIGIT "W" 399 dur-cal = (dur-week [dur-day] / dur-day) 401 duration = "P" (dur-cal [dur-time] / dur-time) 403 In addition, the duration MUST NOT include fractional second values 404 unless the fraction is non-zero. Fractional second values MUST NOT 405 have trailing zeros, to ensure there is only a single representation 406 for each duration. 408 A duration specifies an abstract number of weeks, days, hours, 409 minutes, and/or seconds. A duration specified using weeks or days 410 does not always correspond to an exact multiple of 24 hours. The 411 number of hours/minutes/seconds may vary if it overlaps a period of 412 discontinuity in the event's time zone, for example a change from 413 standard time to daylight-savings time. Leap seconds MUST NOT be 414 considered when adding or subtracting a duration to/from a 415 LocalDateTime. 417 To add a duration to a LocalDateTime: 419 1. Add any week or day components of the duration to the date. A 420 week is always the same as 7 days. 422 2. If a time zone applies to the LocalDateTime, convert it to a 423 UTCDateTime following the semantics in Section 1.4.5. 425 3. Add any hour, minute or second components of the duration (in 426 absolute time). 428 4. Convert the resulting UTCDateTime back to a LocalDateTime in the 429 time zone that applies. 431 To subtract a duration from a LocalDateTime, the steps apply in 432 reverse: 434 1. If a time zone applies to the LocalDateTime, convert it to UTC 435 following the semantics in Section 1.4.5. 437 2. Subtract any hour, minute or second components of the duration 438 (in absolute time). 440 3. Convert the resulting UTCDateTime back to LocalDateTime in the 441 time zone that applies. 443 4. Subtract any week or day components of the duration from the 444 date. 446 5. If the resulting time does not exist on the date due to a 447 discontinuity in the time zone, use the semantics in 448 Section 1.4.5 to convert to UTC and back to get a valid 449 LocalDateTime. 451 These semantics match the iCalendar DURATION value type ([RFC5545], 452 Section 3.3.6). 454 1.4.7. SignedDuration 456 A SignedDuration represents a length of time that may be positive or 457 negative and is typically used to express the offset of a point in 458 time relative to an associated time. It is represented as a 459 Duration, optionally preceded by a sign character. It is specified 460 by the following ABNF: 462 signed-duration = ["+" / "-"] duration 464 A negative sign indicates a point in time at or before the associated 465 time, a positive or no sign a time at or after the associated time. 467 1.4.8. TimeZoneId 469 Where "TimeZoneId" is given as a data type, it means a "String" that 470 is either a time zone name in the IANA Time Zone Database [TZDB] or a 471 custom time zone identifier defined in the "timeZones" property (see 472 Section 4.7.2). 474 Where an IANA time zone is specified, the zone rules of the 475 respective zone records apply. Custom time zones are interpreted as 476 described in Section 4.7.2. 478 1.4.9. PatchObject 480 A PatchObject is of type "String[*]", and represents an unordered set 481 of patches on a JSON object. Each key is a path represented in a 482 subset of JSON pointer format [RFC6901]. The paths have an implicit 483 leading "/", so each key is prefixed with "/" before applying the 484 JSON pointer evaluation algorithm. 486 A patch within a PatchObject is only valid if all of the following 487 conditions apply: 489 1. The pointer MUST NOT reference inside an array (i.e., you MUST 490 NOT insert/delete from an array; the array MUST be replaced in 491 its entirety instead). 493 2. All parts prior to the last (i.e., the value after the final 494 slash) MUST already exist on the object being patched. 496 3. There MUST NOT be two patches in the PatchObject where the 497 pointer of one is the prefix of the pointer of the other, e.g., 498 "alerts/1/offset" and "alerts". 500 4. The value for the patch MUST be valid for the property being set 501 (of the correct type and obeying any other applicable 502 restrictions), or if null the property MUST be optional. 504 The value associated with each pointer determines how to apply that 505 patch: 507 o If null, remove the property from the patched object. If the key 508 is not present in the parent, this a no-op. 510 o Anything else: The value to set for this property (this may be a 511 replacement or addition to the object being patched). 513 A PatchObject does not define its own "@type" property (see 514 Section 4.1.1). A "@type" property in a patch MUST be handled as any 515 other patched property value. 517 Implementations MUST reject in its entirety a PatchObject if any of 518 its patches is invalid. Implementations MUST NOT apply partial 519 patches. 521 The PatchObject format is used to significantly reduce file size and 522 duplicated content when specifying variations to a common object, 523 such as with recurring events or when translating the data into 524 multiple languages. It can also better preserve semantic intent if 525 only the properties that should differ between the two objects are 526 patched. For example, if one person is not going to a particular 527 instance of a regularly scheduled event, in iCalendar you would have 528 to duplicate the entire event in the override. In JSCalendar this is 529 a small patch to show the difference. As only this property is 530 patched, if the location of the event is changed, the occurrence will 531 automatically still inherit this. 533 1.4.10. Relation 535 A Relation object defines the relation to other objects, using a 536 possibly empty set of relation types. The object that defines this 537 relation is the linking object, while the other object is the linked 538 object. A Relation object has the following properties: 540 o @type: "String" (mandatory) 542 Specifies the type of this object. This MUST be "Relation". 544 o relation: "String[Boolean]" (optional, default: empty Object) 546 Describes how the linked object is related to the linking object. 547 The relation is defined as a set of relation types. If empty, the 548 relationship between the two objects is unspecified. 550 Keys in the set MUST be one of the following values, or specified 551 in the property definition where the Relation object is used, or a 552 value registered in the IANA JSCalendar Enum Values registry, or a 553 vendor-specific value (see Section 3.3): 555 * "first": The linked object is the first in a series the linking 556 object is part of. 558 * "next": The linked object is the next in a series the linking 559 object is part of. 561 * "child": The linked object is a subpart of the linking object. 563 * "parent": The linking object is a subpart of the linked object. 565 The value for each key in the map MUST be true. 567 1.4.11. Link 569 A Link object represents an external resource associated with the 570 linking object. It has the following properties: 572 o @type: "String" (mandatory) 573 Specifies the type of this object. This MUST be "Link". 575 o href: "String" (mandatory) 577 A URI [RFC3986] from which the resource may be fetched. 579 This MAY be a "data:" URL [RFC2397], but it is recommended that 580 the file be hosted on a server to avoid embedding arbitrarily 581 large data in JSCalendar object instances. 583 o cid: "String" (optional) 585 This MUST be a valid "content-id" value according to the 586 definition of Section 2 in [RFC2392]. The value MUST be unique 587 within this Link object but has no meaning beyond that. It MAY be 588 different from the link id for this Link object. 590 o contentType: "String" (optional) 592 The media type [RFC6838] of the resource, if known. 594 o size: "UnsignedInt" (optional) 596 The size, in octets, of the resource when fully decoded (i.e., the 597 number of octets in the file the user would download), if known. 598 Note that this is an informational estimate, and implementations 599 must be prepared to handle the actual size being quite different 600 when the resource is fetched. 602 o rel: "String" (optional) 604 Identifies the relation of the linked resource to the object. If 605 set, the value MUST be a relation type from the IANA registry 606 [LINKRELS], as established in [RFC8288]. 608 o display: "String" (optional) 610 Describes the intended purpose of a link to an image. If set, the 611 "rel" property MUST be set to "icon". The value MUST be one of 612 the following values, another value registered in the IANA 613 JSCalendar Enum Values registry, or a vendor-specific value (see 614 Section 3.3): 616 * "badge": an image meant to be displayed alongside the title of 617 the object. 619 * "graphic": a full image replacement for the object itself. 621 * "fullsize": an image that is used to enhance the object. 623 * "thumbnail": a smaller variant of "fullsize" to be used when 624 space for the image is constrained. 626 o title: "String" (optional) 628 A human-readable plain-text description of the resource. 630 2. JSCalendar Objects 632 This section describes the calendar object types specified by 633 JSCalendar. 635 2.1. JSEvent 637 Media type: "application/jscalendar+json;type=jsevent" 639 A JSEvent represents a scheduled amount of time on a calendar, 640 typically a meeting, appointment, reminder or anniversary. It is 641 required to start at a certain point in time and typically has a non- 642 zero duration. Multiple participants may partake in the event at 643 multiple locations. 645 The @type (Section 4.1.1) property value MUST be "jsevent". 647 2.2. JSTask 649 Media type: "application/jscalendar+json;type=jstask" 651 A JSTask represents an action-item, assignment, to-do or work item. 652 It may start and be due at certain points in time, may take some 653 estimated time to complete, and may recur, none of which is required. 655 The @type (Section 4.1.1) property value MUST be "jstask". 657 2.3. JSGroup 659 Media type: "application/jscalendar+json;type=jsgroup" 661 A JSGroup is a collection of JSEvent (Section 2.1) and/or JSTask 662 (Section 2.2) objects. Typically, objects are grouped by topic 663 (e.g., by keywords) or calendar membership. 665 The @type (Section 4.1.1) property value MUST be "jsgroup". 667 3. Structure of JSCalendar Objects 669 A JSCalendar object is a JSON object [RFC8259], which MUST be valid 670 I-JSON (a stricter subset of JSON) [RFC7493]. Property names and 671 values are case-sensitive. 673 The object has a collection of properties, as specified in the 674 following sections. Properties are specified as being either 675 mandatory or optional. Optional properties may have a default value, 676 if explicitly specified in the property definition. 678 3.1. Object Type 680 JSCalendar objects MUST name their type in the "@type" property, if 681 not explicitly specified otherwise for the respective object type. A 682 notable exception to this rule is the PatchObject (Section 1.4.9). 684 3.2. Normalization and Equivalence 686 JSCalendar aims to provide unambiguous definitions for value types 687 and properties, but does not define a general normalization or 688 equivalence method for JSCalendar objects and types. This is because 689 the notion of equivalence might range from byte-level equivalence to 690 semantic equivalence, depending on the respective use case. 692 Normalization of JSCalendar objects is hindered because of the 693 following reasons: 695 o Custom JSCalendar properties may contain arbitrary JSON values, 696 including arrays. However, equivalence of arrays might or might 697 not depend on the order of elements, depending on the respective 698 property definition. 700 o Several JSCalendar property values are defined as URIs and media 701 types, but normalization of these types is inherently protocol- 702 and scheme-specific, depending on the use-case of the equivalence 703 definition (see Section 6 of [RFC3986]). 705 Considering this, the definition of equivalence and normalization is 706 left to client and server implementations and to be negotiated by a 707 calendar exchange protocol or defined elsewhere. 709 3.3. Vendor-specific Property Extensions, Values and Types 711 Vendors MAY add additional properties to the calendar object to 712 support their custom features. To avoid conflict, the names of these 713 properties MUST be prefixed by a domain name controlled by the vendor 714 followed by a colon, e.g., "example.com:customprop". If the value is 715 a new JSCalendar object, it either MUST include a "@type" property or 716 it MUST explicitly be specified to not require a type designator. 717 The type name MUST be prefixed with a domain name controlled by the 718 vendor. 720 Some JSCalendar properties allow vendor-specific value extensions. 721 Such vendor-specific values MUST be prefixed by a domain name 722 controlled by the vendor followed by a colon, e.g., 723 "example.com:customrel". 725 Vendors are strongly encouraged to register any new property values 726 or extensions that are useful to other systems as well, rather than 727 use a vendor-specific prefix. 729 4. Common JSCalendar Properties 731 This section describes the properties that are common to the various 732 JSCalendar object types. Specific JSCalendar object types may only 733 support a subset of these properties. The object type definitions in 734 Section 5 describe the set of supported properties per type. 736 4.1. Metadata Properties 738 4.1.1. @type 740 Type: "String" (mandatory). 742 Specifies the type which this object represents. This MUST be one of 743 the following values: 745 o "jsevent": a JSCalendar event (Section 2.1). 747 o "jstask": a JSCalendar task (Section 2.2). 749 o "jsgroup": a JSCalendar group (Section 2.3). 751 4.1.2. uid 753 Type: "String" (mandatory). 755 A globally unique identifier, used to associate the object as the 756 same across different systems, calendars and views. The value of 757 this property MUST be unique across all JSCalendar objects, even if 758 they are of different type. [RFC4122] describes a range of 759 established algorithms to generate universally unique identifiers 760 (UUID). UUID version 4, described in Section 4.4 of [RFC4122], is 761 RECOMMENDED. 763 For compatibility with [RFC5545] UIDs, implementations MUST be able 764 to receive and persist values of at least 255 octets for this 765 property, but they MUST NOT truncate values in the middle of a UTF-8 766 multi-octet sequence. 768 4.1.3. relatedTo 770 Type: "String[Relation]" (optional). 772 Relates the object to other JSCalendar objects. This is represented 773 as a map of the UIDs of the related objects to information about the 774 relation. 776 If an object is split to make a "this and future" change to a 777 recurrence, the original object MUST be truncated to end at the 778 previous occurrence before this split, and a new object created to 779 represent all the occurrences after the split. A "next" relation 780 MUST be set on the original object's relatedTo property for the UID 781 of the new object. A "first" relation for the UID of the first 782 object in the series MUST be set on the new object. Clients can then 783 follow these UIDs to get the complete set of objects if the user 784 wishes to modify them all at once. 786 4.1.4. prodId 788 Type: "String" (optional). 790 The identifier for the product that last updated the JSCalendar 791 object. This should be set whenever the data in the object is 792 modified (i.e., whenever the "updated" property is set). 