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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 3, 2021 September 30, 2020 7 JSCalendar: A JSON representation of calendar data 8 draft-ietf-calext-jscalendar-31 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 3, 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 . . . . . . . . . . . . . . . . . . . . . . 11 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 . . . . . . . . . . . . . . . 14 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 . . . . . . . . . . . . . . . . . . . . . . 16 84 4.1.4. prodId . . . . . . . . . . . . . . . . . . . . . . . 17 85 4.1.5. created . . . . . . . . . . . . . . . . . . . . . . . 17 86 4.1.6. updated . . . . . . . . . . . . . . . . . . . . . . . 17 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 . . . . . . . . . . . . . . . . . . . . . . 21 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 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 1.4.10. Relation 523 A Relation object defines the relation to other objects, using a 524 possibly empty set of relation types. The object that defines this 525 relation is the linking object, while the other object is the linked 526 object. A Relation object has the following properties: 528 o @type: "String" (mandatory) 530 Specifies the type of this object. This MUST be "Relation". 532 o relation: "String[Boolean]" (optional, default: empty Object) 534 Describes how the linked object is related to the linking object. 535 The relation is defined as a set of relation types. If empty, the 536 relationship between the two objects is unspecified. 538 Keys in the set MUST be one of the following values, or specified 539 in the property definition where the Relation object is used, or a 540 value registered in the IANA JSCalendar Enum Values registry, or a 541 vendor-specific value (see Section 3.3): 543 * "first": The linked object is the first in a series the linking 544 object is part of. 546 * "next": The linked object is the next in a series the linking 547 object is part of. 549 * "child": The linked object is a subpart of the linking object. 551 * "parent": The linking object is a subpart of the linked object. 553 The value for each key in the map MUST be true. 555 1.4.11. Link 557 A Link object represents an external resource associated with the 558 linking object. It has the following properties: 560 o @type: "String" (mandatory) 562 Specifies the type of this object. This MUST be "Link". 564 o href: "String" (mandatory) 566 A URI [RFC3986] from which the resource may be fetched. 568 This MAY be a "data:" URL [RFC2397], but it is recommended that 569 the file be hosted on a server to avoid embedding arbitrarily 570 large data in JSCalendar object instances. 572 o cid: "String" (optional) 573 This MUST be a valid "content-id" value according to the 574 definition of Section 2 in [RFC2392]. The value MUST be unique 575 within this Link object but has no meaning beyond that. It MAY be 576 different from the link id for this Link object. 578 o contentType: "String" (optional) 580 The media type [RFC6838] of the resource, if known. 582 o size: "UnsignedInt" (optional) 584 The size, in octets, of the resource when fully decoded (i.e., the 585 number of octets in the file the user would download), if known. 586 Note that this is an informational estimate, and implementations 587 must be prepared to handle the actual size being quite different 588 when the resource is fetched. 590 o rel: "String" (optional) 592 Identifies the relation of the linked resource to the object. If 593 set, the value MUST be a relation type from the IANA registry 594 [LINKRELS], as established in [RFC8288]. 596 o display: "String" (optional) 598 Describes the intended purpose of a link to an image. If set, the 599 "rel" property MUST be set to "icon". The value MUST be one of 600 the following values, another value registered in the IANA 601 JSCalendar Enum Values registry, or a vendor-specific value (see 602 Section 3.3): 604 * "badge": an image meant to be displayed alongside the title of 605 the object. 607 * "graphic": a full image replacement for the object itself. 609 * "fullsize": an image that is used to enhance the object. 611 * "thumbnail": a smaller variant of "fullsize" to be used when 612 space for the image is constrained. 614 o title: "String" (optional) 616 A human-readable plain-text description of the resource. 618 2. JSCalendar Objects 620 This section describes the calendar object types specified by 621 JSCalendar. 623 2.1. JSEvent 625 Media type: "application/jscalendar+json;type=jsevent" 627 A JSEvent represents a scheduled amount of time on a calendar, 628 typically a meeting, appointment, reminder or anniversary. It is 629 required to start at a certain point in time and typically has a non- 630 zero duration. Multiple participants may partake in the event at 631 multiple locations. 633 The @type (Section 4.1.1) property value MUST be "jsevent". 635 2.2. JSTask 637 Media type: "application/jscalendar+json;type=jstask" 639 A JSTask represents an action-item, assignment, to-do or work item. 640 It may start and be due at certain points in time, may take some 641 estimated time to complete, and may recur, none of which is required. 643 The @type (Section 4.1.1) property value MUST be "jstask". 645 2.3. JSGroup 647 Media type: "application/jscalendar+json;type=jsgroup" 649 A JSGroup is a collection of JSEvent (Section 2.1) and/or JSTask 650 (Section 2.2) objects. Typically, objects are grouped by topic 651 (e.g., by keywords) or calendar membership. 653 The @type (Section 4.1.1) property value MUST be "jsgroup". 655 3. Structure of JSCalendar Objects 657 A JSCalendar object is a JSON object [RFC8259], which MUST be valid 658 I-JSON (a stricter subset of JSON) [RFC7493]. Property names and 659 values are case-sensitive. 661 The object has a collection of properties, as specified in the 662 following sections. Properties are specified as being either 663 mandatory or optional. Optional properties may have a default value, 664 if explicitly specified in the property definition. 666 3.1. Object Type 668 JSCalendar objects MUST name their type in the "@type" property, if 669 not explicitly specified otherwise for the respective object type. A 670 notable exception to this rule is the PatchObject (Section 1.4.9). 672 3.2. Normalization and Equivalence 674 JSCalendar aims to provide unambiguous definitions for value types 675 and properties, but does not define a general normalization or 676 equivalence method for JSCalendar objects and types. This is because 677 the notion of equivalence might range from byte-level equivalence to 678 semantic equivalence, depending on the respective use case. 680 Normalization of JSCalendar objects is hindered because of the 681 following reasons: 683 o Custom JSCalendar properties may contain arbitrary JSON values, 684 including arrays. However, equivalence of arrays might or might 685 not depend on the order of elements, depending on the respective 686 property definition. 688 o Several JSCalendar property values are defined as URIs and media 689 types, but normalization of these types is inherently protocol- 690 and scheme-specific, depending on the use-case of the equivalence 691 definition (see Section 6 of [RFC3986]). 693 Considering this, the definition of equivalence and normalization is 694 left to client and server implementations and to be negotiated by a 695 calendar exchange protocol or defined elsewhere. 697 3.3. Vendor-specific Property Extensions, Values and Types 699 Vendors MAY add additional properties to the calendar object to 700 support their custom features. To avoid conflict, the names of these 701 properties MUST be prefixed by a domain name controlled by the vendor 702 followed by a colon, e.g., "example.com:customprop". If the value is 703 a new JSCalendar object, it either MUST include a "@type" property or 704 it MUST explicitly be specified to not require a type designator. 705 The type name MUST be prefixed with a domain name controlled by the 706 vendor. 708 Some JSCalendar properties allow vendor-specific value extensions. 709 Such vendor-specific values MUST be prefixed by a domain name 710 controlled by the vendor followed by a colon, e.g., 711 "example.com:customrel". 713 Vendors are strongly encouraged to register any new property values 714 or extensions that are useful to other systems as well, rather than 715 use a vendor-specific prefix. 717 4. Common JSCalendar Properties 719 This section describes the properties that are common to the various 720 JSCalendar object types. Specific JSCalendar object types may only 721 support a subset of these properties. The object type definitions in 722 Section 5 describe the set of supported properties per type. 724 4.1. Metadata Properties 726 4.1.1. @type 728 Type: "String" (mandatory). 730 Specifies the type which this object represents. This MUST be one of 731 the following values: 733 o "jsevent": a JSCalendar event (Section 2.1). 735 o "jstask": a JSCalendar task (Section 2.2). 737 o "jsgroup": a JSCalendar group (Section 2.3). 739 4.1.2. uid 741 Type: "String" (mandatory). 743 A globally unique identifier, used to associate the object as the 744 same across different systems, calendars and views. The value of 745 this property MUST be unique across all JSCalendar objects, even if 746 they are of different type. [RFC4122] describes a range of 747 established algorithms to generate universally unique identifiers 748 (UUID). UUID version 4, described in Section 4.4 of [RFC4122], is 749 RECOMMENDED. 751 For compatibility with [RFC5545] UIDs, implementations MUST be able 752 to receive and persist values of at least 255 octets for this 753 property, but they MUST NOT truncate values in the middle of a UTF-8 754 multi-octet sequence. 756 4.1.3. relatedTo 758 Type: "String[Relation]" (optional). 760 Relates the object to other JSCalendar objects. This is represented 761 as a map of the UIDs of the related objects to information about the 762 relation. 764 If an object is split to make a "this and future" change to a 765 recurrence, the original object MUST be truncated to end at the 766 previous occurrence before this split, and a new object created to 767 represent all the occurrences after the split. A "next" relation 768 MUST be set on the original object's relatedTo property for the UID 769 of the new object. A "first" relation for the UID of the first 770 object in the series MUST be set on the new object. Clients can then 771 follow these UIDs to get the complete set of objects if the user 772 wishes to modify them all at once. 774 4.1.4. prodId 776 Type: "String" (optional). 778 The identifier for the product that last updated the JSCalendar 779 object. This should be set whenever the data in the object is 780 modified (i.e., whenever the "updated" property is set). 782 The vendor of the implementation MUST ensure that this is a globally 783 unique identifier, using some technique such as an FPI value, as 784 defined in [ISO.9070.1991]. 786 This property SHOULD NOT be used to alter the interpretation of a 787 JSCalendar object beyond the semantics specified in this document. 788 For example, it is not to be used to further the understanding of 789 non-standard properties, a practice that is known to cause long-term 790 interoperability problems. 792 4.1.5. created 794 Type: "UTCDateTime" (optional). 796 The date and time this object was initially created. 798 4.1.6. updated 800 Type: "UTCDateTime" (mandatory). 802 The date and time the data in this object was last modified (or its 803 creation date/time if not modified since). 805 4.1.7. sequence 807 Type: "UnsignedInt" (optional, default: 0). 809 Initially zero, this MUST be incremented by one every time a change 810 is made to the object, except if the change only modifies the 811 "participants" property (see Section 4.4.5). 813 This is used as part of iTIP [RFC5546] to know which version of the 814 object a scheduling message relates to. 816 4.1.8. method 818 Type: "String" (optional). 820 The iTIP [RFC5546] method, in lowercase. This MUST only be present 821 if the JSCalendar object represents an iTIP scheduling message. 823 4.2. What and Where Properties 825 4.2.1. title 827 Type: "String" (optional, default: empty String). 829 A short summary of the object. 831 4.2.2. description 833 Type: "String" (optional, default: empty String). 835 A longer-form text description of the object. The content is 836 formatted according to the "descriptionContentType" property. 838 4.2.3. descriptionContentType 840 Type: "String" (optional, default: "text/plain"). 842 Describes the media type [RFC6838] of the contents of the 843 "description" property. Media types MUST be sub-types of type 844 "text", and SHOULD be "text/plain" or "text/html" [MEDIATYPES]. They 845 MAY include parameters and the "charset" parameter value MUST be 846 "utf-8", if specified. Descriptions of type "text/html" MAY contain 847 "cid" URLs [RFC2392] to reference links in the calendar object by use 848 of the "cid" property of the Link object. 850 4.2.4. showWithoutTime 852 Type: "Boolean" (optional, default: false). 854 Indicates that the time is not important to display to the user when 855 rendering this calendar object. An example of this is an event that 856 conceptually occurs all day or across multiple days, such as "New 857 Year's Day" or "Italy Vacation". While the time component is 858 important for free-busy calculations and checking for scheduling 859 clashes, calendars may choose to omit displaying it and/or display 860 the object separately to other objects to enhance the user's view of 861 their schedule. 863 Such events are also commonly known as "all-day" events. 865 4.2.5. locations 867 Type: "Id[Location]" (optional). 869 A map of location ids to Location objects, representing locations 870 associated with the object. 872 A Location object has the following properties. It MUST have at 873 least one property other than the "relativeTo" property. 875 o @type: "String" (mandatory) 877 Specifies the type of this object. This MUST be "Location". 879 o name: "String" (optional) 881 The human-readable name of the location. 883 o description: "String" (optional) 885 Human-readable, plain-text instructions for accessing this 886 location. This may be an address, set of directions, door access 887 code, etc. 889 o locationTypes: "String[Boolean]" (optional) 891 A set of one or more location types that describe this location. 