Calendaring Extensions R. Tse
Internet-Draft P. Tam
Updates: Ribose
5545,6321,6350,6351,7953,7265,7 C. Daboo
095 (if approved) Apple Inc.
Intended status: Informational K. Murchison
Expires: October 21, 2018 FastMail Pty Ltd
April 19, 2018

The vObject Model and vFormat Syntax
draft-calconnect-vobject-vformat-01

Abstract

This document specifies the vObject data model and its corresponding syntax vFormat.

vObject represents the generalized data model, and vFormat the generalized data format, of the following specifications and fully covers them:

This work is produced by the CalConnect TC-VCARD and TC-CALENDAR committees.

Status of This Memo

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

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

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

This Internet-Draft will expire on October 21, 2018.

Copyright Notice

Copyright (c) 2018 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 (https://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.

Table of Contents

1. Introduction

The ubiquitous vCard [RFC6350] and iCalendar [RFC5545] standards are known as the "vObject" or "VCOMPONENT" family of standards. Named by the convention where the component type identifiers usually start with the letter "v", all of them use very similar, if not identical, syntax.

Yet due to diverged implementations of these "vObject" standards, different implementations often generate different output even when given identical content, causing interoperability concerns and the general inability to determine equivalence of vObjects for integrity concerns (2.1.2).

This document defines the "vObject" data model that is a generalized model that fully covers the needs of these standards, and the "vFormat" serialization syntax that is the generalized syntax of all vObject-compliant serialization formats.

This document also describes the normalized form of the vObject data model and the normalization process for vFormat syntax.

The normalized forms and normalization methods described in this document are fully compatible with the vCard 4.0 [RFC6350] and iCalendar [RFC5545] specifications.

This work is produced by the CalConnect TC-VCARD [CALCONNECT-VCARD] and TC-CALENDAR [CALCONNECT-CALENDAR] committees.

2. Terms and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

The key words "Private Use", "Experimental Use", "Hierarchical Allocation", "First Come First Served", "Expert Review", "Specification Required", "RFC Required", "IETF Review", "Standards Action" and "IESG Approval" in this document are to be interpreted as described in Section 4 of [RFC8126].

Notation in this document is described in ABNF [RFC5234] as used by [RFC6350].

Definitions from [RFC6350] apply to this specification except when explicitly overridden.

All names of properties, property parameters, enumerated property values, and property parameter values are case-insensitive. However, all property values are case-sensitive, unless otherwise stated.

2.1. Definitions

vObject

the generalized data model of the vCard component (VCARD) and iCalendar (VCALENDAR) component defined in this document
vFormat

the native serialization format of vObject, which is the textual format representation using the BEGIN: and END: component keywords
inner vObject, sub-component

a vObject located within a vObject
outer vObject, super-component

a vObject that this vObject is located within
Client User Application (CUA)

the vObject client implementation that interfaces with the user
calendar date

as defined in 2.1.8

3. Symbols And Abbreviations

3.1. Operators

bitlen(S)

The length of string S in bits (e.g., bitlen(101) == 3).
S + T

addition of two 32-bit vectors S and T with a mod 2^32 bit wrap around.
sort(list)

sorts a list according to alphabetical order (A-Z) of its elements.
upcase(char)

characters in lower case SHOULD be replaced with its corresponding upper case character. The input is expected to be in UTF-8 ASCII.

4. vObject Data Model

The vObject data model is the generalized data model from the implied data models of vCard [RFC6350] and iCalendar [RFC5545].

While both vCard [RFC6350] and iCalendar [RFC5545] specify data formats for different purposes, the data model behind them follow an identical logical structure (using components, properties and parameters) with similar requirements.

By creating a generalized data model ("vObject") that is compatible with both, we are able to ensure that newly developed data modification techniques for vObject would be interoperable on all other vObject-compliant models.

4.1. vObject-compliant models

The implied data models behind these formats are compliant to the vObject data model:

4.2. Elements

Data within a vObject is arranged through a logical hierarchy composed of the following elements:

4.3. Equivalence

Two vObjects are considered identical in content if their normalized forms are textually equivalent.

4.4. Component

A vObject is based on the representation of the "component" element. All vObjects are composed of at least one component element.

A component:

A component type is identified by the component name, and every component instance is distinguished by the value of its uniqueness identifier property.

A component is often used to model an object in the object-oriented sense, such as a vCard or an iCalendar object.

The order of components MAY represent order of the objects, which is important for example in a VPATCH component [VPATCH], representing the patching order, which is not a commutative process.

4.4.1. Uniqueness Identifying Property

As a vObject component can contain inner components, it is important that those inner components can be distinguished from each other.

A vObject component’s uniqueness identifier property is a property whose value can uniquely identify the immediate component that contains it.