794 The vendor of the implementation MUST ensure that this is a globally 795 unique identifier, using some technique such as an FPI value, as 796 defined in [ISO.9070.1991]. 798 This property SHOULD NOT be used to alter the interpretation of a 799 JSCalendar object beyond the semantics specified in this document. 800 For example, it is not to be used to further the understanding of 801 non-standard properties, a practice that is known to cause long-term 802 interoperability problems. 804 4.1.5. created 806 Type: "UTCDateTime" (optional). 808 The date and time this object was initially created. 810 4.1.6. updated 812 Type: "UTCDateTime" (mandatory). 814 The date and time the data in this object was last modified (or its 815 creation date/time if not modified since). 817 4.1.7. sequence 819 Type: "UnsignedInt" (optional, default: 0). 821 Initially zero, this MUST be incremented by one every time a change 822 is made to the object, except if the change only modifies the 823 "participants" property (see Section 4.4.5). 825 This is used as part of iTIP [RFC5546] to know which version of the 826 object a scheduling message relates to. 828 4.1.8. method 830 Type: "String" (optional). 832 The iTIP [RFC5546] method, in lowercase. This MUST only be present 833 if the JSCalendar object represents an iTIP scheduling message. 835 4.2. What and Where Properties 837 4.2.1. title 839 Type: "String" (optional, default: empty String). 841 A short summary of the object. 843 4.2.2. description 845 Type: "String" (optional, default: empty String). 847 A longer-form text description of the object. The content is 848 formatted according to the "descriptionContentType" property. 850 4.2.3. descriptionContentType 852 Type: "String" (optional, default: "text/plain"). 854 Describes the media type [RFC6838] of the contents of the 855 "description" property. Media types MUST be sub-types of type 856 "text", and SHOULD be "text/plain" or "text/html" [MEDIATYPES]. They 857 MAY include parameters and the "charset" parameter value MUST be 858 "utf-8", if specified. Descriptions of type "text/html" MAY contain 859 "cid" URLs [RFC2392] to reference links in the calendar object by use 860 of the "cid" property of the Link object. 862 4.2.4. showWithoutTime 864 Type: "Boolean" (optional, default: false). 866 Indicates that the time is not important to display to the user when 867 rendering this calendar object. An example of this is an event that 868 conceptually occurs all day or across multiple days, such as "New 869 Year's Day" or "Italy Vacation". While the time component is 870 important for free-busy calculations and checking for scheduling 871 clashes, calendars may choose to omit displaying it and/or display 872 the object separately to other objects to enhance the user's view of 873 their schedule. 875 Such events are also commonly known as "all-day" events. 877 4.2.5. locations 879 Type: "Id[Location]" (optional). 881 A map of location ids to Location objects, representing locations 882 associated with the object. 884 A Location object has the following properties. It MUST have at 885 least one property other than the "relativeTo" property. 887 o @type: "String" (mandatory) 889 Specifies the type of this object. This MUST be "Location". 891 o name: "String" (optional) 893 The human-readable name of the location. 895 o description: "String" (optional) 897 Human-readable, plain-text instructions for accessing this 898 location. This may be an address, set of directions, door access 899 code, etc. 901 o locationTypes: "String[Boolean]" (optional) 903 A set of one or more location types that describe this location. 904 All types MUST be from the Location Types Registry [LOCATIONTYPES] 905 as defined in [RFC4589]. The set is represented as a map, with 906 the keys being the location types. The value for each key in the 907 map MUST be true. 909 o relativeTo: "String" (optional) 911 Specifies the relation between this location and the time of the 912 JSCalendar object. This is primarily to allow events representing 913 travel to specify the location of departure (at the start of the 914 event) and location of arrival (at the end); this is particularly 915 important if these locations are in different time zones, as a 916 client may wish to highlight this information for the user. 918 This MUST be one of the following values, another value registered 919 in the IANA JSCalendar Enum Values registry, or a vendor-specific 920 value (see Section 3.3). Any value the client or server doesn't 921 understand should be treated the same as if this property is 922 omitted. 924 * "start": The event/task described by this JSCalendar object 925 occurs at this location at the time the event/task starts. 927 * "end": The event/task described by this JSCalendar object 928 occurs at this location at the time the event/task ends. 930 o timeZone: "TimeZoneId" (optional) 932 A time zone for this location. 934 o coordinates: "String" (optional) 936 A "geo:" URI [RFC5870] for the location. 938 o links: "Id[Link]" (optional) 940 A map of link ids to Link objects, representing external resources 941 associated with this location, for example a vCard or image. If 942 there are no links, this MUST be omitted (rather than specified as 943 an empty set). 945 4.2.6. virtualLocations 947 Type: "Id[VirtualLocation]" (optional). 949 A map of virtual location ids to VirtualLocation objects, 950 representing virtual locations, such as video conferences or chat 951 rooms, associated with the object. 953 A VirtualLocation object has the following properties. 955 o @type: "String" (mandatory) 957 Specifies the type of this object. This MUST be 958 "VirtualLocation". 960 o name: "String" (optional, default: empty String) 962 The human-readable name of the virtual location. 964 o description: "String" (optional) 966 Human-readable plain-text instructions for accessing this virtual 967 location. This may be a conference access code, etc. 969 o uri: "String" (mandatory) 971 A URI [RFC3986] that represents how to connect to this virtual 972 location. 974 This may be a telephone number (represented using the "tel:" 975 scheme, e.g., "tel:+1-555-555-5555") for a teleconference, a web 976 address for online chat, or any custom URI. 978 4.2.7. links 980 Type: "Id[Link]" (optional). 982 A map of link ids to Link objects, representing external resources 983 associated with the object. 985 Links with a rel of "enclosure" MUST be considered by the client as 986 attachments for download. 988 Links with a rel of "describedby" MUST be considered by the client to 989 be an alternative representation of the description. 991 Links with a rel of "icon" MUST be considered by the client to be an 992 image that it may use when presenting the calendar data to a user. 993 The "display" property may be set to indicate the purpose of this 994 image. 996 4.2.8. locale 998 Type: "String" (optional). 1000 The language tag as defined in [RFC5646] that best describes the 1001 locale used for the text in the calendar object, if known. 1003 4.2.9. keywords 1005 Type: "String[Boolean]" (optional). 1007 A set of keywords or tags that relate to the object. The set is 1008 represented as a map, with the keys being the keywords. The value 1009 for each key in the map MUST be true. 1011 4.2.10. categories 1013 Type: "String[Boolean]" (optional). 1015 A set of categories that relate to the calendar object. The set is 1016 represented as a map, with the keys being the categories specified as 1017 URIs. The value for each key in the map MUST be true. 1019 In contrast to keywords, categories typically are structured. For 1020 example, a vendor owning the domain "example.com" might define the 1021 categories "http://example.com/categories/sports/american-football" 1022 and "http://example.com/categories/music/r-b". 1024 4.2.11. color 1026 Type: "String" (optional). 1028 A color clients MAY use when displaying this calendar object. The 1029 value is a color name taken from the set of names defined in 1030 Section 4.3 of CSS Color Module Level 3 [COLORS], or an RGB value in 1031 hexadecimal notation, as defined in Section 4.2.1 of CSS Color Module 1032 Level 3. 1034 4.3. Recurrence Properties 1036 Some events and tasks occur at regular or irregular intervals. 1037 Rather than having to copy the data for every occurrence there can be 1038 a master event with rules to generate recurrences, and/or overrides 1039 that add extra dates or exceptions to the rules. 1041 The recurrence set is the complete set of instances for an object. 1042 It is generated by considering the following properties in order, all 1043 of which are optional: 1045 1. The recurrenceRules property (Section 4.3.2) generates a set of 1046 extra date-times on which the object occurs. 1048 2. The excludedRecurrenceRules property (Section 4.3.3) generates a 1049 set of date-times that are to be removed from the previously 1050 generated set of date-times on which the object occurs. 1052 3. The recurrenceOverrides property (Section 4.3.4) defines date- 1053 times which are added or excluded to form the final set. (This 1054 property may also contain changes to the object to apply to 1055 particular instances.) 1057 4.3.1. recurrenceId 1059 Type: "LocalDateTime" (optional). 1061 If present, this JSCalendar object represents one occurrence of a 1062 recurring JSCalendar object. If present the "recurrenceRules" and 1063 "recurrenceOverrides" properties MUST NOT be present. 1065 The value is a date-time either produced by the "recurrenceRules" of 1066 the master event, or added as a key to the "recurrenceOverrides" 1067 property of the master event. 1069 4.3.2. recurrenceRules 1071 Type: "RecurrenceRule[]" (optional). 1073 Defines a set of recurrence rules (repeating patterns) for recurring 1074 calendar objects. 1076 A JSEvent recurs by applying the recurrence rules to the "start" 1077 date-time. 1079 A JSTask recurs by applying the recurrence rules to the "start" date- 1080 time, if defined, otherwise it recurs by the "due" date-time, if 1081 defined. If the task defines neither a "start" nor "due" date-time, 1082 it MUST NOT define a "recurrenceRules" property. 1084 If multiple recurrence rules are given, each rule is to be applied 1085 and then the union of the results used, ignoring any duplicates. 1087 A RecurrenceRule object is a JSON object mapping of a RECUR value 1088 type in iCalendar [RFC5545] [RFC7529] and has the same semantics. It 1089 has the following properties: 1091 o @type: "String" (mandatory) 1093 Specifies the type of this object. This MUST be "RecurrenceRule". 1095 o frequency: "String" (mandatory) 1097 The time span covered by each iteration of this recurrence rule 1098 (see Section 4.3.2.1 for full semantics). This MUST be one of the 1099 following values: 1101 * "yearly" 1103 * "monthly" 1105 * "weekly" 1107 * "daily" 1109 * "hourly" 1111 * "minutely" 1113 * "secondly" 1115 This is the FREQ part from iCalendar, converted to lowercase. 1117 o interval: "UnsignedInt" (optional, default: 1) 1119 The interval of iteration periods at which the recurrence repeats. 1120 If included, it MUST be an integer >= 1. 1122 This is the INTERVAL part from iCalendar. 1124 o rscale: "String" (optional, default: "gregorian") 1126 The calendar system in which this recurrence rule operates, in 1127 lowercase. This MUST be either a CLDR-registered calendar system 1128 name [CLDR], or a vendor-specific value (see Section 3.3). 1130 This is the RSCALE part from iCalendar RSCALE [RFC7529], converted 1131 to lowercase. 1133 o skip: "String" (optional, default: "omit") 1135 The behaviour to use when the expansion of the recurrence produces 1136 invalid dates. This property only has an effect if the frequency 1137 is "yearly" or "monthly". It MUST be one of the following values: 1139 * "omit" 1141 * "backward" 1143 * "forward" 1145 This is the SKIP part from iCalendar RSCALE [RFC7529], converted 1146 to lowercase. 1148 o firstDayOfWeek: "String" (optional, default: "mo") 1149 The day on which the week is considered to start, represented as a 1150 lowercase abbreviated two-letter English day of the week. If 1151 included, it MUST be one of the following values: 1153 * "mo" 1155 * "tu" 1157 * "we" 1159 * "th" 1161 * "fr" 1163 * "sa" 1165 * "su" 1167 This is the WKST part from iCalendar. 1169 o byDay: "NDay[]" (optional) 1171 Days of the week on which to repeat. An "NDay" object has the 1172 following properties: 1174 * @type: "String" (mandatory) 1176 Specifies the type of this object. This MUST be "NDay". 1178 * day: "String" (mandatory) 1180 A day of the week on which to repeat; the allowed values are 1181 the same as for the "firstDayOfWeek" RecurrenceRule property. 1183 This is the day-of-the-week of the BYDAY part in iCalendar, 1184 converted to lowercase. 1186 * nthOfPeriod: "Int" (optional) 1188 If present, rather than representing every occurrence of the 1189 weekday defined in the "day" property, it represents only a 1190 specific instance within the recurrence period. The value can 1191 be positive or negative, but MUST NOT be zero. A negative 1192 integer means nth-last of period. 1194 This is the ordinal part of the BYDAY value in iCalendar (e.g., 1195 1 or -3). 1197 o byMonthDay: "Int[]" (optional) 1199 Days of the month on which to repeat. Valid values are between 1 1200 and the maximum number of days any month may have in the calendar 1201 given by the "rscale" property, and the negative values of these 1202 numbers. For example, in the Gregorian calendar valid values are 1203 1 to 31 and -31 to -1. Negative values offset from the end of the 1204 month. The array MUST have at least one entry if included. 1206 This is the BYMONTHDAY part in iCalendar. 1208 o byMonth: "String[]" (optional) 1210 The months in which to repeat. Each entry is a string 1211 representation of a number, starting from "1" for the first month 1212 in the calendar (e.g., "1" means January with the Gregorian 1213 calendar), with an optional "L" suffix (see [RFC7529]) for leap 1214 months (this MUST be uppercase, e.g., "3L"). The array MUST have 1215 at least one entry if included. 1217 This is the BYMONTH part from iCalendar. 1219 o byYearDay: "Int[]" (optional) 1221 The days of the year on which to repeat. Valid values are between 1222 1 and the maximum number of days any year may have in the calendar 1223 given by the "rscale" property, and the negative values of these 1224 numbers. For example, in the Gregorian calendar valid values are 1225 1 to 366 and -366 to -1. Negative values offset from the end of 1226 the year. The array MUST have at least one entry if included. 1228 This is the BYYEARDAY part from iCalendar. 1230 o byWeekNo: "Int[]" (optional) 1232 Weeks of the year in which to repeat. Valid values are between 1 1233 and the maximum number of weeks any year may have in the calendar 1234 given by the "rscale" property, and the negative values of these 1235 numbers. For example, in the Gregorian calendar valid values are 1236 1 to 53 and -53 to -1. The array MUST have at least one entry if 1237 included. 1239 This is the BYWEEKNO part from iCalendar. 1241 o byHour: "UnsignedInt[]" (optional) 1242 The hours of the day in which to repeat. Valid values are 0 to 1243 23. The array MUST have at least one entry if included. This is 1244 the BYHOUR part from iCalendar. 1246 o byMinute: "UnsignedInt[]" (optional) 1248 The minutes of the hour in which to repeat. Valid values are 0 to 1249 59. The array MUST have at least one entry if included. 