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Versions: (draft-kewisch-et-al-icalendar-in-json) 00 01 02 03 04 05 06 07 08 09 10 RFC 7265

Network Working Group                                         P. Kewisch
Internet-Draft                                                   Mozilla
Intended status: Standards Track                                C. Daboo
Expires: September 27, 2013                                  Apple, Inc.
                                                             M. Douglass
                                                                     RPI
                                                          March 26, 2013


                  jCal: The JSON format for iCalendar
                      draft-ietf-jcardcal-jcal-00

Abstract

   This specification defines "jCal", a JSON format for iCalendar data.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 27, 2013.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.




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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Conventions Used in This Document  . . . . . . . . . . . . . .  4
   3.  Converting from iCalendar to jCal  . . . . . . . . . . . . . .  5
     3.1.  Pre-processing . . . . . . . . . . . . . . . . . . . . . .  5
     3.2.  iCalendar stream (RFC5545 section 3.4) . . . . . . . . . .  5
     3.3.  Components (RFC5545 section 3.6) . . . . . . . . . . . . .  6
     3.4.  Properties (RFC5545 section 3.7 and 3.8) . . . . . . . . .  7
       3.4.1.  Special Cases for Properties . . . . . . . . . . . . .  8
         3.4.1.1.  Multi-valued Properties (RFC5545 Section 3.1.2)  .  8
         3.4.1.2.  GEO Property (RFC5545 Section 3.8.1.6) . . . . . .  8
         3.4.1.3.  REQUEST-STATUS Property (RFC5545 Section 
                   3.8.8.3) . . . . . . . . . . . . . . . . . . . . .  9
     3.5.  Parameters (RFC5545 section 3.2) . . . . . . . . . . . . .  9
       3.5.1.  VALUE parameter  . . . . . . . . . . . . . . . . . . . 10
       3.5.2.  Multi-value Parameters . . . . . . . . . . . . . . . . 10
     3.6.  Values (RFC5545 section 3.3) . . . . . . . . . . . . . . . 11
       3.6.1.  Binary (RFC5545 section 3.3.1) . . . . . . . . . . . . 11
       3.6.2.  Boolean  (RFC5545 section 3.3.2) . . . . . . . . . . . 12
       3.6.3.  Calendar User Address (RFC5545 section 3.3.3)  . . . . 12
       3.6.4.  Date (RFC5545 section 3.3.4) . . . . . . . . . . . . . 12
       3.6.5.  Date-Time (RFC5545 section 3.3.5)  . . . . . . . . . . 13
       3.6.6.  Duration (RFC5545 section 3.3.6) . . . . . . . . . . . 13
       3.6.7.  Float (RFC5545 section 3.3.7)  . . . . . . . . . . . . 13
       3.6.8.  Integer (RFC5545 section 3.3.8)  . . . . . . . . . . . 14
       3.6.9.  Period of Time (RFC5545 section 3.3.9) . . . . . . . . 14
       3.6.10. Recurrence Rule (RFC5545 section 3.3.10) . . . . . . . 14
       3.6.11. Text (RFC5545 section 3.3.11)  . . . . . . . . . . . . 16
       3.6.12. Time (RFC5545 section 3.3.12)  . . . . . . . . . . . . 16
       3.6.13. URI (RFC5545 section 3.3.13) . . . . . . . . . . . . . 16
       3.6.14. UTC Offset (RFC5545 section 3.3.14)  . . . . . . . . . 16
     3.7.  Extensions . . . . . . . . . . . . . . . . . . . . . . . . 17
   4.  Converting from jCal into iCalendar  . . . . . . . . . . . . . 17
   5.  Handling Unrecognized Properties or Parameters . . . . . . . . 17
   6.  Implementation Status (to be removed prior to publication
       as an RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . 19
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 20
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 20
   9.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 21
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 21
     10.2. Informative References . . . . . . . . . . . . . . . . . . 22
   Appendix A.  ABNF Schema . . . . . . . . . . . . . . . . . . . . . 22
   Appendix B.  Examples  . . . . . . . . . . . . . . . . . . . . . . 24
     B.1.  Example 1  . . . . . . . . . . . . . . . . . . . . . . . . 24
       B.1.1.  iCalendar Data . . . . . . . . . . . . . . . . . . . . 24
       B.1.2.  jCal Data  . . . . . . . . . . . . . . . . . . . . . . 25



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     B.2.  Example 2  . . . . . . . . . . . . . . . . . . . . . . . . 25
       B.2.1.  iCalendar Data . . . . . . . . . . . . . . . . . . . . 26
       B.2.2.  jCal Data  . . . . . . . . . . . . . . . . . . . . . . 26
   Appendix C.  Change History (to be removed prior to
                publication as an RFC)  . . . . . . . . . . . . . . . 29














































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1.  Introduction

   The iCalendar data format [RFC5545] is a widely deployed interchange
   format for calendaring and scheduling data.  While many applications
   and services consume and generate calendar data, iCalendar is a
   specialized format that requires its own parser/generator.  In
   contrast, JSON-based formats as defined in [RFC4627] are the native
   format for JavaScript widgets and libraries and it is appropriate to
   have a standard form of calendar data that is easier to work with
   than iCalendar.