892 All types MUST be from the Location Types Registry [LOCATIONTYPES] 893 as defined in [RFC4589]. The set is represented as a map, with 894 the keys being the location types. The value for each key in the 895 map MUST be true. 897 o relativeTo: "String" (optional) 898 Specifies the relation between this location and the time of the 899 JSCalendar object. This is primarily to allow events representing 900 travel to specify the location of departure (at the start of the 901 event) and location of arrival (at the end); this is particularly 902 important if these locations are in different time zones, as a 903 client may wish to highlight this information for the user. 905 This MUST be one of the following values, another value registered 906 in the IANA JSCalendar Enum Values registry, or a vendor-specific 907 value (see Section 3.3). Any value the client or server doesn't 908 understand should be treated the same as if this property is 909 omitted. 911 * "start": The event/task described by this JSCalendar object 912 occurs at this location at the time the event/task starts. 914 * "end": The event/task described by this JSCalendar object 915 occurs at this location at the time the event/task ends. 917 o timeZone: "TimeZoneId" (optional) 919 A time zone for this location. 921 o coordinates: "String" (optional) 923 A "geo:" URI [RFC5870] for the location. 925 o links: "Id[Link]" (optional) 927 A map of link ids to Link objects, representing external resources 928 associated with this location, for example a vCard or image. If 929 there are no links, this MUST be omitted (rather than specified as 930 an empty set). 932 4.2.6. virtualLocations 934 Type: "Id[VirtualLocation]" (optional). 936 A map of virtual location ids to VirtualLocation objects, 937 representing virtual locations, such as video conferences or chat 938 rooms, associated with the object. 940 A VirtualLocation object has the following properties. 942 o @type: "String" (mandatory) 944 Specifies the type of this object. This MUST be 945 "VirtualLocation". 947 o name: "String" (optional, default: empty String) 949 The human-readable name of the virtual location. 951 o description: "String" (optional) 953 Human-readable plain-text instructions for accessing this virtual 954 location. This may be a conference access code, etc. 956 o uri: "String" (mandatory) 958 A URI [RFC3986] that represents how to connect to this virtual 959 location. 961 This may be a telephone number (represented using the "tel:" 962 scheme, e.g., "tel:+1-555-555-5555") for a teleconference, a web 963 address for online chat, or any custom URI. 965 4.2.7. links 967 Type: "Id[Link]" (optional). 969 A map of link ids to Link objects, representing external resources 970 associated with the object. 972 Links with a rel of "enclosure" MUST be considered by the client as 973 attachments for download. 975 Links with a rel of "describedby" MUST be considered by the client to 976 be an alternative representation of the description. 978 Links with a rel of "icon" MUST be considered by the client to be an 979 image that it may use when presenting the calendar data to a user. 980 The "display" property may be set to indicate the purpose of this 981 image. 983 4.2.8. locale 985 Type: "String" (optional). 987 The language tag as defined in [RFC5646] that best describes the 988 locale used for the text in the calendar object, if known. 990 4.2.9. keywords 992 Type: "String[Boolean]" (optional). 994 A set of keywords or tags that relate to the object. The set is 995 represented as a map, with the keys being the keywords. The value 996 for each key in the map MUST be true. 998 4.2.10. categories 1000 Type: "String[Boolean]" (optional). 1002 A set of categories that relate to the calendar object. The set is 1003 represented as a map, with the keys being the categories specified as 1004 URIs. The value for each key in the map MUST be true. 1006 In contrast to keywords, categories typically are structured. For 1007 example, a vendor owning the domain "example.com" might define the 1008 categories "http://example.com/categories/sports/american-football" 1009 and "http://example.com/categories/music/r-b". 1011 4.2.11. color 1013 Type: "String" (optional). 1015 A color clients MAY use when displaying this calendar object. The 1016 value is a color name taken from the set of names defined in 1017 Section 4.3 of CSS Color Module Level 3 [COLORS], or an RGB value in 1018 hexadecimal notation, as defined in Section 4.2.1 of CSS Color Module 1019 Level 3. 1021 4.3. Recurrence Properties 1023 Some events and tasks occur at regular or irregular intervals. 1024 Rather than having to copy the data for every occurrence there can be 1025 a master event with rules to generate recurrences, and/or overrides 1026 that add extra dates or exceptions to the rules. 1028 The recurrence set is the complete set of instances for an object. 1029 It is generated by considering the following properties in order, all 1030 of which are optional: 1032 1. The recurrenceRules property (Section 4.3.2) generates a set of 1033 extra date-times on which the object occurs. 1035 2. The excludedRecurrenceRules property (Section 4.3.3) generates a 1036 set of date-times that are to be removed from the previously 1037 generated set of date-times on which the object occurs. 1039 3. The recurrenceOverrides property (Section 4.3.4) defines date- 1040 times which are added or excluded to form the final set. (This 1041 property may also contain changes to the object to apply to 1042 particular instances.) 1044 4.3.1. recurrenceId 1046 Type: "LocalDateTime" (optional). 1048 If present, this JSCalendar object represents one occurrence of a 1049 recurring JSCalendar object. If present the "recurrenceRules" and 1050 "recurrenceOverrides" properties MUST NOT be present. 1052 The value is a date-time either produced by the "recurrenceRules" of 1053 the master event, or added as a key to the "recurrenceOverrides" 1054 property of the master event. 1056 4.3.2. recurrenceRules 1058 Type: "RecurrenceRule[]" (optional). 1060 Defines a set of recurrence rules (repeating patterns) for recurring 1061 calendar objects. 1063 A JSEvent recurs by applying the recurrence rules to the "start" 1064 date-time. 1066 A JSTask recurs by applying the recurrence rules to the "start" date- 1067 time, if defined, otherwise it recurs by the "due" date-time, if 1068 defined. If the task defines neither a "start" nor "due" date-time, 1069 it MUST NOT define a "recurrenceRules" property. 1071 If multiple recurrence rules are given, each rule is to be applied 1072 and then the union of the results used, ignoring any duplicates. 1074 A RecurrenceRule object is a JSON object mapping of a RECUR value 1075 type in iCalendar [RFC5545] [RFC7529] and has the same semantics. It 1076 has the following properties: 1078 o @type: "String" (mandatory) 1080 Specifies the type of this object. This MUST be "RecurrenceRule". 1082 o frequency: "String" (mandatory) 1084 The time span covered by each iteration of this recurrence rule 1085 (see Section 4.3.2.1 for full semantics). This MUST be one of the 1086 following values: 1088 * "yearly" 1089 * "monthly" 1091 * "weekly" 1093 * "daily" 1095 * "hourly" 1097 * "minutely" 1099 * "secondly" 1101 This is the FREQ part from iCalendar, converted to lowercase. 1103 o interval: "UnsignedInt" (optional, default: 1) 1105 The interval of iteration periods at which the recurrence repeats. 1106 If included, it MUST be an integer >= 1. 1108 This is the INTERVAL part from iCalendar. 1110 o rscale: "String" (optional, default: "gregorian") 1112 The calendar system in which this recurrence rule operates, in 1113 lowercase. This MUST be either a CLDR-registered calendar system 1114 name [CLDR], or a vendor-specific value (see Section 3.3). 1116 This is the RSCALE part from iCalendar RSCALE [RFC7529], converted 1117 to lowercase. 1119 o skip: "String" (optional, default: "omit") 1121 The behaviour to use when the expansion of the recurrence produces 1122 invalid dates. This property only has an effect if the frequency 1123 is "yearly" or "monthly". It MUST be one of the following values: 1125 * "omit" 1127 * "backward" 1129 * "forward" 1131 This is the SKIP part from iCalendar RSCALE [RFC7529], converted 1132 to lowercase. 1134 o firstDayOfWeek: "String" (optional, default: "mo") 1135 The day on which the week is considered to start, represented as a 1136 lowercase abbreviated two-letter English day of the week. If 1137 included, it MUST be one of the following values: 1139 * "mo" 1141 * "tu" 1143 * "we" 1145 * "th" 1147 * "fr" 1149 * "sa" 1151 * "su" 1153 This is the WKST part from iCalendar. 1155 o byDay: "NDay[]" (optional) 1157 Days of the week on which to repeat. An "NDay" object has the 1158 following properties: 1160 * @type: "String" (mandatory) 1162 Specifies the type of this object. This MUST be "NDay". 1164 * day: "String" (mandatory) 1166 A day of the week on which to repeat; the allowed values are 1167 the same as for the "firstDayOfWeek" RecurrenceRule property. 1169 This is the day-of-the-week of the BYDAY part in iCalendar, 1170 converted to lowercase. 1172 * nthOfPeriod: "Int" (optional) 1174 If present, rather than representing every occurrence of the 1175 weekday defined in the "day" property, it represents only a 1176 specific instance within the recurrence period. The value can 1177 be positive or negative, but MUST NOT be zero. A negative 1178 integer means nth-last of period. 1180 This is the ordinal part of the BYDAY value in iCalendar (e.g., 1181 1 or -3). 1183 o byMonthDay: "Int[]" (optional) 1185 Days of the month on which to repeat. Valid values are between 1 1186 and the maximum number of days any month may have in the calendar 1187 given by the "rscale" property, and the negative values of these 1188 numbers. For example, in the Gregorian calendar valid values are 1189 1 to 31 and -31 to -1. Negative values offset from the end of the 1190 month. The array MUST have at least one entry if included. 1192 This is the BYMONTHDAY part in iCalendar. 1194 o byMonth: "String[]" (optional) 1196 The months in which to repeat. Each entry is a string 1197 representation of a number, starting from "1" for the first month 1198 in the calendar (e.g., "1" means January with the Gregorian 1199 calendar), with an optional "L" suffix (see [RFC7529]) for leap 1200 months (this MUST be uppercase, e.g., "3L"). The array MUST have 1201 at least one entry if included. 1203 This is the BYMONTH part from iCalendar. 1205 o byYearDay: "Int[]" (optional) 1207 The days of the year on which to repeat. Valid values are between 1208 1 and the maximum number of days any year may have in the calendar 1209 given by the "rscale" property, and the negative values of these 1210 numbers. For example, in the Gregorian calendar valid values are 1211 1 to 366 and -366 to -1. Negative values offset from the end of 1212 the year. The array MUST have at least one entry if included. 1214 This is the BYYEARDAY part from iCalendar. 1216 o byWeekNo: "Int[]" (optional) 1218 Weeks of the year in which to repeat. Valid values are between 1 1219 and the maximum number of weeks any year may have in the calendar 1220 given by the "rscale" property, and the negative values of these 1221 numbers. For example, in the Gregorian calendar valid values are 1222 1 to 53 and -53 to -1. The array MUST have at least one entry if 1223 included. 1225 This is the BYWEEKNO part from iCalendar. 1227 o byHour: "UnsignedInt[]" (optional) 1228 The hours of the day in which to repeat. Valid values are 0 to 1229 23. The array MUST have at least one entry if included. This is 1230 the BYHOUR part from iCalendar. 1232 o byMinute: "UnsignedInt[]" (optional) 1234 The minutes of the hour in which to repeat. Valid values are 0 to 1235 59. The array MUST have at least one entry if included. 1237 This is the BYMINUTE part from iCalendar. 1239 o bySecond: "UnsignedInt[]" (optional) 1241 The seconds of the minute in which to repeat. Valid values are 0 1242 to 60. The array MUST have at least one entry if included. 1244 This is the BYSECOND part from iCalendar. 1246 o bySetPosition: "Int[]" (optional) 1248 The occurrences within the recurrence interval to include in the 1249 final results. Negative values offset from the end of the list of 1250 occurrences. The array MUST have at least one entry if included. 1251 This is the BYSETPOS part from iCalendar. 1253 o count: "UnsignedInt" (optional) 1255 The number of occurrences at which to range-bound the recurrence. 1256 This MUST NOT be included if an "until" property is specified. 1258 This is the COUNT part from iCalendar. 1260 o until: "LocalDateTime" (optional) 1262 The date-time at which to finish recurring. The last occurrence 1263 is on or before this date-time. This MUST NOT be included if a 1264 "count" property is specified. Note: if not specified otherwise 1265 for a specific JSCalendar object, this date is to be interpreted 1266 in the time zone specified in the JSCalendar object's "timeZone" 1267 property. 1269 This is the UNTIL part from iCalendar. 1271 4.3.2.1. Interpreting recurrence rules 1273 A recurrence rule specifies a set of date-times for recurring 1274 calendar objects. A recurrence rule has the following semantics. 1275 Note, wherever "year", "month" or "day of month" is used, this is 1276 within the calendar system given by the "rscale" property, which 1277 defaults to "gregorian" if omitted. 1279 1. A set of candidates is generated. This is every second within a 1280 period defined by the frequency property value: 1282 * "yearly": every second from midnight on the 1st day of a year 1283 (inclusive) to midnight the 1st day of the following year 1284 (exclusive). 1286 If skip is not "omit", the calendar system has leap months and 1287 there is a byMonth property, generate candidates for the leap 1288 months even if they don't occur in this year. 1290 If skip is not "omit" and there is a byMonthDay property, 1291 presume each month has the maximum number of days any month 1292 may have in this calendar system when generating candidates, 1293 even if it's more than this month actually has. 1295 * "monthly": every second from midnight on the 1st day of a 1296 month (inclusive) to midnight on the 1st of the following 1297 month (exclusive). 1299 If skip is not "omit" and there is a byMonthDay property, 1300 presume the month has the maximum number of days any month may 1301 have in this calendar system when generating candidates, even 1302 if it's more than this month actually has. 1304 * "weekly": every second from midnight (inclusive) on the first 1305 day of the week (as defined by the firstDayOfWeek property, or 1306 Monday if omitted), to midnight 7 days later (exclusive). 1308 * "daily": every second from midnight at the start of the day 1309 (inclusive) to midnight at the end of the day (exclusive). 1311 * "hourly": every second from the beginning of the hour 1312 (inclusive) to the beginning of the next hour (exclusive). 1314 * "minutely": every second from the beginning of the minute 1315 (inclusive) to the beginning of the next minute (exclusive). 