1251 This is the BYMINUTE part from iCalendar. 1253 o bySecond: "UnsignedInt[]" (optional) 1255 The seconds of the minute in which to repeat. Valid values are 0 1256 to 60. The array MUST have at least one entry if included. 1258 This is the BYSECOND part from iCalendar. 1260 o bySetPosition: "Int[]" (optional) 1262 The occurrences within the recurrence interval to include in the 1263 final results. Negative values offset from the end of the list of 1264 occurrences. The array MUST have at least one entry if included. 1265 This is the BYSETPOS part from iCalendar. 1267 o count: "UnsignedInt" (optional) 1269 The number of occurrences at which to range-bound the recurrence. 1270 This MUST NOT be included if an "until" property is specified. 1272 This is the COUNT part from iCalendar. 1274 o until: "LocalDateTime" (optional) 1276 The date-time at which to finish recurring. The last occurrence 1277 is on or before this date-time. This MUST NOT be included if a 1278 "count" property is specified. Note: if not specified otherwise 1279 for a specific JSCalendar object, this date is to be interpreted 1280 in the time zone specified in the JSCalendar object's "timeZone" 1281 property. 1283 This is the UNTIL part from iCalendar. 1285 4.3.2.1. Interpreting recurrence rules 1287 A recurrence rule specifies a set of date-times for recurring 1288 calendar objects. A recurrence rule has the following semantics. 1289 Note, wherever "year", "month" or "day of month" is used, this is 1290 within the calendar system given by the "rscale" property, which 1291 defaults to "gregorian" if omitted. 1293 1. A set of candidates is generated. This is every second within a 1294 period defined by the frequency property value: 1296 * "yearly": every second from midnight on the 1st day of a year 1297 (inclusive) to midnight the 1st day of the following year 1298 (exclusive). 1300 If skip is not "omit", the calendar system has leap months and 1301 there is a byMonth property, generate candidates for the leap 1302 months even if they don't occur in this year. 1304 If skip is not "omit" and there is a byMonthDay property, 1305 presume each month has the maximum number of days any month 1306 may have in this calendar system when generating candidates, 1307 even if it's more than this month actually has. 1309 * "monthly": every second from midnight on the 1st day of a 1310 month (inclusive) to midnight on the 1st of the following 1311 month (exclusive). 1313 If skip is not "omit" and there is a byMonthDay property, 1314 presume the month has the maximum number of days any month may 1315 have in this calendar system when generating candidates, even 1316 if it's more than this month actually has. 1318 * "weekly": every second from midnight (inclusive) on the first 1319 day of the week (as defined by the firstDayOfWeek property, or 1320 Monday if omitted), to midnight 7 days later (exclusive). 1322 * "daily": every second from midnight at the start of the day 1323 (inclusive) to midnight at the end of the day (exclusive). 1325 * "hourly": every second from the beginning of the hour 1326 (inclusive) to the beginning of the next hour (exclusive). 1328 * "minutely": every second from the beginning of the minute 1329 (inclusive) to the beginning of the next minute (exclusive). 1331 * "secondly": the second itself, only. 1333 2. Each date-time candidate is compared against all of the byX 1334 properties of the rule except bySetPosition. If any property in 1335 the rule does not match the date-time, the date-time is 1336 eliminated. Each byX property is an array; the date-time matches 1337 the property if it matches any of the values in the array. The 1338 properties have the following semantics: 1340 * byMonth: the date-time is in the given month. 1342 * byWeekNo: the date-time is in the nth week of the year. 1343 Negative numbers mean the nth last week of the year. This 1344 corresponds to weeks according to week numbering as defined in 1345 ISO.8601.2004, with a week defined as a seven day period, 1346 starting on the firstDayOfWeek property value or Monday if 1347 omitted. Week number one of the calendar year is the first 1348 week that contains at least four days in that calendar year. 1350 If the date-time is not valid (this may happen when generating 1351 candidates with a skip property in effect), it is always 1352 eliminated by this property. 1354 * byYearDay: the date-time is on the nth day of year. Negative 1355 numbers mean the nth last day of the year. 1357 If the date-time is not valid (this may happen when generating 1358 candidates with a skip property in effect), it is always 1359 eliminated by this property. 1361 * byMonthDay: the date-time is on the given day of the month. 1362 Negative numbers mean the nth last day of the month. 1364 * byDay: the date-time is on the given day of the week. If the 1365 day is prefixed by a number, it is the nth occurrence of that 1366 day of the week within the month (if frequency is monthly) or 1367 year (if frequency is yearly). Negative numbers means nth 1368 last occurrence within that period. 1370 * byHour: the date-time has the given hour value. 1372 * byMinute: the date-time has the given minute value. 1374 * bySecond: the date-time has the given second value. 1376 If a skip property is defined and is not "omit", there may be 1377 candidates that do not correspond to valid dates (e.g., 31st 1378 February in the Gregorian calendar). In this case, the 1379 properties MUST be considered in the order above and: 1381 1. After applying the byMonth filter, if the candidate's month 1382 is invalid for the given year, increment it (if skip is 1383 "forward") or decrement it (if skip is "backward") until a 1384 valid month is found, incrementing/decrementing the year as 1385 well if passing through the beginning/end of the year. This 1386 only applies to calendar systems with leap months. 1388 2. After applying the byMonthDay filter, if the day of the month 1389 is invalid for the given month and year, change the date to 1390 the first day of the next month (if skip is "forward") or the 1391 last day of the current month (if skip is "backward"). 1393 3. If any valid date produced after applying the skip is already 1394 a candidate, eliminate the duplicate. (For example after 1395 adjusting, 30th February and 31st February would both become 1396 the same "real" date, so one is eliminated as a duplicate.) 1398 3. If a bySetPosition property is included, this is now applied to 1399 the ordered list of remaining dates. This property specifies the 1400 indexes of date-times to keep; all others should be eliminated. 1401 Negative numbers are indexes from the end of the list, with -1 1402 being the last item. 1404 4. Any date-times before the start date of the event are eliminated 1405 (see below for why this might be needed). 1407 5. If a skip property is included and is not "omit", eliminate any 1408 date-times that have already been produced by previous iterations 1409 of the algorithm. (This is not possible if skip is "omit".) 1411 6. If further dates are required (we have not reached the until 1412 date, or count limit) skip the next (interval - 1) sets of 1413 candidates, then continue from step 1. 1415 When determining the set of occurrence dates for an event or task, 1416 the following extra rules must be applied: 1418 1. The initial date-time to which the rule is applied (the "start" 1419 date-time for events; the "start" or "due" date-time for tasks) 1420 is always the first occurrence in the expansion (and is counted 1421 if the recurrence is limited by a "count" property), even if it 1422 would normally not match the rule. 1424 2. The first set of candidates to consider is that which would 1425 contain the initial date-time. This means the first set may 1426 include candidates before the initial date-time; such candidates 1427 are eliminated from the results in step (4) as outlined before. 1429 3. The following properties MUST be implicitly added to the rule 1430 under the given conditions: 1432 * If frequency is not "secondly" and no bySecond property: Add a 1433 bySecond property with the sole value being the seconds value 1434 of the initial date-time. 1436 * If frequency is not "secondly" or "minutely", and no byMinute 1437 property: Add a byMinute property with the sole value being 1438 the minutes value of the initial date-time. 1440 * If frequency is not "secondly", "minutely" or "hourly" and no 1441 byHour property: Add a byHour property with the sole value 1442 being the hours value of the initial date-time. 1444 * If frequency is "weekly" and no byDay property: Add a byDay 1445 property with the sole value being the day-of-the-week of the 1446 initial date-time. 1448 * If frequency is "monthly" and no byDay property and no 1449 byMonthDay property: Add a byMonthDay property with the sole 1450 value being the day-of-the-month of the initial date-time. 1452 * If frequency is "yearly" and no byYearDay property: 1454 + If there are no byMonth or byWeekNo properties, and either 1455 there is a byMonthDay property or there is no byDay 1456 property: Add a byMonth property with the sole value being 1457 the month of the initial date-time. 1459 + If there is no byMonthDay, byWeekNo or byDay properties: 1460 Add a byMonthDay property with the sole value being the 1461 day-of-the-month of the initial date-time. 1463 + If there is a byWeekNo property and no byMonthDay or byDay 1464 properties: Add a byDay property with the sole value being 1465 the day-of-the-week of the initial date-time. 1467 4.3.3. excludedRecurrenceRules 1469 Type: "RecurrenceRule[]" (optional). 1471 Defines a set of recurrence rules (repeating patterns) for date-times 1472 on which the object will not occur. The rules are interpreted the 1473 same as for the "recurrenceRules" property (see Section 4.3.2), with 1474 the exception that the initial date-time to which the rule is applied 1475 (the "start" date-time for events; the "start" or "due" date-time for 1476 tasks) is only considered part of the expansion if it matches the 1477 rule. The resulting set of date-times are then removed from those 1478 generated by the recurrenceRules property, as described in 1479 Section 4.3. 1481 4.3.4. recurrenceOverrides 1483 Type: "LocalDateTime[PatchObject]" (optional). 1485 A map of the recurrence ids (the date-time produced by the recurrence 1486 rule) to an object of patches to apply to the generated occurrence 1487 object. 1489 If the recurrence id does not match a date-time from the recurrence 1490 rule (or no rule is specified), it is to be treated as an additional 1491 occurrence (like an RDATE from iCalendar). The patch object may 1492 often be empty in this case. 1494 If the patch object defines the "excluded" property of an occurrence 1495 to be true, this occurrence is omitted from the final set of 1496 recurrences for the calendar object (like an EXDATE from iCalendar). 1497 Such a patch object MUST NOT patch any other property. 1499 By default, an occurrence inherits all properties from the main 1500 object except the start (or due) date-time, which is shifted to match 1501 the recurrence id LocalDateTime. However, individual properties of 1502 the occurrence can be modified by a patch, or multiple patches. It 1503 is valid to patch the "start" property value, and this patch takes 1504 precedence over the value generated from the recurrence id. Both the 1505 recurrence id as well as the patched "start" date-time may occur 1506 before the original JSCalendar object's "start" or "due" date. 1508 A pointer in the PatchObject MUST be ignored if it starts with one of 1509 the following prefixes: 1511 o @type 1513 o excludedRecurrenceRules 1515 o method 1517 o privacy 1519 o prodId 1521 o recurrenceId 1523 o recurrenceOverrides 1525 o recurrenceRules 1527 o relatedTo 1528 o replyTo 1530 o uid 1532 4.3.5. excluded 1534 Type: "Boolean" (optional, default: false). 1536 Defines if this object is an overridden, excluded instance of a 1537 recurring JSCalendar object (see Section 4.3.4). If this property 1538 value is true, this calendar object instance MUST be removed from the 1539 occurrence expansion. The absence of this property, or the presence 1540 of its default value false, indicates that this instance MUST be 1541 included in the occurrence expansion. 1543 4.4. Sharing and Scheduling Properties 1545 4.4.1. priority 1547 Type: "Int" (optional, default: 0). 1549 Specifies a priority for the calendar object. This may be used as 1550 part of scheduling systems to help resolve conflicts for a time 1551 period. 1553 The priority is specified as an integer in the range 0 to 9. A value 1554 of 0 specifies an undefined priority, for which the treatment will 1555 vary by situation. A value of 1 is the highest priority. A value of 1556 2 is the second highest priority. Subsequent numbers specify a 1557 decreasing ordinal priority. A value of 9 is the lowest priority. 1558 Other integer values are reserved for future use. 1560 4.4.2. freeBusyStatus 1562 Type: "String" (optional, default: "busy"). 1564 Specifies how this calendar object should be treated when calculating 1565 free-busy state. This MUST be one of the following values, another 1566 value registered in the IANA JSCalendar Enum Values registry, or a 1567 vendor-specific value (see Section 3.3): 1569 o "free": The object should be ignored when calculating whether the 1570 user is busy. 1572 o "busy": The object should be included when calculating whether the 1573 user is busy. 1575 4.4.3. privacy 1577 Type: "String" (optional, default: "public"). 1579 Calendar objects are normally collected together and may be shared 1580 with other users. The privacy property allows the object owner to 1581 indicate that it should not be shared, or should only have the time 1582 information shared but the details withheld. Enforcement of the 1583 restrictions indicated by this property are up to the API via which 1584 this object is accessed. 1586 This property MUST NOT affect the information sent to scheduled 1587 participants; it is only interpreted by protocols that share the 1588 calendar objects belonging to one user with other users. 1590 The value MUST be one of the following values, another value 1591 registered in the IANA JSCalendar Enum Values registry, or a vendor- 1592 specific value (see Section 3.3). Any value the client or server 1593 doesn't understand should be preserved but treated as equivalent to 1594 "private". 1596 o "public": The full details of the object are visible to those whom 1597 the object's calendar is shared with. 1599 o "private": The details of the object are hidden; only the basic 1600 time and metadata is shared. The following properties MAY be 1601 shared, any other properties MUST NOT be shared: 1603 * @type 1605 * created 1607 * due 1609 * duration 1611 * estimatedDuration 1613 * freeBusyStatus 1615 * privacy 1617 * recurrenceOverrides. Only patches which apply to another 1618 permissible property are allowed to be shared. 1620 * sequence 1622 * showWithoutTime 1623 * start 1625 * timeZone 1627 * timeZones 1629 * uid 1631 * updated 1633 o "secret": The object is hidden completely (as though it did not 1634 exist) when the calendar this object is in is shared. 1636 4.4.4. replyTo 1638 Type: "String[String]" (optional). 