   The purpose of this specification is to define "jCal", a JSON format
   for iCalendar data. jCal is defined as a straightforward mapping into
   JSON from iCalendar, so that iCalendar data can be converted to JSON,
   and then back to iCalendar, without losing any semantic meaning in
   the data.  Anyone creating jCal calendar data according to this
   specification will know that their data can be converted to a valid
   iCalendar representation as well.

   The key design considerations are essentially the same as those for
   [RFC6321], that is:

      Round-tripping (converting an iCalendar instance to jCal and back)
      will give the same semantic result as the starting point.  For
      example, all components, properties and property parameters are
      guaranteed to be preserved, with the exception of those which have
      default values.

      Ordering of elements will not necessarily be preserved.

      Preserve the semantics of the iCalendar data.  While a simple
      consumer can easily browse the calendar data in jCal, a full
      understanding of iCalendar is still required in order to modify
      and/or fully comprehend the calendar data.

      Ability to handle many extensions to the underlying iCalendar
      specification without requiring an update to this document.

2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   The underlying format used for jCal is JSON.  Consequently, the terms
   "object" and "array" as well as the four primitive types are to be
   interpreted as described in Section 1 of [RFC4627].




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   Some examples in this document contain "partial" JSON documents used
   for illustrative purposes.  In these examples, three periods "..."
   are used to indicate a portion of the document that has been removed
   for compactness.

3.  Converting from iCalendar to jCal

   This section describes how iCalendar data is converted to jCal using
   a simple mapping between the iCalendar data model and JSON elements.

3.1.  Pre-processing

   iCalendar uses a line folding mechanism to limit lines of data to a
   maximum line length (typically 72 characters) to ensure maximum
   likelihood of preserving data integrity as it is transported via
   various means (e.g., email) - see Section 3.1 of [RFC5545].  Prior to
   converting iCalendar data into jCal all folded lines MUST be
   unfolded.

   iCalendar data uses an "escape" character sequence for text values
   and property parameter values.  When such text elements are converted
   into jCal the escaping MUST be removed.

   iCalendar uses a base64 encoding for binary data.  However, it does
   not restrict the encoding from being applied to non-binary value
   types.  So the following rules MUST be applied when processing a
   property with the "ENCODING" property parameter set to "BASE64":

   o  If the property value type is "BINARY", the base64 encoding MUST
      be preserved.

   o  If the value type is not "BINARY", the "ENCODING" property
      parameter MUST be removed, and the value MUST be base64 decoded.

   When base64 encoding and decoding is used, it MUST conform to Section
   4 of [RFC4648], which is the base64 method used in [RFC5545].

   One key difference in the formatting of values used in iCalendar and
   jCal is that in jCal the specification uses date/time and utc-offset
   values aligned with the complete representation, extended format of
   [ISO.8601.2004].

3.2.  iCalendar stream (RFC5545 section 3.4)

   At the top level of the iCalendar object model is an "iCalendar
   stream".  This stream encompasses multiple "iCalendar objects".  In
   jCal, the entire stream is represented by an array, where the first
   element is the string "icalendar" and subsequent elements are



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   iCalendar objects represented as described in this document.

   In the typical case where there is only one iCalendar object,
   encapsulation inside an "icalendar" array MAY be omitted.

   An iCalendar stream can contain one or more iCalendar objects.  Each
   iCalendar object, delimited by "BEGIN:VCALENDAR" and "END:VCALENDAR",
   is represented by a fixed length array with three elements:

   1.  The string "vcalendar"

   2.  An array of jCal properties

   3.  An array of jCal components

   The representation of an iCalendar object in JSON will be named
   "vcalendar component" throughout this document.

   Example:

   ["icalendar",
     ["vcalendar",
       [ /* properties */ ],
       [ /* components */ ]
     ],
     ["vcalendar",
       [ /* properties */ ],
       [ /* components */ ]
     ],
     ...
   ]

   iCalendar objects are comprised of a set of "components",
   "properties", "parameters" and "values".  A "component" can contain
   other "components" or "properties".  A "property" has a "value" and a
   set of zero or more "parameters".

   An iCalendar object may contain a mix of iCalendar component types,
   for example vevent objects delimited by "BEGIN:VEVENT" and "END:
   VEVENT", task objects delimited by "BEGIN:VTODO" and "END:VTODO".

3.3.  Components (RFC5545 section 3.6)

   Each calendar component in the "VCALENDAR" object, delimited by
   "BEGIN" and "END", will be converted to a fixed length array with
   three fields that have a specific structure:





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   1.  A string with the name of the iCalendar component, but in
       lowercase.

   2.  An array of jCal properties as described in Section 3.4.

   3.  An array of jCal components, representing the sub-components of
       the component in question.

   While the grouping of properties and sub-components does not retain
   the original order specified in the iCalendar stream, the semantics
   of a component are preserved.

   The iCalendar to jCal component mapping is valid for both current
   iCalendar components and any new iCalendar components added in the
   future.  Conversion is to be done in the same way.

   Example:

   ["vevent",
     [ /* Array of jCal properties */ ],
     [ /* Array of jCal sub-components */ ]
   ]

3.4.  Properties (RFC5545 section 3.7 and 3.8)

   iCalendar properties, whether they apply to the "VCALENDAR" object or
   to a component, are handled in a consistent way in the jCal format.

