RFC7095

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Internet Engineering Task Force (IETF) P. Kewisch Request for Comments: 7095 Mozilla Category: Standards Track January 2014 ISSN: 2070-1721 

                jCard: The JSON Format for vCard

Abstract

This specification defines "jCard", a JSON format for vCard data. The vCard data format is a text format for representing and exchanging information about individuals and other entities, for example, telephone numbers, email addresses, structured names, and delivery addresses. JSON is a lightweight, text-based, language- independent data interchange format commonly used in Internet applications.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7095.

Copyright Notice

Copyright (c) 2014 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. 

 3.2.  jCard Object and Syntactic Entities (RFC 6350, Sections

Introduction

The vCard data format RFC6350 provides for the capture and exchange of information normally stored within an address book or directory application. The vCard format has gone through multiple revisions, most recently vCard 4.

As certain similarities exist between vCard and the iCalendar data format RFC5545, there is also an effort to define a JSON-based data format for calendar information called jCal [JCAL] that parallels the format defined in this specification. The term "JSON" describes the JavaScript Object Notation defined in RFC4627.

The purpose of this specification is to define "jCard", a JSON format for vCard data. One main advantage to using a JSON-based format over the classic vCard format is easier processing for JavaScript-based widgets and libraries, especially in the scope of web-based applications.

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

  Round-tripping (converting a vCard instance to jCard 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.

  The Ordering of elements and the case of property and parameter
  names will not necessarily be preserved.

  The vCard data semantics are to be preserved, allowing a simple
  consumer to easily browse the data in jCard.  A full understanding
  of vCard is still required in order to modify and/or fully
  comprehend the directory data.

  Extensions to the underlying vCard specification must not lead to
  requiring an update to jCard.

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 jCard is JSON. Consequently, the terms "object" and "array" as well as the four primitive types (strings, numbers, booleans, and null) are to be interpreted as described in Section 1 of RFC4627.

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.

Converting from vCard to jCard

This section describes how vCard objects are converted to jCard using a simple mapping between the vCard data model and JSON elements.

In RFC6350, vCard objects are comprised of a set of "properties", "parameters", and "values". The top level of a vCard object contains "properties". A "property" has a "value" and a set of zero or more "parameters". Each of these entities has a representation in jCard, defined in the following sections. The representation of a vCard object in JSON will be named "jCard object" throughout this document.

Pre-processing

vCard uses a line-folding mechanism to limit lines of data to a maximum line length (typically 75 octets) to ensure maximum likelihood of preserving data integrity as it is transported via various means (e.g., email) -- see Section 3.2 of RFC6350.

vCard data uses an "escape" character sequence for text values and property parameter values. See Section 3.4 of RFC6350 as well as RFC6868.

When converting from vCard to jCard, first vCard lines MUST be unfolded. Afterwards, any vCard escaping MUST be unescaped. Finally, JSON escaping (e.g., for control characters) MUST be applied.

The reverse order applies when converting from jCard to vCard. First, JSON escaping MUST be unescaped. Afterwards, vCard escaping MUST be applied. Finally, long lines SHOULD be folded as described in RFC6350.

One key difference in the formatting of values used in vCard and jCard is that in jCard the specification uses date/time values aligned with the extended format of [ISO.8601.2004], which is more commonly used in Internet applications that make use of the JSON format. The sections of this document describing the various date and time formats contain more information on the use of the complete representation, reduced accuracy, or truncated representation.

jCard Object and Syntactic Entities (RFC 6350, Sections 6.1.1 and

  6.1.2)

In Sections 6.1.1 and 6.1.2 of RFC6350, the BEGIN and END properties delimit a syntactic vCard entity. In jCard, each syntactic entity is represented by an array with two elements and is named "jCard object". The first element is the string "vcard", and the second element is an array of jCard properties as described in Section 3.3, belonging to the entity.

Although RFC6350 defines BEGIN and END to be properties, they MUST NOT appear as properties of the jCard. Instead, the jCard object is sufficient to define a vCard entity. When converting from jCard to vCard, the BEGIN and END properties MUST be added to enclose the properties of the jCard object.

Example:

["vcard", [ 

 /* Add properties in place of this comment */
 ]

]

Consumers of this format wishing to define content that can represent multiple jCard objects within the same JSON document can use a simple JSON array, each element being a single jCard object.

Properties (RFC 6350, Section 6)

Each individual vCard property is represented in jCard by an array with three fixed elements, followed by one or more additional elements, depending on if the property is a multi-valued property as described in Section 3.3 of RFC6350.

The array consists of the following fixed elements:

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

   format specifies that property names are case insensitive and
   recommends that they be rendered in uppercase.  In jCard, they
   MUST be in lowercase.