Every vObject component MUST contain a single, component uniqueness identifier property. The uniqueness identifier property can be different according to component types, and the uniqueness scope of that property MAY be different. At a minimum, the uniqueness identifier property value MUST be unique within the immediate component that contains the uniqueness identifier property.

For example:

The list of uniqueness identifier properties for every vObject component that complies with this document can be found in the IANA registry described in Section 12.1.2.

New vObject components defined according to this document MUST define a uniqueness identifier property for that component, and it MUST be registered in the said IANA registry.

4.4.2. Normalizing A Component

4.4.2.1. Sorted Component Properties

Properties MUST be first normalized and before sorted, meaning that the property’s values, and its parameters and its values, have been normalized.

The sorting of component properties MUST be performed according to the following order:

4.4.2.2. Sorted Inner Components

Inner components within a vObject must be placed in a sorted order.

The sorting between components MUST be performed according to the following order:

4.4.2.3. Normalized Inner Components

An inner component MUST itself be normalized, meaning that its properties and inner components MUST be normalized.

4.4.3. vObject Property

Properties represent attributes of the vObject itself.

A property:

vObject property value types are listed in Section 4.4.4.

4.4.3.1. Normalized Values

A normalized property MUST have normalized values.

4.4.3.2. Normalized Parameters

A normalized property MUST have normalized property parameters.

Property parameters within the same property MUST each be normalized, and then sorted by parameter name alphabetically.

Property parameters of the same property MUST have unique names.

4.4.4. Property Value

A vObject property MAY have one or more values, depending on the value type.

vObject property values are strongly typed, just like in [RFC5545] and [RFC6350]. Basic value types accepted in vObject properties are defined in Section 6.

vObject compliant formats MAY define additional value types that are not provided in this document, and MAY require separate validation rules, such as the "RECUR" property value type from iCalendar [RFC5545].

Each property MUST define a default value type, and MAY accept alternative, defined, value types.

4.4.5. Normalization Of Property Values

The property value generally does not require any normalization. Please consult individual normalization instructions in each value type’s definition.

4.4.6. Property Parameter

A property parameter is an attribute that applies on a property.

A property parameter contains:

A property parameter MAY represent:

A property MAY have multiple property parameters, for example, the "TYPE" of the value or a category that applies to this value.

4.4.6.1. Value Lists

Certain property parameters allow multiple values. There is no defined order among property parameters in a property parameter list.

In normalized form, values in a value list MUST be sorted alphabetically.

4.4.7. Default Property Parameter Values

Property parameters are allowed to have a default value.

For example, in vObject formats including [RFC5545] and [RFC6350], each property value has a specified data type specified as the VALUE property parameter.

4.4.8. Property Parameter Value

A property parameter value *MAY contain none, one or several property parameter values.

There is generally no order enforced among the list property parameter value list.

vObject property parameter values are strongly typed, just like vObject properties, [RFC5545] and [RFC6350]. Basic value types accepted in vObject property parameter values are defined in Section 6.

vObject compliant formats MAY define additional value types that are not provided in this document, and MAY require separate validation rules, such as the values accepted by the FBTYPE property parameter in iCalendar [RFC5545].

Each property parameter MUST define its accepted value type. While a property MAY accept multiple alternative value types, a property parameter value MUST only accept one value type.

4.4.9. Sorted Parameter Values

Property parameter values within a property parameter MUST be sorted by value.

4.4.10. Property Group

A property group (or just "group") is used to group a set of properties, useful to represent cases where a group of properties are closely related to each other.

In the vCard [RFC6350], the group is used to tie multiple properties into being displayed together.

Each property MUST only have a maximum of one group.

Groups are not ordered and group names are case-insensitive.

5. vFormat Syntax

The "vFormat" format is the generalized syntax from the vCard [RFC6350] and iCalendar [RFC5545] formats, and is the native format for vObject serialization ("vObject native format").

vFormat is called the "native" format for vObjects to distinguish it from alternative representations of vObject data, such as their XML (xCal, xCard) or JSON (jCal, jCard) representations.

Its syntax originated from the textual representation of the iCalendar and vCard formats, and is mostly traceable back to the original vCard and iCalendar specifications [vCard21].

Both of these formats are considered "instances" (or "downstream formats") of vFormat, and fully adhere to vFormat requirements.

Parsing and modification operations that work on vFormat SHOULD work on all its instances, including iCalendar [RFC5545] and vCard [RFC6350].

5.1. ABNF Format Definition

The following ABNF notation defines the vFormat syntax, in accordance with [RFC5234], which also defines CRLF, WSP, DQUOTE, VCHAR, ALPHA, and DIGIT.

