Internet DRAFT - draft-kewisch-vcard-in-json
draft-kewisch-vcard-in-json
Network Working Group P. Kewisch
Internet-Draft Mozilla
Intended status: Standards Track March 18, 2013
Expires: September 19, 2013
jCard: The JSON format for vCard
draft-kewisch-vcard-in-json-01
Abstract
This specification defines "jCard", a JSON format for vCard data.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 19, 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
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described in the Simplified BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Converting from vCard to jCard . . . . . . . . . . . . . . . . 4
3.1. Pre-processing . . . . . . . . . . . . . . . . . . . . . . 4
3.2. vCard Stream . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Properties (RFC6350 section 6) . . . . . . . . . . . . . . 5
3.3.1. Special Cases for Properties . . . . . . . . . . . . . 6
3.3.1.1. Multi-valued Properties . . . . . . . . . . . . . 6
3.3.1.2. Grouping of Properties . . . . . . . . . . . . . . 7
3.4. Parameters (RFC6350 section 5) . . . . . . . . . . . . . . 7
3.4.1. VALUE parameter . . . . . . . . . . . . . . . . . . . 7
3.4.2. Multi-value Parameters . . . . . . . . . . . . . . . . 8
3.5. Values (RFC6350 section 4) . . . . . . . . . . . . . . . . 8
3.5.1. Text (RFC6350 section 4.1) . . . . . . . . . . . . . . 8
3.5.2. URI (RFC6350 section 4.2) . . . . . . . . . . . . . . 9
3.5.3. Date (RFC6350 section 4.3.1) . . . . . . . . . . . . . 9
3.5.4. Time (RFC6350 section 4.3.2) . . . . . . . . . . . . . 10
3.5.5. Date-Time (RFC6350 section 4.3.3) . . . . . . . . . . 10
3.5.6. Date and/or Time (RFC6350 section 4.3.4) . . . . . . . 11
3.5.7. Timestamp (RFC6350 section 4.3.5) . . . . . . . . . . 11
3.5.8. Boolean (RFC6350 section 4.4) . . . . . . . . . . . . 11
3.5.9. Integer (RFC6350 section 4.5) . . . . . . . . . . . . 11
3.5.10. Float (RFC6350 section 4.6) . . . . . . . . . . . . . 12
3.5.11. UTC Offset (RFC6350 section 4.7) . . . . . . . . . . . 12
3.5.12. Language Tag (RFC6350 section 4.8) . . . . . . . . . . 12
3.6. Extensions (RFC6350 section 6.10) . . . . . . . . . . . . 13
4. Converting from jCard into vCard . . . . . . . . . . . . . . . 13
5. Handling Unrecognized Properties or Parameters . . . . . . . . 13
6. Conversion of Date and Time Related Data Types . . . . . . . . 15
6.1. Conversion from jCard to vCard . . . . . . . . . . . . . . 15
6.2. Conversion from vCard to jCard . . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . . 18
Appendix A. ABNF Schema . . . . . . . . . . . . . . . . . . . . . 18
Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 20
B.1. Example: vCard of the author of RFC6350 . . . . . . . . . 20
B.1.1. vCard Data . . . . . . . . . . . . . . . . . . . . . . 20
B.1.2. jCard Data . . . . . . . . . . . . . . . . . . . . . . 21
Appendix C. Open Issues (to be removed prior to publication
as an RFC) . . . . . . . . . . . . . . . . . . . . . 22
Appendix D. Change History (to be removed prior to
publication as an RFC) . . . . . . . . . . . . . . . 23
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1. Introduction
The vCard data format [RFC6350] has gone through multiple revisions,
most recently vCard 4. The goal followed by this format is the
capture and exchange of information normally stored within an address
book or directory application. As certain similarities to the
iCalendar data format [RFC5545] exist it makes sense to define a
JSON-based data format for vCards that is similar to the jCal format
defined in [I-D.kewisch-et-al-icalendar-in-json].
The purpose of this specification is to define "jCard", a JSON format
for vCard data. One main advantage to using a JSON-based format as
defined in [RFC4627] 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
[I-D.kewisch-et-al-icalendar-in-json] 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, with the exception of those which have
default values.
Ordering of elements will not necessarily be preserved.
Preserve the semantics of the vCard data. While a simple consumer
can 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.
Ability to handle many extensions to the underlying vCard
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 jCard 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].
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
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for compactness.
3. Converting from vCard to jCard
This section describes how vCard data is converted to jCard using a
simple mapping between the vCard data model and JSON elements.
3.1. Pre-processing
vCard 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 3.2 of [RFC6350]. Prior to
converting vCard data into jCard all folded lines MUST be unfolded.
vCard data uses an "escape" character sequence for text values and
property parameter values. When such text elements are converted
into jCard the escaping MUST be removed. See Section 3.4 of
[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 complete representation, extended format of
[ISO.8601.2004].