   Each individual iCalendar property is represented in jCal by an array
   with three fixed elements, followed by at one or more additional
   elements, depending on if the property is a multi-value property as
   described in Section 3.1.2 of [RFC5545].

   The array consists of the following fixed elements:

   1.  The name of the property as a string, but in lowercase.

   2.  An object containing the parameters as described in Section 3.5.

   3.  The type identifier string of the value, in lowercase.

   The remaining elements of the array are used for the value of the
   property.  For single-value properties, the array MUST have exactly
   four elements, for multi-valued properties as described in
   Section 3.4.1.1 there can be any number of additional elements.

   The array describing the property can then be inserted into the array
   designated for properties in any component, including the "vcalendar"



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   component described in Section 3.3.

   Example:

   ["vevent",
     [
       ["summary", {}, "text", "Meeting with Fred"],
       ["categories", {}, "text", "Meetings", "Work"]
       ...
     ],
     [ /* sub-components */ ]
   ]

   The property parameters in the second element of the property array
   associate a set of parameter names with their respective value.
   Parameters are further described in Section 3.5.

   To allow for a cleaner implementation, the parameter object MUST be
   present even if there are no parameters.  In this case, an empty
   object MUST be used.

3.4.1.  Special Cases for Properties

   This section describes some properties that have special handling
   when converting to jCal.

3.4.1.1.  Multi-valued Properties (RFC5545 Section 3.1.2)

   Various iCalendar properties defined in [RFC5545], for example the
   "CATEGORIES" property, are defined as multi-valued properties.  In
   jCal these properties are added as further members of the array
   describing the property.

   Note that additional multi-valued properties may be added in
   extensions to the iCalendar format.

3.4.1.2.  GEO Property (RFC5545 Section 3.8.1.6)

   In iCalendar, the "GEO" property value is defined as a semi-colon
   separated list of two "FLOAT" values, the first representing latitude
   and the second longitude.

   In jCal, the value for the "geo" property is represented like a
   multi-value property.  The first value of the property represents the
   latitude, the second value represents the longitude.

   When converting from jCal to iCalendar, the two values MUST be
   converted using a semi-colon as the separator character.



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   Example

   ["vevent",
     [
       ["geo", {}, "float", 37.386013, -122.082932 ]
       ...
     ],
     ...
   ]

3.4.1.3.  REQUEST-STATUS Property (RFC5545 Section 3.8.8.3)

   In iCalendar, the "REQUEST-STATUS" property value is defined as a
   semi-colon separated list of two or three "TEXT" values.  The first
   represents a code, the second a description, and the third any
   additional data.

   In jCal, the value for the "request-status" property is represented
   like a multi-value property.  The first value of the property
   corresponds to the code, the second value corresponds to the
   description and the third value corresponds to the additional data.
   Each value is represented using a string value.  If there is no
   additional data in the iCalendar value, the last element of the array
   SHOULD NOT be present.

   When converting from jCal to iCalendar, the two or three values MUST
   be converted using a semi-colon as the separator character.

   Example:

   ["vevent":
     [
       ["request-status", {}, "text", "2.0", "Success" ],
       ["request-status", {}, "text",
          "3.7",
          "Invalid Calendar User",
          "ATTENDEE:mailto:jsmith@example.org"
       ],
       ...
     ],
     ...
   ]

3.5.  Parameters (RFC5545 section 3.2)

   Property parameters are represented as a JSON object where each key-
   value pair represents the iCalendar parameter name and its value.
   The name of the parameter MUST be in lowercase, the original case of



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   the parameter value MUST be preserved.

   Each individual iCalendar property parameter is represented in jCal
   by a key-value pair in the parameters object.  The key uses the same
   name as the iCalendar property parameter, but in lowercase.  For
   example, the "PARTSTAT" property parameter is represented in jCal by
   the "partstat" key.  The case of the parameter value MUST be
   preserved.

   Example:

   ["vevent":
     [
       ["attendee",
        {
          "partstat": "ACCEPTED",
          "rsvp": "TRUE",
          "role": "REQ-PARTICIPANT"
        },
        "cal-address",
        "mailto:jsmith@example.org"
       ],
       ["summary", {}, "text", "Meeting"],
       ...
     ],
     ...
   ]

3.5.1.  VALUE parameter

   iCalendar defines a "VALUE" property parameter (Section 3.2.20 of
   [RFC5545]).  This property parameter MUST NOT be added to the
   parameters object.  Instead, the value type is always explicitly
   mentioned in the third element of the array describing the property.
   Thus, when converting from iCalendar to jCal, any "VALUE" property
   parameters are skipped.  When converting from jCal into iCalendar,
   the appropriate "VALUE" property parameter MUST be included in the
   iCalendar property if the value type is not the default value type
   for that property.

3.5.2.  Multi-value Parameters

   In [RFC5545], some parameters allow using a COMMA-separated list of
   values.  To ease processing in jCal, the value of a parameter with
   multiple values MUST be represented in an array containing the
   separated values.  The array elements MUST be string values.  Single-
   value parameters SHOULD be represented using a single string value,
   but an array with one element MAY also be used.  An example for a



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   such parameter is the iCalendar "DELEGATED-FROM" and "DELEGATED-TO"
   parameter, more such parameters may be added in extensions.