1317 * "secondly": the second itself, only. 1319 2. Each date-time candidate is compared against all of the byX 1320 properties of the rule except bySetPosition. If any property in 1321 the rule does not match the date-time, the date-time is 1322 eliminated. Each byX property is an array; the date-time matches 1323 the property if it matches any of the values in the array. The 1324 properties have the following semantics: 1326 * byMonth: the date-time is in the given month. 1328 * byWeekNo: the date-time is in the nth week of the year. 1329 Negative numbers mean the nth last week of the year. This 1330 corresponds to weeks according to week numbering as defined in 1331 ISO.8601.2004, with a week defined as a seven day period, 1332 starting on the firstDayOfWeek property value or Monday if 1333 omitted. Week number one of the calendar year is the first 1334 week that contains at least four days in that calendar year. 1336 If the date-time is not valid (this may happen when generating 1337 candidates with a skip property in effect), it is always 1338 eliminated by this property. 1340 * byYearDay: the date-time is on the nth day of year. Negative 1341 numbers mean the nth last day of the year. 1343 If the date-time is not valid (this may happen when generating 1344 candidates with a skip property in effect), it is always 1345 eliminated by this property. 1347 * byMonthDay: the date-time is on the given day of the month. 1348 Negative numbers mean the nth last day of the month. 1350 * byDay: the date-time is on the given day of the week. If the 1351 day is prefixed by a number, it is the nth occurrence of that 1352 day of the week within the month (if frequency is monthly) or 1353 year (if frequency is yearly). Negative numbers means nth 1354 last occurrence within that period. 1356 * byHour: the date-time has the given hour value. 1358 * byMinute: the date-time has the given minute value. 1360 * bySecond: the date-time has the given second value. 1362 If a skip property is defined and is not "omit", there may be 1363 candidates that do not correspond to valid dates (e.g., 31st 1364 February in the Gregorian calendar). In this case, the 1365 properties MUST be considered in the order above and: 1367 1. After applying the byMonth filter, if the candidate's month 1368 is invalid for the given year, increment it (if skip is 1369 "forward") or decrement it (if skip is "backward") until a 1370 valid month is found, incrementing/decrementing the year as 1371 well if passing through the beginning/end of the year. This 1372 only applies to calendar systems with leap months. 1374 2. After applying the byMonthDay filter, if the day of the month 1375 is invalid for the given month and year, change the date to 1376 the first day of the next month (if skip is "forward") or the 1377 last day of the current month (if skip is "backward"). 1379 3. If any valid date produced after applying the skip is already 1380 a candidate, eliminate the duplicate. (For example after 1381 adjusting, 30th February and 31st February would both become 1382 the same "real" date, so one is eliminated as a duplicate.) 1384 3. If a bySetPosition property is included, this is now applied to 1385 the ordered list of remaining dates. This property specifies the 1386 indexes of date-times to keep; all others should be eliminated. 1387 Negative numbers are indexes from the end of the list, with -1 1388 being the last item. 1390 4. Any date-times before the start date of the event are eliminated 1391 (see below for why this might be needed). 1393 5. If a skip property is included and is not "omit", eliminate any 1394 date-times that have already been produced by previous iterations 1395 of the algorithm. (This is not possible if skip is "omit".) 1397 6. If further dates are required (we have not reached the until 1398 date, or count limit) skip the next (interval - 1) sets of 1399 candidates, then continue from step 1. 1401 When determining the set of occurrence dates for an event or task, 1402 the following extra rules must be applied: 1404 1. The initial date-time to which the rule is applied (the "start" 1405 date-time for events; the "start" or "due" date-time for tasks) 1406 is always the first occurrence in the expansion (and is counted 1407 if the recurrence is limited by a "count" property), even if it 1408 would normally not match the rule. 1410 2. The first set of candidates to consider is that which would 1411 contain the initial date-time. This means the first set may 1412 include candidates before the initial date-time; such candidates 1413 are eliminated from the results in step (4) as outlined before. 1415 3. The following properties MUST be implicitly added to the rule 1416 under the given conditions: 1418 * If frequency is not "secondly" and no bySecond property: Add a 1419 bySecond property with the sole value being the seconds value 1420 of the initial date-time. 1422 * If frequency is not "secondly" or "minutely", and no byMinute 1423 property: Add a byMinute property with the sole value being 1424 the minutes value of the initial date-time. 1426 * If frequency is not "secondly", "minutely" or "hourly" and no 1427 byHour property: Add a byHour property with the sole value 1428 being the hours value of the initial date-time. 1430 * If frequency is "weekly" and no byDay property: Add a byDay 1431 property with the sole value being the day-of-the-week of the 1432 initial date-time. 1434 * If frequency is "monthly" and no byDay property and no 1435 byMonthDay property: Add a byMonthDay property with the sole 1436 value being the day-of-the-month of the initial date-time. 1438 * If frequency is "yearly" and no byYearDay property: 1440 + If there are no byMonth or byWeekNo properties, and either 1441 there is a byMonthDay property or there is no byDay 1442 property: Add a byMonth property with the sole value being 1443 the month of the initial date-time. 1445 + If there is no byMonthDay, byWeekNo or byDay properties: 1446 Add a byMonthDay property with the sole value being the 1447 day-of-the-month of the initial date-time. 1449 + If there is a byWeekNo property and no byMonthDay or byDay 1450 properties: Add a byDay property with the sole value being 1451 the day-of-the-week of the initial date-time. 1453 4.3.3. excludedRecurrenceRules 1455 Type: "RecurrenceRule[]" (optional). 1457 Defines a set of recurrence rules (repeating patterns) for date-times 1458 on which the object will not occur. The rules are interpreted the 1459 same as for the "recurrenceRules" property (see Section 4.3.2), with 1460 the exception that the initial date-time to which the rule is applied 1461 (the "start" date-time for events; the "start" or "due" date-time for 1462 tasks) is only considered part of the expansion if it matches the 1463 rule. The resulting set of date-times are then removed from those 1464 generated by the recurrenceRules property, as described in 1465 Section 4.3. 1467 4.3.4. recurrenceOverrides 1469 Type: "LocalDateTime[PatchObject]" (optional). 1471 A map of the recurrence ids (the date-time produced by the recurrence 1472 rule) to an object of patches to apply to the generated occurrence 1473 object. 1475 If the recurrence id does not match a date-time from the recurrence 1476 rule (or no rule is specified), it is to be treated as an additional 1477 occurrence (like an RDATE from iCalendar). The patch object may 1478 often be empty in this case. 1480 If the patch object defines the "excluded" property of an occurrence 1481 to be true, this occurrence is omitted from the final set of 1482 recurrences for the calendar object (like an EXDATE from iCalendar). 1483 Such a patch object MUST NOT patch any other property. 1485 By default, an occurrence inherits all properties from the main 1486 object except the start (or due) date-time, which is shifted to match 1487 the recurrence id LocalDateTime. However, individual properties of 1488 the occurrence can be modified by a patch, or multiple patches. It 1489 is valid to patch the "start" property value, and this patch takes 1490 precedence over the value generated from the recurrence id. Both the 1491 recurrence id as well as the patched "start" date-time may occur 1492 before the original JSCalendar object's "start" or "due" date. 1494 A pointer in the PatchObject MUST be ignored if it starts with one of 1495 the following prefixes: 1497 o @type 1499 o excludedRecurrenceRules 1501 o method 1503 o privacy 1505 o prodId 1507 o recurrenceId 1509 o recurrenceOverrides 1511 o recurrenceRules 1513 o relatedTo 1514 o replyTo 1516 o uid 1518 4.3.5. excluded 1520 Type: "Boolean" (optional, default: false). 1522 Defines if this object is an overridden, excluded instance of a 1523 recurring JSCalendar object (see Section 4.3.4). If this property 1524 value is true, this calendar object instance MUST be removed from the 1525 occurrence expansion. The absence of this property, or the presence 1526 of its default value false, indicates that this instance MUST be 1527 included in the occurrence expansion. 1529 4.4. Sharing and Scheduling Properties 1531 4.4.1. priority 1533 Type: "Int" (optional, default: 0). 1535 Specifies a priority for the calendar object. This may be used as 1536 part of scheduling systems to help resolve conflicts for a time 1537 period. 1539 The priority is specified as an integer in the range 0 to 9. A value 1540 of 0 specifies an undefined priority, for which the treatment will 1541 vary by situation. A value of 1 is the highest priority. A value of 1542 2 is the second highest priority. Subsequent numbers specify a 1543 decreasing ordinal priority. A value of 9 is the lowest priority. 1544 Other integer values are reserved for future use. 1546 4.4.2. freeBusyStatus 1548 Type: "String" (optional, default: "busy"). 1550 Specifies how this calendar object should be treated when calculating 1551 free-busy state. This MUST be one of the following values, another 1552 value registered in the IANA JSCalendar Enum Values registry, or a 1553 vendor-specific value (see Section 3.3): 1555 o "free": The object should be ignored when calculating whether the 1556 user is busy. 1558 o "busy": The object should be included when calculating whether the 1559 user is busy. 1561 4.4.3. privacy 1563 Type: "String" (optional, default: "public"). 1565 Calendar objects are normally collected together and may be shared 1566 with other users. The privacy property allows the object owner to 1567 indicate that it should not be shared, or should only have the time 1568 information shared but the details withheld. Enforcement of the 1569 restrictions indicated by this property are up to the API via which 1570 this object is accessed. 1572 This property MUST NOT affect the information sent to scheduled 1573 participants; it is only interpreted by protocols that share the 1574 calendar objects belonging to one user with other users. 1576 The value MUST be one of the following values, another value 1577 registered in the IANA JSCalendar Enum Values registry, or a vendor- 1578 specific value (see Section 3.3). Any value the client or server 1579 doesn't understand should be preserved but treated as equivalent to 1580 "private". 1582 o "public": The full details of the object are visible to those whom 1583 the object's calendar is shared with. 1585 o "private": The details of the object are hidden; only the basic 1586 time and metadata is shared. The following properties MAY be 1587 shared, any other properties MUST NOT be shared: 1589 * @type 1591 * created 1593 * due 1595 * duration 1597 * estimatedDuration 1599 * freeBusyStatus 1601 * privacy 1603 * recurrenceOverrides. Only patches which apply to another 1604 permissible property are allowed to be shared. 1606 * sequence 1608 * showWithoutTime 1609 * start 1611 * timeZone 1613 * timeZones 1615 * uid 1617 * updated 1619 o "secret": The object is hidden completely (as though it did not 1620 exist) when the calendar this object is in is shared. 1622 4.4.4. replyTo 1624 Type: "String[String]" (optional). 1626 Represents methods by which participants may submit their response to 1627 the organizer of the calendar object. The keys in the property value 1628 are the available methods and MUST only contain ASCII alphanumeric 1629 characters (A-Za-z0-9). The value is a URI for the method specified 1630 in the key. Future methods may be defined in future specifications 1631 and registered with IANA; a calendar client MUST ignore any method it 1632 does not understand, but MUST preserve the method key and URI. This 1633 property MUST be omitted if no method is defined (rather than being 1634 specified as an empty object). 1636 The following methods are defined: 1638 o "imip": The organizer accepts an iMIP [RFC6047] response at this 1639 email address. The value MUST be a "mailto:" URI. 1641 o "web": Opening this URI in a web browser will provide the user 1642 with a page where they can submit a reply to the organizer. The 1643 value MUST be a URL using the "https:" scheme. 1645 o "other": The organizer is identified by this URI but the method 1646 for submitting the response is undefined. 1648 4.4.5. participants 1650 Type: "Id[Participant]" (optional). 1652 A map of participant ids to participants, describing their 1653 participation in the calendar object. 1655 If this property is set and any participant has a sendTo property, 1656 then the "replyTo" property of this calendar object MUST define at 1657 least one reply method. 1659 A Participant object has the following properties: 1661 o @type: "String" (mandatory) 1663 Specifies the type of this object. This MUST be "Participant". 1665 o name: "String" (optional) 1667 The display name of the participant (e.g., "Joe Bloggs"). 1669 o email: "String" (optional) 1671 The email address for the participant. 1673 o description: "String" (optional). 1675 A plain text description of this participant. For example, this 1676 may include more information about their role in the event or how 1677 best to contact them. 1679 o sendTo: "String[String]" (optional) 1681 Represents methods by which the participant may receive the 1682 invitation and updates to the calendar object. 1684 The keys in the property value are the available methods and MUST 1685 only contain ASCII alphanumeric characters (A-Za-z0-9). The value 1686 is a URI for the method specified in the key. Future methods may 1687 be defined in future specifications and registered with IANA; a 1688 calendar client MUST ignore any method it does not understand, but 1689 MUST preserve the method key and URI. This property MUST be 1690 omitted if no method is defined (rather than being specified as an 1691 empty object). 1693 The following methods are defined: 1695 * "imip": The participant accepts an iMIP [RFC6047] request at 1696 this email address. The value MUST be a "mailto:" URI. It MAY 1697 be different from the value of the participant's "email" 1698 property. 