2. An object containing the parameters as described in Section 3.4. 

   If the property has no parameters, an empty object is used to
   represent that.

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

   important that parsers check this to determine the data type of
   the value and that they do not rely on assumptions.  For example,
   for structured values, the data type will be "array".

The remaining elements of the array are used for one or more values of the property. For single-value properties, the array has exactly four elements; for multi-valued properties, each value is another element, and there can be any number of additional elements.

In the following example, the "categories" property is multi-valued and has two values, while all other properties are single-valued:

["vcard", 

 [
   ["version", {}, "text", "4.0"],
   ["fn", {}, "text", "John Doe"],
   ["gender", {}, "text", "M"],
   ["categories", {}, "text", "computers", "cameras"],
   ...
 ]

]

As described in Section 3.3.1.3, a property value may be a structured property value, in which case it is represented as an array encapsulated in the array that represents the overall property.

Strictly speaking, this means that the property value is not represented in the format indicated by the type identifier but by an array instead. However, the values inside the encapsulated array are of the format identified by the type identifier.

The above also holds for multi-valued properties, where some of the values may be structured property values and therefore are represented as an encapsulated array.

A special case is where a value in an encapsulated array consists of multiple components itself, in which case it is represented as yet another nested array, with elements matching the value type. Section 3.3.1.3 describes this in more detail.

The above illustrates that it's important for the parser to check the format of each property value, as it might either directly match the value type, or it might be a structured value where nested subelements match the value type.

Special Cases for Properties

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

The VERSION Property

The vCard format specification RFC6350 defines the "VERSION" property to be mandatory. The jCard "version" property MUST be represented in the corresponding jCard component, with the same value as in the vCard. vCards that conform to RFC 6350 will contain the value "4.0".

Also in accordance to RFC6350, the "version" property MUST be the first element of the array containing the properties of a jCard.

Grouping of Properties

In vCard RFC6350, related properties can be grouped together using a grouping construct. The grouping is accomplished by adding a prefix (which consists of the group name followed by a dot) to the property name.

In jCard, the same grouping is achieved through a "group" parameter that holds the group name. In jCard, a property name therefore MUST NOT be prefixed by a group name.

The "GROUP" parameter MUST NOT be used in vCard; as per RFC6350, it is merely registered to reserve the parameter, avoiding collisions. Formal registration of the "GROUP" parameter is described in Section 7.1.

3.3.1.2.1. Group Conversion Rules

In jCard, the parameter's value is a single opaque string. Conversion rules are as follows:

o From vCard to jCard, the group construct (see RFC6350, 

  Section 3.3) is removed.  In its place, the "group" parameter is
  used.  Its value is a string corresponding to the group name,
  which is case insensitive both in vCard and jCard.  The name's
  case SHOULD be converted into lowercase.

o When converting from jCard to vCard, the value of the "group" 

  parameter followed by a dot is prefixed to the property name, and
  the "group" parameter is discarded.  The "GROUP" parameter MUST
  NOT appear in the resulting vCard.  Following the recommendations
  in RFC6350, the name's case SHOULD be converted into uppercase.

Example:

CONTACT.FN:Mr. John Q. Public\, Esq.

is equivalent to:

[ "fn", { "group": "CONTACT" }, "text", "Mr. John Q. Public, Esq." ]

Structured Property Values

The vCard specification defines properties with structured values, for example, "GENDER" or "ADR". In vCard, a structured text value consists of one or multiple text components, delimited by the SEMICOLON character. Its equivalent in jCard is a structured property value, which is an array containing one element for each text component, with empty/missing text components represented by zero-length strings.

vCard Example:

ADR:;;123 Main Street;Any Town;CA;91921-1234;U.S.A.

jCard Example:

["adr", {}, "text", 

 [
 "", "", "123 Main Street",
 "Any Town", "CA", "91921-1234", "U.S.A."
 ]

]

Some vCard properties, for example, ADR, also allow a structured value element that itself has multiple values. In this case, the element of the array describing the structured value is itself an array with one element for each of the component's multiple values.

vCard Example:

ADR:;;My Street,Left Side,Second Shack;Hometown;PA;18252;U.S.A.

jCard Example:

["adr", {}, "text", 

 [
 "", "",
 ["My Street", "Left Side", "Second Shack"],
 "Hometown", "PA", "18252", "U.S.A."
 ]

]

In both cases, the array element values MUST have the primitive type that matches the jCard type identifier. In RFC6350, there are only structured text values and thus only JSON strings are used. For example, extensions may define structured number or boolean values, where JSON number or boolean types MUST be used.

