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Applications JSON data formats for vCard and iCalendar 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.

The vCard data format 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 , there is also an effort to define a JSON-based data format for calendar information called jCal that parallels the format defined in this specification. The term JSON describes the JavaScript Object Notation defined in . 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 and , 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. Ordering of elements and 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.

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 . 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 . 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.

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

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

In Section 6.1.1 and 6.1.2, 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", the second element is an array of jCard properties as described in , belonging to the entity. Although 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:

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.

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 . The array consists of the following fixed elements: 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. An object containing the parameters as described in . If the property has no parameters, an empty object is used to represent that. 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:

As described in , 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. describes this in more detail. The above illustrates the importance 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 sub-elements match the value type.

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

The vCard format specification defines the VERSION property to be mandatory. The "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 , the "version" property MUST be the first element of the array containing the properties of a jCard.

In vCard related properties can be grouped together using a grouping construct. The grouping is accomplished by adding a prefix to the property name, which consists of the group name followed by a dot. 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 it is merely registered to reserve the parameter, avoiding collisions. Formal registration occurs in .

In jCard, the parameter's value is a single opaque string. Conversion rules are as follows: From vCard to jCard, the group construct (see , Section 3.3, Page 7) 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. 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 recommendations in , the name's case SHOULD be converted into uppercase.

Example:

is equivalent to:

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:

jCard Example:

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:

jCard Example:

In both cases, the array element values MUST have the primitive type that matches the jCard type identifier. In , there are only structured text values and thus only JSON strings are used. Extensions may for example 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:

Per Section 6.3.1, 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:

jCard Example:

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:

vCard defines a "VALUE" property parameter (Section 5.2 of ). 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: If the property has a "VALUE" parameter, that parameter's value is used as the value type. If the property has no "VALUE" parameter but has a default value type, the default value type is used. 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: If the property's value type is "unknown", no "VALUE" parameter is included. If the property's value type is the default type for that property, no "VALUE" parameter is included. Otherwise, a "VALUE" parameter is included, and the value type is used as the parameter value. See for information on handling unknown value types.

In , 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, although a more simple implementation might prefer an array with one string element. An example for a such 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:

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

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 .

vCard "URI" property values are represented by a property with the type identifier "uri". The value elements are JSON strings.

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 , but represented using the extended format specified in , 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 Section 4.3.1 apply. Whenever the extended format is not applicable, the basic format MUST be used.

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

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 , but represented using the extended format specified in , 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 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 , where they are not permitted.

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

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 , but represented using the extended format specified in , Section 4.3. If the complete representation is not used, the same date and time format restrictions as in and apply. Just as in , truncation of the date part is permitted.

This table contains possible conversions between the vCard DATE-TIME format its jCard date-time. This information is just an example and not a formal specification of the syntax. The specification can be found in and : 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 Reduced --0412T2320 --04-12T23:20 Truncated and Reduced --04T2320 --04T23:20 Truncated and Reduced ---12T2320 ---12T23:20 Truncated and Reduced --0412T2320 --04-12T23:20 Truncated and Reduced --04T23 --04T23 As specified in , 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.

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 (), a date () or a time () value. Just as in Section 4.3.4, a stand-alone time value MUST always be preceded by a "T".

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 , but represented using the extended format and complete representation specified in , Section 4.3.2.

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

vCard "BOOLEAN" property values are represented by a property with the type identifier "boolean". The value element is a JSON boolean value.

vCard "INTEGER" property values are represented by a property with the type identifier "integer". The value elements are JSON primitive number values.

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.

vCard "FLOAT" property values are represented by a property with the type identifier "float". The value elements are JSON primitive number values.

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.

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 , with the exception that the hour and minute components are separated by a ":" character, for consistency with the timezone offset, extended format.

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 .

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 for how to deal with default values for unrecognized extension properties or property parameters.

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 . Character escaping and line folding MUST be applied to the resulting vCard data as required by and . 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 which have the jCard type identifier "unknown".

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 they need 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 , nor any extensions to it. The type is hence registered to the vCard Value Data Types registroy in .

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 is critical that if the default type is not known that the value type "unknown" is used. If this requirement is ignored and for example "text" is used, additional escaping may occur which 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.

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: If the value type specified in jCard matches the default value type in vCard, the VALUE parameter MAY be omitted. 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.