1700 * "other": The participant is identified by this URI but the 1701 method for submitting the invitation is undefined. 1703 o kind: "String" (optional) 1705 What kind of entity this participant is, if known. 1707 This MUST be one of the following values, another value registered 1708 in the IANA JSCalendar Enum Values registry, or a vendor-specific 1709 value (see Section 3.3). Any value the client or server doesn't 1710 understand should be treated the same as if this property is 1711 omitted. 1713 * "individual": a single person 1715 * "group": a collection of people invited as a whole 1717 * "location": a physical location that needs to be scheduled, 1718 e.g., a conference room 1720 * "resource": a non-human resource other than a location, such as 1721 a projector 1723 o roles: "String[Boolean]" (mandatory) 1725 A set of roles that this participant fulfills. 1727 At least one role MUST be specified for the participant. The keys 1728 in the set MUST be one of the following values, another value 1729 registered in the IANA JSCalendar Enum Values registry, or a 1730 vendor-specific value (see Section 3.3): 1732 * "owner": The participant is an owner of the object. This 1733 signifies they have permission to make changes to it that 1734 affect the other participants. Non-owner participants may only 1735 change properties that just affect themselves (for example 1736 setting their own alerts or changing their rsvp status). 1738 * "attendee": The participant is expected to be present at the 1739 event. 1741 * "optional": The participant's involvement with the event is 1742 optional. This is expected to be primarily combined with the 1743 "attendee" role. 1745 * "informational": The participant is copied for informational 1746 reasons, and is not expected to attend. 1748 * "chair": The participant is in charge of the event/task when it 1749 occurs. 1751 * "contact": The participant is someone that may be contacted for 1752 information about the event. 1754 The value for each key in the map MUST be true. It is expected 1755 that no more than one of the roles "attendee" and "informational" 1756 be present; if more than one are given, "attendee" takes 1757 precedence over "informational". Roles that are unknown to the 1758 implementation MUST be preserved. 1760 o locationId: "String" (optional) 1762 The location at which this participant is expected to be 1763 attending. 1765 If the value does not correspond to any location id in the 1766 "locations" property of the JSCalendar object, this MUST be 1767 treated the same as if the participant's locationId were omitted. 1769 o language: "String" (optional) 1771 The language tag as defined in [RFC5646] that best describes the 1772 participant's preferred language, if known. 1774 o participationStatus: "String" (optional, default: "needs-action") 1776 The participation status, if any, of this participant. 1778 The value MUST be one of the following values, another value 1779 registered in the IANA JSCalendar Enum Values registry, or a 1780 vendor-specific value (see Section 3.3): 1782 * "needs-action": No status yet set by the participant. 1784 * "accepted": The invited participant will participate. 1786 * "declined": The invited participant will not participate. 1788 * "tentative": The invited participant may participate. 1790 * "delegated": The invited participant has delegated their 1791 attendance to another participant, as specified in the 1792 delegatedTo property. 1794 o participationComment: "String" (optional) 1796 A note from the participant to explain their participation status. 1798 o expectReply: "Boolean" (optional, default: false) 1799 If true, the organizer is expecting the participant to notify them 1800 of their participation status. 1802 o scheduleAgent: "String" (optional, default: "server") 1804 Who is responsible for sending scheduling messages with this 1805 calendar object to the participant. 1807 The value MUST be one of the following values, another value 1808 registered in the IANA JSCalendar Enum Values registry, or a 1809 vendor-specific value (see Section 3.3): 1811 * "server": The calendar server will send the scheduling 1812 messages. 1814 * "client": The calendar client will send the scheduling 1815 messages. 1817 * "none": No scheduling messages are to be sent to this 1818 participant. 1820 o scheduleForceSend: "Boolean" (optional, default: false) 1822 A client may set the property on a participant to true to request 1823 that the server send a scheduling message to the participant when 1824 it would not normally do so (e.g. if no significant change is made 1825 the object or the scheduleAgent is set to client). The property 1826 MUST NOT be stored in the JSCalendar object on the server or 1827 appear in a scheduling message. 1829 o scheduleSequence: "UnsignedInt" (optional, default: 0) 1831 The sequence number of the last response from the participant. If 1832 defined, this MUST be a non-negative integer. 1834 This can be used to determine whether the participant has sent a 1835 new response following significant changes to the calendar object, 1836 and to determine if future responses are responding to a current 1837 or older view of the data. 1839 o scheduleStatus: "String[]" (optional) 1841 A list of status codes, as defined in Section 3.8.8.3 of 1842 [RFC5545], returned from the processing of the most recent 1843 scheduling message sent to this participant. 1845 Servers MUST only add or change this property when they send a 1846 scheduling message to the participant. Clients SHOULD NOT change 1847 or remove this property if it was provided by the server. Clients 1848 MAY add, change, or remove the property for participants where the 1849 client is handling the scheduling. 1851 This property MUST NOT be included in scheduling messages. 1853 o scheduleUpdated: "UTCDateTime" (optional) 1855 The timestamp for the most recent response from this participant. 1857 This is the "updated" property of the last response when using 1858 iTIP. It can be compared to the "updated" property in future 1859 responses to detect and discard older responses delivered out of 1860 order. 1862 o invitedBy: "String" (optional) 1864 The participant id of the participant who invited this one, if 1865 known. 1867 o delegatedTo: "String[Boolean]" (optional) 1869 A set of participant ids that this participant has delegated their 1870 participation to. Each key in the set MUST be the id of a 1871 participant. The value for each key in the map MUST be true. If 1872 there are no delegates, this MUST be omitted (rather than 1873 specified as an empty set). 1875 o delegatedFrom: "String[Boolean]" (optional) 1877 A set of participant ids that this participant is acting as a 1878 delegate for. Each key in the set MUST be the id of a 1879 participant. The value for each key in the map MUST be true. If 1880 there are no delegators, this MUST be omitted (rather than 1881 specified as an empty set). 1883 o memberOf: "String[Boolean]" (optional) 1885 A set of group participants that were invited to this calendar 1886 object, which caused this participant to be invited due to their 1887 membership in the group(s). Each key in the set MUST be the id of 1888 a participant. The value for each key in the map MUST be true. 1889 If there are no groups, this MUST be omitted (rather than 1890 specified as an empty set). 1892 o links: "Id[Link]" (optional) 1893 A map of link ids to Link objects, representing external resources 1894 associated with this participant, for example a vCard or image. 1895 If there are no links, this MUST be omitted (rather than specified 1896 as an empty set). 1898 o progress: "String" (optional; only allowed for participants of a 1899 JSTask). Represents the progress of the participant for this 1900 task. It MUST NOT be set if the "participationStatus" of this 1901 participant is any value other than "accepted". See Section 5.2.5 1902 for allowed values and semantics. 1904 o progressUpdated: "UTCDateTime" (optional; only allowed for 1905 participants of a JSTask). Specifies the date-time the progress 1906 property was last set on this participant. See Section 5.2.6 for 1907 allowed values and semantics. 1909 o percentComplete: "UnsignedInt" (optional; only allowed for 1910 participants of a JSTask). Represents the percent completion of 1911 the participant for this task. The property value MUST be a 1912 positive integer between 0 and 100. 1914 4.5. Alerts Properties 1916 4.5.1. useDefaultAlerts 1918 Type: "Boolean" (optional, default: false). 1920 If true, use the user's default alerts and ignore the value of the 1921 "alerts" property. Fetching user defaults is dependent on the API 1922 from which this JSCalendar object is being fetched, and is not 1923 defined in this specification. If an implementation cannot determine 1924 the user's default alerts, or none are set, it MUST process the 1925 alerts property as if "useDefaultAlerts" is set to false. 1927 4.5.2. alerts 1929 Type: "Id[Alert]" (optional). 1931 A map of alert ids to Alert objects, representing alerts/reminders to 1932 display or send to the user for this calendar object. 1934 An Alert Object has the following properties: 1936 o @type: "String" (mandatory) 1938 Specifies the type of this object. This MUST be "Alert". 1940 o trigger: "OffsetTrigger|AbsoluteTrigger|UnknownTrigger" 1941 (mandatory) 1943 Defines when to trigger the alert. New types may be defined in 1944 future documents. 1946 An "OffsetTrigger" object has the following properties: 1948 * @type: "String" (mandatory) 1950 Specifies the type of this object. This MUST be 1951 "OffsetTrigger". 1953 * offset: "SignedDuration" (mandatory). 1955 Defines the offset at which to trigger the alert relative to 1956 the time property defined in the "relativeTo" property of the 1957 alert. Negative durations signify alerts before the time 1958 property, positive durations signify alerts after. 1960 * relativeTo: "String" (optional, default: "start") 1962 Specifies the time property that the alert offset is relative 1963 to. The value MUST be one of: 1965 + "start": triggers the alert relative to the start of the 1966 calendar object 1968 + "end": triggers the alert relative to the end/due time of 1969 the calendar object 1971 An "AbsoluteTrigger" object has the following properties: 1973 * @type: "String" (mandatory) 1975 Specifies the type of this object. This MUST be 1976 "AbsoluteTrigger". 1978 * when: "UTCDateTime" (mandatory). 1980 Defines a specific UTC date-time when the alert is triggered. 1982 An "UnknownTrigger" object is an object that contains a "@type" 1983 property whose value is not recognized (i.e., not "OffsetTrigger" 1984 or "AbsoluteTrigger"), plus zero or more other properties. This 1985 is for compatibility with client extensions and future 1986 specifications. Implementations SHOULD NOT trigger for trigger 1987 types they do not understand, but MUST preserve them. 1989 o acknowledged: "UTCDateTime" (optional) 1991 This records when an alert was last acknowledged. This is set 1992 when the user has dismissed the alert; other clients that sync 1993 this property SHOULD automatically dismiss or suppress duplicate 1994 alerts (alerts with the same alert id that triggered on or before 1995 this date-time). 1997 For a recurring calendar object, setting the "acknowledged" 1998 property MUST NOT add a new override to the "recurrenceOverrides" 1999 property. If the alert is not already overridden, the 2000 acknowledged property MUST be set on the alert in the master 2001 event/task. 2003 Certain kinds of alert action may not provide feedback as to when 2004 the user sees them, for example email based alerts. For those 2005 kinds of alerts, this property MUST be set immediately when the 2006 alert is triggered and the action successfully carried out. 2008 o relatedTo: "String[Relation]" (optional) 2010 Relates this alert to other alerts in the same JSCalendar object. 2011 If the user wishes to snooze an alert, the application MUST create 2012 an alert to trigger after snoozing. This new snooze alert MUST 2013 set a parent relation to the identifier of the original alert. 2015 o action: "String" (optional, default: "display") 2017 Describes how to alert the user. 2019 The value MUST be at most one of the following values, a value 2020 registered in the IANA JSCalendar Enum Values registry, or a 2021 vendor-specific value (see Section 3.3): 2023 * "display": The alert should be displayed as appropriate for the 2024 current device and user context. 2026 * "email": The alert should trigger an email sent out to the 2027 user, notifying about the alert. This action is typically only 2028 appropriate for server implementations. 2030 4.6. Multilingual Properties 2032 4.6.1. localizations 2034 Type: "String[PatchObject]" (optional). 2036 A map of language tags [RFC5646] to patch objects, which localize the 2037 calendar object into the locale of the respective language tag. 2039 See the description of PatchObject (Section 1.4.9) for the structure 2040 of the PatchObject. The patches are applied to the top-level 2041 calendar object. In addition, the "locale" property of the patched 2042 object is set to the language tag. All pointers for patches MUST end 2043 with one of the following suffixes; any patch that does not follow 2044 this MUST be ignored unless otherwise specified in a future RFC: 2046 o title 2048 o description 2050 o name 2052 A patch MUST NOT have the prefix "recurrenceOverrides"; any 2053 localization of the override MUST be a patch to the localizations 2054 property inside the override instead. For example, a patch to 2055 "locations/abcd1234/title" is permissible, but a patch to "uid" or 2056 "recurrenceOverrides/2020-01-05T14:00:00/title" is not. 2058 Note that this specification does not define how to maintain validity 2059 of localized content. For example, a client application changing a 2060 JSCalendar object's title property might also need to update any 2061 localizations of this property. Client implementations SHOULD 2062 provide the means to manage localizations, but how to achieve this is 2063 specific to the application's workflow and requirements. 2065 4.7. Time Zone Properties 2067 4.7.1. timeZone 2069 Type: "TimeZoneId|null" (optional, default: null). 2071 Identifies the time zone the object is scheduled in, or null for 2072 floating time. This is either a name from the IANA Time Zone 2073 Database [TZDB] or the id of a custom time zone from the "timeZones" 2074 property (Section 4.7.2). If omitted, this MUST be presumed to be 2075 null (i.e., floating time). 2077 4.7.2. timeZones 2079 Type: "TimeZoneId[TimeZone]" (optional). 2081 Maps identifiers of custom time zones to their time zone definitions. 2082 The following restrictions apply for each key in the map: 2084 o To avoid conflict with names in the IANA Time Zone Database 2085 [TZDB], it MUST start with the "/" character. 