   DQUOTE characters used to encapsulate the separated values MUST NOT
   be added to the jCal parameter value.

   Example 1:

   ...
   ["attendee",
    {
      "delegated-to": ["mailto:jdoe@example.org",
                       "mailto:jqpublic@example.org"]
    },
    "cal-address",
    "mailto:jsmith@example.org"
   ],
   ...

   Example 2:

   ...
   ["attendee",
    {
      "delegated-to": "mailto:jdoe@example.org"
    },
    "cal-address",
    "mailto:jsmith@example.org"
   ],
   ...

3.6.  Values (RFC5545 section 3.3)

   The type of an iCalendar value is explicitly mentioned in the third
   element of the array describing a jCal property.  The actual values
   of the property can be found in the fourth and following elements of
   the array.

3.6.1.  Binary (RFC5545 section 3.3.1)

   Description:  iCalendar "BINARY" properties are represented by a
      property with type identifier "binary".  The value is base64
      encoded data, conforming to Section 4 of [RFC4648], which is the
      base64 method used in [RFC5545].







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   Example:

   ...
   ["attach", {}, "binary", "SGVsbG8gV29ybGQh"],
   ...

3.6.2.  Boolean  (RFC5545 section 3.3.2)

   Description:  iCalendar "BOOLEAN" properties are represented by a
      property with the type identifier "boolean".  The value is a
      boolean JSON value.

   Example:

   ...
   ["x-non-smoking", {}, "boolean", true],
   ...

3.6.3.  Calendar User Address (RFC5545 section 3.3.3)

   Description:  iCalendar "CAL-ADDRESS" properties are represented by a
      property with the type identifier "cal-address".  The value is a
      string with the URI as described in [RFC3986].

   Example:

   ...
   ["attendee", {}, "cal-address", "mailto:kewisch@example.com"],
   ...

3.6.4.  Date (RFC5545 section 3.3.4)

   Description:  iCalendar "DATE" properties are represented by a
      property with the type identifier "date".  The value is the same
      date value specified by [RFC5545], but formatted using the
      [ISO.8601.2004] complete representation, extended format.  The
      textual format specifies a four-digit year, two-digit month, and
      two-digit day of the month, separated by the "-" character.

   Example:

   ...
   ["dtstart", {}, "date", "2011-05-17"],
   ...







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3.6.5.  Date-Time (RFC5545 section 3.3.5)

   Description:  iCalendar "DATE-TIME" properties are represented by a
      property with the type identifier "date-time".  The value is the
      same date value specified by [RFC5545], but formatted using the
      [ISO.8601.2004] complete representation, extended format.  The
      same restrictions with respect to leap seconds and timezone
      offsets as specified in [RFC5545] Section 3.3.5 apply.

   Example:

   ...
   ["dtstart", {}, "date-time", "2012-10-17T12:00:00"],
   ["dtstamp", {}, "date-time", "2012-10-17T12:00:00Z"],
   ["dtend",
    { "tzid": "Europe/Berlin" },
    "date-time",
    "2011-10-17T13:00:00"
   ],
   ...

3.6.6.  Duration (RFC5545 section 3.3.6)

   Description:  iCalendar "DURATION" properties are represented by a
      property with the type identifier "duration".  The value is the
      same duration value specified by [RFC5545] as a string.

   Example:

   ...
   ["duration", {}, "duration", "P1D"],
   ...

3.6.7.  Float (RFC5545 section 3.3.7)

   Description:  iCalendar "FLOAT" properties are represented by a
      property with the type identifier "float".  The value is the
      floating point number as a JSON primitive number value.

   Example:

   ...
   ["x-grade", {}, "float", 1.3],
   ...







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3.6.8.  Integer (RFC5545 section 3.3.8)

   Description:  iCalendar "INTEGER" properties are represented by a
      property with the type identifier "integer".  The value is the
      floating point number as a JSON primitive number value.

   Examples:

   ...
   ["percent-complete", {}, "integer", 42],
   ...

3.6.9.  Period of Time (RFC5545 section 3.3.9)

   Description:  iCalendar "PERIOD" properties are represented by a jCal
      property with the type identifier "period".  The property value is
      an array, with the first element representing the start of the
      period and the second element representing the end of the period.
      As in [RFC5545], the start of the period is always formatted as a
      date-time value and the end of the period MUST be either a date-
      time or duration value.  Any date, date-time or duration values
      contained in the period value MUST be formatted in accordance to
      the rules for date, date-time or duration values specified in this
      document.

   Example:

   ...
   ["freebusy",
    { "fbtype": "FREE" },
    "period",
    ["1997-03-08T16:00:00Z", "P1D"]
   ],
   ...

3.6.10.  Recurrence Rule (RFC5545 section 3.3.10)

   Description:  iCalendar "RECUR" properties are represented by a
      property with the type identifier "recur".  The value is an object
      describing the structured data as specified by [RFC5545].  Each
      rule part is described by the combination of key and value.  The
      key specifies the name of the rule part and MUST be converted to
      lowercase.  The value of the rule part MUST be mapped by the
      following rules:

      *  The value of the "freq" and "wskt" rule parts MUST be a string
         as specified in [RFC5545], with case preserved.