1640 Represents methods by which participants may submit their response to 1641 the organizer of the calendar object. The keys in the property value 1642 are the available methods and MUST only contain ASCII alphanumeric 1643 characters (A-Za-z0-9). The value is a URI for the method specified 1644 in the key. Future methods may be defined in future specifications 1645 and registered with IANA; a calendar client MUST ignore any method it 1646 does not understand, but MUST preserve the method key and URI. This 1647 property MUST be omitted if no method is defined (rather than being 1648 specified as an empty object). 1650 The following methods are defined: 1652 o "imip": The organizer accepts an iMIP [RFC6047] response at this 1653 email address. The value MUST be a "mailto:" URI. 1655 o "web": Opening this URI in a web browser will provide the user 1656 with a page where they can submit a reply to the organizer. The 1657 value MUST be a URL using the "https:" scheme. 1659 o "other": The organizer is identified by this URI but the method 1660 for submitting the response is undefined. 1662 4.4.5. participants 1664 Type: "Id[Participant]" (optional). 1666 A map of participant ids to participants, describing their 1667 participation in the calendar object. 1669 If this property is set and any participant has a sendTo property, 1670 then the "replyTo" property of this calendar object MUST define at 1671 least one reply method. 1673 A Participant object has the following properties: 1675 o @type: "String" (mandatory) 1677 Specifies the type of this object. This MUST be "Participant". 1679 o name: "String" (optional) 1681 The display name of the participant (e.g., "Joe Bloggs"). 1683 o email: "String" (optional) 1685 The email address for the participant. 1687 o description: "String" (optional). 1689 A plain text description of this participant. For example, this 1690 may include more information about their role in the event or how 1691 best to contact them. 1693 o sendTo: "String[String]" (optional) 1695 Represents methods by which the participant may receive the 1696 invitation and updates to the calendar object. 1698 The keys in the property value are the available methods and MUST 1699 only contain ASCII alphanumeric characters (A-Za-z0-9). The value 1700 is a URI for the method specified in the key. Future methods may 1701 be defined in future specifications and registered with IANA; a 1702 calendar client MUST ignore any method it does not understand, but 1703 MUST preserve the method key and URI. This property MUST be 1704 omitted if no method is defined (rather than being specified as an 1705 empty object). 1707 The following methods are defined: 1709 * "imip": The participant accepts an iMIP [RFC6047] request at 1710 this email address. The value MUST be a "mailto:" URI. It MAY 1711 be different from the value of the participant's "email" 1712 property. 1714 * "other": The participant is identified by this URI but the 1715 method for submitting the invitation is undefined. 1717 o kind: "String" (optional) 1719 What kind of entity this participant is, if known. 1721 This MUST be one of the following values, another value registered 1722 in the IANA JSCalendar Enum Values registry, or a vendor-specific 1723 value (see Section 3.3). Any value the client or server doesn't 1724 understand should be treated the same as if this property is 1725 omitted. 1727 * "individual": a single person 1729 * "group": a collection of people invited as a whole 1731 * "location": a physical location that needs to be scheduled, 1732 e.g., a conference room 1734 * "resource": a non-human resource other than a location, such as 1735 a projector 1737 o roles: "String[Boolean]" (mandatory) 1739 A set of roles that this participant fulfills. 1741 At least one role MUST be specified for the participant. The keys 1742 in the set MUST be one of the following values, another value 1743 registered in the IANA JSCalendar Enum Values registry, or a 1744 vendor-specific value (see Section 3.3): 1746 * "owner": The participant is an owner of the object. This 1747 signifies they have permission to make changes to it that 1748 affect the other participants. Non-owner participants may only 1749 change properties that just affect themselves (for example 1750 setting their own alerts or changing their rsvp status). 1752 * "attendee": The participant is expected to be present at the 1753 event. 1755 * "optional": The participant's involvement with the event is 1756 optional. This is expected to be primarily combined with the 1757 "attendee" role. 1759 * "informational": The participant is copied for informational 1760 reasons, and is not expected to attend. 1762 * "chair": The participant is in charge of the event/task when it 1763 occurs. 1765 * "contact": The participant is someone that may be contacted for 1766 information about the event. 1768 The value for each key in the map MUST be true. It is expected 1769 that no more than one of the roles "attendee" and "informational" 1770 be present; if more than one are given, "attendee" takes 1771 precedence over "informational". Roles that are unknown to the 1772 implementation MUST be preserved. 1774 o locationId: "String" (optional) 1776 The location at which this participant is expected to be 1777 attending. 1779 If the value does not correspond to any location id in the 1780 "locations" property of the JSCalendar object, this MUST be 1781 treated the same as if the participant's locationId were omitted. 1783 o language: "String" (optional) 1785 The language tag as defined in [RFC5646] that best describes the 1786 participant's preferred language, if known. 1788 o participationStatus: "String" (optional, default: "needs-action") 1790 The participation status, if any, of this participant. 1792 The value MUST be one of the following values, another value 1793 registered in the IANA JSCalendar Enum Values registry, or a 1794 vendor-specific value (see Section 3.3): 1796 * "needs-action": No status yet set by the participant. 1798 * "accepted": The invited participant will participate. 1800 * "declined": The invited participant will not participate. 1802 * "tentative": The invited participant may participate. 1804 * "delegated": The invited participant has delegated their 1805 attendance to another participant, as specified in the 1806 delegatedTo property. 1808 o participationComment: "String" (optional) 1810 A note from the participant to explain their participation status. 1812 o expectReply: "Boolean" (optional, default: false) 1813 If true, the organizer is expecting the participant to notify them 1814 of their participation status. 1816 o scheduleAgent: "String" (optional, default: "server") 1818 Who is responsible for sending scheduling messages with this 1819 calendar object to the participant. 1821 The value MUST be one of the following values, another value 1822 registered in the IANA JSCalendar Enum Values registry, or a 1823 vendor-specific value (see Section 3.3): 1825 * "server": The calendar server will send the scheduling 1826 messages. 1828 * "client": The calendar client will send the scheduling 1829 messages. 1831 * "none": No scheduling messages are to be sent to this 1832 participant. 1834 o scheduleForceSend: "Boolean" (optional, default: false) 1836 A client may set the property on a participant to true to request 1837 that the server send a scheduling message to the participant when 1838 it would not normally do so (e.g. if no significant change is made 1839 the object or the scheduleAgent is set to client). The property 1840 MUST NOT be stored in the JSCalendar object on the server or 1841 appear in a scheduling message. 1843 o scheduleSequence: "UnsignedInt" (optional, default: 0) 1845 The sequence number of the last response from the participant. If 1846 defined, this MUST be a non-negative integer. 1848 This can be used to determine whether the participant has sent a 1849 new response following significant changes to the calendar object, 1850 and to determine if future responses are responding to a current 1851 or older view of the data. 1853 o scheduleStatus: "String[]" (optional) 1855 A list of status codes, as defined in Section 3.8.8.3 of 1856 [RFC5545], returned from the processing of the most recent 1857 scheduling message sent to this participant. 1859 Servers MUST only add or change this property when they send a 1860 scheduling message to the participant. Clients SHOULD NOT change 1861 or remove this property if it was provided by the server. Clients 1862 MAY add, change, or remove the property for participants where the 1863 client is handling the scheduling. 1865 This property MUST NOT be included in scheduling messages. 1867 o scheduleUpdated: "UTCDateTime" (optional) 1869 The timestamp for the most recent response from this participant. 1871 This is the "updated" property of the last response when using 1872 iTIP. It can be compared to the "updated" property in future 1873 responses to detect and discard older responses delivered out of 1874 order. 1876 o invitedBy: "String" (optional) 1878 The participant id of the participant who invited this one, if 1879 known. 1881 o delegatedTo: "String[Boolean]" (optional) 1883 A set of participant ids that this participant has delegated their 1884 participation to. Each key in the set MUST be the id of a 1885 participant. The value for each key in the map MUST be true. If 1886 there are no delegates, this MUST be omitted (rather than 1887 specified as an empty set). 1889 o delegatedFrom: "String[Boolean]" (optional) 1891 A set of participant ids that this participant is acting as a 1892 delegate for. Each key in the set MUST be the id of a 1893 participant. The value for each key in the map MUST be true. If 1894 there are no delegators, this MUST be omitted (rather than 1895 specified as an empty set). 1897 o memberOf: "String[Boolean]" (optional) 1899 A set of group participants that were invited to this calendar 1900 object, which caused this participant to be invited due to their 1901 membership in the group(s). Each key in the set MUST be the id of 1902 a participant. The value for each key in the map MUST be true. 1903 If there are no groups, this MUST be omitted (rather than 1904 specified as an empty set). 1906 o links: "Id[Link]" (optional) 1907 A map of link ids to Link objects, representing external resources 1908 associated with this participant, for example a vCard or image. 1909 If there are no links, this MUST be omitted (rather than specified 1910 as an empty set). 1912 o progress: "String" (optional; only allowed for participants of a 1913 JSTask). Represents the progress of the participant for this 1914 task. It MUST NOT be set if the "participationStatus" of this 1915 participant is any value other than "accepted". See Section 5.2.5 1916 for allowed values and semantics. 1918 o progressUpdated: "UTCDateTime" (optional; only allowed for 1919 participants of a JSTask). Specifies the date-time the progress 1920 property was last set on this participant. See Section 5.2.6 for 1921 allowed values and semantics. 1923 o percentComplete: "UnsignedInt" (optional; only allowed for 1924 participants of a JSTask). Represents the percent completion of 1925 the participant for this task. The property value MUST be a 1926 positive integer between 0 and 100. 1928 4.5. Alerts Properties 1930 4.5.1. useDefaultAlerts 1932 Type: "Boolean" (optional, default: false). 1934 If true, use the user's default alerts and ignore the value of the 1935 "alerts" property. Fetching user defaults is dependent on the API 1936 from which this JSCalendar object is being fetched, and is not 1937 defined in this specification. If an implementation cannot determine 1938 the user's default alerts, or none are set, it MUST process the 1939 alerts property as if "useDefaultAlerts" is set to false. 1941 4.5.2. alerts 1943 Type: "Id[Alert]" (optional). 1945 A map of alert ids to Alert objects, representing alerts/reminders to 1946 display or send to the user for this calendar object. 1948 An Alert Object has the following properties: 1950 o @type: "String" (mandatory) 1952 Specifies the type of this object. This MUST be "Alert". 1954 o trigger: "OffsetTrigger|AbsoluteTrigger|UnknownTrigger" 1955 (mandatory) 1957 Defines when to trigger the alert. New types may be defined in 1958 future documents. 1960 An "OffsetTrigger" object has the following properties: 1962 * @type: "String" (mandatory) 1964 Specifies the type of this object. This MUST be 1965 "OffsetTrigger". 1967 * offset: "SignedDuration" (mandatory). 1969 Defines the offset at which to trigger the alert relative to 1970 the time property defined in the "relativeTo" property of the 1971 alert. Negative durations signify alerts before the time 1972 property, positive durations signify alerts after. 1974 * relativeTo: "String" (optional, default: "start") 1976 Specifies the time property that the alert offset is relative 1977 to. The value MUST be one of: 1979 + "start": triggers the alert relative to the start of the 1980 calendar object 1982 + "end": triggers the alert relative to the end/due time of 1983 the calendar object 1985 An "AbsoluteTrigger" object has the following properties: 1987 * @type: "String" (mandatory) 1989 Specifies the type of this object. This MUST be 1990 "AbsoluteTrigger". 1992 * when: "UTCDateTime" (mandatory). 1994 Defines a specific UTC date-time when the alert is triggered. 1996 An "UnknownTrigger" object is an object that contains a "@type" 1997 property whose value is not recognized (i.e., not "OffsetTrigger" 1998 or "AbsoluteTrigger"), plus zero or more other properties. This 1999 is for compatibility with client extensions and future 2000 specifications. Implementations SHOULD NOT trigger for trigger 2001 types they do not understand, but MUST preserve them. 2003 o acknowledged: "UTCDateTime" (optional) 2005 This records when an alert was last acknowledged. This is set 2006 when the user has dismissed the alert; other clients that sync 2007 this property SHOULD automatically dismiss or suppress duplicate 2008 alerts (alerts with the same alert id that triggered on or before 2009 this date-time). 2011 For a recurring calendar object, setting the "acknowledged" 2012 property MUST NOT add a new override to the "recurrenceOverrides" 2013 property. If the alert is not already overridden, the 2014 acknowledged property MUST be set on the alert in the master 2015 event/task. 2017 Certain kinds of alert action may not provide feedback as to when 2018 the user sees them, for example email based alerts. For those 2019 kinds of alerts, this property MUST be set immediately when the 2020 alert is triggered and the action successfully carried out. 2022 o relatedTo: "String[Relation]" (optional) 2024 Relates this alert to other alerts in the same JSCalendar object. 2025 If the user wishes to snooze an alert, the application MUST create 2026 an alert to trigger after snoozing. This new snooze alert MUST 2027 set a parent relation to the identifier of the original alert. 2029 o action: "String" (optional, default: "display") 2031 Describes how to alert the user. 2033 The value MUST be at most one of the following values, a value 2034 registered in the IANA JSCalendar Enum Values registry, or a 2035 vendor-specific value (see Section 3.3): 2037 * "display": The alert should be displayed as appropriate for the 2038 current device and user context. 2040 * "email": The alert should trigger an email sent out to the 2041 user, notifying about the alert. This action is typically only 2042 appropriate for server implementations. 