A vObject is defined by the following notation:

vobjects = 1*vobject

vobject = "BEGIN:" comp-name CRLF
          *contentline
          *vobject
          "END:" comp-name CRLF

comp-name = name

prop-name = name

prop-values = prop-value / prop-list / prop-structured

prop-value = VALUE-CHAR

prop-list = prop-value *("," prop-value)
  ; An unordered list containing multiple property values

prop-structured = prop-value *(";" prop-value)
  ; A structured list that consist of multiple property fields
  ; for multiple property values

contentline = [group "."] prop-name params ":" prop-values CRLF
  ; Folding and unfolding procedures described in Section 3.2 of
  ; [RFC6350] applies:
  ;   * When parsing a content line, folded lines *MUST* first be
  ;     unfolded accordingly.
  ;   * When generating a content line, lines longer than 75
  ;     characters *SHOULD* be folded accordingly.
  ;   * When normalizing a content line, the content line *MUST*
  ;     be folded when the line is longer than 75 characters.

group = name

params = *(";" param)

param = name "=" param-value *("," param-value)
  ; Allowed parameters depend on property name.

name = 1*(ALPHA / DIGIT / "-")

param-value = *SAFE-CHAR / DQUOTE *QSAFE-CHAR DQUOTE
param-values = param-value *("," param-single-value)

NON-ASCII = UTF8-2 / UTF8-3 / UTF8-4
  ; UTF8-{2,3,4} are defined in <<RFC3629>>
  ; TODO: generalize this to UTF-32

QSAFE-CHAR = WSP / "!" / %x23-7E / NON-ASCII
  ; Any character except CTLs, DQUOTE

SAFE-CHAR = WSP / "!" / %x23-39 / %x3C-7E / NON-ASCII
  ; Any character except CTLs, DQUOTE, ";", ":"

VALUE-CHAR = WSP / VCHAR / NON-ASCII
  ; Any textual character

5.1.1. Component

A component:

The vCard [RFC6350] and iCalendar [RFC5545] data formats both conform to vFormat, and their syntaxes are considered to be restricted instances of the vObject syntax.

5.1.1.1. Component Name In Uppercase

The component name of a vObject MUST be uppercased, for both the BEGIN: and END: content lines.

Example (even though this is not technically allowed by [RFC6350]):

BEGIN:vCard

Should be normalized to:

BEGIN:VCARD

5.1.1.2. Order Of Inner Components And Properties

Properties MUST be placed before inner components are listed.

5.1.1.3. Maintain Validity

Certain vObject formats places certain restrictions or requirements on property line locations. Normalization procedures MUST NOT affect the validity of the normalized vObject.

For example, in the VCARD component [RFC6350], the "VERSION" property line is REQUIRED to be placed immediately below the "BEGIN" line.

In this case, when normalizing the VCARD component, the common normalization procedure MUST be first applied, and the "VERSION" property line MUST be restored to the valid location as required by its specifications [RFC6350].

5.1.2. Property

A property can be represented by one content line (a line that ends with a line break), but can also be "folded" (3.1) to use multiple lines.

A property begins with the property name (e.g., TEL), followed by a COLON delimiter and the property’s value.

5.1.2.1. Uppercased Property Name

The property name MUST be normalized to uppercase letters.

5.1.2.2. Normalized Parameters

The last property parameter of a property MUST NOT have a trailing SEMICOLON.

5.1.2.3. Wrapped Content Line

When exporting a normalized property content line, it MUST be folded at the character limit when it exceeds 75 characters. Each folded line MUST be delimited by the character sequence of a line break and a single white space (CRLF, SPACE (U+0020)). This rule only applies to normalized output.

For example, the original form:

NOTE:This is a very long description on a long line that exceeds 75 characters.

When exported to normalized output MUST give out:

NOTE:This is a very long description on a long line that exceeds 75 charac
 ters.

5.1.3. Property Value

The property’s values are defined as the content after the property name and COLON delimiter, until the end of the unfolded content line.

If a property accepts multiple values, the definition of delimitation is defined in Section 6.

vObject compliant formats that defines additional value types MAY require separate validation rules on top of vFormat syntax.

If the property value type of a property value is not the default value type, the VALUE parameter MUST be present to specify the type of the property value.

vFormat representation of different value types are provided in Section 6.

5.2. Normalizing Property Values

The property value generally does not require any normalization.

5.2.1. Property Parameter

Property parameters exist between the property name and the COLON delimiter in a property line.

Each property parameter in a list of property parameters MUST be separated by a SEMICOLON character.

The property parameter name and the property parameter value is separated with an equal sign ("=").

5.2.1.1. Multiple Property Parameters

If the property accepts multiple property parameters values, they MUST be separated by a SEMICOLON character as a list.

5.2.1.2. Expanded Form Of Property Parameter Value List

When there are multiple instances of a property parameter on the same property, such as in "TYPE=home;TYPE=work", it is considered equivalent to "TYPE=home\,work".