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      *  The value of the "until" rule part MUST be a date or date-time
         value formatted in accordance to the rules for date or date-
         time specified in this document.

      *  The "count" and "interval" rule parts MUST be specified as a
         single number value.

      *  The "bysecond", "byminute", "byhour", "bymonthday",
         "byyearday", "byweekno", "bymonth" and "bysetpos" rule parts
         MUST each be specified as an array with multiple number values.
         Single-value rule parts SHOULD be represented using a single
         string value, but an array with one element MAY also be used.

      *  The "byday" rule part MUST be specified as an array with
         multiple string values.  A single-value "byday" rule part
         SHOULD be represented using a single string value, but an array
         with one element MAY also be used.

   Example 1:

   ...
   ["rrule",
    {},
    "recur",
    {
      "freq": "YEARLY",
      "count": 5,
      "byday": [ "-1SU", "2MO" ],
      "bymonth": 10
    }
   ],
   ...

   Example 2:

   ...
   ["rrule",
    {},
    "recur",
    {
      "freq": "MONTHLY",
      "interval": 2,
      "bymonthday": [ 1, 15, -1 ],
      "until": "2013-10-01"
    }
   ],
   ...




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3.6.11.  Text (RFC5545 section 3.3.11)

   Description:  iCalendar "TEXT" properties are represented by a
      property with the type identifier "text".  The value is the same
      text value specified by [RFC5545] as a string.

   Example:

   ...
   ["comment", {}, "text", "hello, world"],
   ...

3.6.12.  Time (RFC5545 section 3.3.12)

   Description:  iCalendar "TIME" propertes are represented by a
      property with the type identifier "time".  The value is the same
      date value specified by [RFC5545], but formatted using the
      [ISO.8601.2004] complete representation, extended format.  The
      same restrictions with respect to leap seconds, time fractions,
      and timezone offsets as specified in [RFC5545] Section 3.3.12
      apply.

   Example:

   ...
   ["x-time-local", {}, "time", "12:30:00"],
   ["x-time-utc", {}, "time", "12:30:00Z"],
   ["x-time-offset", { "tzid": "Europe/Berlin" }, "time", "12:30:00"],
   ...

3.6.13.  URI (RFC5545 section 3.3.13)

   Description:  iCalendar "URI" properties are represented by a
      property with the type identifier "uri".  The value is a string
      with the URI.

   Example:

   ...
   ["tzurl", {}, "uri", "http://example.org/tz/Europe-Berlin.ics"],
   ...

3.6.14.  UTC Offset (RFC5545 section 3.3.14)








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   Description:  iCalendar "UTC-OFFSET" properties are represented by a
      property with the type identifier "utc-offset".  The value is a
      string with the same UTC offset value specified by [RFC5545], with
      the exception that the hour and minute components are separated by
      a ":" character, for consistency with the [ISO.8601.2004] timezone
      offset, extended format.

   Example:

   ...
   ["tzoffsetfrom", {}, "utc-offset", "-05:00"],
   ["tzoffsetto", {}, "utc-offset", "+12:45"],
   ..


3.7.  Extensions

   iCalendar extension properties and property parameters (those with an
   "X-" prefix in their name) are handled in the same way as other
   properties and property parameters: the property is represented by an
   array, the property parameter represented by an object.  The property
   or parameter name uses the same name as for the iCalendar extension,
   but in lowercase.  For example, the "X-FOO" property in iCalendar
   turns into the "x-foo" jCal property.  See Section 5 for how to deal
   with default values for unrecognized extension properties or property
   parameters.

4.  Converting from jCal into iCalendar

   When converting component, property and property parameter values,
   the names SHOULD be converted to uppercase.  Although iCalendar names
   are case insensitive, common practice is to keep them all uppercase
   following the actual definitions in [RFC5545].

   Backslash escaping and line folding MUST be applied to the resulting
   iCalendar data as required by [RFC5545].

   Non-binary value types MUST NOT be base64 encoded.

   jCal properties that do not specify the default type for the
   iCalendar property MUST add a VALUE parameter when converting to
   iCalendar. jCal properties that specify the default type SHOULD NOT
   add a VALUE parameter.

5.  Handling Unrecognized Properties or Parameters

   In iCalendar, properties have a default value type specified by their
   definition, e.g.  "SUMMARY"'s value type is "TEXT" and "DURATION"'s



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   is "DURATION".  When a property uses its default value type, the
   "VALUE" property parameter does not need to be specified on the
   property.

   When new properties are defined or "X-" properties used, an iCalendar
   to jCal converter might not recognize them, and not know what the
   appropriate default value types are, yet they need to be able to
   preserve the values.  A similar issue arises for unrecognized
   property parameters.  As a result, the following rules are applied
   when dealing with unrecognized properties and property parameters:

   o  When converting iCalendar into jCal:

      *  Any property that does not include a "VALUE" property parameter
         and whose default value type is not known, MUST be converted to
         a string object.  The content of that string is the unprocessed
         value text.

      *  Any unrecognized property parameter MUST be converted to a
         string value, with its content set to the property parameter
         value text, treated as if it were a "TEXT" value.

   o  When converting jCal into iCalendar:

      *  Since jCal always explicitly specifies the value type, it can
         always be converted to iCalendar using the VALUE parameter.