2044 4.6. Multilingual Properties 2046 4.6.1. localizations 2048 Type: "String[PatchObject]" (optional). 2050 A map of language tags [RFC5646] to patch objects, which localize the 2051 calendar object into the locale of the respective language tag. 2053 See the description of PatchObject (Section 1.4.9) for the structure 2054 of the PatchObject. The patches are applied to the top-level 2055 calendar object. In addition, the "locale" property of the patched 2056 object is set to the language tag. All pointers for patches MUST end 2057 with one of the following suffixes; any patch that does not follow 2058 this MUST be ignored unless otherwise specified in a future RFC: 2060 o title 2062 o description 2064 o name 2066 A patch MUST NOT have the prefix "recurrenceOverrides"; any 2067 localization of the override MUST be a patch to the localizations 2068 property inside the override instead. For example, a patch to 2069 "locations/abcd1234/title" is permissible, but a patch to "uid" or 2070 "recurrenceOverrides/2020-01-05T14:00:00/title" is not. 2072 Note that this specification does not define how to maintain validity 2073 of localized content. For example, a client application changing a 2074 JSCalendar object's title property might also need to update any 2075 localizations of this property. Client implementations SHOULD 2076 provide the means to manage localizations, but how to achieve this is 2077 specific to the application's workflow and requirements. 2079 4.7. Time Zone Properties 2081 4.7.1. timeZone 2083 Type: "TimeZoneId|null" (optional, default: null). 2085 Identifies the time zone the object is scheduled in, or null for 2086 floating time. This is either a name from the IANA Time Zone 2087 Database [TZDB] or the TimeZoneId of a custom time zone from the 2088 "timeZones" property (Section 4.7.2). If omitted, this MUST be 2089 presumed to be null (i.e., floating time). 2091 4.7.2. timeZones 2093 Type: "TimeZoneId[TimeZone]" (optional). 2095 Maps identifiers of custom time zones to their time zone definitions. 2096 The following restrictions apply for each key in the map: 2098 o To avoid conflict with names in the IANA Time Zone Database 2099 [TZDB], it MUST start with the "/" character. 2101 o It MUST be a valid "paramtext" value as specified in Section 3.1. 2102 of [RFC5545]. 2104 o At least one other property in the same JSCalendar object MUST 2105 reference a time zone using this identifier (i.e., orphaned time 2106 zones are not allowed). 2108 An identifier need only be unique to this JSCalendar object. A 2109 JSCalendar object may be part in a hierarchy of other JSCalendar 2110 objects (say, a JSEvent is an entry in a JSGroup). In this case, the 2111 set of time zones is the sum of the time zone definitions of this 2112 object and its parent objects. If multiple time zones with the same 2113 identifier exist, then the definition closest to the calendar object 2114 in relation to its parents MUST be used. (In context of JSEvent, a 2115 time zone definition in its timeZones property has precedence over a 2116 definition of the same id in the JSGroup). Time zone definitions in 2117 any children of the calendar object MUST be ignored. 2119 A TimeZone object maps a VTIMEZONE component from iCalendar [RFC5545] 2120 and the semantics are as defined there. A valid time zone MUST 2121 define at least one transition rule in the "standard" or "daylight" 2122 property. Its properties are: 2124 o @type: "String" (mandatory) 2126 Specifies the type of this object. This MUST be "TimeZone". 2128 o tzId: "String" (mandatory). 2130 The TZID property from iCalendar. 2132 o updated: "UTCDateTime" (optional) 2134 The LAST-MODIFIED property from iCalendar. 2136 o url: "String" (optional) 2138 The TZURL property from iCalendar. 2140 o validUntil: "UTCDateTime" (optional) 2142 The TZUNTIL property from iCalendar specified in [RFC7808]. 2144 o aliases: "String[Boolean]" (optional) 2145 Maps the TZID-ALIAS-OF properties from iCalendar specified in 2146 [RFC7808] to a JSON set of aliases. The set is represented as an 2147 object, with the keys being the aliases. The value for each key 2148 in the map MUST be true. 2150 o standard: "TimeZoneRule[]" (optional) 2152 The STANDARD sub-components from iCalendar. The order MUST be 2153 preserved during conversion. 2155 o daylight: "TimeZoneRule[]" (optional). 2157 The DAYLIGHT sub-components from iCalendar. The order MUST be 2158 preserved during conversion. 2160 A TimeZoneRule object maps a STANDARD or DAYLIGHT sub-component from 2161 iCalendar, with the restriction that at most one recurrence rule is 2162 allowed per rule. It has the following properties: 2164 o @type: "String" (mandatory) 2166 Specifies the type of this object. This MUST be "TimeZoneRule". 2168 o start: "LocalDateTime" (mandatory) 2170 The DTSTART property from iCalendar. 2172 o offsetFrom: "String" (mandatory) 2174 The TZOFFSETFROM property from iCalendar. 2176 o offsetTo: "String" (mandatory) 2178 The TZOFFSETTO property from iCalendar. 2180 o recurrenceRules: "RecurrenceRule[]" (optional) 2182 The RRULE property mapped as specified in Section 4.3.2. During 2183 recurrence rule evaluation, the "until" property value MUST be 2184 interpreted as a local time in the UTC time zone. 2186 o recurrenceOverrides: "LocalDateTime[PatchObject]" (optional) 2188 Maps the RDATE properties from iCalendar. The set is represented 2189 as an object, with the keys being the recurrence dates. The patch 2190 object MUST be the empty JSON object ({}). 2192 o names: "String[Boolean]" (optional) 2193 Maps the TZNAME properties from iCalendar to a JSON set. The set 2194 is represented as an object, with the keys being the names, 2195 excluding any "tznparam" component from iCalendar. The value for 2196 each key in the map MUST be true. 2198 o comments: "String[]" (optional). Maps the COMMENT properties from 2199 iCalendar. The order MUST be preserved during conversion. 2201 5. Type-specific JSCalendar Properties 2203 5.1. JSEvent Properties 2205 In addition to the common JSCalendar object properties (Section 4) a 2206 JSEvent has the following properties: 2208 5.1.1. start 2210 Type: "LocalDateTime" (mandatory). 2212 The date/time the event starts in the event's time zone (as specified 2213 in the "timeZone" property, see Section 4.7.1). 2215 5.1.2. duration 2217 Type: "Duration" (optional, default: "PT0S"). 2219 The zero or positive duration of the event in the event's start time 2220 zone. The end time of an event can be found by adding the duration 2221 to the event's start time. 2223 A JSEvent MAY involve start and end locations that are in different 2224 time zones (e.g., a trans-continental flight). This can be expressed 2225 using the "relativeTo" and "timeZone" properties of the JSEvent's 2226 Location objects (see Section 4.2.5). 2228 5.1.3. status 2230 Type: "String" (optional, default: "confirmed"). 2232 The scheduling status (Section 4.4) of a JSEvent. If set, it MUST be 2233 one of the following values, another value registered in the IANA 2234 JSCalendar Enum Values registry, or a vendor-specific value (see 2235 Section 3.3): 2237 o "confirmed": Indicates the event is definitely happening. 2239 o "cancelled": Indicates the event has been cancelled. 2241 o "tentative": Indicates the event may happen. 2243 5.2. JSTask Properties 2245 In addition to the common JSCalendar object properties (Section 4) a 2246 JSTask has the following properties: 2248 5.2.1. due 2250 Type: "LocalDateTime" (optional). 2252 The date/time the task is due in the task's time zone. 2254 5.2.2. start 2256 Type: "LocalDateTime" (optional). 2258 The date/time the task should start in the task's time zone. 2260 5.2.3. estimatedDuration 2262 Type: "Duration" (optional). 2264 Specifies the estimated positive duration of time the task takes to 2265 complete. 2267 5.2.4. percentComplete 2269 Type: "UnsignedInt" (optional). 2271 Represents the percent completion of the task overall. The property 2272 value MUST be a positive integer between 0 and 100. 2274 5.2.5. progress 2276 Type: "String" (optional). 2278 Defines the progress of this task. If omitted, the default progress 2279 (Section 4.4) of a JSTask is defined as follows (in order of 2280 evaluation): 2282 o "completed": if the "progress" property value of all participants 2283 is "completed". 2285 o "failed": if at least one "progress" property value of a 2286 participant is "failed". 2288 o "in-process": if at least one "progress" property value of a 2289 participant is "in-process". 2291 o "needs-action": If none of the other criteria match. 2293 If set, it MUST be one of the following values, another value 2294 registered in the IANA JSCalendar Enum Values registry, or a vendor- 2295 specific value (see Section 3.3): 2297 o "needs-action": Indicates the task needs action. 2299 o "in-process": Indicates the task is in process. 2301 o "completed": Indicates the task is completed. 2303 o "failed": Indicates the task failed. 2305 o "cancelled": Indicates the task was cancelled. 2307 5.2.6. progressUpdated 2309 Type: "UTCDateTime" (optional). 2311 Specifies the date/time the "progress" property of either the task 2312 overall (Section 5.2.5) or a specific participant (Section 4.4.5) was 2313 last updated. 2315 If the task is recurring and has future instances, a client may want 2316 to keep track of the last progress update timestamp of a specific 2317 task recurrence, but leave other instances unchanged. One way to 2318 achieve this is by overriding the progressUpdated property in the 2319 task "recurrenceOverrides" property. However, this could produce a 2320 long list of timestamps for regularly recurring tasks. An 2321 alternative approach is to split the JSTask into a current, single 2322 instance of JSTask with this instance progress update time and a 2323 future recurring instance. See also Section 4.1.3 on splitting. 2325 5.3. JSGroup Properties 2327 JSGroup supports the following common JSCalendar properties 2328 (Section 4): 2330 o @type 2332 o uid 2334 o prodId 2335 o created 2337 o updated 2339 o title 2341 o description 2343 o descriptionContentType 2345 o links 2347 o locale 2349 o keywords 2351 o categories 2353 o color 2355 o timeZones 2357 In addition, the following JSGroup-specific properties are supported: 2359 5.3.1. entries 2361 Type: "(JSTask|JSEvent)[]" (mandatory). 2363 A collection of group members. Implementations MUST ignore entries 2364 of unknown type. 2366 5.3.2. source 2368 Type: "String" (optional). 2370 The source from which updated versions of this group may be retrieved 2371 from. The value MUST be a URI. 2373 6. Examples 2375 The following examples illustrate several aspects of the JSCalendar 2376 data model and format. The examples may omit mandatory or additional 2377 properties, which is indicated by a placeholder property with key 2378 "...". While most of the examples use calendar event objects, they 2379 are also illustrative for tasks. 2381 6.1. Simple event 2383 This example illustrates a simple one-time event. It specifies a 2384 one-time event that begins on January 15, 2020 at 1pm New York local 2385 time and ends after 1 hour. 2387 { 2388 "@type": "jsevent", 2389 "uid": "a8df6573-0474-496d-8496-033ad45d7fea", 2390 "updated": "2020-01-02T18:23:04Z", 2391 "title": "Some event", 2392 "start": "2020-01-15T13:00:00", 2393 "timeZone": "America/New_York", 2394 "duration": "PT1H" 2395 } 2397 6.2. Simple task 2399 This example illustrates a simple task for a plain to-do item. 2401 { 2402 "@type": "jstask", 2403 "uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2", 2404 "updated": "2020-01-09T14:32:01Z", 2405 "title": "Do something" 2406 } 2408 6.3. Simple group 2410 This example illustrates a simple calendar object group that contains 2411 an event and a task. 2413 { 2414 "@type": "jsgroup", 2415 "uid": "bf0ac22b-4989-4caf-9ebd-54301b4ee51a", 2416 "updated": "2020-01-15T18:00:00Z", 2417 "name": "A simple group", 2418 "entries": [{ 2419 "@type": "jsevent", 2420 "uid": "a8df6573-0474-496d-8496-033ad45d7fea", 2421 "updated": "2020-01-02T18:23:04Z", 2422 "title": "Some event", 2423 "start": "2020-01-15T13:00:00", 2424 "timeZone": "America/New_York", 2425 "duration": "PT1H" 2426 }, 2427 { 2428 "@type": "jstask", 2429 "uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2", 2430 "updated": "2020-01-09T14:32:01Z", 2431 "title": "Do something" 2432 }] 2433 } 2435 6.4. All-day event 2437 This example illustrates an event for an international holiday. It 2438 specifies an all-day event on April 1 that occurs every year since 2439 the year 1900. 2441 { 2442 "...": "", 2443 "title": "April Fool's Day", 2444 "showWithoutTime": true, 2445 "start": "1900-04-01T00:00:00", 2446 "duration": "P1D", 2447 "recurrenceRules": [{ 2448 "@type": "RecurrenceRule", 2449 "frequency": "yearly" 2450 }] 2451 } 2453 6.5. Task with a due date 2455 This example illustrates a task with a due date. It is a reminder to 2456 buy groceries before 6pm Vienna local time on January 19, 2020. The 2457 calendar user expects to need 1 hour for shopping. 2459 { 2460 "...": "", 2461 "title": "Buy groceries", 2462 "due": "2020-01-19T18:00:00", 2463 "timeZone": "Europe/Vienna", 2464 "estimatedDuration": "PT1H" 2465 } 2467 6.6. Event with end time zone 2469 This example illustrates the use of end time zones by use of an 2470 international flight. The flight starts on April 1, 2020 at 9am in 2471 Berlin local time. The duration of the flight is scheduled at 10 2472 hours 30 minutes. The time at the flight's destination is in the 2473 same time zone as Tokyo. Calendar clients could use the end time 2474 zone to display the arrival time in Tokyo local time and highlight 2475 the time zone difference of the flight. The location names can serve 2476 as input for navigation systems. 2478 { 2479 "...": "", 2480 "title": "Flight XY51 to Tokyo", 2481 "start": "2020-04-01T09:00:00", 2482 "timeZone": "Europe/Berlin", 2483 "duration": "PT10H30M", 2484 "locations": { 2485 "418d0b9b-b656-4b3c-909f-5b149ca779c9": { 2486 "@type": "Location", 2487 "rel": "start", 2488 "name": "Frankfurt Airport (FRA)" 2489 }, 2490 "c2c7ac67-dc13-411e-a7d4-0780fb61fb08": { 2491 "@type": "Location", 2492 "rel": "end", 2493 "name": "Narita International Airport (NRT)", 2494 "timeZone": "Asia/Tokyo" 2495 } 2496 } 2497 } 2499 6.7. Floating-time event (with recurrence) 2501 This example illustrates the use of floating time. Since January 1, 2502 2020, a calendar user blocks 30 minutes every day to practice Yoga at 2503 7am local time, in whatever time zone the user is located on that 2504 date. 2506 { 2507 "...": "", 2508 "title": "Yoga", 2509 "start": "2020-01-01T07:00:00", 2510 "duration": "PT30M", 2511 "recurrenceRules": [{ 2512 "@type": "RecurrenceRule", 2513 "frequency": "daily" 2514 }] 2515 } 2517 6.8. Event with multiple locations and localization 2519 This example illustrates an event that happens at both a physical and 2520 a virtual location. Fans can see a live concert on premises or 2521 online. The event title and descriptions are localized. 