5.2.1.3. Uppercased Property Parameter Names

The property parameter name MUST be normalized into uppercase letters in form of a Unicode string (7).

Property parameter names (together with their values) MUST be sorted alphabetically.

Example:

TEL;VALUE=uri;type=home:tel:+1-888-888-8888

The normalized form is:

TEL;TYPE="home";VALUE="uri":tel:+1-888-888-8888

5.2.1.4. Join Identical Property Parameter Names

If a property parameter occurs more than once within a property, the property parameter is considered to contain a list of property parameter values joined by the parameter separator.

Such instances of property parameters with identical names MUST be joined into one instance with its value a sorted list of the property parameter values.

For example, the vCard TEL property’s TYPE parameter [RFC6350] describes that TYPE=home,work and TYPE=work;TYPE=home are considered equivalent.

Example:

TEL;TYPE=home;Type=work;VALUE=uri:tel:+1-888-888-8888

The normalized form is:

TEL;TYPE="home","work";VALUE=uri:tel:+1-888-888-8888

5.2.2. Express Default Property Value Types

In vObject formats including [RFC5545] and [RFC6350], each property value has a specified data type either as specified by property definition or optionally assigned.

When normalizing a property, the property data value type MUST always be specified. If the value type is not explicitly specified, it MUST be filled in according to the vObject format.

Example:

TEL:+1-888-888-8888

The normalized form is:

TEL;VALUE="text":+1-888-888-8888

5.2.3. Property Parameter Value

If a property parameter accepts multiple values, these value elements MUST be separated by a COMMA (U+002C).

Property parameter value elements that contain the COLON (U+003A), SEMICOLON (U+003B), or COMMA (U+002C) character separators MUST be specified as quoted-string text values. Property parameter values MUST NOT contain the DQUOTE (U+0022) character. The DQUOTE character is used as a delimiter for parameter values that contain restricted characters or URI text.

5.3. Normalizing Property Parameter Values

5.3.1. Wrapped Parameter Values

Property parameter values MUST be individually wrapped with the DQUOTE characters. In [RFC6350], the DQUOTE character is used to delimit values within a list that contain restricted characters or URI text and is optional.

Example:

TEL;TYPE=home,work;VALUE=uri:tel:+1-888-888-8888

The normalized vFormat output is:

TEL;TYPE="home","work";VALUE="uri":tel:+1-888-888-8888

5.3.2. Property Group

The syntax of a property group is defined in Section 5.

Property groups MUST NOT be removed during normalization. This is contrary to [RFC6350] that allows stripping off groups.

6. vObject Value Types

6.1. Meta Value Types

6.1.1. FIELDSET

Some properties and parameters require values defined in terms of multiple parts.

This construct of multiple structured values is called a "FIELDSET". These structured property values MUST have their value parts separated by a SEMICOLON character. Each value in FIELDSET MUST have the same value type as defined.

In vFormat syntax, an element within any FIELDSET field MUST NOT contain an unescaped the SEMICOLON character to prevent breaking of the FIELDSET syntax.

6.1.1.1. Syntax

When used to describe a value type, the FIELDSET(field-1-value-type, …​) function is defined as a structure of fields separated by the SEMICOLON character, where each of its fields is of value type field-i-value-type, where i represents the index of the specific field.

6.1.1.2. Example 1

The "CLIENTPIDMAP" property of [RFC6350] takes a tuple of "INTEGER" and "URI" separated by a SEMICOLON.

The notation in vObject given for its value type would be this indicating that the first value is an INTEGER, while the latter value is a URI:

FIELDSET(INTEGER, URI)

6.1.1.3. Example 2

The "N" property of [RFC6350] defines its value of having 5 values at once, and each of these values are a LIST of TEXT.

The notation in vObject given for its value type would be this indicating that there are 5 fields in this FIELDSET, and each value element of it MUST be a LIST of TEXT elements:

FIELDSET(5\*LIST(TEXT))

6.1.1.4. Normalizing a FIELDSET

When normalizing a FIELDSET, each value MUST have been normalized, but the order of FIELDSET elements MUST NOT be rearranged.

6.1.2. LIST

Properties and parameters MAY specify its value to be an unordered list of values. There is no significance to the order of values in a list.

This construct is called the "LIST". Each value in the LIST MUST have the same value type.

In vFormat syntax, values in a list of values MUST be separated by a delimiting character. The default delimiter character is the COMMA character. An element within any LIST element MUST NOT contain an unescaped delimiter character to prevent breaking of the LIST syntax.

A property MAY specify that its LIST elements are delimited by another character other than the COMMA, for example, the RECUR property of [RFC5545] uses the SEMICOLON character as a delimiter. This is allowed when explicitly specified in the defining syntax, given the restriction that any element within does not contain an unescaped delimiter character (i.e., in this case, the SEMICOLON).