Although it is allowed for a structured property value to hold just one component, it is RECOMMENDED to represent it as a single text value instead, omitting the array completely. Nevertheless, a simple implementation MAY choose to retain the array, with a single text value as its element.

Similarly, structured values that consist of two text components with one being optional (for example, "GENDER") can be represented as a single text value. Therefore, parsers of jCard data SHOULD check even known property values for structured information by considering the JSON data type of the value, which can be an array or a primitive value. This is especially important for languages where accessing array members is done by the same construct as accessing characters of a string.

Examples:

["gender", {}, "text", ["F", "grrrl"] ], ["gender", {}, "text", "M" ]

Per Section 6.3.1 of RFC6350, the component separator MUST be specified even if the component value is missing. Similarly, the jCard array containing the structured data MUST contain all required elements, even if they are empty.

vCard Example:

ADR;LABEL="123 Maple Ave\nSuite 901\nVancouver BC\nA1B 2C9\nCan 

ada":;;;;;;

jCard Example:

["adr", 

{"label":"123 Maple Ave\nSuite 901\nVancouver BC\nA1B 2C9\nCanada"},
"text",
["", "", "", "", "", "", ""]

]

Parameters (RFC 6350, Section 5)

Property parameters are represented as a JSON object where each key- value pair represents the vCard parameter name and its value. The name of the parameter MUST be in lowercase; the original case of the parameter value MUST be preserved. For example, the "LANGUAGE" property parameter is represented in jCard by the "language" key. Any new vCard parameters added in the future will be converted in the same way.

Example:

["role", { "language": "tr" }, "text", "roca"],

VALUE Parameter

vCard defines a "VALUE" property parameter (Section 5.2 of RFC6350). This property parameter MUST NOT be added to the parameters object. Instead, the value type is signaled through the type identifier in the third element of the array describing the property. When converting a property from vCard to jCard, the value type is determined as follows:

1. If the property has a "VALUE" parameter, that parameter's value 

   is used as the value type.

2. If the property has no "VALUE" parameter but has a default value 

   type, the default value type is used.

3. If the property has no "VALUE" parameter and has no default value 

   type, "unknown" is used.

Converting from jCard into vCard is done as follows:

1. If the property's value type is "unknown", no "VALUE" parameter 

   is included.

2. If the property's value type is the default type for that 

   property, no "VALUE" parameter is included.

3. Otherwise, a "VALUE" parameter is included, and the value type is 

   used as the parameter value.

See Section 5 for information on handling unknown value types.

Multi-Valued Parameters

In RFC6350, some parameters allow using a comma-separated list of values. To ease processing in jCard, the value for such parameters 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, although a more simple implementation might prefer an array with one string element. An example of such a parameter is the vCard "SORT-AS" parameter; more such parameters may be added in extensions.

The vCard specification requires encapsulation between DQUOTE characters if a parameter value contains a colon, a semicolon, or a comma. These extra DQUOTE characters do not belong to the actual parameter value and hence are not included when the parameter is converted to jCard.

Example:

["vcard", 

 [
   ["version", {}, "text", "4.0"],
   ["n",
    { "sort-as": ["Harten", "Rene"] },
    "text",
    ["van der Harten", "Rene", "J.", "Sir", "R.D.O.N."]
   ],
   ["fn", {}, "text", "Rene van der Harten"]
   ...
 ]

]

Values (RFC 6350, Section 4)

The following subsections specify how vCard property value data types (which are defined in Section 4 of RFC6350) are represented in jCard.

Text (RFC 6350, Section 4.1)

Description: vCard "TEXT" property values are represented by a 

  property with the type identifier "text".  The value elements are
  JSON strings.  For details on structured text values, see
  Section 3.3.1.3.

Example:

["kind", {}, "text", "group"]

URI (RFC 6350, Section 4.2)

Description: vCard "URI" property values are represented by a 

  property with the type identifier "uri".  The value elements are
  JSON strings.

Example:

["source", {}, "uri", "ldap://ldap.example.com/cn=babs%20jensen"]

Date (RFC 6350, Section 4.3.1)

Description: vCard "DATE" property values are represented by a 

  property with the type identifier "date".  The value elements are
  JSON strings with the same date value specified by RFC6350, but
  represented using the extended format specified in
  [ISO.8601.2004], Section 4.1.2.  If the complete representation is
  not used, the same date format restrictions regarding reduced
  accuracy, truncated representation, and expanded representation
  noted in RFC6350, Section 4.3.1 apply.  Whenever the extended
  format is not applicable, the basic format MUST be used.