2523 { 2524 "...": "", 2525 "title": "Live from Music Bowl: The Band", 2526 "description": "Go see the biggest music event ever!", 2527 "locale": "en", 2528 "start": "2020-07-04T17:00:00", 2529 "timeZone": "America/New_York", 2530 "duration": "PT3H", 2531 "locations": { 2532 "c0503d30-8c50-4372-87b5-7657e8e0fedd": { 2533 "@type": "Location", 2534 "name": "The Music Bowl", 2535 "description": "Music Bowl, Central Park, New York", 2536 "coordinates": "geo:40.7829,-73.9654" 2537 } 2538 }, 2539 "virtualLocations": { 2540 "1": { 2541 "@type": "VirtualLocation", 2542 "name": "Free live Stream from Music Bowl", 2543 "uri": "https://stream.example.com/the_band_2020" 2544 } 2545 }, 2546 "localizations": { 2547 "de": { 2548 "title": "Live von der Music Bowl: The Band!", 2549 "description": "Schau dir das groesste Musikereignis an!", 2550 "virtualLocations/1/name": "Gratis Live-Stream aus der Music Bowl" 2551 } 2552 } 2553 } 2554 6.9. Recurring event with overrides 2556 This example illustrates the use of recurrence overrides. A math 2557 course at a University is held for the first time on January 8, 2020 2558 at 9am London time and occurs every week until June 24, 2020. Each 2559 lecture lasts for one hour and 30 minutes and is located at the 2560 Mathematics department. This event has exceptional occurrences: at 2561 the last occurrence of the course is an exam, which lasts for 2 hours 2562 and starts at 10am. Also, the location of the exam differs from the 2563 usual location. On April 1 no course is held. On January 7 at 2pm 2564 is an optional introduction course, that occurs before the first 2565 regular lecture. 2567 { 2568 "...": "", 2569 "title": "Calculus I", 2570 "start": "2020-01-08T09:00:00", 2571 "timeZone": "Europe/London", 2572 "duration": "PT1H30M", 2573 "locations": { 2574 "0dfb8ace-aad1-4734-b3b4-a2fe3d6ae1c5": { 2575 "@type": "Location", 2576 "title": "Math lab room 1", 2577 "description": "Math Lab I, Department of Mathematics" 2578 } 2579 }, 2580 "recurrenceRules": [{ 2581 "@type": "RecurrenceRule", 2582 "frequency": "weekly", 2583 "until": "2020-06-24T09:00:00" 2584 }], 2585 "recurrenceOverrides": { 2586 "2020-01-07T14:00:00": { 2587 "title": "Introduction to Calculus I (optional)" 2588 }, 2589 "2020-04-01T09:00:00": { 2590 "excluded": true 2591 }, 2592 "2020-06-25T09:00:00": { 2593 "title": "Calculus I Exam", 2594 "start": "2020-06-25T10:00:00", 2595 "duration": "PT2H", 2596 "locations": { 2597 "84d639ca-37ac-4a86-81e5-9bbba8eb4053": { 2598 "@type": "Location", 2599 "title": "Big Auditorium", 2600 "description": "Big Auditorium, Other Road" 2601 } 2602 } 2603 } 2604 } 2605 } 2607 6.10. Recurring event with participants 2609 This example illustrates scheduled events. A team meeting occurs 2610 every week since January 8, 2020 at 9am Johannesburg time. The event 2611 owner also chairs the event. Participants meet in a virtual meeting 2612 room. An attendee has accepted the invitation, but on March 4, 2020 2613 he is unavailable and declined participation for this occurrence. 2615 { 2616 "...": "", 2617 "title": "FooBar team meeting", 2618 "start": "2020-01-08T09:00:00", 2619 "timeZone": "Africa/Johannesburg", 2620 "duration": "PT1H", 2621 "virtualLocations": { 2622 "3f41b47b-a5eb-494f-90eb-19d279486d84": { 2623 "@type": "VirtualLocation", 2624 "name": "ChatMe meeting room", 2625 "uri": "https://chatme.example.com?id=1234567&pw=a8a24627b63d396e" 2626 } 2627 }, 2628 "recurrenceRules": [{ 2629 "@type": "RecurrenceRule", 2630 "frequency": "weekly" 2631 }], 2632 "replyTo": { 2633 "imip": "mailto:f245f875-7f63-4a5e-a2c8@schedule.example.com" 2634 }, 2635 "participants": { 2636 "dG9tQGZvb2Jhci5xlLmNvbQ": { 2637 "@type": "Participant", 2638 "name": "Tom Tool", 2639 "email": "tom@foobar.example.com", 2640 "sendTo": { 2641 "imip": "mailto:tom@calendar.example.com" 2642 }, 2643 "participationStatus": "accepted", 2644 "roles": { 2645 "attendee": true 2646 } 2647 }, 2648 "em9lQGZvb2GFtcGxlLmNvbQ": { 2649 "@type": "Participant", 2650 "name": "Zoe Zelda", 2651 "email": "zoe@foobar.example.com", 2652 "sendTo": { 2653 "imip": "mailto:zoe@foobar.example.com" 2654 }, 2655 "participationStatus": "accepted", 2656 "roles": { 2657 "owner": true, 2658 "attendee": true, 2659 "chair": true 2660 } 2661 } 2662 }, 2663 "recurrenceOverrides": { 2664 "2020-03-04T09:00:00": { 2665 "participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus": 2666 "declined" 2667 } 2668 } 2669 } 2671 7. Security Considerations 2673 Calendaring and scheduling information is very privacy-sensitive. It 2674 can reveal the social network of a user; location information of this 2675 user and those in their social network; identity and credentials 2676 information; and the patterns of behavior of the user in both the 2677 physical and cyber realm. Additionally, calendar events and tasks 2678 can could influence the physical location of a user or their cyber 2679 behavior within a known time window. Its transmission and storage 2680 must be done carefully to protect it from possible threats, such as 2681 eavesdropping, replay, message insertion, deletion, modification, and 2682 on-path attacks. 2684 The data being stored and transmitted may be used in systems with 2685 real world consequences. For example, a home automation system may 2686 turn an alarm on and off. Or a coworking space may charge money to 2687 the organiser of an event that books one of their meeting rooms. 2688 Such systems must be careful to authenticate all data they receive to 2689 prevent them from being subverted, and ensure the change comes from 2690 an authorized entity. 2692 This document just defines the data format; such considerations are 2693 primarily the concern of the API or method of storage and 2694 transmission of such files. 2696 7.1. Expanding Recurrences 2698 A recurrence rule may produce infinite occurrences of an event. 2699 Implementations MUST handle expansions carefully to prevent 2700 accidental or deliberate resource exhaustion. 2702 Conversely, a recurrence rule may be specified that does not expand 2703 to anything. It is not always possible to tell this through static 2704 analysis of the rule, so implementations MUST be careful to avoid 2705 getting stuck in infinite loops, or otherwise exhausting resources 2706 while searching for the next occurrence. 2708 Events recur in the event's time zone. If the user is in a different 2709 time zone, daylight saving transitions may cause an event that 2710 normally occurs at, for example, 9am to suddenly shift an hour 2711 earlier. This may be used in an attempt to cause a participant to 2712 miss an important meeting. User agents must be careful to translate 2713 date-times correctly between time zones and may wish to call out 2714 unexpected changes in the time of a recurring event. 2716 7.2. JSON Parsing 2718 The Security Considerations of [RFC8259] apply to the use of JSON as 2719 the data interchange format. 2721 As for any serialization format, parsers need to thoroughly check the 2722 syntax of the supplied data. JSON uses opening and closing tags for 2723 several types and structures, and it is possible that the end of the 2724 supplied data will be reached when scanning for a matching closing 2725 tag; this is an error condition, and implementations need to stop 2726 scanning at the end of the supplied data. 2728 JSON also uses a string encoding with some escape sequences to encode 2729 special characters within a string. Care is needed when processing 2730 these escape sequences to ensure that they are fully formed before 2731 the special processing is triggered, with special care taken when the 2732 escape sequences appear adjacent to other (non-escaped) special 2733 characters or adjacent to the end of data (as in the previous 2734 paragraph). 2736 If parsing JSON into a non-textual structured data format, 2737 implementations may need to allocate storage to hold JSON string 2738 elements. Since JSON does not use explicit string lengths, the risk 2739 of denial of service due to resource exhaustion is small, but 2740 implementations may still wish to place limits on the size of 2741 allocations they are willing to make in any given context, to avoid 2742 untrusted data causing excessive memory allocation. 2744 7.3. URI Values 2746 Several JSCalendar properties contain URIs as values, and processing 2747 these properties requires extra care. Section 7 of [RFC3986] 2748 discusses security risks related to URIs. 2750 Fetching remote resources carries inherent risks. Connections must 2751 only be allowed on well known ports, using allowed protocols 2752 (generally just HTTP/HTTPS on their default ports). The URL must be 2753 resolved externally and not allowed to access internal resources. 2754 Connecting to an external source reveals IP (and therefore generally 2755 location) information. 2757 A maliciously constructed JSCalendar object may contain a very large 2758 number of URIs. In the case of published calendars with a large 2759 number of subscribers, such objects could be widely distributed. 2760 Implementations should be careful to limit the automatic fetching of 2761 linked resources to reduce the risk of this being an amplification 2762 vector for a denial-of-service attack. 2764 7.4. Spam 2766 Calendar systems may receive JSCalendar files from untrusted sources, 2767 in particular as attachments to emails. This can be a vector for an 2768 attacker to inject spam into a user's calendar. This may confuse, 2769 annoy, and mislead users, or overwhelm their calendar with bogus 2770 events, preventing them from seeing legitimate ones. 2772 Heuristic, statistical or machine-learning-based filters can be 2773 effective in filtering out spam. Authentication mechanisms such as 2774 DKIM [RFC6376] can help establish the source of messages and 2775 associate the data with existing relationships (such as an address 2776 book contact). Misclassifications are always possible, however, and 2777 providing a mechanism for users to quickly correct this is advised. 2779 Confusable unicode characters may be used to trick a user into 2780 trusting a JSCalendar file that appears to come from a known contact 2781 but is actually from a similar-looking source controlled by an 2782 attacker. 2784 7.5. Duplication 2786 It is important for calendar systems to maintain the UID of an event 2787 when updating it to avoid unexpected duplication of events. 2788 Consumers of the data may not remove the previous version of the 2789 event if it has a different UID. This can lead to a confusing 2790 situation for the user, with many variations of the event and no 2791 indication of which one is correct. Care must be taken by consumers 2792 of the data to remove old events where possible to avoid an 2793 accidental denial-of-service attack due to the volume of data. 2795 7.6. Time Zones 2797 Events recur in a particular time zone. When this differs from the 2798 user's current time zone, it may unexpectedly cause an occurrence to 2799 shift in time for that user due to a daylight savings change in the 2800 event's time zone. A maliciously crafted event could attempt to 2801 confuse users with such an event to ensure a meeting is missed. 2803 8. IANA Considerations 2805 8.1. Media Type Registration 2807 This document defines a media type for use with JSCalendar data 2808 formatted in JSON. 2810 Type name: application 2812 Subtype name: jscalendar+json 2814 Required parameters: type 2816 The "type" parameter conveys the type of the JSCalendar data in 2817 the body part, with the value being one of "jsevent", "jstask", or 2818 "jsgroup". The parameter MUST NOT occur more than once. It MUST 2819 match the value of the "@type" property of the JSON-formatted 2820 JSCalendar object in the body. 2822 Optional parameters: none 2824 Encoding considerations: Same as encoding considerations of 2825 application/json as specified in RFC8529, Section 11 [RFC8259]. 2827 Security considerations: See Section 7 of this document. 2829 Interoperability considerations: While JSCalendar is designed to 2830 avoid ambiguities as much as possible, when converting objects 2831 from other calendar formats to/from JSCalendar it is possible that 2832 differing representations for the same logical data might arise, 2833 or ambiguities in interpretation. The semantic equivalence of two 2834 JSCalendar objects may be determined differently by different 2835 applications, for example where URL values differ in case between 2836 the two objects. 2838 Published specification: This specification. 2840 Applications that use this media type: Applications that currently 2841 make use of the text/calendar and application/calendar+json media 2842 types can use this as an alternative. Similarly, applications 2843 that use the application/json media type to transfer calendaring 2844 data can use this to further specify the content. 2846 Fragment identifier considerations: A JSON Pointer fragment 2847 identifier may be used, as defined in [RFC6901], Section 6. 2849 Additional information: 2851 Magic number(s): N/A 2853 File extensions(s): N/A 2855 Macintosh file type code(s): N/A 2857 Person & email address to contact for further information: 2858 calsify@ietf.org 2860 Intended usage: COMMON 2862 Restrictions on usage: N/A 2864 Author: See the "Author's Address" section of this document. 2866 Change controller: IETF 2868 8.2. Creation of "JSCalendar Properties" Registry 2870 The IANA will create the "JSCalendar Properties" registry to allow 2871 interoperability of extensions to JSCalendar objects. 2873 This registry follows the Expert Review process ([RFC8126], 2874 Section 4.5). If the "intended use" field is "common", sufficient 2875 documentation is required to enable interoperability. Preliminary 2876 community review for this registry is optional but strongly 2877 encouraged. 2879 A registration can have an intended use of "common", "reserved", or 2880 "obsolete". The IANA will list common-use registrations prominently 2881 and separately from those with other intended use values. 2883 A "reserved" registration reserves a property name without assigning 2884 semantics to avoid name collisions with future extensions or protocol 2885 use. 2887 An "obsolete" registration denotes a property that is no longer 2888 expected to be added by up-to-date systems. A new property has 2889 probably been defined covering the obsolete property's semantics. 2891 The JSCalendar property registration procedure is not a formal 2892 standards process but rather an administrative procedure intended to 2893 allow community comment and sanity checking without excessive time 2894 delay. It is designed to encourage vendors to document and register 2895 new properties they add for use cases not covered by the original 2896 specification, leading to increased interoperability. 2898 8.2.1. Preliminary Community Review 2900 Notice of a potential new registration SHOULD be sent to the Calext 2901 mailing list for review. This mailing list is 2902 appropriate to solicit community feedback on a proposed new property. 2904 Properties registrations must be marked with their intended use: 2905 "common", "reserved" or "obsolete". 2907 The intent of the public posting to this list is to solicit comments 2908 and feedback on the choice of the property name, the unambiguity of 2909 the specification document, and a review of any interoperability or 2910 security considerations. The submitter may submit a revised 2911 registration proposal or abandon the registration completely at any 2912 time. 2914 8.2.2. Submit Request to IANA 2916 Registration requests can be sent to . 