      *  If the value type specified in jCal matches the default value
         type in iCalendar, the VALUE parameter SHOULD be omitted.

   Example: The following is an example of an unrecognized iCalendar
   property (that uses a "DATE-TIME" value as its default), and the
   equivalent jCal representation of that property.

   iCalendar:

   X-PROPERTY:20110512T120000Z

   jCal:

   ...
   ["x-property", {}, "text", "20110512T120000Z"],
   ...

   Example: The following is an example of a jCal property (where the
   corresponding iCalendar property uses a "INTEGER" value as its
   default), and the equivalent iCalendar representation of that
   property.



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   jCal:

   ...
   ["percent-complete", {}, "integer", 95],
   ...

   iCalendar:

   PERCENT-COMPLETE:95

   Example: The following is an example of an unrecognized iCalendar
   property parameter (that uses a "FLOAT" value as its default)
   specified on a recognized iCalendar property, and the equivalent jCal
   representation of that property and property parameter.

   iCalendar:

   DTSTART;X-PARAM=30.3;VALUE=DATE:20110512

   jCal:

   ...
   ["dtstart", { "x-param": "30.3" }, "date", "2011-05-12"],
   ...

6.  Implementation Status (to be removed prior to publication as an RFC)

   This section describes libraries known to implement this draft as per
   [I-D.sheffer-running-code].

   1.  ICAL.js - Philipp Kewisch, James Lal. A JavaScript parser for
       iCalendar (rfc5545)

       Source:  https://github.com/kewisch/ical.js/

       Maturity:  production

       Coverage:  All aspects of this draft, up to version 01.  Includes
          an online validator. (as of rev 847c67c501, 2013-02-14)

       Licensing:  MPL, Mozilla Public License 2.0

   2.  Py Calendar - Cyrus Daboo. iCalendar/vCard Library

       Source:  https://svn.calendarserver.org/repository/
          calendarserver/PyCalendar/branches/json/





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       Maturity:  production

       Coverage:  All aspects of this draft, up to version 01.

       Licensing:  Apache License, Version 2.0

   Additionally, interoperability testing of this draft is an ongoing
   effort under members of calconnect, the Calendaring and Scheduling
   Consortium.  CalDAV Vendors are looking into supporting this draft.

7.  Security Considerations

   For security considerations specific to calendar data, see Section 7
   of [RFC5545].  Since this specification is a mapping from iCalendar,
   no new security concerns are introduced related to calendar data.

   The use of JSON as a format does have security risks.  Section 7 of
   [RFC4627] discusses these risks.

8.  IANA Considerations

   This document defines a MIME media type for use with iCalendar in
   JSON data.  This media type SHOULD be used for the transfer of
   calendaring data in JSON.

   Type name:  application

   Subtype name:  calendar+json

   Required parameters:  none

   Optional parameters:  method, component and optinfo as defined for
      the text/calendar media type in [RFC5545].

   Encoding considerations:  Same as encoding considerations of
      application/json as specified in [RFC4627].

   Security considerations:  See Section 7.

   Interoperability considerations:  This media type provides an
      alternative format for iCalendar data based on JSON.

   Published specification:  This specification.

   Applications which use this media type:  Applications that currently
      make use of the text/calendar media type can use this as an
      alternative.  Similarly, Applications that use the application/
      json media type to transfer calendaring data can use this to



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      further specify the content.

   Person & email address to contact for further information:
      calsify@ietf.org

   Intended usage:  COMMON

   Restrictions on usage:  There are no restrictions on where this media
      type can be used.

   Author:  See the "Author's Address" section of this document.

   Change controller:  IETF

9.  Acknowledgments

   The authors would like to thank the following for their valuable
   contributions: William Gill, Erwin Rehme, and Dave Thewlis.  This
   specification originated from the work of the XML-JSON technical
   committee of the Calendaring and Scheduling Consortium.

10.  References

10.1.  Normative References

   [ISO.8601.2004]             International Organization for
                               Standardization, ""Data elements and
                               interchange formats -- Information
                               interchange -- Representation of dates
                               and times"", ISO 8601, 12 2004.

   [RFC2119]                   Bradner, S., "Key words for use in RFCs
                               to Indicate Requirement Levels", BCP 14,
                               RFC 2119, March 1997.

   [RFC3986]                   Berners-Lee, T., Fielding, R., and L.
                               Masinter, "Uniform Resource Identifier
                               (URI): Generic Syntax", STD 66, RFC 3986,
                               January 2005.

   [RFC4648]                   Josefsson, S., "The Base16, Base32, and
                               Base64 Data Encodings", RFC 4648,
                               October 2006.

   [RFC5234]                   Crocker, D. and P. Overell, "Augmented
                               BNF for Syntax Specifications: ABNF",
                               STD 68, RFC 5234, January 2008.




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   [RFC5545]                   Desruisseaux, B., "Internet Calendaring
                               and Scheduling Core Object Specification
                               (iCalendar)", RFC 5545, September 2009.

   [RFC6321]                   Daboo, C., Douglass, M., and S. Lees,
                               "xCal: The XML Format for iCalendar",
                               RFC 6321, August 2011.