2087 o It MUST be a valid "paramtext" value as specified in Section 3.1. 2088 of [RFC5545]. 2090 o At least one other property in the same JSCalendar object MUST 2091 reference a time zone using this identifier (i.e., orphaned time 2092 zones are not allowed). 2094 An identifier need only be unique to this JSCalendar object. A 2095 JSCalendar object may be part in a hierarchy of other JSCalendar 2096 objects (say, a JSEvent is an entry in a JSGroup). In this case, the 2097 set of time zones is the sum of the time zone definitions of this 2098 object and its parent objects. If multiple time zones with the same 2099 identifier exist, then the definition closest to the calendar object 2100 in relation to its parents MUST be used. (In context of JSEvent, a 2101 time zone definition in its timeZones property has precedence over a 2102 definition of the same id in the JSGroup). Time zone definitions in 2103 any children of the calendar object MUST be ignored. 2105 A TimeZone object maps a VTIMEZONE component from iCalendar [RFC5545] 2106 and the semantics are as defined there. A valid time zone MUST 2107 define at least one transition rule in the "standard" or "daylight" 2108 property. Its properties are: 2110 o @type: "String" (mandatory) 2112 Specifies the type of this object. This MUST be "TimeZone". 2114 o tzId: "String" (mandatory). 2116 The TZID property from iCalendar. 2118 o updated: "UTCDateTime" (optional) 2120 The LAST-MODIFIED property from iCalendar. 2122 o url: "String" (optional) 2124 The TZURL property from iCalendar. 2126 o validUntil: "UTCDateTime" (optional) 2128 The TZUNTIL property from iCalendar specified in [RFC7808]. 2130 o aliases: "String[Boolean]" (optional) 2131 Maps the TZID-ALIAS-OF properties from iCalendar specified in 2132 [RFC7808] to a JSON set of aliases. The set is represented as an 2133 object, with the keys being the aliases. The value for each key 2134 in the map MUST be true. 2136 o standard: "TimeZoneRule[]" (optional) 2138 The STANDARD sub-components from iCalendar. The order MUST be 2139 preserved during conversion. 2141 o daylight: "TimeZoneRule[]" (optional). 2143 The DAYLIGHT sub-components from iCalendar. The order MUST be 2144 preserved during conversion. 2146 A TimeZoneRule object maps a STANDARD or DAYLIGHT sub-component from 2147 iCalendar, with the restriction that at most one recurrence rule is 2148 allowed per rule. It has the following properties: 2150 o @type: "String" (mandatory) 2152 Specifies the type of this object. This MUST be "TimeZoneRule". 2154 o start: "LocalDateTime" (mandatory) 2156 The DTSTART property from iCalendar. 2158 o offsetFrom: "String" (mandatory) 2160 The TZOFFSETFROM property from iCalendar. 2162 o offsetTo: "String" (mandatory) 2164 The TZOFFSETTO property from iCalendar. 2166 o recurrenceRules: "RecurrenceRule[]" (optional) 2168 The RRULE property mapped as specified in Section 4.3.2. During 2169 recurrence rule evaluation, the "until" property value MUST be 2170 interpreted as a local time in the UTC time zone. 2172 o recurrenceOverrides: "LocalDateTime[PatchObject]" (optional) 2174 Maps the RDATE properties from iCalendar. The set is represented 2175 as an object, with the keys being the recurrence dates. The patch 2176 object MUST be the empty JSON object ({}). 2178 o names: "String[Boolean]" (optional) 2179 Maps the TZNAME properties from iCalendar to a JSON set. The set 2180 is represented as an object, with the keys being the names 2181 (excluding any "tznparam" component from iCalendar). The value 2182 for each key in the map MUST be true. 2184 o comments: "String[]" (optional). Maps the COMMENT properties from 2185 iCalendar. The order MUST be preserved during conversion. 2187 5. Type-specific JSCalendar Properties 2189 5.1. JSEvent Properties 2191 In addition to the common JSCalendar object properties (Section 4) a 2192 JSEvent has the following properties: 2194 5.1.1. start 2196 Type: "LocalDateTime" (mandatory). 2198 The date/time the event starts in the event's time zone (as specified 2199 in the "timeZone" property, see Section 4.7.1). 2201 5.1.2. duration 2203 Type: "Duration" (optional, default: "PT0S"). 2205 The zero or positive duration of the event in the event's start time 2206 zone. The end time of an event can be found by adding the duration 2207 to the event's start time. 2209 A JSEvent MAY involve start and end locations that are in different 2210 time zones (e.g., a trans-continental flight). This can be expressed 2211 using the "relativeTo" and "timeZone" properties of the JSEvent's 2212 Location objects (see Section 4.2.5). 2214 5.1.3. status 2216 Type: "String" (optional, default: "confirmed"). 2218 The scheduling status (Section 4.4) of a JSEvent. If set, it MUST be 2219 one of the following values, another value registered in the IANA 2220 JSCalendar Enum Values registry, or a vendor-specific value (see 2221 Section 3.3): 2223 o "confirmed": Indicates the event is definitely happening. 2225 o "cancelled": Indicates the event has been cancelled. 2227 o "tentative": Indicates the event may happen. 2229 5.2. JSTask Properties 2231 In addition to the common JSCalendar object properties (Section 4) a 2232 JSTask has the following properties: 2234 5.2.1. due 2236 Type: "LocalDateTime" (optional). 2238 The date/time the task is due in the task's time zone. 2240 5.2.2. start 2242 Type: "LocalDateTime" (optional). 2244 The date/time the task should start in the task's time zone. 2246 5.2.3. estimatedDuration 2248 Type: "Duration" (optional). 2250 Specifies the estimated positive duration of time the task takes to 2251 complete. 2253 5.2.4. percentComplete 2255 Type: "UnsignedInt" (optional). 2257 Represents the percent completion of the task overall. The property 2258 value MUST be a positive integer between 0 and 100. 2260 5.2.5. progress 2262 Type: "String" (optional). 2264 Defines the progress of this task. If omitted, the default progress 2265 (Section 4.4) of a JSTask is defined as follows (in order of 2266 evaluation): 2268 o "completed": if the "progress" property value of all participants 2269 is "completed". 2271 o "failed": if at least one "progress" property value of a 2272 participant is "failed". 2274 o "in-process": if at least one "progress" property value of a 2275 participant is "in-process". 2277 o "needs-action": If none of the other criteria match. 2279 If set, it MUST be one of the following values, another value 2280 registered in the IANA JSCalendar Enum Values registry, or a vendor- 2281 specific value (see Section 3.3): 2283 o "needs-action": Indicates the task needs action. 2285 o "in-process": Indicates the task is in process. 2287 o "completed": Indicates the task is completed. 2289 o "failed": Indicates the task failed. 2291 o "cancelled": Indicates the task was cancelled. 2293 5.2.6. progressUpdated 2295 Type: "UTCDateTime" (optional). 2297 Specifies the date/time the "progress" property of either the task 2298 overall (Section 5.2.5) or a specific participant (Section 4.4.5) was 2299 last updated. 2301 If the task is recurring and has future instances, a client may want 2302 to keep track of the last progress update timestamp of a specific 2303 task recurrence, but leave other instances unchanged. One way to 2304 achieve this is by overriding the progressUpdated property in the 2305 task "recurrenceOverrides" property. However, this could produce a 2306 long list of timestamps for regularly recurring tasks. An 2307 alternative approach is to split the JSTask into a current, single 2308 instance of JSTask with this instance progress update time and a 2309 future recurring instance. See also Section 4.1.3 on splitting. 2311 5.3. JSGroup Properties 2313 JSGroup supports the following common JSCalendar properties 2314 (Section 4): 2316 o @type 2318 o uid 2320 o prodId 2321 o created 2323 o updated 2325 o title 2327 o description 2329 o descriptionContentType 2331 o links 2333 o locale 2335 o keywords 2337 o categories 2339 o color 2341 o timeZones 2343 In addition, the following JSGroup-specific properties are supported: 2345 5.3.1. entries 2347 Type: "(JSTask|JSEvent)[]" (mandatory). 2349 A collection of group members. Implementations MUST ignore entries 2350 of unknown type. 2352 5.3.2. source 2354 Type: "String" (optional). 2356 The source from which updated versions of this group may be retrieved 2357 from. The value MUST be a URI. 2359 6. Examples 2361 The following examples illustrate several aspects of the JSCalendar 2362 data model and format. The examples may omit mandatory or additional 2363 properties, which is indicated by a placeholder property with key 2364 "...". While most of the examples use calendar event objects, they 2365 are also illustrative for tasks. 2367 6.1. Simple event 2369 This example illustrates a simple one-time event. It specifies a 2370 one-time event that begins on January 15, 2020 at 1pm New York local 2371 time and ends after 1 hour. 2373 { 2374 "@type": "jsevent", 2375 "uid": "a8df6573-0474-496d-8496-033ad45d7fea", 2376 "updated": "2020-01-02T18:23:04Z", 2377 "title": "Some event", 2378 "start": "2020-01-15T13:00:00", 2379 "timeZone": "America/New_York", 2380 "duration": "PT1H" 2381 } 2383 6.2. Simple task 2385 This example illustrates a simple task for a plain to-do item. 2387 { 2388 "@type": "jstask", 2389 "uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2", 2390 "updated": "2020-01-09T14:32:01Z", 2391 "title": "Do something" 2392 } 2394 6.3. Simple group 2396 This example illustrates a simple calendar object group that contains 2397 an event and a task. 2399 { 2400 "@type": "jsgroup", 2401 "uid": "bf0ac22b-4989-4caf-9ebd-54301b4ee51a", 2402 "updated": "2020-01-15T18:00:00Z", 2403 "name": "A simple group", 2404 "entries": [{ 2405 "@type": "jsevent", 2406 "uid": "a8df6573-0474-496d-8496-033ad45d7fea", 2407 "updated": "2020-01-02T18:23:04Z", 2408 "title": "Some event", 2409 "start": "2020-01-15T13:00:00", 2410 "timeZone": "America/New_York", 2411 "duration": "PT1H" 2412 }, 2413 { 2414 "@type": "jstask", 2415 "uid": "2a358cee-6489-4f14-a57f-c104db4dc2f2", 2416 "updated": "2020-01-09T14:32:01Z", 2417 "title": "Do something" 2418 }] 2419 } 2421 6.4. All-day event 2423 This example illustrates an event for an international holiday. It 2424 specifies an all-day event on April 1 that occurs every year since 2425 the year 1900. 2427 { 2428 "...": "", 2429 "title": "April Fool's Day", 2430 "showWithoutTime": true, 2431 "start": "1900-04-01T00:00:00", 2432 "duration": "P1D", 2433 "recurrenceRules": [{ 2434 "@type": "RecurrenceRule", 2435 "frequency": "yearly" 2436 }] 2437 } 2439 6.5. Task with a due date 2441 This example illustrates a task with a due date. It is a reminder to 2442 buy groceries before 6pm Vienna local time on January 19, 2020. The 2443 calendar user expects to need 1 hour for shopping. 2445 { 2446 "...": "", 2447 "title": "Buy groceries", 2448 "due": "2020-01-19T18:00:00", 2449 "timeZone": "Europe/Vienna", 2450 "estimatedDuration": "PT1H" 2451 } 2453 6.6. Event with end time zone 2455 This example illustrates the use of end time zones by use of an 2456 international flight. The flight starts on April 1, 2020 at 9am in 2457 Berlin local time. The duration of the flight is scheduled at 10 2458 hours 30 minutes. The time at the flight's destination is in the 2459 same time zone as Tokyo. Calendar clients could use the end time 2460 zone to display the arrival time in Tokyo local time and highlight 2461 the time zone difference of the flight. The location names can serve 2462 as input for navigation systems. 2464 { 2465 "...": "", 2466 "title": "Flight XY51 to Tokyo", 2467 "start": "2020-04-01T09:00:00", 2468 "timeZone": "Europe/Berlin", 2469 "duration": "PT10H30M", 2470 "locations": { 2471 "418d0b9b-b656-4b3c-909f-5b149ca779c9": { 2472 "@type": "Location", 2473 "rel": "start", 2474 "name": "Frankfurt Airport (FRA)" 2475 }, 2476 "c2c7ac67-dc13-411e-a7d4-0780fb61fb08": { 2477 "@type": "Location", 2478 "rel": "end", 2479 "name": "Narita International Airport (NRT)", 2480 "timeZone": "Asia/Tokyo" 2481 } 2482 } 2483 } 2485 6.7. Floating-time event (with recurrence) 2487 This example illustrates the use of floating time. Since January 1, 2488 2020, a calendar user blocks 30 minutes every day to practice Yoga at 2489 7am local time, in whatever time zone the user is located on that 2490 date. 2492 { 2493 "...": "", 2494 "title": "Yoga", 2495 "start": "2020-01-01T07:00:00", 2496 "duration": "PT30M", 2497 "recurrenceRules": [{ 2498 "@type": "RecurrenceRule", 2499 "frequency": "daily" 2500 }] 2501 } 2503 6.8. Event with multiple locations and localization 2505 This example illustrates an event that happens at both a physical and 2506 a virtual location. Fans can see a live concert on premises or 2507 online. The event title and descriptions are localized. 2509 { 2510 "...": "", 2511 "title": "Live from Music Bowl: The Band", 2512 "description": "Go see the biggest music event ever!", 2513 "locale": "en", 2514 "start": "2020-07-04T17:00:00", 2515 "timeZone": "America/New_York", 2516 "duration": "PT3H", 2517 "locations": { 2518 "c0503d30-8c50-4372-87b5-7657e8e0fedd": { 2519 "@type": "Location", 2520 "name": "The Music Bowl", 2521 "description": "Music Bowl, Central Park, New York", 2522 "coordinates": "geo:40.7829,-73.9654" 2523 } 2524 }, 2525 "virtualLocations": { 2526 "1": { 2527 "@type": "VirtualLocation", 2528 "name": "Free live Stream from Music Bowl", 2529 "uri": "https://stream.example.com/the_band_2020" 2530 } 2531 }, 2532 "localizations": { 2533 "de": { 2534 "title": "Live von der Music Bowl: The Band!", 2535 "description": "Schau dir das groesste Musikereignis an!", 2536 "virtualLocations/6f3696c6-1e07-47d0-9ce1-f50014b0041a/name": 2537 "Gratis Live-Stream aus der Music Bowl" 2538 } 2539 } 2540 } 2542 6.9. Recurring event with overrides 2544 This example illustrates the use of recurrence overrides. A math 2545 course at a University is held for the first time on January 8, 2020 2546 at 9am London time and occurs every week until June 24, 2020. Each 2547 lecture lasts for one hour and 30 minutes and is located at the 2548 Mathematics department. This event has exceptional occurrences: at 2549 the last occurrence of the course is an exam, which lasts for 2 hours 2550 and starts at 10am. Also, the location of the exam differs from the 2551 usual location. On April 1 no course is held. On January 7 at 2pm 2552 is an optional introduction course, that occurs before the first 2553 regular lecture. 