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:

jCard:

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:

vCard:

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

jCard:

vCard:

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:

jCard:

This section describes libraries known to implement this draft as per . ICAL.js - Philipp Kewisch, James Lal. A JavaScript parser for iCalendar (rfc5545) https://github.com/mozilla-comm/ical.js/ alpha (for jCard) Currently geared towards jCal, therefore not all formats are supported. Includes an online validator. (as of rev 847c67c501, 2013-02-14) MPL, Mozilla Public License 2.0 Py Calendar - Cyrus Daboo. iCalendar/vCard Library https://svn.calendarserver.org/repository/calendarserver/PyCalendar/branches/json/ production All aspects of this draft, up to version 01. Apache License, Version 2.0 ez-vcard - Michael Angstadt. A vCard parser library written in Java https://code.google.com/p/ez-vcard/ production All aspects of this draft. New BSD License 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.

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 . Even though JSON is considered a safe subset of JavaScript, it should be kept in mind that a flaw in the parser processing JSON could still impose a threat which doesn't arise with conventional vCard data. With this in mind, a parser for JSON data should be used for jCard that is 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 . 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 and associated extensions, and all of the security considerations described in Section 9 of , or any associated extensions, are applicable.

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. application vcard+json none "version", as defined for the text/vcard media media type in , Section 10.1. Same as encoding considerations of application/json as specified in , Section 6. See . This media type provides an alternative format for vCard data based on JSON. This specification. 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. N/A N/A N/A N/A N/A vcarddav@ietf.org COMMON There are no restrictions on where this media type can be used. See the "Author's Address" section of this document. IETF

IANA has added the GROUP parameter to the vCard Parameters registry, initialied in Section 10.3.2 of . Usage of the GROUP parameter is further described in of this document. <empty> GROUP To simplify the jCard format. 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 , nor in xCard . 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. 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.

IANA has added the UNKNOWN value data type to the vCard Value Data Types registry, initialized in Section 10.3.3 of . Usage of the UNKNOWN type is further described in of this document. UNKNOWN To allow preserving property values whose default value type is not known during round-tripping between jCard and vCard. (Not applicable) The UNKNOWN value data type is reserved for the exclusive use of the jCard format. It MUST NOT be used in plain vCard . 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.

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

&rfc2119; &rfc4627; &rfc5234; &rfc5646; &rfc6350; &rfc6868; International Organization for Standardization International Organization for Standardization &rfc5545; &rfc6321; &rfc6351; &I-D.sheffer-running-code; &I-D.ietf-jcardcal-jcal; The Calendaring and Scheduling Consortium

Below is an ABNF schema as per for vCard in JSON. ABNF Symbols not described here are taken from . The schema is non-normative and given for reference only. The numeric section numbers given in the comments refer to section in . 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 . Additional schemas may be available on the internet at .

This section contains an example of a vCard object with its jCard representation.

Remove this section prior to publishing 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 Pubication as a WG draft Changed grouping syntax to use new GROUP parameter and added respective IANA section Added timestamp and date-and-or-time types instead of converting them from date/time/date-time Added a further sentence on preprocessing and escaping to clarify that JSON escaping must be used Described how to handle structured text values and structured text components with multiple values. Corrections and additions to the ABNF Section, adaptions to example Made more clear that complete representation is not mandatory Added sheffer-running-code section Changed handling of unknown property parameter types Minor corrections to sections regarding dates, fixing typos Add LABEL property example and description Added acknowledgements More typos fixed Added reference to rfc6868 Various editorial changes per jcardcal issue tracker Resolved a few MAY/SHOULD conflicts Put the VERSION property into its own section Improved GROUP/UNKNOWN registrations by only putting vcard related information into the registration template Removed vcard stream construct. Added reference to RFC6868 for both directions Corrected some examples and ABNF Updated UNKNOWN registration text to match with jCal text. Various editoral changes based on the IETF reviews. Please see http://trac.tools.ietf.org/wg/jcardcal/trac/ for details. More editoral changes based on the IETF reviews. Please see http://trac.tools.ietf.org/wg/jcardcal/trac/ for details. Merged examples for single/multi-valued properties Move IANA registrations for GROUP and UNKNOWN to the end of the document Corrected a few examples, e.g. use of "lang" vs "language" or missing version property.