ABNF syntax:

date-complete = year "-" month "-" day ;YYYY-MM-DD

date-noreduc = date-complete 

          / "--" month "-" day ; --MM-DD
          / "---" day          ; ---DDD

date = date-noreduc 

  / year; YYYY
  / year "-" month ; YYYY-MM
  / "--" month     ; --MM

Examples:

["bday", {}, "date", "1985-04-12"], ["bday", {}, "date", "1985-04"], ["bday", {}, "date", "1985"], ["bday", {}, "date", "--04-12"], ["bday", {}, "date", "---12"]

This table contains possible conversions between the vCard DATE format and jCard date. This information is just an example and not a formal specification of the syntax. The specification can be found in [ISO.8601.2000] and [ISO.8601.2004]. 

               +-----------+----------+------------+
               |           | vCard    | jCard      |
               +-----------+----------+------------+
               | Complete  | 19850412 | 1985-04-12 |
               |           |          |            |
               | Reduced   | 1985-04  | 1985-04    |
               |           |          |            |
               | Reduced   | 1985     | 1985       |
               |           |          |            |
               | Truncated | --0412   | --04-12    |
               |           |          |            |
               | Truncated | --04     | --04       |
               |           |          |            |
               | Truncated | ---12    | ---12      |
               +-----------+----------+------------+

Time (RFC 6350, Section 4.3.2)

Description: vCard "TIME" property values are represented by a 

  property with the type identifier "time".  The value elements are
  JSON strings with the same time value specified by RFC6350, but
  represented using the extended format specified in
  [ISO.8601.2004], Section 4.2.  If the complete representation is
  not used, the same time format restrictions regarding reduced
  accuracy, decimal fraction, and truncated representation noted in
  RFC6350, Section 4.3.2 apply.  Whenever the extended format is
  not applicable, the basic format MUST be used.  The seconds value
  of 60 MUST only be used to account for positive "leap" seconds,
  and the midnight hour is always represented by 00, never 24.
  Fractions of a second are not supported by this format.  In jCard,
  UTC offsets are permitted within a time value; note that this
  differs from jCal [JCAL], where they are not permitted.

ABNF syntax:

time-notrunc = hour [":" minute [":" second]] [zone]

time = time-notrunc 

  / "-" minute ":" second [zone]; -mm:ss
  / "-" minute [zone]; -mm
  / "--" second [zone]; --ss

Examples:

["x-time-local", {}, "time", "12:30:00"], ["x-time-utc", {}, "time", "12:30:00Z"], ["x-time-offset", {}, "time", "12:30:00-08:00"], ["x-time-reduced", {}, "time", "23"], ["x-time-truncated", {}, "time", "-30"]

This table contains possible conversions between the vCard TIME format and jCard time. This information is just an example and not a formal specification of the syntax. The specification can be found in [ISO.8601.2000] and [ISO.8601.2004]. 

                 +-----------+--------+----------+
                 |           | vCard  | jCard    |
                 +-----------+--------+----------+
                 | Complete  | 232050 | 23:20:50 |
                 |           |        |          |
                 | Reduced   | 2320   | 23:20    |
                 |           |        |          |
                 | Reduced   | 23     | 23       |
                 |           |        |          |
                 | Truncated | -2050  | -20:50   |
                 |           |        |          |
                 | Truncated | -20    | -20      |
                 |           |        |          |
                 | Truncated | --50   | --50     |
                 +-----------+--------+----------+

Also, all combinations may have any zone designator appended, as in the complete representation.

Date-Time (RFC 6350, Section 4.3.3)

Description: vCard "DATE-TIME" property values are represented by a 

  property with the type identifier "date-time".  The value elements
  are JSON strings with the same date value specified by RFC6350,
  but represented using the extended format specified in
  [ISO.8601.2004], Section 4.3.  If the complete representation is

  not used, the same date and time format restrictions noted in
  Sections 3.5.3 and 3.5.4 apply.  Just as described in RFC6350,
  truncation of the date part is permitted.

Example:

["anniversary", {}, "date-time", "2013-02-14T12:30:00"], ["anniversary", {}, "date-time", "2013-01-10T19:00:00Z"], ["anniversary", {}, "date-time", "2013-08-15T09:45:00+01:00"], ["anniversary", {}, "date-time", "---15T09:45:00+01:00"]

This table contains possible conversions between the vCard DATE-TIME format and jCard date-time. This information is just an example and not a formal specification of the syntax. The specification can be found in [ISO.8601.2000] and [ISO.8601.2004].