3.2. vCard Stream
In certain cases it makes sense to group a sequence of vcard objects
into a stream of objects. While the vCard 4 standard doesn't define
a stream of vcard objects, having one makes it easier to identify
multiple jCard objects and also ensures compatibility to jCal. A
jCard stream is identified by an array, where the first element is
the string "vcardstream". Subsequent elements are vCard objects
represented as described in this document.
In the typical case where there is only one vCard object,
encapsulation inside a "vcardstream" array MAY be omitted.
A vCard stream can contain one or more vCard objects. Each vCard
object, delimited by "BEGIN:VCARD" and "END:VCARD", is represented in
JSON as a fixed length array with two elements:
1. The string "vcard"
2. An array of jCard properties
The representation of a vCard object in JSON will be named "vcard
component" throughout this document.
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Example:
["vcardstream",
["vcard",
[ /* properties */ ]
],
["vcard",
[ /* properties */ ]
],
...
]
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".
vCard objects are delimited by the general properties "BEGIN" and
"END" with the fixed value "VCARD" as defined in Section 6.1.1 and
6.1.2 of [RFC6350]. In addition, the vCard format is versioned,
therefore the "version" property is mandatory. To comply with
Section 6.7.9 of [RFC6350], the value of the version property MUST be
"4.0".
3.3. Properties (RFC6350 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-value 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 string, but in lowercase.
2. An object containing the parameters as described in Section 3.4.
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 3.3.1.1 there can be any number of additional elements.
The array describing the property can then be inserted into the array
designated for properties in the "vcard" component.
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Example:
["vcard",
[
["version", {}, "text", "4.0"],
["fn", {}, "text", "John Doe"],
["gender", {}, "text", "M"],
...
],
]
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 3.4.
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.
3.3.1. Special Cases for Properties
This section describes some properties that have special handling
when converting to jCard.
3.3.1.1. Multi-valued Properties
Various vCard properties defined in [RFC6350], 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.
Example:
["vcard",
[
["categories", {}, "text", "computers", "cameras"],
...
],
...
]
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3.3.1.2. Grouping of Properties
[RFC6350] Section 3.3 defines a grouping construct that is used to
group related properties together. In jCard, each grouped property
appears as a separate property containing the group name and property
name, separated by a "." character. This was done to maintain
compatibilty of array elements with
[I-D.kewisch-et-al-icalendar-in-json].
Example:
["vcard",
[
["groupname.email", {}, "text", "johndoe@example.org"],
...
],
...
]
3.4. Parameters (RFC6350 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 "LANG" property
parameter is represented in jCard by the "lang" key. Any new vCard
parameters added in the future will be converted in the same way.
Example:
["vcard",
[
["role", { "lang": "tr" }, "text", "roca"],
...
],
...
]
3.4.1. 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 always explicitly
mentioned in the third element of the array describing the property.
Thus, when converting from vCard to jCard, any "VALUE" property
parameters are skipped. When converting from jCard into vCard, the
appropriate "VALUE" property parameter MUST be included in the vCard
property if the value type is not the default value type for that
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property.
3.4.2. Multi-value Parameters
In [RFC6350], some parameters allow using a COMMA-separated list of
values. To ease processing in jCard, the value to 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, but an array with one
element MAY also be used. An example for a such parameter is the
vCard "SORT-AS" parameter, more such parameters may be added in
extensions.
DQUOTE characters used to encapsulate the separated values MUST NOT
be added to the jCard parameter value.
Example 1:
["vcard",
[
["n",
{ "sort-as": ["Harten", "Rene"] },
"text",
"van der Harten;Rene,J.;Sir;R.D.O.N."
],
["fn", {}, "text", "Rene van der Harten"]
...
],
...
]
3.5. Values (RFC6350 section 4)
The type of a vCard value is explicitly mentioned in the third
element of the array describing a jCard property. The actual values
of the property can be found in the fourth and following elements of
the array.
3.5.1. Text (RFC6350 section 4.1)
Description: vCard "TEXT" property values are represented by a
property with the type identifier "text". The value elements are
JSON strings.
Example:
...
["kind", {}, "text", "group"],
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...
3.5.2. URI (RFC6350 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"],
...
3.5.3. Date (RFC6350 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
formatted using the [ISO.8601.2004] complete representation,
extended format. The same date format restrictions regarding
reduced accuracy, truncated representation and expanded
representation noted in [RFC6350] Section 4.1.2.3 apply. Whenever
the extended format is not applicable, the basic format is to be
used.
ABNF Schema:
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", "--0412"],
["bday", {}, "date", "---12"],
...
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3.5.4. Time (RFC6350 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
formatted using the [ISO.8601.2004] complete representation,
extended format. The same date 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 is to 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.