2918 8.2.3. Designated Expert Review 2920 The primary concern of the designated expert (DE) is preventing name 2921 collisions and encouraging the submitter to document security and 2922 privacy considerations. For a common-use registration, the DE is 2923 expected to confirm that suitable documentation, as described in 2924 Section 4.6 of [RFC8126], is available to ensure interoperability. 2925 That documentation will usually be in an RFC, but simple definitions 2926 are likely to use a web/wiki page, and if a sentence or two is deemed 2927 sufficient it could be described in the registry itself. The DE 2928 should also verify that the property name does not conflict with work 2929 that is active or already published within the IETF. A published 2930 specification is not required for reserved or obsolete registrations. 2932 The DE will either approve or deny the registration request and 2933 publish a notice of the decision to the Calext WG mailing list or its 2934 successor, as well as inform IANA. A denial notice must be justified 2935 by an explanation, and, in the cases where it is possible, concrete 2936 suggestions on how the request can be modified so as to become 2937 acceptable should be provided. 2939 8.2.4. Change Procedures 2941 Once a JSCalendar property has been published by the IANA, the change 2942 controller may request a change to its definition. The same 2943 procedure that would be appropriate for the original registration 2944 request is used to process a change request. 2946 JSCalendar property registrations may not be deleted; properties that 2947 are no longer believed appropriate for use can be declared obsolete 2948 by a change to their "intended use" field; such properties will be 2949 clearly marked in the lists published by the IANA. 2951 Significant changes to a JSCalendar property's definition should be 2952 requested only when there are serious omissions or errors in the 2953 published specification, as such changes may cause interoperability 2954 issues. When review is required, a change request may be denied if 2955 it renders entities that were valid under the previous definition 2956 invalid under the new definition. 2958 The owner of a JSCalendar property may pass responsibility to another 2959 person or agency by informing the IANA; this can be done without 2960 discussion or review. 2962 8.2.5. JSCalendar Properties Registry Template 2964 o Property Name: The name of the property. The property name MUST 2965 NOT already be registered for any of the object types listed in 2966 the "Property Context" field of this registration. Other object 2967 types MAY already have registered a different property with the 2968 same name, however the same name SHOULD only be used when the 2969 semantics are analogous. 2971 o Property Type: The type of this property, using type signatures as 2972 specified in Section 1.3. The property type MUST be registed in 2973 the Type Registry. 2975 o Property Context: A comma-separated list of JSCalendar object 2976 types this property is allowed on. 2978 o Reference or Description: A brief description or RFC number and 2979 section reference where the property is specified (omitted for 2980 "reserved" property names). 2982 o Intended Use: Common, reserved, or obsolete. 2984 o Change Controller: Who may request a change to this entry's 2985 definition ("IETF" for IETF-stream RFCs). 2987 8.2.6. Initial Contents for the JSCalendar Properties Registry 2989 The following table lists the initial entries of the JSCalendar 2990 Properties registry. All properties are for common-use. All RFC 2991 section references are for this document. The change controller for 2992 all these properties is "IETF". 2994 +---------------+----------------------------+------------+---------+ 2995 | Property Name | Property Type | Property | Referen | 2996 | | | Context | ce or D | 2997 | | | | escript | 2998 | | | | ion | 2999 +---------------+----------------------------+------------+---------+ 3000 | @type | String | JSEvent, | Section | 3001 | | | JSTask, | 4.1.1, | 3002 | | | JSGroup, A | Section | 3003 | | | bsoluteTri | 4.5.2, | 3004 | | | gger, | Section | 3005 | | | Alert, | 1.4.11 | 3006 | | | Link, | , Secti | 3007 | | | Location, | on 4.2. | 3008 | | | NDay, Offs | 5, Sect | 3009 | | | etTrigger, | ion 4.4 | 3010 | | | Participan | .5, Sec | 3011 | | | t, Recurre | tion 4. | 3012 | | | nceRule, | 3.2, Se | 3013 | | | Relation, | ction 4 | 3014 | | | TimeZone, | .1.3, S | 3015 | | | TimeZoneRu | ection | 3016 | | | le, Virtua | 4.7.2, | 3017 | | | lLocation | Section | 3018 | | | | 4.7.2, | 3019 | | | | Section | 3020 | | | | 4.2.6 | 3021 | | | | | 3022 | acknowledged | UTCDateTime | Alert | Section | 3023 | | | | 4.5.2 | 3024 | | | | | 3025 | action | String | Alert | Section | 3026 | | | | 4.5.2 | 3027 | | | | | 3028 | alerts | Id[Alert] | JSEvent, | Section | 3029 | | | JSTask | 4.5.2 | 3030 | | | | | 3031 | aliases | String[Boolean] | TimeZone | Section | 3032 | | | | 4.7.2 | 3033 | | | | | 3034 | byDay | NDay[] | Recurrence | Section | 3035 | | | Rule | 4.3.2 | 3036 | | | | | 3037 | byHour | UnsignedInt[] | Recurrence | Section | 3038 | | | Rule | 4.3.2 | 3039 | | | | | 3040 | byMinute | UnsignedInt[] | Recurrence | Section | 3041 | | | Rule | 4.3.2 | 3042 | | | | | 3043 | byMonth | String[] | Recurrence | Section | 3044 | | | Rule | 4.3.2 | 3045 | | | | | 3046 | byMonthDay | Int[] | Recurrence | Section | 3047 | | | Rule | 4.3.2 | 3048 | | | | | 3049 | bySecond | UnsignedInt[] | Recurrence | Section | 3050 | | | Rule | 4.3.2 | 3051 | | | | | 3052 | bySetPosition | Int[] | Recurrence | Section | 3053 | | | Rule | 4.3.2 | 3054 | | | | | 3055 | byWeekNo | Int[] | Recurrence | Section | 3056 | | | Rule | 4.3.2 | 3057 | | | | | 3058 | byYearDay | Int[] | Recurrence | Section | 3059 | | | Rule | 4.3.2 | 3060 | | | | | 3061 | categories | String[Boolean] | JSEvent, | Section | 3062 | | | JSTask, | 4.2.10 | 3063 | | | JSGroup | | 3064 | | | | | 3065 | cid | String | Link | Section | 3066 | | | | 1.4.11 | 3067 | | | | | 3068 | color | String | JSEvent, | Section | 3069 | | | JSTask, | 4.2.11 | 3070 | | | JSGroup | | 3071 | | | | | 3072 | comments | String[] | TimeZoneRu | Section | 3073 | | | le | 4.7.2 | 3074 | | | | | 3075 | contentType | String | Link | Section | 3076 | | | | 1.4.11 | 3077 | | | | | 3078 | coordinates | String | Location | Section | 3079 | | | | 4.2.5 | 3080 | | | | | 3081 | count | UnsignedInt | Recurrence | Section | 3082 | | | Rule | 4.3.2 | 3083 | | | | | 3084 | created | UTCDateTime | JSEvent, | Section | 3085 | | | JSTask, | 4.1.5 | 3086 | | | JSGroup | | 3087 | | | | | 3088 | day | String | NDay | Section | 3089 | | | | 4.3.2 | 3090 | | | | | 3091 | daylight | TimeZoneRule | TimeZone | Section | 3092 | | | | 4.7.2 | 3093 | | | | | 3094 | delegatedFrom | String[Boolean] | Participan | Section | 3095 | | | t | 4.4.5 | 3096 | | | | | 3097 | delegatedTo | String[Boolean] | Participan | Section | 3098 | | | t | 4.4.5 | 3099 | | | | | 3100 | description | String | JSEvent, | Section | 3101 | | | JSTask, | 4.2.2, | 3102 | | | Location, | Section | 3103 | | | Participan | 4.2.5, | 3104 | | | t, Virtual | Section | 3105 | | | Location | 4.4.5, | 3106 | | | | Section | 3107 | | | | 4.2.6 | 3108 | | | | | 3109 | descriptionCo | String | JSEvent, | Section | 3110 | ntentType | | JSTask | 4.2.3 | 3111 | | | | | 3112 | display | String | Link | Section | 3113 | | | | 1.4.11 | 3114 | | | | | 3115 | due | LocalDateTime | JSTask | Section | 3116 | | | | 5.2.1 | 3117 | | | | | 3118 | duration | Duration | JSEvent | Section | 3119 | | | | 5.1.2 | 3120 | | | | | 3121 | email | String | Participan | Section | 3122 | | | t | 4.4.5 | 3123 | | | | | 3124 | entries | (JSTask|JSEvent)[] | JSGroup | Section | 3125 | | | | 5.3.1 | 3126 | | | | | 3127 | estimatedDura | Duration | JSTask | Section | 3128 | tion | | | 5.2.3 | 3129 | | | | | 3130 | excluded | Boolean | JSEvent, | Section | 3131 | | | JSTask | 4.3.5 | 3132 | | | | | 3133 | excludedRecur | RecurrenceRule[] | JSEvent, | Section | 3134 | renceRules | | JSTask | 4.3.3 | 3135 | | | | | 3136 | expectReply | Boolean | Participan | Section | 3137 | | | t | 4.4.5 | 3138 | | | | | 3139 | firstDayOfWee | String | Recurrence | Section | 3140 | k | | Rule | 4.3.2 | 3141 | | | | | 3142 | freeBusyStatu | String | JSEvent, | Section | 3143 | s | | JSTask | 4.4.2 | 3144 | | | | | 3145 | frequency | String | Recurrence | Section | 3146 | | | Rule | 4.3.2 | 3147 | | | | | 3148 | href | String | Link | Section | 3149 | | | | 1.4.11 | 3150 | | | | | 3151 | interval | UnsignedInt | Recurrence | Section | 3152 | | | Rule | 4.3.2 | 3153 | | | | | 3154 | invitedBy | String | Participan | Section | 3155 | | | t | 4.4.5 | 3156 | | | | | 3157 | keywords | String[Boolean] | JSEvent, | Section | 3158 | | | JSTask, | 4.2.9 | 3159 | | | JSGroup | | 3160 | | | | | 3161 | kind | String | Participan | Section | 3162 | | | t | 4.4.5 | 3163 | | | | | 3164 | language | String | Participan | Section | 3165 | | | t | 4.4.5 | 3166 | | | | | 3167 | links | Id[Link] | JSGroup, | Section | 3168 | | | JSEvent, | 4.2.7, | 3169 | | | JSTask, | Section | 3170 | | | Location, | 4.2.5, | 3171 | | | Participan | Section | 3172 | | | t | 4.4.5 | 3173 | | | | | 3174 | locale | String | JSGroup, | Section | 3175 | | | JSEvent, | 4.2.8 | 3176 | | | JSTask | | 3177 | | | | | 3178 | localizations | String[PatchObject] | JSEvent, | Section | 3179 | | | JSTask | 4.6.1 | 3180 | | | | | 3181 | locationId | String | Participan | Section | 3182 | | | t | 4.4.5 | 3183 | | | | | 3184 | locations | Id[Location] | JSEvent, | Section | 3185 | | | JSTask | 4.2.5 | 3186 | | | | | 3187 | locationTypes | String[Boolean] | Location | Section | 3188 | | | | 4.2.5 | 3189 | | | | | 3190 | memberOf | String[Boolean] | Participan | Section | 3191 | | | t | 4.4.5 | 3192 | | | | | 3193 | method | String | JSEvent, | Section | 3194 | | | JSTask | 4.1.8 | 3195 | | | | | 3196 | name | String | Location, | Section | 3197 | | | VirtualLoc | 4.2.5, | 3198 | | | ation, Par | Section | 3199 | | | ticipant | 4.2.6, | 3200 | | | | Section | 3201 | | | | 4.4.5 | 3202 | | | | | 3203 | names | String[Boolean] | TimeZoneRu | Section | 3204 | | | le | 4.7.2 | 3205 | | | | | 3206 | nthOfPeriod | Int | NDay | Section | 3207 | | | | 4.3.2 | 3208 | | | | | 3209 | offset | SignedDuration | OffsetTrig | Section | 3210 | | | ger | 4.5.2 | 3211 | | | | | 3212 | offsetFrom | UTCDateTime | TimeZoneRu | Section | 3213 | | | le | 4.7.2 | 3214 | | | | | 3215 | offsetTo | UTCDateTime | TimeZoneRu | Section | 3216 | | | le | 4.7.2 | 3217 | | | | | 3218 | participants | Id[Participant] | JSEvent, | Section | 3219 | | | JSTask | 4.4.5 | 3220 | | | | | 3221 | participation | String | Participan | Section | 3222 | Comment | | t | 4.4.5 | 3223 | | | | | 3224 | participation | String | Participan | Section | 3225 | Status | | t | 4.4.5 | 3226 | | | | | 3227 | percentComple | UnsignedInt | JSTask, Pa | Section | 3228 | te | | rticipant | 5.2.4 | 3229 | | | | | 3230 | priority | Int | JSEvent, | Section | 3231 | | | JSTask | 4.4.1 | 3232 | | | | | 3233 | privacy | String | JSEvent, | Section | 3234 | | | JSTask | 4.4.3 | 3235 | | | | | 3236 | prodId | String | JSEvent, | Section | 3237 | | | JSTask, | 4.1.4 | 3238 | | | JSGroup | | 3239 | | | | | 3240 | progress | String | JSTask, Pa | Section | 3241 | | | rticipant | 5.2.5 | 3242 | | | | | 3243 | progressUpdat | UTCDateTime | JSTask, Pa | Section | 3244 | ed | | rticipant | 5.2.6 | 3245 | | | | | 3246 | recurrenceId | LocalDateTime | JSEvent, | Section | 3247 | | | JSTask | 4.3.1 | 3248 | | | | | 3249 | recurrenceOve | LocalDateTime[PatchObject] | JSEvent, | Section | 3250 | rrides | | JSTask, Ti | 4.3.4, | 3251 | | | meZoneRule | Section | 3252 | | | | 4.7.2 | 3253 | | | | | 3254 | recurrenceRul | RecurrenceRule[] | JSEvent, | Section | 3255 | es | | JSTask, Ti | 4.3.2, | 3256 | | | meZoneRule | Section | 3257 | | | | 4.7.2 | 3258 | | | | | 3259 | rel | String | Link | Section | 3260 | | | | 1.4.11 | 3261 | | | | | 3262 | relatedTo | String[Relation] | JSEvent, | Section | 3263 | | | JSTask, | 4.1.3, | 3264 | | | Alert | Section | 3265 | | | | 4.5.2 | 3266 | | | | | 3267 | relation | String[Boolean] | Relation | Section | 3268 | | | | 1.4.10 | 3269 | | | | | 3270 | relativeTo | String | OffsetTrig | Section | 3271 | | | ger, | 4.5.2, | 3272 | | | Location | Section | 3273 | | | | 4.2.5 | 3274 | | | | | 3275 | replyTo | String[String] | JSEvent, | Section | 3276 | | | JSTask | 4.4.4 | 3277 | | | | | 3278 | roles | String[Boolean] | Participan | Section | 3279 | | | t | 4.4.5 | 3280 | | | | | 3281 | rscale | String | Recurrence | Section | 3282 | | | Rule | 4.3.2 | 3283 | | | | | 3284 | standard | TimeZoneRule | TimeZone | Section | 3285 | | | | 4.7.2 | 3286 | | | | | 3287 | start | LocalDateTime | TimeZoneRu | Section | 3288 | | | le | 4.7.2 | 3289 | | | | | 3290 | scheduleAgent | String | Participan | Section | 3291 | | | t | 4.4.5 | 3292 | | | | | 3293 | scheduleForce | Boolean | Participan | Section | 3294 | Send | | t | 4.4.5 | 3295 | | | | | 3296 | scheduleSeque | UnsignedInt | Participan | Section | 3297 | nce | | t | 4.4.5 | 3298 | | | | | 3299 | scheduleStatu | String[] | Participan | Section | 3300 | s | | t | 4.4.5 | 3301 | | | | | 3302 | scheduleUpdat | UTCDateTime | Participan | Section | 3303 | ed | | t | 4.4.5 | 3304 | | | | | 3305 | sendTo | String[String] | Participan | Section | 3306 | | | t | 4.4.5 | 3307 | | | | | 3308 | sequence | UnsignedInt | JSEvent, | Section | 3309 | | | JSTask | 4.1.7 | 3310 | | | | | 3311 | showWithoutTi | Boolean | JSEvent, | Section | 3312 | me | | JSTask | 4.2.4 | 3313 | | | | | 3314 | size | UnsignedInt | Link | Section | 3315 | | | | 1.4.11 | 3316 | | | | | 3317 | skip | String | Recurrence | Section | 3318 | | | Rule | 4.3.2 | 3319 | | | | | 3320 | source | String | JSGroup | Section | 3321 | | | | 5.3.2 | 3322 | | | | | 3323 | start | LocalDateTime | JSEvent, | Section | 3324 | | | JSTask | 5.1.1, | 3325 | | | | Section | 3326 | | | | 5.2.2 | 3327 | | | | | 3328 | status | String | JSEvent | Section | 3329 | | | | 5.1.3 | 3330 | | | | | 3331 | timeZone | TimeZoneId|null | JSEvent, | Section | 3332 | | | JSTask, | 4.7.1, | 3333 | | | Location | Section | 3334 | | | | 4.2.5 | 3335 | | | | | 3336 | timeZones | TimeZoneId[TimeZone] | JSEvent, | Section | 3337 | | | JSTask | 4.7.2 | 3338 | | | | | 3339 | title | String | JSEvent, | Section | 3340 | | | JSTask, | 4.2.1 | 3341 | | | JSGroup, | | 3342 | | | Link | | 3343 | | | | | 3344 | trigger | OffsetTrigger|AbsoluteTrig | Alert | Section | 3345 | | ger|UnknownTrigger | | 4.5.2 | 3346 | | | | | 3347 | tzId | String | TimeZone | Section | 3348 | | | | 4.7.2 | 3349 | | | | | 3350 | uid | String | JSEvent, | Section | 3351 | | | JSTask, | 4.1.2 | 3352 | | | JSGroup | | 3353 | | | | | 3354 | until | LocalDateTime | Recurrence | Section | 3355 | | | Rule | 4.3.2 | 3356 | | | | | 3357 | updated | UTCDateTime | JSEvent, | Section | 3358 | | | JSTask, | 4.1.6 | 3359 | | | JSGroup | | 3360 | | | | | 3361 | uri | String | VirtualLoc | Section | 3362 | | | ation | 4.2.6 | 3363 | | | | | 3364 | url | String | TimeZone | Section | 3365 | | | | 4.7.2 | 3366 | | | | | 3367 | useDefaultAle | Boolean | JSEvent, | Section | 3368 | rts | | JSTask | 4.5.1 | 3369 | | | | | 3370 | validUntil | UTCDateTime | TimeZone | Section | 3371 | | | | 4.7.2 | 3372 | | | | | 3373 | virtualLocati | Id[VirtualLocation] | JSEvent, | Section | 3374 | ons | | JSTask | 4.2.6 | 3375 | | | | | 3376 | when | UTCDateTime | AbsoluteTr | Section | 3377 | | | igger | 4.5.2 | 3378 +---------------+----------------------------+------------+---------+ 3380 Table 1 3382 8.3. Creation of "JSCalendar Types" Registry 3384 The IANA will create the "JSCalendar Types" registry to avoid name 3385 collisions and provide a complete reference for all data types used 3386 for JSCalendar property values. The registration process is the same 3387 as for the JSCalendar Properties registry, as defined in Section 8.2. 