+----------------+----------------------+---------------------------+ | Representation | vCard | jCard | +----------------+----------------------+---------------------------+ | Complete | 19850412T232050 | 1985-04-12T23:20:50 | | | | | | Complete | 19850412T232050Z | 1985-04-12T23:20:50Z | | | | | | Complete | 19850412T232050+0400 | 1985-04-12T23:20:50+04:00 | | | | | | Complete | 19850412T232050+04 | 1985-04-12T23:20:50+04 | | | | | | Reduced | 19850412T2320 | 1985-04-12T23:20 | | | | | | Reduced | 19850412T23 | 1985-04-12T23 | | | | | | Truncated and | --0412T2320 | --04-12T23:20 | | Reduced | | | | | | | | Truncated and | --04T2320 | --04T23:20 | | Reduced | | | | | | | | Truncated and | ---12T2320 | ---12T23:20 | | Reduced | | | | | | | | Truncated and | --0412T2320 | --04-12T23:20 | | Reduced | | | | | | | | Truncated and | --04T23 | --04T23 | | Reduced | | | +----------------+----------------------+---------------------------+

As specified in [ISO.8601.2000], the lower-order components may not be omitted in the date part (reduced accuracy) and the higher-order components may not be omitted in the time part (truncation). Also, all combinations may have any zone designator appended, as in the complete representation.

Date and/or Time (RFC 6350, Section 4.3.4)

Description: vCard "DATE-AND-OR-TIME" property values are 

  represented by a property with the type identifier "date-and-or-
  time".  The value elements are either a date-time (Section 3.5.5),
  a date (Section 3.5.3), or a time (Section 3.5.4) value.  Just as
  described in Section 4.3.4 of RFC6350, a stand-alone time value
  MUST always be preceded by a "T".

Example:

["bday", {}, "date-and-or-time", "2013-02-14T12:30:00"], ["bday", {}, "date-and-or-time", "---22T14:00"] ["bday", {}, "date-and-or-time", "1985"], ["bday", {}, "date-and-or-time", "T12:30"]

Timestamp (RFC 6350, Section 4.3.5)

Description: vCard "TIMESTAMP" property values are represented by a 

  property with the type identifier "timestamp".  The value elements
  are JSON strings with the same timestamp value specified by
  RFC6350, but represented using the extended format and complete
  representation specified in [ISO.8601.2004], Section 4.3.2.

Example:

["rev", {}, "timestamp", "2013-02-14T12:30:00"], ["rev", {}, "timestamp", "2013-02-14T12:30:00Z"], ["rev", {}, "timestamp", "2013-02-14T12:30:00-05"], ["rev", {}, "timestamp", "2013-02-14T12:30:00-05:00"]

This table contains possible conversions between the vCard TIMESTAMP format and jCard timestamp. This information is just an example and not a formal specification of the syntax. The specification can be found in [ISO.8601.2000] and [ISO.8601.2004].

+----------------+----------------------+---------------------------+ | Representation | vCard | jCard | +----------------+----------------------+---------------------------+ | Complete | 19850412T232050 | 1985-04-12T23:20:50 | | | | | | Complete | 19850412T232050Z | 1985-04-12T23:20:50Z | | | | | | Complete | 19850412T232050+0400 | 1985-04-12T23:20:50+04:00 | | | | | | Complete | 19850412T232050+04 | 1985-04-12T23:20:50+04 | +----------------+----------------------+---------------------------+

Boolean (RFC 6350, Section 4.4)

Description: vCard "BOOLEAN" property values are represented by a 

  property with the type identifier "boolean".  The value element is
  a JSON boolean value.

Example:

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

Integer (RFC 6350, Section 4.5)

Description: vCard "INTEGER" property values are represented by a 

  property with the type identifier "integer".  The value elements
  are JSON primitive number values.

Examples:

["x-karma-points", {}, "integer", 42]

JSON allows decimals (e.g., 3.14) and exponents (e.g., 2e10) to be used in numeric values. jCard does not prohibit this for "integer" property values. However, since vCard does not support decimals or exponents in integers, any decimals and exponents MUST be eliminated when converting an "integer" value type property from jCard to vCard.

3.5.10. Float (RFC 6350, Section 4.6)

Description: vCard "FLOAT" property values are represented by a 

  property with the type identifier "float".  The value elements are
  JSON primitive number values.

Example:

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

JSON allows exponents (e.g., 2e10) to be used in numeric values. jCard does not prohibit this for "float" property values. However, since vCard does not support exponents in floats, any exponents MUST be eliminated when converting a "float" value type property from jCard to vCard.

3.5.11. UTC Offset (RFC 6350, Section 4.7)

Description: vCard "UTC-OFFSET" property values are represented by a 

  property with the type identifier "utc-offset".  The value
  elements are JSON strings with the same UTC offset value specified
  by RFC6350, 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:

// Note: RFC6350 mentions use of utc-offset // for the TZ property as NOT RECOMMENDED ["tz", {}, "utc-offset", "-05:00"]

3.5.12. Language Tag (RFC 6350, Section 4.8)

Description: vCard "LANGUAGE-TAG" property values are represented by 

  a property with the type identifier "language-tag".  The value
  elements are JSON strings containing a single language-tag, as
  defined in RFC5646.