6.1.2.1. Syntax

When used to describe a value type, the LIST(value-type) function is defined as a list of elements separated by the COMMA character, where each of its elements is of value type value-type.

When used to describe a value type, the LIST(value-type) function is defined as a list of elements separated by the COMMA character, where each of its elements is of value type value-type.

In the case where a delimiter character for the LIST is not a COMMA, the LIST(value-type, delimiter) syntax is used to define the delimiter, where each of its elements is of value type value-type, and the delimiting character is specified to be delimiter.

6.1.2.2. Example 1

The "NICKNAME" property of [RFC6350] defines its value to be an unordered list of TEXT.

In vObject notation its value type is defined to be:

LIST(TEXT)

6.1.2.3. Example 2

The "RECUR" property of [RFC5545] defines its value to be an unordered list of ASSIGN, separated by the SEMICOLON character.

In vObject notation its value type is defined to be:

LIST(KEYVALUE, ";")

6.1.2.4. Normalizing a LIST

When normalizing a LIST, each value of it MUST be normalized, and the values MUST be sorted alphabetically.

For example, values of [RFC5545] RESOURCES, FREEBUSY, EXDATE, RDATE, CATEGORIES, MUST be sorted alphabetically when normalized.

6.1.3. MAP

A MAP serves the function of a key-value table. It is realized using the LIST value type with values of the value type KEYVALUE.

Each value in the MAP MUST use the KEYVALUE value type.

There is no inherent order of the values within a MAP. Values within its key value pairs MAY be of different value types as defined.

In vFormat syntax, as with LIST, values in a list of values MUST be separated by a delimiting character. The default delimiter character is the SEMICOLON character. An element within any MAP element MUST NOT contain an unescaped delimiter character to prevent breaking of the MAP syntax.

6.1.3.1. Syntax

This value type is described using the MAP(kv_1, kv_2, …​) function, where each kv_i represents a property of the value type KEYVALUE.

In the case where a delimiter character for the MAP is not a SEMICOLON, the MAP(delimiter, kv_1, kv_2) syntax is used to define the delimiter, where each of its elements is of value type KEYVALUE, and the delimiting character is specified to be delimiter.

6.1.3.2. Example

The "RECUR" property of [RFC5545] defines its value to be a MAP, separated by the SEMICOLON character.

In vObject notation its value type is defined to be:

MAP(
  KEYVALUE(FREQ, TEXT),
  KEYVALUE(UNTIL, ISO-DATE-COMPLETE / ISO-DATE-TIME-BASIC),
  KEYVALUE(COUNT, INTEGER),
  KEYVALUE(INTERVAL, INTEGER),
  KEYVALUE(BYSECOND, LIST(INTEGER)),
  KEYVALUE(BYMINUTE, LIST(INTEGER)),
  KEYVALUE(BYHOUR, LIST(INTEGER)),
  KEYVALUE(BYDAY, LIST(INTEGER)),
  KEYVALUE(BYMONTHDAY, LIST(INTEGER)),
  KEYVALUE(BYYEARDAY, LIST(INTEGER)),
  KEYVALUE(BYWEEKNO, LIST(INTEGER)),
  KEYVALUE(BYMONTH, LIST(INTEGER)),
  KEYVALUE(BYSETPOS, INTEGER),
  KEYVALUE(WKST, TEXT)
)

6.1.3.3. Normalizing a MAP

When normalizing a MAP, each value of it MUST be normalized, and the values MUST be sorted alphabetically according to its key.

6.2. Basic Value Types

6.2.1. TEXT

This corresponds to the TEXT value type in 4.1 and 3.3.11.

6.2.1.1. Value Name

TEXT

6.2.1.2. Purpose

This value type defines values that contain free-form, human-readable text.

6.2.1.3. Format Definition 

text       = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
  ; Folded according to description above

ESCAPED-CHAR = ("\\" / "\;" / "\," / "\N" / "\n")
  ; \\ encodes \, \N or \n encodes newline
  ; \; encodes ;, \, encodes ,

TSAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-5B /
            %x5D-7E / NON-US-ASCII
  ; Any character except CONTROLs not needed by the current
  ; character set, DQUOTE, ";", ":", "\", ","

6.2.1.4. Description

For historic reasons, the COMMA and SEMICOLON characters MUST be escaped with a preceding BACKSLASH character (U+005C). The historic usage of the "text" value type accepting multiple values MUST NOT be used unless the multiple values are provided through a LIST.

An intentional line break MUST be represented by the sequence of "\n" or "\N" (BACKSLASH followed by a LATIN SMALL LETTER N (U+006E) or a LATIN CAPITAL LETTER N (U+004E)).