3389 8.3.1. JSCalendar Types Registry Template 3391 o Type Name: The name of the type. 3393 o Reference or Description: A brief description or RFC number and 3394 section reference where the Type is specified (may be omitted for 3395 "reserved" type names). 3397 o Intended Use: Common, reserved, or obsolete. 3399 o Change Controller: Who may request a change to this entry's 3400 definition ("IETF" for IETF-stream RFCs). 3402 8.3.2. Initial Contents for the JSCalendar Types Registry 3404 The following table lists the initial entries of the JSCalendar Types 3405 registry. All properties are for common-use. All RFC section 3406 references are for this document. The change controller for all 3407 these properties is "IETF". 3409 +-----------------+--------------------------+ 3410 | Type Name | Reference or Description | 3411 +-----------------+--------------------------+ 3412 | Alert | Section 4.5.2 | 3413 | | | 3414 | Boolean | Section 1.3 | 3415 | | | 3416 | Duration | Section 1.4.6 | 3417 | | | 3418 | Id | Section 1.4.1 | 3419 | | | 3420 | Int | Section 1.4.2 | 3421 | | | 3422 | LocalDateTime | Section 1.4.5 | 3423 | | | 3424 | Link | Section 1.4.11 | 3425 | | | 3426 | Location | Section 4.2.5 | 3427 | | | 3428 | NDay | Section 4.3.2 | 3429 | | | 3430 | Number | Section 1.3 | 3431 | | | 3432 | Participant | Section 4.4.5 | 3433 | | | 3434 | PatchObject | Section 1.4.9 | 3435 | | | 3436 | RecurrenceRule | Section 4.3.2 | 3437 | | | 3438 | Relation | Section 1.4.10 | 3439 | | | 3440 | SignedDuration | Section 1.4.7 | 3441 | | | 3442 | String | Section 1.3 | 3443 | | | 3444 | TimeZone | Section 4.7.2 | 3445 | | | 3446 | TimeZoneId | Section 1.4.8 | 3447 | | | 3448 | TimeZoneRule | Section 4.7.2 | 3449 | | | 3450 | UnsignedInt | Section 1.4.3 | 3451 | | | 3452 | UTCDateTime | Section 1.4.4 | 3453 | | | 3454 | VirtualLocation | Section 4.2.6 | 3455 +-----------------+--------------------------+ 3457 Table 2 3459 8.4. Creation of "JSCalendar Enum Values" Registry 3461 The IANA will create the "JSCalendar Enum Values" registry to allow 3462 interoperable extension of semantics for properties with enumerable 3463 values. Each such property will have a subregistry of allowed 3464 values. The registration process for a new enum value or adding a 3465 new enumerable property is the same as for the JSCalendar Properties 3466 registry, as defined in Section 8.2. 3468 8.4.1. JSCalendar Enum Property Template 3470 This template is for adding a subregistry for a new enumerable 3471 property to the JSCalendar Enum registry. 3473 o Property Name: the name(s) of the property or properties where 3474 these values may be used. This MUST be registered in the 3475 JSCalendar Properties registry. 3477 o Context: the list of allowed object types where the property or 3478 properties may appear, as registered in the JSCalendar Properties 3479 registry. This disambiguates where there may be two distinct 3480 properties with the same name in different contexts. 3482 o Change Controller: ("IETF" for properties defined in IETF-stream 3483 RFCs). 3485 o Initial Contents: The initial list of defined values for this 3486 enum, using the template defined in Section 8.4.2. A subregistry 3487 will be created with these values for this property name/context 3488 tuple. 3490 8.4.2. JSCalendar Enum Value Template 3492 This template is for adding a new enum value to a subregistry in the 3493 JSCalendar Enum registry. 3495 o Enum Value: The verbatim value of the enum. 3497 o Reference or Description: A brief description or RFC number and 3498 section reference for the semantics of this value. 3500 8.4.3. Initial Contents for the JSCalendar Enum Values registry 3502 For each subregistry created in this section, all RFC section 3503 references are for this document. 3505 ------------------------------------------------------------ 3507 Property Name: action 3509 Context: Alert 3511 Change Controller: IETF 3513 Initial Contents: 3515 +------------+--------------------------+ 3516 | Enum Value | Reference or Description | 3517 +------------+--------------------------+ 3518 | display | Section 4.5.2 | 3519 | | | 3520 | email | Section 4.5.2 | 3521 +------------+--------------------------+ 3523 Table 3 3525 ------------------------------------------------------------ 3527 Property Name: display 3529 Context: Link 3531 Change Controller: IETF 3533 Initial Contents: 3535 +------------+--------------------------+ 3536 | Enum Value | Reference or Description | 3537 +------------+--------------------------+ 3538 | badge | Section 1.4.11 | 3539 | | | 3540 | graphic | Section 1.4.11 | 3541 | | | 3542 | fullsize | Section 1.4.11 | 3543 | | | 3544 | thumbnail | Section 1.4.11 | 3545 +------------+--------------------------+ 3547 Table 4 3549 ------------------------------------------------------------ 3551 Property Name: freeBusyStatus 3553 Context: JSEvent, JSTask 3555 Change Controller: IETF 3557 Initial Contents: 3559 +------------+--------------------------+ 3560 | Enum Value | Reference or Description | 3561 +------------+--------------------------+ 3562 | free | Section 4.4.2 | 3563 | | | 3564 | busy | Section 4.4.2 | 3565 +------------+--------------------------+ 3567 Table 5 3569 ------------------------------------------------------------ 3571 Property Name: kind 3573 Context: Participant 3575 Change Controller: IETF 3577 Initial Contents: 3579 +------------+--------------------------+ 3580 | Enum Value | Reference or Description | 3581 +------------+--------------------------+ 3582 | individual | Section 4.4.5 | 3583 | | | 3584 | group | Section 4.4.5 | 3585 | | | 3586 | resource | Section 4.4.5 | 3587 | | | 3588 | location | Section 4.4.5 | 3589 +------------+--------------------------+ 3591 Table 6 3593 ------------------------------------------------------------ 3595 Property Name: participationStatus 3597 Context: Participant 3599 Change Controller: IETF 3601 Initial Contents: 3603 +--------------+--------------------------+ 3604 | Enum Value | Reference or Description | 3605 +--------------+--------------------------+ 3606 | needs-action | Section 4.4.5 | 3607 | | | 3608 | accepted | Section 4.4.5 | 3609 | | | 3610 | declined | Section 4.4.5 | 3611 | | | 3612 | tenative | Section 4.4.5 | 3613 | | | 3614 | delegated | Section 4.4.5 | 3615 +--------------+--------------------------+ 3617 Table 7 3619 ------------------------------------------------------------ 3621 Property Name: privacy 3623 Context: JSEvent, JSTask 3625 Change Controller: IETF 3627 Initial Contents: 3629 +------------+--------------------------+ 3630 | Enum Value | Reference or Description | 3631 +------------+--------------------------+ 3632 | public | Section 4.4.3 | 3633 | | | 3634 | private | Section 4.4.3 | 3635 | | | 3636 | secret | Section 4.4.3 | 3637 +------------+--------------------------+ 3639 Table 8 3641 ------------------------------------------------------------ 3643 Property Name: progress 3645 Context: JSTask, Participant 3647 Change Controller: IETF 3649 Initial Contents: 3651 +--------------+--------------------------+ 3652 | Enum Value | Reference or Description | 3653 +--------------+--------------------------+ 3654 | needs-action | Section 5.2.5 | 3655 | | | 3656 | in-process | Section 5.2.5 | 3657 | | | 3658 | completed | Section 5.2.5 | 3659 | | | 3660 | failed | Section 5.2.5 | 3661 | | | 3662 | cancelled | Section 5.2.5 | 3663 +--------------+--------------------------+ 3665 Table 9 3667 ------------------------------------------------------------ 3669 Property Name: relation 3671 Context: Relation 3673 Change Controller: IETF 3675 Initial Contents: 3677 +------------+--------------------------+ 3678 | Enum Value | Reference or Description | 3679 +------------+--------------------------+ 3680 | first | Section 1.4.10 | 3681 | | | 3682 | next | Section 1.4.10 | 3683 | | | 3684 | child | Section 1.4.10 | 3685 | | | 3686 | parent | Section 1.4.10 | 3687 +------------+--------------------------+ 3689 Table 10 3691 ------------------------------------------------------------ 3693 Property Name: relativeTo 3695 Context: OffsetTrigger, Location 3697 Change Controller: IETF 3698 Initial Contents: 3700 +------------+--------------------------+ 3701 | Enum Value | Reference or Description | 3702 +------------+--------------------------+ 3703 | start | Section 4.5.2 | 3704 | | | 3705 | end | Section 4.5.2 | 3706 +------------+--------------------------+ 3708 Table 11 3710 ------------------------------------------------------------ 3712 Property Name: roles 3714 Context: Participant 3716 Change Controller: IETF 3718 Initial Contents: 3720 +---------------+--------------------------+ 3721 | Enum Value | Reference or Description | 3722 +---------------+--------------------------+ 3723 | owner | Section 4.4.5 | 3724 | | | 3725 | attendee | Section 4.4.5 | 3726 | | | 3727 | optional | Section 4.4.5 | 3728 | | | 3729 | informational | Section 4.4.5 | 3730 | | | 3731 | chair | Section 4.4.5 | 3732 | | | 3733 | contact | Section 4.4.5 | 3734 +---------------+--------------------------+ 3736 Table 12 3738 ------------------------------------------------------------ 3740 Property Name: scheduleAgent 3742 Context: Participant 3744 Change Controller: IETF 3745 Initial Contents: 3747 +------------+--------------------------+ 3748 | Enum Value | Reference or Description | 3749 +------------+--------------------------+ 3750 | server | Section 4.4.5 | 3751 | | | 3752 | client | Section 4.4.5 | 3753 | | | 3754 | none | Section 4.4.5 | 3755 +------------+--------------------------+ 3757 Table 13 3759 ------------------------------------------------------------ 3761 Property Name: status 3763 Context: JSEvent 3765 Change Controller: IETF 3767 Initial Contents: 3769 +------------+--------------------------+ 3770 | Enum Value | Reference or Description | 3771 +------------+--------------------------+ 3772 | confirmed | Section 5.1.3 | 3773 | | | 3774 | cancelled | Section 5.1.3 | 3775 | | | 3776 | tentative | Section 5.1.3 | 3777 +------------+--------------------------+ 3779 Table 14 3781 9. Acknowledgments 3783 The authors would like to thank the members of CalConnect for their 3784 valuable contributions. This specification originated from the work 3785 of the API technical committee of CalConnect, the Calendaring and 3786 Scheduling Consortium. 3788 10. References 3789 10.1. Normative References 3791 [CLDR] "Unicode Common Locale Data Repository", 3792 . 3794 [COLORS] "CSS Color Module", . 3796 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 3797 Requirement Levels", BCP 14, RFC 2119, 3798 DOI 10.17487/RFC2119, March 1997, 3799 . 3801 [RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource 3802 Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998, 3803 . 3805 [RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397, 3806 DOI 10.17487/RFC2397, August 1998, 3807 . 3809 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: 3810 Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, 3811 . 3813 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 3814 Resource Identifier (URI): Generic Syntax", STD 66, 3815 RFC 3986, DOI 10.17487/RFC3986, January 2005, 3816 . 3818 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally 3819 Unique IDentifier (UUID) URN Namespace", RFC 4122, 3820 DOI 10.17487/RFC4122, July 2005, 3821 . 3823 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 3824 Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006, 3825 . 3827 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 3828 Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, 3829 . 3831 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 3832 Specifications: ABNF", STD 68, RFC 5234, 3833 DOI 10.17487/RFC5234, January 2008, 3834 . 3836 [RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and 3837 Scheduling Core Object Specification (iCalendar)", 3838 RFC 5545, DOI 10.17487/RFC5545, September 2009, 3839 . 3841 [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent 3842 Interoperability Protocol (iTIP)", RFC 5546, 3843 DOI 10.17487/RFC5546, December 2009, 3844 . 3846 [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying 3847 Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, 3848 September 2009, . 3850 [RFC5870] Mayrhofer, A. and C. Spanring, "A Uniform Resource 3851 Identifier for Geographic Locations ('geo' URI)", 3852 RFC 5870, DOI 10.17487/RFC5870, June 2010, 3853 . 3855 [RFC6047] Melnikov, A., Ed., "iCalendar Message-Based 3856 Interoperability Protocol (iMIP)", RFC 6047, 3857 DOI 10.17487/RFC6047, December 2010, 3858 . 3860 [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type 3861 Specifications and Registration Procedures", BCP 13, 3862 RFC 6838, DOI 10.17487/RFC6838, January 2013, 3863 . 3865 [RFC6901] Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed., 3866 "JavaScript Object Notation (JSON) Pointer", RFC 6901, 3867 DOI 10.17487/RFC6901, April 2013, 3868 . 3870 [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493, 3871 DOI 10.17487/RFC7493, March 2015, 3872 . 3874 [RFC7529] Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules 3875 in the Internet Calendaring and Scheduling Core Object 3876 Specification (iCalendar)", RFC 7529, 3877 DOI 10.17487/RFC7529, May 2015, 3878 . 3880 [RFC7808] Douglass, M. and C. Daboo, "Time Zone Data Distribution 3881 Service", RFC 7808, DOI 10.17487/RFC7808, March 2016, 3882 . 3884 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 3885 Writing an IANA Considerations Section in RFCs", BCP 26, 3886 RFC 8126, DOI 10.17487/RFC8126, June 2017, 3887 . 3889 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 3890 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 3891 May 2017, . 3893 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 3894 Interchange Format", STD 90, RFC 8259, 3895 DOI 10.17487/RFC8259, December 2017, 3896 . 3898 [RFC8288] Nottingham, M., "Web Linking", RFC 8288, 3899 DOI 10.17487/RFC8288, October 2017, 3900 . 3902 [TZDB] "IANA Time Zone Database", 3903 . 3905 10.2. Informative References 3907 [LINKRELS] 3908 "IANA Link Relation Types", 3909 . 3912 [LOCATIONTYPES] 3913 "IANA Location Types Registry", 3914 . 3917 [MEDIATYPES] 3918 "IANA Media Types", . 3921 [RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed., 3922 "DomainKeys Identified Mail (DKIM) Signatures", STD 76, 3923 RFC 6376, DOI 10.17487/RFC6376, September 2011, 3924 . 3926 [RFC7265] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON 3927 Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May 3928 2014, . 3930 [RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986, 3931 DOI 10.17487/RFC7986, October 2016, 3932 . 3934 Authors' Addresses 3936 Neil Jenkins 3937 Fastmail 3938 PO Box 234 3939 Collins St West 3940 Melbourne VIC 8007 3941 Australia 3943 Email: neilj@fastmailteam.com 3944 URI: https://www.fastmail.com 3946 Robert Stepanek 3947 Fastmail 3948 PO Box 234 3949 Collins St West 3950 Melbourne VIC 8007 3951 Australia 3953 Email: rsto@fastmailteam.com 3954 URI: https://www.fastmail.com