Example:

["lang", {}, "language-tag", "de"]

Extensions (RFC 6350, Section 6.10)

vCard 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 vCard extension, but in lowercase. For example, the "X-FOO" property in vCard turns into the "x-foo" jCard property. See Section 5 for how to deal with default values for unrecognized extension properties or property parameters.

Converting from jCard into vCard

When converting property and property parameter values, the names SHOULD be converted to uppercase. Although vCard names are case insensitive, common practice is to keep them all uppercase following the actual definitions in RFC6350.

Character escaping and line folding MUST be applied to the resulting vCard data as required by RFC6350 and RFC6868.

When converting to vCard, the "VALUE" parameter MUST be added to properties whose default value type is unknown but do not have a jCard type identifier "unknown". The "VALUE" parameter MAY be omitted for properties using the default value type. The "VALUE" parameter MUST be omitted for properties that have the jCard type identifier "unknown".

Handling Unrecognized Properties or Parameters

In vCard, properties can have one or more value types as specified by their definition, with one of those values being defined as the default. When a property uses its default value type, the "VALUE" property parameter does not need to be specified on the property. For example, "BDAY"'s default value type is "date-and-or-time", so "VALUE=date-and-or-time" need not be set as a property parameter. However, "BDAY" also allows a "text" value to be specified, and if that is used, "VALUE=text" has to be set as a property parameter.

When new properties are defined or "X-" properties used, a vCard-to- jCard converter might not recognize them, and not know what the appropriate default value types are, yet it needs to be able to preserve the values. A similar issue arises for unrecognized property parameters.

In jCard, a new "unknown" property value type is introduced. Its purpose is to allow preserving unknown property values when round- tripping between jCard and vCard. To avoid collisions, this specification reserves the "UNKNOWN" property value type in vCard. It MUST NOT be used in any vCard as specified by RFC6350, nor any extensions to it. The type is hence registered to the "vCard Value Data Types" registry; see Section 7.2.

Converting vCard into jCard

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

To correctly implement this format, it's critical to use the value type "unknown" when the default value type is not known. If this requirement is ignored and, for example, "text" is used, additional escaping may occur that breaks round-tripping values.

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.

Converting jCard into vCard

In jCard, the value type is always explicitly specified. It is converted to vCard using the vCard "VALUE" parameter, except in the following two cases:

o If the value type specified in jCard matches the default value 

  type in vCard, the "VALUE" parameter MAY be omitted.

o If the value type specified in jCard is set to "unknown", the 

  "VALUE" parameter MUST NOT be specified.  The value MUST be taken
  over in vCard without processing.

Examples

The following is an example of an unrecognized vCard property (that uses a "URI" value as its default), and the equivalent jCard representation of that property.

vCard:

X-COMPLAINT-URI:mailto:[email protected]

jCard:

["x-complaint-uri", {}, "unknown", "mailto:[email protected]"]

The following is an example of how to cope with jCard data where the parser was unable to identify the value type. Note how the "unknown" value type is not added to the vCard data, and escaping, aside from standard JSON string escaping, is not processed.

jCard:

["x-coffee-data", {}, "unknown", "Stenophylla;Guinea\\,Africa"]

vCard:

X-COFFEE-DATA:Stenophylla;Guinea\,Africa

There are no standard properties in RFC6350 that have a default type of integer. Consequently, this example uses the following extended property that we treat as having a default type (namely, integer) known to the parser in order to illustrate how a property with a known default type would be transformed.

jCard:

["x-karma-points", {}, "integer", 95]

vCard:

X-KARMA-POINTS:95

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

vCard:

GENDER;X-PROBABILITY=0.8:M

jCard:

["gender", { "x-probability": "0.8" }, "text", "M"]

Security Considerations

This specification defines how vCard data can be "translated" between two different data formats -- the original text format and JSON -- with a one-to-one mapping to ensure all the semantic data in one format (properties, parameters, and values) are preserved in the other. It does not change the semantic meaning of the underlying data itself, or impose or remove any security considerations that apply to the underlying data.

The use of JSON as a format does have its own inherent security risks as discussed in Section 7 of RFC4627. Even though JSON is considered a safe subset of JavaScript, it should be kept in mind that a flaw in the parser for JSON data could still impose a threat that doesn't arise with conventional vCard data.

With this in mind when using jCard, the parser for JSON data should be aware of the security implications. For example, the use of JavaScript's eval() function is only allowed using the regular expression in Section 6 of RFC4627. A native parser with full awareness of the JSON format should be preferred.