10.2.  Informative References

   [I-D.sheffer-running-code]  Sheffer, Y. and A. Farrel, "Improving
                               Awareness of Running Code: the
                               Implementation Status Section",
                               draft-sheffer-running-code-02 (work in
                               progress), January 2013.

   [RFC4627]                   Crockford, D., "The application/json
                               Media Type for JavaScript Object Notation
                               (JSON)", RFC 4627, July 2006.

   [calconnect-artifacts]      The Calendaring and Scheduling
                               Consortium, "Code Artifacts and Schemas",
                               <http://www.calconnect.org/
                               artifacts.shtml>.

Appendix A.  ABNF Schema

   Below is an ABNF schema as per [RFC5234] for iCalendar in JSON.  ABNF
   Symbols not described here are taken from [RFC4627].  The schema is
   non-normative and given for reference only.

   The numeric section numbers given in the comments refer to section in
   [RFC5545].  Additional semantic restrictions apply, especially
   regarding the allowed properties and sub-components per component.
   Details on these restrictions can be found in this document and
   [RFC5545].

   Additional schemas may be available on the internet at
   [calconnect-artifacts].

   ; An iCalendar Stream is an array with the first element being the
   ; string "icalendar". All remaining elements are jcalobjects.
   jcalstream = begin-array
                DQUOTE "icalendar" DQUOTE
                *(value-separator jcalobject)
                end-array

   ; A jCal Object is a component with the component-name "vcalendar".



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   ; Restrictions to which properties and sub-components may be
   ; specified are to be taken from RFC5545.
   jcalobject = component

   ; A jCal component consists of the name string, properties array and
   ; component array
   component = begin-array
               DQUOTE component-name DQUOTE value-separator
               properties-array value-separator
               components-array
               end-array

   components-array = begin-array
                      [ component *(value-separator component) ]
                      end-array

   ; A jCal property consists of the name string, parameters object,
   ; type string and one or more values as specified in this document.
   property = begin-array
              DQUOTE property-name DQUOTE value-separator
              params-object value-separator
              DQUOTE type-name DQUOTE
              propery-value *(value-separator property-value)
              end-array
   properties-array = begin-array
                      [ property *(value-separator property) ]
                      end-array

   ; Property values depend on the type-name. Aside from the value types
   ; mentioned here, extensions may make use of other JSON value types.
   property-value = string / number / boolean

   ; The jCal params-object is a JSON object which follows the semantic
   ; guidelines described in this document.
   params-object = begin-object
                   [ params-member *(value-separator params-member) ]
                   end-object
   params-member = DQUOTE param-name DQUOTE name-separator param-value
   param-value = string

   ; The type MUST be a valid type as described by this document. New
   ; value types can be added by extensions.
   type-name = "binary" / "boolean" / "cal-address" / "date" /
               "date-time" / "duration" / "float" / "integer" /
               "period" / "recur" / "text" / "time" / "uri" /
               "utc-offset" / x-type





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   ; Component, property, parameter and type names MUST be lowercase.
   ; Additional semantic restrictions apply as described by this
   ; document and RFC5545.
   component-name = lowercase-name
   property-name = lowercase-name
   param-name = lowercase-name
   x-type = lowercase-name
   lowercase-name = 1*(%x61-7A / DIGIT / "-")

Appendix B.  Examples

   This section contains two examples of iCalendar objects with their
   jCal representation.

B.1.  Example 1

B.1.1.  iCalendar Data

   BEGIN:VCALENDAR
   CALSCALE:GREGORIAN
   PRODID:-//Example Inc.//Example Calendar//EN
   VERSION:2.0
   BEGIN:VEVENT
   DTSTAMP:20080205T191224Z
   DTSTART:20081006
   SUMMARY:Planning meeting
   UID:4088E990AD89CB3DBB484909
   END:VEVENT
   END:VCALENDAR






















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B.1.2.  jCal Data

   ["vcalendar",
     [
       ["calscale", {}, "text", "GREGORIAN"],
       ["prodid", {}, "text", "-//Example Inc.//Example Calendar//EN"],
       ["version", {}, "text", "2.0"]
     ],
     [
       ["vevent",
         [
           ["dtstamp", {}, "date-time", "2008-02-05T19:12:24Z"],
           ["dtstart", {}, "date", "2008-10-06"],
           ["summary", {}, "text", "Planning meeting"],
           ["uid", {}, "text", "4088E990AD89CB3DBB484909"],
         ],
         []
       ]
     ]
   ]

B.2.  Example 2





























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B.2.1.  iCalendar Data

   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//Example Corp.//Example Client//EN
   BEGIN:VTIMEZONE
   LAST-MODIFIED:20040110T032845Z
   TZID:US/Eastern
   BEGIN:DAYLIGHT
   DTSTART:20000404T020000
   RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4
   TZNAME:EDT
   TZOFFSETFROM:-0500
   TZOFFSETTO:-0400
   END:DAYLIGHT
   BEGIN:STANDARD
   DTSTART:20001026T020000
   RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
   TZNAME:EST
   TZOFFSETFROM:-0400
   TZOFFSETTO:-0500
   END:STANDARD
   END:VTIMEZONE
   BEGIN:VEVENT
   DTSTAMP:20060206T001121Z
   DTSTART;TZID=US/Eastern:20060102T120000
   DURATION:PT1H
   RRULE:FREQ=DAILY;COUNT=5
   RDATE;TZID=US/Eastern;VALUE=PERIOD:20060102T150000/PT2H
   SUMMARY:Event #2
   DESCRIPTION:We are having a meeting all this week at 12 pm fo
    r one hour\, with an additional meeting on the first day 2 h
    ours long.\nPlease bring your own lunch for the 12 pm meetin
    gs.
   UID:00959BC664CA650E933C892C@example.com
   END:VEVENT
   BEGIN:VEVENT
   DTSTAMP:20060206T001121Z
   DTSTART;TZID=US/Eastern:20060104T140000
   DURATION:PT1H
   RECURRENCE-ID;TZID=US/Eastern:20060104T120000
   SUMMARY:Event #2 bis
   UID:00959BC664CA650E933C892C@example.com
   END:VEVENT
   END:VCALENDAR