6.2.1.5. Associated parameters

6.2.1.6. Example

This multiple line value for the NOTE value of vCard:

TC VCARD
The Calendaring And Scheduling Consortium
July 20, 2017

requires application of the following formatting rules:

and therefore SHOULD be represented as:

NOTE:TC VCARD\nThe Calendaring And Scheduling Consortium\nJuly 20\, 2017

6.2.1.7. Normalization

Values of the TEXT data type MUST convert all line breaks ("\n" or "\N") into the character sequence "\n" (BACKSLASH followed by a LATIN SMALL LETTER N (U+006E)).

6.2.2. URI

This corresponds to the URI value type in 4.2 and 3.3.13.

6.2.2.1. Value Name

URI

6.2.2.2. Purpose

This value type defines values that are represented by data referenced by a uniform resource identifier (URI), the value is what the URI points to, not the URI itself.

6.2.2.3. Format Definition 

uri = <As defined in Section 3 of [RFC3986]>

[CREF1]`uri` is defined in .

6.2.2.4. Description

When a property parameter value is a URI value type, the URI MUST be specified as a quoted-string value.

6.2.2.5. Example

This value for the PHOTO property of vCard:

PHOTO:http://www.example.com/pub/photos/jqpublic.gif

PHOTO:data:image/jpeg;base64,MIICajCCAdOgAwIBAgICBEUwDQYJKoZIhv
 AQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bm
 ljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlvbiBTeXN0
 <...remainder of base64-encoded data...>

6.2.2.6. Normalization

No normalization procedures are needed.

6.2.3. BOOLEAN

This corresponds to the BOOLEAN value types in 4.4 and 3.3.2.

6.2.3.1. Value Name

BOOLEAN

6.2.3.2. Purpose

This value type is used to identify properties that contain either a "TRUE" or "FALSE" Boolean value.

6.2.3.3. Format Definition 

boolean    = "TRUE" / "FALSE"

6.2.3.4. Description

Parsing of "TRUE" and "FALSE" values SHOULD be case-insensitive, but a writer of such value MUST only output of this value type in uppercase.

6.2.3.5. Examples

6.2.3.6. Normalization

Values of the BOOLEAN data type MUST be normalized to uppercase, i.e., the values "TRUE" and "FALSE".

6.2.4. INTEGER

The INTEGER-64 and INTEGER-32 value types corresponds to the INTEGER value types in 4.5 and in 3.3.8 respectively.

6.2.4.1. Value Name

INTEGER

(INTEGER-32 for storing 32-bit integer, INTEGER-64 for storing 64-bit integer)

6.2.4.2. Purpose

Representation of a signed integer value.

6.2.4.3. Format Definition 

integer = (["+"] / "-") 1*DIGIT

6.2.4.4. Description

If a preceding sign is not specified, the value is assumed positive "". While the format accepts the optional "" PLUS sign, a writer that conforms to this document SHOULD not write the "+" sign for clarity reasons.

The valid ranges for INTEGER-32 and INTEGER-64 are:

6.2.4.5. Examples

6.2.4.6. Normalization

A positive integer when normalized MUST not have the optional "+" sign.

6.2.5. FLOAT

This corresponds to the FLOAT value types in 3.3.7 and 4.6.

6.2.5.1. Value Name

FLOAT

6.2.5.2. Purpose

Representation of a real-number value.

6.2.5.3. Format Definition 

float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT]

6.2.5.4. Description

If a preceding sign is not specified, the value is assumed positive "+".

Implementations MUST support a precision equal or better than that of the IEEE "binary64" format [IEEE.754.2008].

Scientific notation is disallowed.

6.2.5.5. Examples

6.2.5.6. Normalization

No normalization procedures are needed.

Trailing zeros, such as 100.10000 MUST be kept as it indicates accuracy of the number.

6.2.6. LANGUAGE-TAG

This corresponds to the LANGUAGE-TAG value type in 4.8.

6.2.6.1. Value Name

LANGUAGE-TAG

6.2.6.2. Purpose

Representing a language tag, as defined in [RFC5646].

6.2.6.3. Format Definition

Defined in [RFC5646].

6.2.6.4. Description

A single language tag

6.2.6.5. Examples

6.2.6.6. Normalization

The normalization procedure of the LANGUAGE-TAG data type follows the procedure described in 2.1.1.

As the language tag is comprised of a mixture of these components, [RFC5646] provides a rule that applies this procedure across all language tags:

6.2.7. Binary

This corresponds to the BINARY value type in 3.3.1.

6.2.7.1. Value Name

BINARY

6.2.7.2. Purpose

This value type defines values that contain inline binary data encoded in characters. For example, an inline "ATTACH" property of an iCalendar object or an inline "PHOTO" property image inside a vCard object.