2555 { 2556 "...": "", 2557 "title": "Calculus I", 2558 "start": "2020-01-08T09:00:00", 2559 "timeZone": "Europe/London", 2560 "duration": "PT1H30M", 2561 "locations": { 2562 "0dfb8ace-aad1-4734-b3b4-a2fe3d6ae1c5": { 2563 "@type": "Location", 2564 "title": "Math lab room 1", 2565 "description": "Math Lab I, Department of Mathematics" 2566 } 2567 }, 2568 "recurrenceRules": [{ 2569 "@type": "RecurrenceRule", 2570 "frequency": "weekly", 2571 "until": "2020-06-24T09:00:00" 2572 }], 2573 "recurrenceOverrides": { 2574 "2020-01-07T14:00:00": { 2575 "title": "Introduction to Calculus I (optional)" 2576 }, 2577 "2020-04-01T09:00:00": { 2578 "excluded": true 2579 }, 2580 "2020-06-25T09:00:00": { 2581 "title": "Calculus I Exam", 2582 "start": "2020-06-25T10:00:00", 2583 "duration": "PT2H", 2584 "locations": { 2585 "84d639ca-37ac-4a86-81e5-9bbba8eb4053": { 2586 "@type": "Location", 2587 "title": "Big Auditorium", 2588 "description": "Big Auditorium, Other Road" 2589 } 2590 } 2591 } 2592 } 2593 } 2595 6.10. Recurring event with participants 2597 This example illustrates scheduled events. A team meeting occurs 2598 every week since January 8, 2020 at 9am Johannesburg time. The event 2599 owner also chairs the event. Participants meet in a virtual meeting 2600 room. An attendee has accepted the invitation, but on March 4, 2020 2601 he is unavailable and declined participation for this occurrence. 2603 { 2604 "...": "", 2605 "title": "FooBar team meeting", 2606 "start": "2020-01-08T09:00:00", 2607 "timeZone": "Africa/Johannesburg", 2608 "duration": "PT1H", 2609 "virtualLocations": { 2610 "3f41b47b-a5eb-494f-90eb-19d279486d84": { 2611 "@type": "VirtualLocation", 2612 "name": "ChatMe meeting room", 2613 "uri": "https://chatme.example.com?id=1234567&pw=a8a24627b63d396e" 2614 } 2615 }, 2616 "recurrenceRules": [{ 2617 "@type": "RecurrenceRule", 2618 "frequency": "weekly" 2619 }], 2620 "replyTo": { 2621 "imip": "mailto:f245f875-7f63-4a5e-a2c8@schedule.example.com" 2622 }, 2623 "participants": { 2624 "dG9tQGZvb2Jhci5xlLmNvbQ": { 2625 "@type": "Participant", 2626 "name": "Tom Tool", 2627 "email": "tom@foobar.example.com", 2628 "sendTo": { 2629 "imip": "mailto:tom@calendar.example.com" 2630 }, 2631 "participationStatus": "accepted", 2632 "roles": { 2633 "attendee": true 2634 } 2635 }, 2636 "em9lQGZvb2GFtcGxlLmNvbQ": { 2637 "@type": "Participant", 2638 "name": "Zoe Zelda", 2639 "email": "zoe@foobar.example.com", 2640 "sendTo": { 2641 "imip": "mailto:zoe@foobar.example.com" 2642 }, 2643 "participationStatus": "accepted", 2644 "roles": { 2645 "owner": true, 2646 "attendee": true, 2647 "chair": true 2648 } 2649 } 2650 }, 2651 "recurrenceOverrides": { 2652 "2020-03-04T09:00:00": { 2653 "participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus": 2654 "declined" 2655 } 2656 } 2657 } 2659 7. Security Considerations 2661 Calendaring and scheduling information is very privacy-sensitive. It 2662 can reveal the social network of a user; location information of this 2663 user and those in their social network; identity and credentials 2664 information; and the patterns of behavior of the user in both the 2665 physical and cyber realm. Additionally, calendar events and tasks 2666 can could influence the physical location of a user or their cyber 2667 behavior within a known time window. It's transmission and storage 2668 must be done carefully to protect it from possible threats, such as 2669 eavesdropping, replay, message insertion, deletion, modification, and 2670 on-path attacks. 2672 The data being stored and transmitted may be used in systems with 2673 real world consequences. For example, a home automation system may 2674 turn an alarm on and off. Or a coworking space may charge money to 2675 the organiser of an event that books one of their meeting rooms. 2676 Such systems must be careful to authenticate all data they receive to 2677 prevent them from being subverted, and ensure the change comes from 2678 an authorized entity. 2680 This document just defines the data format; such considerations are 2681 primarily the concern of the API or method of storage and 2682 transmission of such files. 2684 7.1. Expanding Recurrences 2686 A recurrence rule may produce infinite occurrences of an event. 2687 Implementations MUST handle expansions carefully to prevent 2688 accidental or deliberate resource exhaustion. 2690 Conversely, a recurrence rule may be specified that does not expand 2691 to anything. It is not always possible to tell this through static 2692 analysis of the rule, so implementations MUST be careful to avoid 2693 getting stuck in infinite loops, or otherwise exhausting resources 2694 while searching for the next occurrence. 2696 Events recur in the event's time zone. If the user is in a different 2697 time zone, daylight saving transitions may cause an event that 2698 normally occurs at, for example, 9am to suddenly shift an hour 2699 earlier. This may be used in an attempt to cause a participant to 2700 miss an important meeting. User agents must be careful to translate 2701 date-times correctly between time zones and may wish to call out 2702 unexpected changes in the time of a recurring event. 2704 7.2. JSON Parsing 2706 The Security Considerations of [RFC8259] apply to the use of JSON as 2707 the data interchange format. 2709 As for any serialization format, parsers need to thoroughly check the 2710 syntax of the supplied data. JSON uses opening and closing tags for 2711 several types and structures, and it is possible that the end of the 2712 supplied data will be reached when scanning for a matching closing 2713 tag; this is an error condition, and implementations need to stop 2714 scanning at the end of the supplied data. 2716 JSON also uses a string encoding with some escape sequences to encode 2717 special characters within a string. Care is needed when processing 2718 these escape sequences to ensure that they are fully formed before 2719 the special processing is triggered, with special care taken when the 2720 escape sequences appear adjacent to other (non-escaped) special 2721 characters or adjacent to the end of data (as in the previous 2722 paragraph). 2724 If parsing JSON into a non-textual structured data format, 2725 implementations may need to allocate storage to hold JSON string 2726 elements. Since JSON does not use explicit string lengths, the risk 2727 of denial of service due to resource exhaustion is small, but 2728 implementations may still wish to place limits on the size of 2729 allocations they are willing to make in any given context, to avoid 2730 untrusted data causing excessive memory allocation. 2732 7.3. URI Values 2734 Several JSCalendar properties contain URIs as values, and processing 2735 these properties requires extra care. Section 7 of [RFC3986] 2736 discusses security risks related to URIs. 2738 Fetching remote resources carries inherent risks. Connections must 2739 only be allowed on well known ports, using allowed protocols 2740 (generally just HTTP/HTTPS on their default ports). The URL must be 2741 resolved externally and not allowed to access internal resources. 2742 Connecting to an external source reveals IP (and therefore generally 2743 location) information. 2745 A maliciously constructed JSCalendar object may contain a very large 2746 number of URIs. In the case of published calendars with a large 2747 number of subscribers, such objects could be widely distributed. 2748 Implementations should be careful to limit the automatic fetching of 2749 linked resources to reduce the risk of this being an amplification 2750 vector for a denial-of-service attack. 2752 7.4. Spam 2754 Calendar systems may receive JSCalendar files from untrusted sources, 2755 in particular as attachments to emails. This can be a vector for an 2756 attacker to inject spam into a user's calendar. This may confuse, 2757 annoy, and mislead users, or overwhelm their calendar with bogus 2758 events, preventing them from seeing legitimate ones. 2760 Heuristic, statistical or machine-learning-based filters can be 2761 effective in filtering out spam. Authentication mechanisms such as 2762 DKIM [RFC6376] can help establish the source of messages and 2763 associate the data with existing relationships (such as an address 2764 book contact). Misclassifications are always possible, however, and 2765 providing a mechanism for users to quickly correct this is advised. 2767 Confusable unicode characters may be used to trick a user into 2768 trusting a JSCalendar file that appears to come from a known contact 2769 but is actually from a similar-looking source controlled by an 2770 attacker. 2772 7.5. Duplication 2774 It is important for calendar systems to maintain the UID of an event 2775 when updating it to avoid unexpected duplication of events. 2776 Consumers of the data may not remove the previous version of the 2777 event if it has a different UID. This can lead to a confusing 2778 situation for the user, with many variations of the event and no 2779 indication of which one is correct. Care must be taken by consumers 2780 of the data to remove old events where possible to avoid an 2781 accidental denial-of-service attack due to the volume of data. 2783 7.6. Time Zones 2785 Events recur in a particular time zone. When this differs from the 2786 user's current time zone, it may unexpectedly cause an occurrence to 2787 shift in time for that user due to a daylight savings change in the 2788 event's time zone. A maliciously crafted event could attempt to 2789 confuse users with such an event to ensure a meeting is missed. 2791 8. IANA Considerations 2793 8.1. Media Type Registration 2795 This document defines a media type for use with JSCalendar data 2796 formatted in JSON. 2798 Type name: application 2800 Subtype name: jscalendar+json 2802 Required parameters: type 2804 The "type" parameter conveys the type of the JSCalendar data in 2805 the body part, with the value being one of "jsevent", "jstask", or 2806 "jsgroup". The parameter MUST NOT occur more than once. It MUST 2807 match the value of the "@type" property of the JSON-formatted 2808 JSCalendar object in the body. 2810 Optional parameters: none 2812 Encoding considerations: Same as encoding considerations of 2813 application/json as specified in RFC8529, Section 11 [RFC8259]. 2815 Security considerations: See Section 7 of this document. 2817 Interoperability considerations: While JSCalendar is designed to 2818 avoid ambiguities as much as possible, when converting objects 2819 from other calendar formats to/from JSCalendar it is possible that 2820 differing representations for the same logical data might arise, 2821 or ambiguities in interpretation. The semantic equivalence of two 2822 JSCalendar objects may be determined differently by different 2823 applications, for example where URL values differ in case between 2824 the two objects. 2826 Published specification: This specification. 2828 Applications that use this media type: Applications that currently 2829 make use of the text/calendar and application/calendar+json media 2830 types can use this as an alternative. Similarly, applications 2831 that use the application/json media type to transfer calendaring 2832 data can use this to further specify the content. 2834 Fragment identifier considerations: A JSON Pointer fragment 2835 identifier may be used, as defined in [RFC6901], Section 6. 2837 Additional information: 2839 Magic number(s): N/A 2841 File extensions(s): N/A 2843 Macintosh file type code(s): N/A 2845 Person & email address to contact for further information: 2846 calsify@ietf.org 2848 Intended usage: COMMON 2850 Restrictions on usage: N/A 2852 Author: See the "Author's Address" section of this document. 2854 Change controller: IETF 2856 8.2. Creation of "JSCalendar Properties" Registry 2858 The IANA will create the "JSCalendar Properties" registry to allow 2859 interoperability of extensions to JSCalendar objects. 2861 This registry follows the Expert Review process ([RFC8126], 2862 Section 4.5). If the "intended use" field is "common", sufficient 2863 documentation is required to enable interoperability. Preliminary 2864 community review for this registry is optional but strongly 2865 encouraged. 2867 A registration can have an intended use of "common", "reserved", or 2868 "obsolete". The IANA will list common-use registrations prominently 2869 and separately from those with other intended use values. 2871 A "reserved" registration reserves a property name without assigning 2872 semantics to avoid name collisions with future extensions or protocol 2873 use. 2875 An "obsolete" registration denotes a property that is no longer 2876 expected to be added by up-to-date systems. A new property has 2877 probably been defined covering the obsolete property's semantics. 2879 The JSCalendar property registration procedure is not a formal 2880 standards process but rather an administrative procedure intended to 2881 allow community comment and sanity checking without excessive time 2882 delay. It is designed to encourage vendors to document and register 2883 new properties they add for use cases not covered by the original 2884 specification, leading to increased interoperability. 2886 8.2.1. Preliminary Community Review 2888 Notice of a potential new registration SHOULD be sent to the Calext 2889 mailing list for review. This mailing list is 2890 appropriate to solicit community feedback on a proposed new property. 2892 Properties registrations must be marked with their intended use: 2893 "common", "reserved" or "obsolete". 2895 The intent of the public posting to this list is to solicit comments 2896 and feedback on the choice of the property name, the unambiguity of 2897 the specification document, and a review of any interoperability or 2898 security considerations. The submitter may submit a revised 2899 registration proposal or abandon the registration completely at any 2900 time. 2902 8.2.2. Submit Request to IANA 2904 Registration requests can be sent to . 2906 8.2.3. Designated Expert Review 2908 The primary concern of the designated expert (DE) is preventing name 2909 collisions and encouraging the submitter to document security and 2910 privacy considerations. For a common-use registration, the DE is 2911 expected to confirm that suitable documentation, as described in 2912 Section 4.6 of [RFC8126], is available to ensure interoperability. 2913 That documentation will usually be in an RFC, but simple definitions 2914 are likely to use a web/wiki page, and if a sentence or two is deemed 2915 sufficient it could be described in the registry itself. The DE 2916 should also verify that the property name does not conflict with work 2917 that is active or already published within the IETF. A published 2918 specification is not required for reserved or obsolete registrations. 2920 The DE will either approve or deny the registration request and 2921 publish a notice of the decision to the Calext WG mailing list or its 2922 successor, as well as inform IANA. A denial notice must be justified 2923 by an explanation, and, in the cases where it is possible, concrete 2924 suggestions on how the request can be modified so as to become 2925 acceptable should be provided. 