Contrary to [I-D.kewisch-et-al-icalendar-in-json], UTC offsets are
permitted within a time value.
ABNF Schema:
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", "12:30:00-0800"],
["x-time-reduced", "time", "23"],
["x-time-truncated", "time", "-30"],
...
3.5.5. Date-Time (RFC6350 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 formatted using the [ISO.8601.2004] complete representation,
extended format. The same restrictions with respect to leap
seconds, fractions of a second and UTC offsets as in Section 3.5.4
apply. Just as in [RFC6350], truncation of the date part is
permitted.
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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+0100"],
["anniversary", {}, "date-time", "---15T09:45:00+0100"],
...
3.5.6. Date and/or Time (RFC6350 section 4.3.4)
Description: jCard has no direct equivalent to vCard's "DATE-AND-OR-
TIME" property value data type. Instead, the specified date,
date-time or time format MUST be detected and the property MUST be
represented by a property with the detected type identifier. See
Section 6 for more information on how conversion between jCard and
vCard should be handled.
3.5.7. Timestamp (RFC6350 section 4.3.5)
Description: jCard has no direct equivalent to vCard's "TIMESTAMP"
property value data type. Instead, the specified complete date
and time of day combination MUST be represented by a property with
the "date-time" identifier. See Section 6 for more information on
how conversion between jCard and vCard should be handled.
3.5.8. Boolean (RFC6350 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],
...
3.5.9. Integer (RFC6350 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],
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...
3.5.10. Float (RFC6350 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],
...
3.5.11. UTC Offset (RFC6350 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 (RFC6350 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"],
..
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3.6. Extensions (RFC6350 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.
4. 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].
Backslash escaping and line folding MUST be applied to the resulting
vCard data as required by [RFC6350].
When converting to vCard, the VALUE parameter MUST be added to
properties whose default value type is unknown. The VALUE parameter
SHOULD NOT be added to properties using the default value type.
5. Handling Unrecognized Properties or Parameters
In vCard, properties have a default value type specified by their
definition, e.g. "BDAY"'s value type is "date-and-or-time", but it
can also be reset to a single "text" value. 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, a vCard to
jCard 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 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 string object. The content of that string is the unprocessed
value text.
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* 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 jCard into vCard:
* Since jCard always explicitly specifies the value type, it can
always be converted to vCard using the VALUE parameter.
* If the value type specified in jCard matches the default value
type in vCard, the VALUE parameter SHOULD be omitted.
Example: The following is an example of an unrecognized vCard
property (that uses an "URI" value as its default), and the
equivalent jCard representation of that property.
vCard:
X-COMPLAINT-URI:mailto:abuse@example.org
jCard:
...
["x-complaint-uri", {}, "text", "mailto:abuse@example.org"],
...
Example: The following is an example of a jCard property (where the
corresponding vCard property uses a "INTEGER" value as its default),
and the equivalent vCard representation of that property. It is
assumed that the parser has knowledge of the default data type for
the "x-karma-points" property.
jCard:
...
["x-karma-points", {}, "integer", 95],
...
vCard:
X-KARMA-POINTS:95
Example: 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.
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vCard:
GENDER;X-PROBABILITY=0.8:M
jCard:
...
["gender", { "x-probability": "0.8" }, "text", "M"],
...
6. Conversion of Date and Time Related Data Types
[RFC6350] defines the data types DATE, DATE-TIME, TIME, DATE-AND-OR-
TIME and TIMESTAMP, covering various aspects of dates and times. As
jCard is more "strongly typed", some of these types have been
consolidated. This section aims to aid conversion between jCard and
vCard and vice versa.
Regardless of the date/time related property converted, jCard and
vCard use different representations of the [ISO.8601.2004] format.
The date format MUST be adjusted during conversion.
6.1. Conversion from jCard to vCard
o If the property type of the jCard property matches the property's
default type, the VALUE parameter MUST NOT be added to the vCard
property.
o For property types "date-and-or-time" or "timestamp", the property
value MUST be converted to a permitted date and/or time format as
specified in [RFC6350] Section 4.3.4 and 4.3.5 and the VALUE
parameter MUST NOT be added to the vCard property. If a permitted
conversion cannot be done, the VALUE parameter must be added with
the closest available date/time format identifier.
o If the default type is unknown or the jCal property type does not
match the default type, the VALUE parameter MUST be specified.
6.2. Conversion from vCard to jCard
o If the parser knows the default type of the property and it is one
of "DATE", "DATE-TIME" or "TIME", the properties can be directly
converted following the guidelines of the respective format type
in this document.
o For the property type "date-and-or-time", the parser SHOULD detect
if it is handling either a date, a time, or a date-time and use
the respective format identifier in jCard.
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o For the property type "timestamp", the parser MUST use the format
type identifier "date-time" in the jCard property.
o If the (default) property type is unknown, the property value MUST
be treated as opaque text and the "text" format type identifier
MUST be used.