6.2.7.3. Format Definition 

binary = *(4b-char) [b-end]
  ; A "BASE64" encoded character string, as defined by [RFC4648].

b-end  = (2b-char "==") / (3b-char "=")

b-char = ALPHA / DIGIT / "+" / "/"

[CREF2]The "BASE64" encoded character string is defined in .

6.2.7.4. Description

Property values with this value type MUST specify the parameter "ENCODING" with parameter value "BASE64", and the inline binary data MUST be character encoded using the "BASE64" encoding method defined in [RFC2045].

6.2.7.5. Example

This value for the NOTE value of vCard:

The following is an example of a "BASE64" encoded binary value data:

ATTACH;FMTTYPE=image/vnd.microsoft.icon;ENCODING=BASE64;VALUE
=BINARY:AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAgIAAAICAgADAwMAA////AAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAMwAAAAAAABNEMQAAAAAAAkQgAAAAAAJEREQgAA
ACECQ0QgEgAAQxQzM0E0AABERCRCREQAADRDJEJEQwAAAhA0QwEQAAAAAERE
AAAAAAAAREQAAAAAAAAkQgAAAAAAAAMgAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAA

6.2.8. KEYVALUE

6.2.8.1. Value Name

KEYVALUE(key, value-type)

6.2.8.2. Purpose

Representation of a key-value pair: a key key linked to a value of value type value-type.

6.2.8.3. Format Definition 

assign-key    = *(TSAFE-CHAR)
assign-value  = prop-values

assign        = assign-key "=" assign-value

6.2.8.4. Description

The separation delimiter between the key and value is the EQUAL sign character, =. The value of KEYVALUE MUST NOT contain the unescaped EQUAL sign character for the avoidance of doubt.

If the KEYVALUE value is accepted within a list, the key value must be unique amongst the list.

This value type is also a core component of the MAP value type.

6.2.8.5. Examples

6.2.8.6. Normalization

Its value MUST be normalized according to the value-type of that value.

6.3. Date and Time Value Types

These date and time related value types are based on [ISO.8601.2004] and [ISO.8601.2000].

Multiple of such values can be specified using the comma-separated notation.

6.3.1. ISO-DATE-COMPLETE

This corresponds to the DATE value type in 3.3.4.

6.3.1.1. Value Name

ISO-DATE-COMPLETE

6.3.1.2. Purpose

Representation of a complete calendar date defined in [ISO.8601.2004].

6.3.1.3. Format Definition 

iso-date               = iso-date-value
iso-date-value         = iso-date-fullyear iso-date-month iso-date-mday
iso-date-fullyear      = 4DIGIT
iso-date-month         = 2DIGIT   ;01-12
iso-date-mday          = 2DIGIT   ;01-28, 01-29, 01-30, 01-31
                                  ;based on month/year

6.3.1.4. Description

This value format is based on the "basic format" calendar date (specified in 4.1.2.2 "Complete representations").

The value MUST be represented textually as "YYYYMMDD", with its components "YYYY" a four-digit year, "MM" a two-digit month, and "DD" a two-digit day of the month as described in the definition.

6.3.1.5. Example

The following represents July 1, 1997:

6.3.1.6. Normalization

No normalization procedures are needed.

6.3.2. ISO-DATE-FLEX

Representation of a calendar date [ISO.8601.2004] that does not require complete representation.

This corresponds to the DATE value type in 4.3.1.

6.3.2.1. Value Name

ISO-DATE-FLEX

6.3.2.2. Purpose

This value type defines a calendar date format that allows entry of a complete calendar date [ISO.8601.2004], a reduced accuracy date [ISO.8601.2004] and a truncated date [ISO.8601.2004].

6.3.2.3. Format Definition 

iso-date-flex   = iso-date /
                  iso-date-reduced /
                  iso-date-truncated

iso-date-reduced = iso-date-fullyear / iso-date-year-month
iso-date-year-month = iso-date-fullyear "-" iso-date-month

iso-date-truncated =  iso-date-truncated-month-day /
                      iso-date-truncated-month-only /
                      iso-date-truncated-day-only

iso-date-truncated-month-day  = "--" iso-date-month iso-date-mday
iso-date-truncated-month-only =  "--" iso-date-month
iso-date-truncated-day-only   =  "---" iso-date-mday

6.3.2.4. Description

This value format accepts:

The value can be represented in these ways:

Example:

6.3.2.5. Normalization

No normalization procedures are needed.

6.3.3. ISO-TIME-COMPLETE

This corresponds to the "time" portion of the TIMESTAMP value type in 4.3.5.

6.3.3.1. Value Name

ISO-TIME-COMPLETE

6.3.3.2. Purpose

Representation of a complete time of day with a UTC offset [ISO.8601.2004].