2927 8.2.4. Change Procedures 2929 Once a JSCalendar property has been published by the IANA, the change 2930 controller may request a change to its definition. The same 2931 procedure that would be appropriate for the original registration 2932 request is used to process a change request. 2934 JSCalendar property registrations may not be deleted; properties that 2935 are no longer believed appropriate for use can be declared obsolete 2936 by a change to their "intended use" field; such properties will be 2937 clearly marked in the lists published by the IANA. 2939 Significant changes to a JSCalendar property's definition should be 2940 requested only when there are serious omissions or errors in the 2941 published specification, as such changes may cause interoperability 2942 issues. When review is required, a change request may be denied if 2943 it renders entities that were valid under the previous definition 2944 invalid under the new definition. 2946 The owner of a JSCalendar property may pass responsibility to another 2947 person or agency by informing the IANA; this can be done without 2948 discussion or review. 2950 8.2.5. JSCalendar Properties Registry Template 2952 o Property Name: The name of the property. The property name MUST 2953 NOT already be registered for any of the object types listed in 2954 the "Property Context" field of this registration. Other object 2955 types MAY already have registered a different property with the 2956 same name, however the same name SHOULD only be used when the 2957 semantics are analogous. 2959 o Property Type: The type of this property, using type signatures as 2960 specified in Section 1.3. The property type MUST be registed in 2961 the Type Registry. 2963 o Property Context: A comma-separated list of JSCalendar object 2964 types this property is allowed on. 2966 o Reference or Description: A brief description or RFC number and 2967 section reference where the property is specified (omitted for 2968 "reserved" property names). 2970 o Intended Use: Common, reserved, or obsolete. 2972 o Change Controller: Who may request a change to this entry's 2973 definition ("IETF" for IETF-stream RFCs). 2975 8.2.6. Initial Contents for the JSCalendar Properties Registry 2977 The following table lists the initial entries of the JSCalendar 2978 Properties registry. All properties are for common-use. All RFC 2979 section references are for this document. The change controller for 2980 all these properties is "IETF". 2982 +---------------+----------------------------+------------+---------+ 2983 | Property Name | Property Type | Property | Referen | 2984 | | | Context | ce or D | 2985 | | | | escript | 2986 | | | | ion | 2987 +---------------+----------------------------+------------+---------+ 2988 | @type | String | JSEvent, | Section | 2989 | | | JSTask, | 4.1.1, | 2990 | | | JSGroup, A | Section | 2991 | | | bsoluteTri | 4.5.2, | 2992 | | | gger, | Section | 2993 | | | Alert, | 1.4.11 | 2994 | | | Link, | , Secti | 2995 | | | Location, | on 4.2. | 2996 | | | NDay, Offs | 5, Sect | 2997 | | | etTrigger, | ion 4.4 | 2998 | | | Participan | .5, Sec | 2999 | | | t, Recurre | tion 4. | 3000 | | | nceRule, | 3.2, Se | 3001 | | | Relation, | ction 4 | 3002 | | | TimeZone, | .1.3, S | 3003 | | | TimeZoneRu | ection | 3004 | | | le, Virtua | 4.7.2, | 3005 | | | lLocation | Section | 3006 | | | | 4.7.2, | 3007 | | | | Section | 3008 | | | | 4.2.6 | 3009 | | | | | 3010 | acknowledged | UTCDateTime | Alert | Section | 3011 | | | | 4.5.2 | 3012 | | | | | 3013 | action | String | Alert | Section | 3014 | | | | 4.5.2 | 3015 | | | | | 3016 | alerts | Id[Alert] | JSEvent, | Section | 3017 | | | JSTask | 4.5.2 | 3018 | | | | | 3019 | aliases | String[Boolean] | TimeZone | Section | 3020 | | | | 4.7.2 | 3021 | | | | | 3022 | byDay | NDay[] | Recurrence | Section | 3023 | | | Rule | 4.3.2 | 3024 | | | | | 3025 | byHour | UnsignedInt[] | Recurrence | Section | 3026 | | | Rule | 4.3.2 | 3027 | | | | | 3028 | byMinute | UnsignedInt[] | Recurrence | Section | 3029 | | | Rule | 4.3.2 | 3030 | | | | | 3031 | byMonth | String[] | Recurrence | Section | 3032 | | | Rule | 4.3.2 | 3033 | | | | | 3034 | byMonthDay | Int[] | Recurrence | Section | 3035 | | | Rule | 4.3.2 | 3036 | | | | | 3037 | bySecond | UnsignedInt[] | Recurrence | Section | 3038 | | | Rule | 4.3.2 | 3039 | | | | | 3040 | bySetPosition | Int[] | Recurrence | Section | 3041 | | | Rule | 4.3.2 | 3042 | | | | | 3043 | byWeekNo | Int[] | Recurrence | Section | 3044 | | | Rule | 4.3.2 | 3045 | | | | | 3046 | byYearDay | Int[] | Recurrence | Section | 3047 | | | Rule | 4.3.2 | 3048 | | | | | 3049 | categories | String[Boolean] | JSEvent, | Section | 3050 | | | JSTask, | 4.2.10 | 3051 | | | JSGroup | | 3052 | | | | | 3053 | cid | String | Link | Section | 3054 | | | | 1.4.11 | 3055 | | | | | 3056 | color | String | JSEvent, | Section | 3057 | | | JSTask, | 4.2.11 | 3058 | | | JSGroup | | 3059 | | | | | 3060 | comments | String[] | TimeZoneRu | Section | 3061 | | | le | 4.7.2 | 3062 | | | | | 3063 | contentType | String | Link | Section | 3064 | | | | 1.4.11 | 3065 | | | | | 3066 | coordinates | String | Location | Section | 3067 | | | | 4.2.5 | 3068 | | | | | 3069 | count | UnsignedInt | Recurrence | Section | 3070 | | | Rule | 4.3.2 | 3071 | | | | | 3072 | created | UTCDateTime | JSEvent, | Section | 3073 | | | JSTask, | 4.1.5 | 3074 | | | JSGroup | | 3075 | | | | | 3076 | day | String | NDay | Section | 3077 | | | | 4.3.2 | 3078 | | | | | 3079 | daylight | TimeZoneRule | TimeZone | Section | 3080 | | | | 4.7.2 | 3081 | | | | | 3082 | delegatedFrom | String[Boolean] | Participan | Section | 3083 | | | t | 4.4.5 | 3084 | | | | | 3085 | delegatedTo | String[Boolean] | Participan | Section | 3086 | | | t | 4.4.5 | 3087 | | | | | 3088 | description | String | JSEvent, | Section | 3089 | | | JSTask, | 4.2.2, | 3090 | | | Location, | Section | 3091 | | | Participan | 4.2.5, | 3092 | | | t, Virtual | Section | 3093 | | | Location | 4.4.5, | 3094 | | | | Section | 3095 | | | | 4.2.6 | 3096 | | | | | 3097 | descriptionCo | String | JSEvent, | Section | 3098 | ntentType | | JSTask | 4.2.3 | 3099 | | | | | 3100 | display | String | Link | Section | 3101 | | | | 1.4.11 | 3102 | | | | | 3103 | due | LocalDateTime | JSTask | Section | 3104 | | | | 5.2.1 | 3105 | | | | | 3106 | duration | Duration | JSEvent | Section | 3107 | | | | 5.1.2 | 3108 | | | | | 3109 | email | String | Participan | Section | 3110 | | | t | 4.4.5 | 3111 | | | | | 3112 | entries | (JSTask|JSEvent)[] | JSGroup | Section | 3113 | | | | 5.3.1 | 3114 | | | | | 3115 | estimatedDura | Duration | JSTask | Section | 3116 | tion | | | 5.2.3 | 3117 | | | | | 3118 | excluded | Boolean | JSEvent, | Section | 3119 | | | JSTask | 4.3.5 | 3120 | | | | | 3121 | excludedRecur | RecurrenceRule[] | JSEvent, | Section | 3122 | renceRules | | JSTask | 4.3.3 | 3123 | | | | | 3124 | expectReply | Boolean | Participan | Section | 3125 | | | t | 4.4.5 | 3126 | | | | | 3127 | firstDayOfWee | String | Recurrence | Section | 3128 | k | | Rule | 4.3.2 | 3129 | | | | | 3130 | freeBusyStatu | String | JSEvent, | Section | 3131 | s | | JSTask | 4.4.2 | 3132 | | | | | 3133 | frequency | String | Recurrence | Section | 3134 | | | Rule | 4.3.2 | 3135 | | | | | 3136 | href | String | Link | Section | 3137 | | | | 1.4.11 | 3138 | | | | | 3139 | interval | UnsignedInt | Recurrence | Section | 3140 | | | Rule | 4.3.2 | 3141 | | | | | 3142 | invitedBy | String | Participan | Section | 3143 | | | t | 4.4.5 | 3144 | | | | | 3145 | keywords | String[Boolean] | JSEvent, | Section | 3146 | | | JSTask, | 4.2.9 | 3147 | | | JSGroup | | 3148 | | | | | 3149 | kind | String | Participan | Section | 3150 | | | t | 4.4.5 | 3151 | | | | | 3152 | language | String | Participan | Section | 3153 | | | t | 4.4.5 | 3154 | | | | | 3155 | links | Id[Link] | JSGroup, | Section | 3156 | | | JSEvent, | 4.2.7, | 3157 | | | JSTask, | Section | 3158 | | | Location, | 4.2.5, | 3159 | | | Participan | Section | 3160 | | | t | 4.4.5 | 3161 | | | | | 3162 | locale | String | JSGroup, | Section | 3163 | | | JSEvent, | 4.2.8 | 3164 | | | JSTask | | 3165 | | | | | 3166 | localizations | String[PatchObject] | JSEvent, | Section | 3167 | | | JSTask | 4.6.1 | 3168 | | | | | 3169 | locationId | String | Participan | Section | 3170 | | | t | 4.4.5 | 3171 | | | | | 3172 | locations | Id[Location] | JSEvent, | Section | 3173 | | | JSTask | 4.2.5 | 3174 | | | | | 3175 | locationTypes | String[Boolean] | Location | Section | 3176 | | | | 4.2.5 | 3177 | | | | | 3178 | memberOf | String[Boolean] | Participan | Section | 3179 | | | t | 4.4.5 | 3180 | | | | | 3181 | method | String | JSEvent, | Section | 3182 | | | JSTask | 4.1.8 | 3183 | | | | | 3184 | name | String | Location, | Section | 3185 | | | VirtualLoc | 4.2.5, | 3186 | | | ation, Par | Section | 3187 | | | ticipant | 4.2.6, | 3188 | | | | Section | 3189 | | | | 4.4.5 | 3190 | | | | | 3191 | names | String[Boolean] | TimeZoneRu | Section | 3192 | | | le | 4.7.2 | 3193 | | | | | 3194 | nthOfPeriod | Int | NDay | Section | 3195 | | | | 4.3.2 | 3196 | | | | | 3197 | offset | SignedDuration | OffsetTrig | Section | 3198 | | | ger | 4.5.2 | 3199 | | | | | 3200 | offsetFrom | UTCDateTime | TimeZoneRu | Section | 3201 | | | le | 4.7.2 | 3202 | | | | | 3203 | offsetTo | UTCDateTime | TimeZoneRu | Section | 3204 | | | le | 4.7.2 | 3205 | | | | | 3206 | participants | Id[Participant] | JSEvent, | Section | 3207 | | | JSTask | 4.4.5 | 3208 | | | | | 3209 | participation | String | Participan | Section | 3210 | Comment | | t | 4.4.5 | 3211 | | | | | 3212 | participation | String | Participan | Section | 3213 | Status | | t | 4.4.5 | 3214 | | | | | 3215 | percentComple | UnsignedInt | JSTask, Pa | Section | 3216 | te | | rticipant | 5.2.4 | 3217 | | | | | 3218 | priority | Int | JSEvent, | Section | 3219 | | | JSTask | 4.4.1 | 3220 | | | | | 3221 | privacy | String | JSEvent, | Section | 3222 | | | JSTask | 4.4.3 | 3223 | | | | | 3224 | prodId | String | JSEvent, | Section | 3225 | | | JSTask, | 4.1.4 | 3226 | | | JSGroup | | 3227 | | | | | 3228 | progress | String | JSTask, Pa | Section | 3229 | | | rticipant | 5.2.5 | 3230 | | | | | 3231 | progressUpdat | UTCDateTime | JSTask, Pa | Section | 3232 | ed | | rticipant | 5.2.6 | 3233 | | | | | 3234 | recurrenceId | LocalDateTime | JSEvent, | Section | 3235 | | | JSTask | 4.3.1 | 3236 | | | | | 3237 | recurrenceOve | LocalDateTime[PatchObject] | JSEvent, | Section | 3238 | rrides | | JSTask, Ti | 4.3.4, | 3239 | | | meZoneRule | Section | 3240 | | | | 4.7.2 | 3241 | | | | | 3242 | recurrenceRul | RecurrenceRule[] | JSEvent, | Section | 3243 | es | | JSTask, Ti | 4.3.2, | 3244 | | | meZoneRule | Section | 3245 | | | | 4.7.2 | 3246 | | | | | 3247 | rel | String | Link | Section | 3248 | | | | 1.4.11 | 3249 | | | | | 3250 | relatedTo | String[Relation] | JSEvent, | Section | 3251 | | | JSTask, | 4.1.3, | 3252 | | | Alert | Section | 3253 | | | | 4.5.2 | 3254 | | | | | 3255 | relation | String[Boolean] | Relation | Section | 3256 | | | | 1.4.10 | 3257 | | | | | 3258 | relativeTo | String | OffsetTrig | Section | 3259 | | | ger, | 4.5.2, | 3260 | | | Location | Section | 3261 | | | | 4.2.5 | 3262 | | | | | 3263 | replyTo | String[String] | JSEvent, | Section | 3264 | | | JSTask | 4.4.4 | 3265 | | | | | 3266 | roles | String[Boolean] | Participan | Section | 3267 | | | t | 4.4.5 | 3268 | | | | | 3269 | rscale | String | Recurrence | Section | 3270 | | | Rule | 4.3.2 | 3271 | | | | | 3272 | standard | TimeZoneRule | TimeZone | Section | 3273 | | | | 4.7.2 | 3274 | | | | | 3275 | start | LocalDateTime | TimeZoneRu | Section | 3276 | | | le | 4.7.2 | 3277 | | | | | 3278 | scheduleAgent | String | Participan | Section | 3279 | | | t | 4.4.5 | 3280 | | | | | 3281 | scheduleForce | Boolean | Participan | Section | 3282 | Send | | t | 4.4.5 | 3283 | | | | | 3284 | scheduleSeque | UnsignedInt | Participan | Section | 3285 | nce | | t | 4.4.5 | 3286 | | | | | 3287 | scheduleStatu | String[] | Participan | Section | 3288 | s | | t | 4.4.5 | 3289 | | | | | 3290 | scheduleUpdat | UTCDateTime | Participan | Section | 3291 | ed | | t | 4.4.5 | 3292 | | | | | 3293 | sendTo | String[String] | Participan | Section | 3294 | | | t | 4.4.5 | 3295 | | | | | 3296 | sequence | UnsignedInt | JSEvent, | Section | 3297 | | | JSTask | 4.1.7 | 3298 | | | | | 3299 | showWithoutTi | Boolean | JSEvent, | Section | 3300 | me | | JSTask | 4.2.4 | 3301 | | | | | 3302 | size | UnsignedInt | Link | Section | 3303 | | | | 1.4.11 | 3304 | | | | | 3305 | skip | String | Recurrence | Section | 3306 | | | Rule | 4.3.2 | 3307 | | | | | 3308 | source | String | JSGroup | Section | 3309 | | | | 5.3.2 | 3310 | | | | | 3311 | start | LocalDateTime | JSEvent, | Section | 3312 | | | JSTask | 5.1.1, | 3313 | | | | Section | 3314 | | | | 5.2.2 | 3315 | | | | | 3316 | status | String | JSEvent | Section | 3317 | | | | 5.1.3 | 3318 | | | | | 3319 | timeZone | TimeZoneId|null | JSEvent, | Section | 3320 | | | JSTask, | 4.7.1, | 3321 | | | Location | Section | 3322 | | | | 4.2.5 | 3323 | | | | | 3324 | timeZones | TimeZoneId[TimeZone] | JSEvent, | Section | 3325 | | | JSTask | 4.7.2 | 3326 | | | | | 3327 | title | String | JSEvent, | Section | 3328 | | | JSTask, | 4.2.1 | 3329 | | | JSGroup, | | 3330 | | | Link | | 3331 | | | | | 3332 | trigger | OffsetTrigger|AbsoluteTrig | Alert | Section | 3333 | | ger|UnknownTrigger | | 4.5.2 | 3334 | | | | | 3335 | tzId | String | TimeZone | Section | 3336 | | | | 4.7.2 | 3337 | | | | | 3338 | uid | String | JSEvent, | Section | 3339 | | | JSTask, | 4.1.2 | 3340 | | | JSGroup | | 3341 | | | | | 3342 | until | LocalDateTime | Recurrence | Section | 3343 | | | Rule | 4.3.2 | 3344 | | | | | 3345 | updated | UTCDateTime | JSEvent, | Section | 3346 | | | JSTask, | 4.1.6 | 3347 | | | JSGroup | | 3348 | | | | | 3349 | uri | String | VirtualLoc | Section | 3350 | | | ation | 4.2.6 | 3351 | | | | | 3352 | url | String | TimeZone | Section | 3353 | | | | 4.7.2 | 3354 | | | | | 3355 | useDefaultAle | Boolean | JSEvent, | Section | 3356 | rts | | JSTask | 4.5.1 | 3357 | | | | | 3358 | validUntil | UTCDateTime | TimeZone | Section | 3359 | | | | 4.7.2 | 3360 | | | | | 3361 | virtualLocati | Id[VirtualLocation] | JSEvent, | Section | 3362 | ons | | JSTask | 4.2.6 | 3363 | | | | | 3364 | when | UTCDateTime | AbsoluteTr | Section | 3365 | | | igger | 4.5.2 | 3366 +---------------+----------------------------+------------+---------+ 3368 Table 1 3370 8.3. Creation of "JSCalendar Types" Registry 3372 The IANA will create the "JSCalendar Types" registry to avoid name 3373 collisions and provide a complete reference for all data types used 3374 for JSCalendar property values. The registration process is the same 3375 as for the JSCalendar Properties registry, as defined in Section 8.2. 3377 8.3.1. JSCalendar Types Registry Template 3379 o Type Name: The name of the type. 3381 o Reference or Description: A brief description or RFC number and 3382 section reference where the Type is specified (may be omitted for 3383 "reserved" type names). 