7. Security Considerations
For security considerations specific to calendar data, see Section 9
of [RFC6350]. Since this specification is a mapping from vCard, 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 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].
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 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.
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Person & email address to contact for further information:
vcarddav@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 author would like to thank the following for their valuable
contributions: Cyrus Daboo, Mike Douglass, 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
[I-D.kewisch-et-al-icalendar-in-json] Kewisch, P., Daboo, C., and M.
Douglass, "jCal: The JSON
format for iCalendar", draft-
kewisch-et-al-icalendar-in-
json-01 (work in progress),
January 2013.
[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.
[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.
[RFC5646] Phillips, A. and M. Davis,
"Tags for Identifying
Languages", BCP 47, RFC 5646,
September 2009.
[RFC6321] Daboo, C., Douglass, M., and
S. Lees, "xCal: The XML Format
for iCalendar", RFC 6321,
August 2011.
[RFC6350] Perreault, S., "vCard Format
Specification", RFC 6350,
August 2011.
10.2. Informative References
[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 vCard 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
[RFC6350]. 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
[RFC6350].
Additional schemas may be available on the internet at
[calconnect-artifacts].
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; A vCard Stream is an array with the first element being the
; string "vcardstream". All remaining elements are jcardobjects.
jcardstream = begin-array
DQUOTE "vcardstream" DQUOTE
*(value-separator jcardobject)
end-array
jcardobject = component
; A jCard object consists of the name string "vcard" and a properties
; array. Restrictions to which properties and may be specified are to
; be taken from RFC6350.
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
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 jCard 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 = "text" / "uri" / "date" / "time" / "date-time" /
"boolean" / "integer" / "float" / "utc-offset" /
"language-tag" / x-type
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; Property, parameter and type names MUST be lowercase. Additional
; semantic restrictions apply as described by this document and
; RFC6350.
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 RFC6350
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:simon.perreault@viagenie.ca
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
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B.1.2. jCard Data
["vcard",
[
["version", {}, "text", "4.0"],
["fn", {}, "text", "Simon Perreault"],
["n", {}, "text", "Perreault;Simon;;;ing. jr,M.Sc."],
["bday", {}, "date", "--02-03"],
["anniversary", {}, "date-time", "2009-08-08T14:30:00-0500"],
["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",
"simon.perreault@viagenie.ca"
],
["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"]
]
]
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Appendix C. Open Issues (to be removed prior to publication as an RFC)
o [RFC6350] doesn't define any kind of stream for multiple vcard
elements. For similarity with the jCal draft, I have added a
"vcardstream". Is this wanted and does the name fit? (Maybe
rather "jcardstream" ?)
o During conversion to jCard, I have dropped "date-and-or-time" and
"timestamp" formats, since they can equally be represented by the
formats "date", "time" and "date-time". I have added guidelines
to Section 6, but there may be some situations I am unaware of
that make dropping these formats impossible.
o This document defines in Section 3.3.1.2, that grouped properties
are not to be handled differently than normal properties. This
was done for compatibility with the jCal draft to make it easier
for a parser to support both jCal and jCard. Another option would
be to add a pseudo-property with the special type "group", the
property name being the group name and the property value being an
array of properties. Downside is that there is room for an extra
set of parameters in the group container that does not serialize
back to vCard.
o There is some open discussion on the vcarddav and calsify lists
about structured property and parameter values. The origin of
this format comes from jCal, where structured values are very rare
and processing the remaining ones requires a processing library
anyway. Therefore neither structured property values nor
parameter values were added. For jCard on the other hand,
structured values appear quite often. I have come up with three
possible options for structured property values:
1. Use an array as the value, possibly with a null value for any
empty structured property: foo;;bar becomes ["foo", null,
"bar"]
2. Use an object for key-value combinations. Downside is that
the key may not always be known, and needs to be defined at
least for standard properties. (i.e for N: "surnames",
"given", "additional", "honor-prefix", "honor-suffix").
Object values themselves could also be array values, i.e
multiple honorific prefixes. Upside is that it makes it very
easy to access the values even without using a dedicated
client library.
3. Keep the property value as an opaque text and leave any
splitting to client libraries. This makes it very simple to
parse both iCalendar and vCard data into a similar format, but
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puts the burden of parsing the structured value on the client
or client library.
Also, there should be a mention of how multi-values inside a
structured value should be handled. With the second approach,
these could themselves be an array, similar to how this document
currently defines multi-value parameters.
Appendix D. Change History (to be removed prior to publication as an
RFC)
draft-kewisch-vcard-in-json-01
* Added ABNF and improved references in date/time related
sections
* Changes to wording in "vCard Stream" section
* Changes to wording about VALUE parameter when converting to
vCard
* Corrected missing "type" parameter and separator in example
* Minor wording corrections
Author's Address
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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