In addition, it is expected that this new format will result in vCard data being more widely disseminated (e.g., with use in web applications rather than just dedicated "contact managers").

In all cases, application developers have to conform to the semantics of the vCard data as defined by RFC6350 and associated extensions, and all of the security considerations described in Section 9 of RFC6350, or any associated extensions, are applicable.

IANA Considerations

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

Type name: application

Subtype name: vcard+json

Required parameters: none

Optional parameters: "version", as defined for the text/vcard media 

  type in RFC6350, Section 10.1.

Encoding considerations: Same as encoding considerations of 

  application/json as specified in RFC4627, Section 6.

Security considerations: See Section 6.

Interoperability considerations: This media type provides an 

  alternative format for vCard data based on JSON.

Published specification: This specification.

Applications which use this media type: Applications that currently 

  make use of the text/vcard media type can use this as an
  alternative.  Similarly, applications that use the application/
  json media type to transfer directory data can use this to further
  specify the content.

Fragment identifier considerations: N/A

Additional information: 

  Deprecated alias names for this type:  N/A

  Magic number(s):  N/A

  File extension(s):  N/A

  Macintosh file type code(s):  N/A

Person & email address to contact for further information: 

  [email protected]

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

GROUP vCard Parameter

IANA has added the "GROUP" parameter to the "vCard Parameters" registry, initialized in Section 10.3.2 of RFC6350. Usage of the "GROUP" parameter is further described in Section 3.3.1.2 of this document.

Namespace: <empty>

Parameter name: GROUP

Purpose: To simplify the jCard format.

Description: The "GROUP" parameter is reserved for the exclusive use 

  of the jCard format described in this document.  It MUST NOT be
  used in plain vCard RFC6350, nor in xCard RFC6351.

Format definition: When converting from jCard to vCard, the value of 

  the "GROUP" parameter is used as part of the property name.
  Therefore, the value is restricted to characters allowed in
  property names, namely ALPHA, DIGIT, and "-" characters.  When
  used, the "GROUP" parameter MUST NOT be empty.

Example: As this registration serves as a reservation of the "GROUP" 

  parameter so that it is not used in vCard, there is no applicable
  vCard example.  Examples of its usage in jCard can be found in
  this document.

UNKNOWN vCard Value Data Type

IANA has added the "UNKNOWN" value data type to the "vCard Value Data Types" registry, initialized in Section 10.3.3 of RFC6350. Usage of the "UNKNOWN" type is further described in Section 5 of this document.

Value name: UNKNOWN

Purpose: To allow preserving property values whose default value 

  type is not known during round-tripping between jCard and vCard.

Format definition: (Not applicable)

Description: The "UNKNOWN" value data type is reserved for the 

  exclusive use of the jCard format.  It MUST NOT be used in plain
  vCard RFC6350.

Example: As this registration serves as a reservation of the 

  "UNKNOWN" type so that it is not used in vCard, there is no
  applicable vCard example.  Examples of its usage in jCard can be
  found in this document.

Acknowledgments

The author would like to thank the following for their valuable contributions: Cyrus Daboo, Mike Douglass, William Gill, Erwin Rehme, Dave Thewlis, Simon Perreault, Michael Angstadt, Peter Saint-Andre, Bert Greevenbosch, and Javier Godoy. This specification originated from the work of the XML-JSON technical committee of the Calendaring and Scheduling Consortium.

References

Normative References

[ISO.8601.2000] 

          International Organization for Standardization, "Data
          elements and interchange formats -- Information
          interchange -- Representation of dates and times", ISO
          8601, December 2000.

[ISO.8601.2004] 

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

RFC2119 Bradner, S., "Key words for use in RFCs to Indicate 

          Requirement Levels", BCP 14, RFC 2119, March 1997.

RFC4627 Crockford, D., "The application/json Media Type for 

          JavaScript Object Notation (JSON)", RFC 4627, July 2006.

RFC5234 Crocker, D. and P. Overell, "Augmented BNF for Syntax 

          Specifications: ABNF", STD 68, RFC 5234, January 2008.

RFC5646 Phillips, A. and M. Davis, "Tags for Identifying 

          Languages", BCP 47, RFC 5646, September 2009.

RFC6350 Perreault, S., "vCard Format Specification", RFC 6350, 

          August 2011.

RFC6868 Daboo, C., "Parameter Value Encoding in iCalendar and 

          vCard", RFC 6868, February 2013.

Informative References

[JCAL] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON 

          format for iCalendar", Work in Progress, December 2013.

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.