3385 o Intended Use: Common, reserved, or obsolete. 3387 o Change Controller: Who may request a change to this entry's 3388 definition ("IETF" for IETF-stream RFCs). 3390 8.3.2. Initial Contents for the JSCalendar Types Registry 3392 The following table lists the initial entries of the JSCalendar Types 3393 registry. All properties are for common-use. All RFC section 3394 references are for this document. The change controller for all 3395 these properties is "IETF". 3397 +-----------------+--------------------------+ 3398 | Type Name | Reference or Description | 3399 +-----------------+--------------------------+ 3400 | Alert | Section 4.5.2 | 3401 | | | 3402 | Boolean | Section 1.3 | 3403 | | | 3404 | Duration | Section 1.4.6 | 3405 | | | 3406 | Id | Section 1.4.1 | 3407 | | | 3408 | Int | Section 1.4.2 | 3409 | | | 3410 | LocalDateTime | Section 1.4.5 | 3411 | | | 3412 | Link | Section 1.4.11 | 3413 | | | 3414 | Location | Section 4.2.5 | 3415 | | | 3416 | NDay | Section 4.3.2 | 3417 | | | 3418 | Number | Section 1.3 | 3419 | | | 3420 | Participant | Section 4.4.5 | 3421 | | | 3422 | PatchObject | Section 1.4.9 | 3423 | | | 3424 | RecurrenceRule | Section 4.3.2 | 3425 | | | 3426 | Relation | Section 1.4.10 | 3427 | | | 3428 | SignedDuration | Section 1.4.7 | 3429 | | | 3430 | String | Section 1.3 | 3431 | | | 3432 | TimeZone | Section 4.7.2 | 3433 | | | 3434 | TimeZoneId | Section 1.4.8 | 3435 | | | 3436 | TimeZoneRule | Section 4.7.2 | 3437 | | | 3438 | UnsignedInt | Section 1.4.3 | 3439 | | | 3440 | UTCDateTime | Section 1.4.4 | 3441 | | | 3442 | VirtualLocation | Section 4.2.6 | 3443 +-----------------+--------------------------+ 3445 Table 2 3447 8.4. Creation of "JSCalendar Enum Values" Registry 3449 The IANA will create the "JSCalendar Enum Values" registry to allow 3450 interoperable extension of semantics for properties with enumerable 3451 values. Each such property will have a subregistry of allowed 3452 values. The registration process for a new enum value or adding a 3453 new enumerable property is the same as for the JSCalendar Properties 3454 registry, as defined in Section 8.2. 3456 8.4.1. JSCalendar Enum Property Template 3458 This template is for adding a subregistry for a new enumerable 3459 property to the JSCalendar Enum registry. 3461 o Property Name: the name(s) of the property or properties where 3462 these values may be used. This MUST be registered in the 3463 JSCalendar Properties registry. 3465 o Context: the list of allowed object types where the property or 3466 properties may appear, as registered in the JSCalendar Properties 3467 registry. This disambiguates where there may be two distinct 3468 properties with the same name in different contexts. 3470 o Change Controller: ("IETF" for properties defined in IETF-stream 3471 RFCs). 3473 o Initial Contents: The initial list of defined values for this 3474 enum, using the template defined in Section 8.4.2. A subregistry 3475 will be created with these values for this property name/context 3476 tuple. 3478 8.4.2. JSCalendar Enum Value Template 3480 This template is for adding a new enum value to a subregistry in the 3481 JSCalendar Enum registry. 3483 o Enum Value: The verbatim value of the enum. 3485 o Reference or Description: A brief description or RFC number and 3486 section reference for the semantics of this value. 3488 8.4.3. Initial Contents for the JSCalendar Enum Values registry 3490 For each subregistry created in this section, all RFC section 3491 references are for this document. 3493 ------------------------------------------------------------ 3495 Property Name: action 3497 Context: Alert 3499 Change Controller: IETF 3501 Initial Contents: 3503 +------------+--------------------------+ 3504 | Enum Value | Reference or Description | 3505 +------------+--------------------------+ 3506 | display | Section 4.5.2 | 3507 | | | 3508 | email | Section 4.5.2 | 3509 +------------+--------------------------+ 3511 Table 3 3513 ------------------------------------------------------------ 3515 Property Name: display 3517 Context: Link 3519 Change Controller: IETF 3521 Initial Contents: 3523 +------------+--------------------------+ 3524 | Enum Value | Reference or Description | 3525 +------------+--------------------------+ 3526 | badge | Section 1.4.11 | 3527 | | | 3528 | graphic | Section 1.4.11 | 3529 | | | 3530 | fullsize | Section 1.4.11 | 3531 | | | 3532 | thumbnail | Section 1.4.11 | 3533 +------------+--------------------------+ 3535 Table 4 3537 ------------------------------------------------------------ 3539 Property Name: freeBusyStatus 3541 Context: JSEvent, JSTask 3543 Change Controller: IETF 3545 Initial Contents: 3547 +------------+--------------------------+ 3548 | Enum Value | Reference or Description | 3549 +------------+--------------------------+ 3550 | free | Section 4.4.2 | 3551 | | | 3552 | busy | Section 4.4.2 | 3553 +------------+--------------------------+ 3555 Table 5 3557 ------------------------------------------------------------ 3559 Property Name: kind 3561 Context: Participant 3563 Change Controller: IETF 3565 Initial Contents: 3567 +------------+--------------------------+ 3568 | Enum Value | Reference or Description | 3569 +------------+--------------------------+ 3570 | individual | Section 4.4.5 | 3571 | | | 3572 | group | Section 4.4.5 | 3573 | | | 3574 | resource | Section 4.4.5 | 3575 | | | 3576 | location | Section 4.4.5 | 3577 +------------+--------------------------+ 3579 Table 6 3581 ------------------------------------------------------------ 3583 Property Name: participationStatus 3585 Context: Participant 3587 Change Controller: IETF 3589 Initial Contents: 3591 +--------------+--------------------------+ 3592 | Enum Value | Reference or Description | 3593 +--------------+--------------------------+ 3594 | needs-action | Section 4.4.5 | 3595 | | | 3596 | accepted | Section 4.4.5 | 3597 | | | 3598 | declined | Section 4.4.5 | 3599 | | | 3600 | tenative | Section 4.4.5 | 3601 | | | 3602 | delegated | Section 4.4.5 | 3603 +--------------+--------------------------+ 3605 Table 7 3607 ------------------------------------------------------------ 3609 Property Name: privacy 3611 Context: JSEvent, JSTask 3613 Change Controller: IETF 3615 Initial Contents: 3617 +------------+--------------------------+ 3618 | Enum Value | Reference or Description | 3619 +------------+--------------------------+ 3620 | public | Section 4.4.3 | 3621 | | | 3622 | private | Section 4.4.3 | 3623 | | | 3624 | secret | Section 4.4.3 | 3625 +------------+--------------------------+ 3627 Table 8 3629 ------------------------------------------------------------ 3631 Property Name: progress 3633 Context: JSTask, Participant 3635 Change Controller: IETF 3637 Initial Contents: 3639 +--------------+--------------------------+ 3640 | Enum Value | Reference or Description | 3641 +--------------+--------------------------+ 3642 | needs-action | Section 5.2.5 | 3643 | | | 3644 | in-process | Section 5.2.5 | 3645 | | | 3646 | completed | Section 5.2.5 | 3647 | | | 3648 | failed | Section 5.2.5 | 3649 | | | 3650 | cancelled | Section 5.2.5 | 3651 +--------------+--------------------------+ 3653 Table 9 3655 ------------------------------------------------------------ 3657 Property Name: relation 3659 Context: Relation 3661 Change Controller: IETF 3663 Initial Contents: 3665 +------------+--------------------------+ 3666 | Enum Value | Reference or Description | 3667 +------------+--------------------------+ 3668 | first | Section 1.4.10 | 3669 | | | 3670 | next | Section 1.4.10 | 3671 | | | 3672 | child | Section 1.4.10 | 3673 | | | 3674 | parent | Section 1.4.10 | 3675 +------------+--------------------------+ 3677 Table 10 3679 ------------------------------------------------------------ 3681 Property Name: relativeTo 3683 Context: OffsetTrigger, Location 3685 Change Controller: IETF 3686 Initial Contents: 3688 +------------+--------------------------+ 3689 | Enum Value | Reference or Description | 3690 +------------+--------------------------+ 3691 | start | Section 4.5.2 | 3692 | | | 3693 | end | Section 4.5.2 | 3694 +------------+--------------------------+ 3696 Table 11 3698 ------------------------------------------------------------ 3700 Property Name: roles 3702 Context: Participant 3704 Change Controller: IETF 3706 Initial Contents: 3708 +---------------+--------------------------+ 3709 | Enum Value | Reference or Description | 3710 +---------------+--------------------------+ 3711 | owner | Section 4.4.5 | 3712 | | | 3713 | attendee | Section 4.4.5 | 3714 | | | 3715 | optional | Section 4.4.5 | 3716 | | | 3717 | informational | Section 4.4.5 | 3718 | | | 3719 | chair | Section 4.4.5 | 3720 | | | 3721 | contact | Section 4.4.5 | 3722 +---------------+--------------------------+ 3724 Table 12 3726 ------------------------------------------------------------ 3728 Property Name: scheduleAgent 3730 Context: Participant 3732 Change Controller: IETF 3733 Initial Contents: 3735 +------------+--------------------------+ 3736 | Enum Value | Reference or Description | 3737 +------------+--------------------------+ 3738 | server | Section 4.4.5 | 3739 | | | 3740 | client | Section 4.4.5 | 3741 | | | 3742 | none | Section 4.4.5 | 3743 +------------+--------------------------+ 3745 Table 13 3747 ------------------------------------------------------------ 3749 Property Name: status 3751 Context: JSEvent 3753 Change Controller: IETF 3755 Initial Contents: 3757 +------------+--------------------------+ 3758 | Enum Value | Reference or Description | 3759 +------------+--------------------------+ 3760 | confirmed | Section 5.1.3 | 3761 | | | 3762 | cancelled | Section 5.1.3 | 3763 | | | 3764 | tentative | Section 5.1.3 | 3765 +------------+--------------------------+ 3767 Table 14 3769 9. Acknowledgments 3771 The authors would like to thank the members of CalConnect for their 3772 valuable contributions. This specification originated from the work 3773 of the API technical committee of CalConnect, the Calendaring and 3774 Scheduling Consortium. 3776 10. References 3777 10.1. Normative References 3779 [CLDR] "Unicode Common Locale Data Repository", 3780 . 3782 [COLORS] "CSS Color Module", . 3784 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 3785 Requirement Levels", BCP 14, RFC 2119, 3786 DOI 10.17487/RFC2119, March 1997, 3787 . 3789 [RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource 3790 Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998, 3791 . 3793 [RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397, 3794 DOI 10.17487/RFC2397, August 1998, 3795 . 3797 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: 3798 Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, 3799 . 3801 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 3802 Resource Identifier (URI): Generic Syntax", STD 66, 3803 RFC 3986, DOI 10.17487/RFC3986, January 2005, 3804 . 3806 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally 3807 Unique IDentifier (UUID) URN Namespace", RFC 4122, 3808 DOI 10.17487/RFC4122, July 2005, 3809 . 3811 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 3812 Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006, 3813 . 3815 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 3816 Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, 3817 . 3819 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 3820 Specifications: ABNF", STD 68, RFC 5234, 3821 DOI 10.17487/RFC5234, January 2008, 3822 . 3824 [RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and 3825 Scheduling Core Object Specification (iCalendar)", 3826 RFC 5545, DOI 10.17487/RFC5545, September 2009, 3827 . 3829 [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent 3830 Interoperability Protocol (iTIP)", RFC 5546, 3831 DOI 10.17487/RFC5546, December 2009, 3832 . 3834 [RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying 3835 Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, 3836 September 2009, . 3838 [RFC5870] Mayrhofer, A. and C. Spanring, "A Uniform Resource 3839 Identifier for Geographic Locations ('geo' URI)", 3840 RFC 5870, DOI 10.17487/RFC5870, June 2010, 3841 . 3843 [RFC6047] Melnikov, A., Ed., "iCalendar Message-Based 3844 Interoperability Protocol (iMIP)", RFC 6047, 3845 DOI 10.17487/RFC6047, December 2010, 3846 . 3848 [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type 3849 Specifications and Registration Procedures", BCP 13, 3850 RFC 6838, DOI 10.17487/RFC6838, January 2013, 3851 . 3853 [RFC6901] Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed., 3854 "JavaScript Object Notation (JSON) Pointer", RFC 6901, 3855 DOI 10.17487/RFC6901, April 2013, 3856 . 3858 [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493, 3859 DOI 10.17487/RFC7493, March 2015, 3860 . 3862 [RFC7529] Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules 3863 in the Internet Calendaring and Scheduling Core Object 3864 Specification (iCalendar)", RFC 7529, 3865 DOI 10.17487/RFC7529, May 2015, 3866 . 3868 [RFC7808] Douglass, M. and C. Daboo, "Time Zone Data Distribution 3869 Service", RFC 7808, DOI 10.17487/RFC7808, March 2016, 3870 . 3872 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 3873 Writing an IANA Considerations Section in RFCs", BCP 26, 3874 RFC 8126, DOI 10.17487/RFC8126, June 2017, 3875 . 3877 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 3878 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 3879 May 2017, . 3881 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 3882 Interchange Format", STD 90, RFC 8259, 3883 DOI 10.17487/RFC8259, December 2017, 3884 . 3886 [RFC8288] Nottingham, M., "Web Linking", RFC 8288, 3887 DOI 10.17487/RFC8288, October 2017, 3888 . 3890 [TZDB] "IANA Time Zone Database", 3891 . 3893 10.2. Informative References 3895 [LINKRELS] 3896 "IANA Link Relation Types", 3897 . 3900 [LOCATIONTYPES] 3901 "IANA Location Types Registry", 3902 . 3905 [MEDIATYPES] 3906 "IANA Media Types", . 3909 [RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed., 3910 "DomainKeys Identified Mail (DKIM) Signatures", STD 76, 3911 RFC 6376, DOI 10.17487/RFC6376, September 2011, 3912 . 3914 [RFC7265] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON 3915 Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May 3916 2014, . 3918 [RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986, 3919 DOI 10.17487/RFC7986, October 2016, 3920 . 3922 Authors' Addresses 3924 Neil Jenkins 3925 Fastmail 3926 PO Box 234 3927 Collins St West 3928 Melbourne VIC 8007 3929 Australia 3931 Email: neilj@fastmailteam.com 3932 URI: https://www.fastmail.com 3934 Robert Stepanek 3935 Fastmail 3936 PO Box 234 3937 Collins St West 3938 Melbourne VIC 8007 3939 Australia 3941 Email: rsto@fastmailteam.com 3942 URI: https://www.fastmail.com