B.2.2.  jCal Data




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   ["vcalendar",
     [
       ["prodid", {}, "text", "-//Example Corp.//Example Client//EN"],
       ["version", {}, "text", "2.0"],
     ],
     [
       ["vtimezone",
         [
           ["last-modified", {}, "date-time", "2004-01-10T03:28:45Z"],
           ["tzid", {}, "text", "US/Eastern"],
         ],
         [
           ["daylight",
             [
               ["dtstart", {}, "date-time", "2000-04-04T02:00:00"],
               ["rrule",
                {},
                "recur",
                "FREQ=YEARLY;BYDAY=1SU;BYMONTH=4"
               ],
               ["tzname", {}, "text", "EDT"],
               ["tzoffsetfrom", {}, "utc-offset", "-05:00"],
               ["tzoffsetto", {}, "utc-offset", "-04:00"]
             ],
             []
           ],
           ["standard",
             [
               ["dtstart", {}, "date-time", "2000-10-26T02:00:00"],
               ["rrule",
                {},
                "recur",
                "FREQ=YEARLY;BYDAY=1SU;BYMONTH=10"
               ],
               ["tzname", {}, "text", "EST"],
               ["tzoffsetfrom", {}, "utc-offset", "-04:00"],
               ["tzoffsetto", {}, "utc-offset", "-05:00"]
             ],
             []
           ]
         ]
       ],
       ["vevent",
         [
           ["dtstamp", {}, "date-time", "2006-02-06T00:11:21Z"],
           ["dtstart",
            { "tzid": "US/Eastern" },
            "date-time",



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            "2006-01-02T12:00:00"
           ],
           ["duration", {}, "duration", "PT1H"],
           ["rrule", {}, "recur", "FREQ=DAILY;COUNT=5"],
           ["rdate",
            { "tzid": "US/Eastern" },
            "period",
            "2006-01-02T15:00:00/PT2H"
           ],
           ["summary", {}, "text", "Event #2"],
           ["description",
            {},
            "text",
            // Note that comments and string concatenation are not
            // allowed per JSON specification and is used here only
            // to avoid long lines.
            "We are having a meeting all this week at 12 pm for one " +
            "hour, with an additional meeting on the first day 2 " +
            "hours long.\nPlease bring your own lunch for the 12 pm " +
            "meetings."
           ],
           ["uid", {}, "text", "00959BC664CA650E933C892C@example.com"]
         ],
         []
       ],
       ["vevent",
         [
           ["dtstamp", {}, "date-time", "2006-02-06T00:11:21Z"],
           ["dtstart",
            { "tzid": "US/Eastern" },
            "date-time",
            "2006-01-02T14:00:00"
           ],
           ["duration", {}, "duration", "PT1H"],
           ["recurrence-id",
            { "tzid": "US/Eastern" },
            "date-time",
            "2006-01-04T12:00:00"
           ],
           ["summary", {}, "text", "Event #2"],
           ["uid", {}, "text", "00959BC664CA650E933C892C@example.com"]
         ],
         []
       ]
     ]
   ]





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Appendix C.  Change History (to be removed prior to publication as an
             RFC)

   draft-kewisch-et-al-icalendar-in-json-01

      *  Added information on how to handle multi-value parameter.  The
         decision leads to a cleaner draft for a similar proposal for
         vcard.

      *  Removed the open discussion point section regarding the mime
         media type in favor of adding one.

      *  Minor corrections in wording and typo fixes.

   draft-kewisch-et-al-icalendar-in-json-02

      *  Added implementation status section.

      *  Removed various text tables that just show a conversion from
         uppercase to lowercase.

      *  Changed value format for RECUR and PERIOD types

      *  Minor corrections in wording and typo fixes.

   draft-ietf-jcardcal-jcal-00

      *  Pubication as a WG draft

Authors' Addresses

   Philipp Kewisch
   Mozilla Corporation
   650 Castro Street, Suite 300
   Mountain View, CA  94041
   USA

   EMail: mozilla@kewis.ch
   URI:   http://www.mozilla.org/












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   Cyrus Daboo
   Apple Inc.
   1 Infinite Loop
   Cupertino, CA  95014
   USA

   EMail: cyrus@daboo.name
   URI:   http://www.apple.com/


   Mike Douglass
   Rensselaer Polytechnic Institute
   110 8th Street
   Troy, NY  12180
   USA

   EMail: douglm@rpi.edu
   URI:   http://www.rpi.edu/

































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