RFC6351 Perreault, S., "xCard: vCard XML Representation", RFC 

          6351, August 2011.

[calconnect-artifacts] 

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

Appendix A. ABNF Syntax

Below is the ABNF syntax as per RFC5234 for vCard in JSON. ABNF symbols not described here are taken from RFC4627. The syntax is non-normative and given for reference only.

The numeric section numbers given in the comments refer to sections in RFC6350. Additional semantic restrictions apply, especially regarding the allowed properties and subcomponents per component. Details on these restrictions can be found in this document and RFC6350.

Additional ABNF syntax may be available on the Internet at [calconnect-artifacts].

A jCard object uses the name "vcard" and a properties array.
Restrictions to which properties may be specified are to
be taken from RFC 6350.

jcardobject = begin-array 

             DQUOTE component-name DQUOTE value-separator
             properties-array
             end-array
A jCard 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
          property-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 = simple-prop-value / structured-prop-value simple-prop-value = string / number / true / false structured-prop-value = 

   begin-array
   [ structured-element *(value-separator structured-element) ]
   end-array
Each structured element may have multiple values if
semantically allowed.

structured-element = simple-prop-value / structured-multi-prop

structured-multi-prop = 

   begin-array
   [ simple-prop-value *(value-separator simple-prop-value) ]
   end-array
The jCard params-object is a JSON object that 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 / param-multi param-multi = begin-array 

             [ string *(value-separator string) ]
             end-array
The type MUST be a valid type as described by this document. New
value types can be added by extensions.

type-name = "text" / "uri" / "date" / "time" / "date-time" / 

           "boolean" / "integer" / "float" / "utc-offset" /
           "language-tag" / x-type
Property, parameter, and type names MUST be lowercase. Additional
semantic restrictions apply as described by this document and
RFC 6350.

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 an example of a vCard object with its jCard representation.

B.1. Example: vCard of the Author of RFC 6350

B.1.1. vCard Data

BEGIN:VCARD VERSION:4.0 FN:Simon Perreault N:Perreault;Simon;;;ing. jr,M.Sc. BDAY:--0203 ANNIVERSARY:20090808T1430-0500 GENDER:M LANG;PREF=1:fr

LANG;PREF=2:en ORG;TYPE=work:Viagenie ADR;TYPE=work:;Suite D2-630;2875 Laurier; 

Quebec;QC;G1V 2M2;Canada

TEL;VALUE=uri;TYPE="work,voice";PREF=1:tel:+1-418-656-9254;ext=102 TEL;VALUE=uri;TYPE="work,cell,voice,video,text":tel:+1-418-262-6501 EMAIL;TYPE=work:[email protected] GEO;TYPE=work:geo:46.772673,-71.282945 KEY;TYPE=work;VALUE=uri: 

http://www.viagenie.ca/simon.perreault/simon.asc

TZ:-0500 URL;TYPE=home:http://nomis80.org END:VCARD

B.1.2. jCard Data

["vcard", 

 [
   ["version", {}, "text", "4.0"],
   ["fn", {}, "text", "Simon Perreault"],
   ["n",
     {},
     "text",
     ["Perreault", "Simon", "", "", ["ing. jr", "M.Sc."]]
   ],
   ["bday", {}, "date-and-or-time", "--02-03"],
   ["anniversary",
     {},
     "date-and-or-time",
     "2009-08-08T14:30:00-05:00"
   ],
   ["gender", {}, "text", "M"],
   ["lang", { "pref": "1" }, "language-tag", "fr"],
   ["lang", { "pref": "2" }, "language-tag", "en"],
   ["org", { "type": "work" }, "text", "Viagenie"],
   ["adr",
      { "type": "work" },
      "text",
      [
       "",
       "Suite D2-630",
       "2875 Laurier",
       "Quebec",
       "QC",
       "G1V 2M2",
       "Canada"
      ]
   ],

   ["tel",
     { "type": ["work", "voice"], "pref": "1" },
     "uri",
     "tel:+1-418-656-9254;ext=102"
   ],
   ["tel",
     { "type": ["work", "cell", "voice", "video", "text"] },
     "uri",
     "tel:+1-418-262-6501"
   ],
   ["email",
     { "type": "work" },
     "text",
     "[email protected]"
   ],
   ["geo", { "type": "work" }, "uri", "geo:46.772673,-71.282945"],
   ["key",
     { "type": "work" },
     "uri",
     "http://www.viagenie.ca/simon.perreault/simon.asc"
   ],
   ["tz", {}, "utc-offset", "-05:00"],
   ["url", { "type": "home" }, "uri", "http://nomis80.org"]
 ]

]

Author's Address

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

EMail: [email protected] URI: http://www.mozilla.org/

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