6.3.3.3. Format Definition 

iso-time = time-hour time-minute time-second
           [iso-time-utc / iso-utc-offset]

iso-time-hour    = 2DIGIT        ;00-23
iso-time-minute  = 2DIGIT        ;00-59
iso-time-second  = 2DIGIT        ;00-60
;The "60" value is used to account for positive "leap" seconds.

iso-time-utc     = "Z"

6.3.3.4. Description

This value format accepts a time of day value specified as:

The components mean: "hh" a two-digit, 24-hour of the day (00-23), "mm" a two-digit minute in the hour (00-59), and "ss" a two-digit second in the minute (00-60).

The seconds value of 60 MUST only be used to account for positive "leap" seconds. Fractions of a second are not supported by this format.

This value indicates "local time" as specified in 2.1.16. To indicate UTC time, a "Z" character MUST be appended to the basic format as described in 4.2.4 "UTC of day". To indicate a UTC offset, the "utc-offset" section MUST be specified in accordance with 4.2.5.2.

The value of "hhmmssZ" MUST be used instead of the equivalent "hhmmss+0000" or "hhmmss-0000".

Example:

6.3.3.5. Normalization

No normalization procedures are needed.

6.3.4. ISO-TIME-BASIC

This corresponds to the TIME value type in 3.3.12.

6.3.4.1. Value Name

ISO-TIME-BASIC

6.3.4.2. Purpose

Representation of a complete time of day disallowing a UTC offset [ISO.8601.2004].

6.3.4.3. Format Definition 

iso-time-basic = iso-time-hour iso-time-minute iso-time-second
                 [iso-time-utc]

6.3.4.4. Description

This value format is similar to "TIME" except it disallows the additional UTC offset, (the basic formats of 4.2.5.2 "Local time and the difference from UTC").

This value format accepts a time of day value specified as:

The seconds value of 60 MUST only be used to account for positive "leap" seconds. Fractions of a second are not supported by this format.

This value indicates "local time" as specified in 2.1.16. To indicate UTC time, a "Z" character MUST be appended to the basic format as described in 4.2.4 "UTC of day".

Example:

6.3.4.5. Normalization

No normalization procedures are needed.

6.3.5. ISO-TIME-FLEX

This corresponds to the TIME value type in 4.3.2.

6.3.5.1. Value Name

ISO-TIME-FLEX

6.3.5.2. Purpose

This value type defines a time of day format that allows a entry of a complete time of day [ISO.8601.2004], a reduced accuracy date [ISO.8601.2004] and a truncated date representation [ISO.8601.2000].

6.3.5.3. Format Definition 

iso-time-flex = iso-time /
                iso-time-reduced /
                iso-time-truncated

iso-time-zone = iso-time-utc / iso-time-utc-offset

iso-time-reduced =  iso-time-reduced-hour-minute /
                    iso-time-hour

iso-time-reduced-hour-minute = iso-time-hour iso-time-minute

iso-time-truncated =  iso-time-truncated-minute-second /
                      iso-time-truncated-minute-only /
                      iso-time-truncated-second-only
iso-time-truncated-minute-second = "-" iso-time-minute iso-time-second
iso-time-truncated-minute-only = "-" iso-time-minute
iso-time-truncated-second-only = "--" iso-time-second

6.3.5.4. Description

This value format accepts:

The value can be represented in these ways:

The seconds value of 60 MUST only be used to account for positive "leap" seconds. Fractions of a second are not supported by this format.

This value indicates "local time" as specified in 2.1.16. To indicate UTC time, a "Z" character MUST be appended to the basic format as described in 4.2.4 "UTC of day".

This format requires the midnight hour to be represented by "00" (4.2.3 a)), not "24" (4.2.3 b)).

This format supports the specificiation of UTC offsets for the complete representation basic format (defined in 4.2.5.2 basic format), in the form of "hhmmss±HHMM". "HHMM" is the hour and minute of UTC offset, defined in 4.2.5.1 basic format.

Example:

6.3.5.5. Normalization

No normalization procedures are needed.

6.3.6. ISO-UTC-OFFSET

This corresponds to the UTC-OFFSET value type in 4.7.

6.3.6.1. Value Name

ISO-UTC-OFFSET

6.3.6.2. Purpose

Representation of a UTC offset as described in [ISO.8601.2004].

6.3.6.3. Format Definition 

sign = "+" / "-"
iso-utc-offset = sign iso-time-hour [iso-time-minute]

Description:

The value can be represented in two ways:

The PLUS SIGN character MUST be specified for positive UTC offsets (i.e., ahead of UTC). The HYPHEN-MINUS character MUST be specified for negative UTC offsets (i.e., behind of UTC).

The value of "-00" and "-0000" are not allowed. The time-minute, if present, MUST NOT be 60; if absent, it defaults to zero.

6.3.6.4. Example

The following UTC offsets are given for standard time for New York (five hours behind UTC) and Geneva (one hour ahead of UTC):

6.3.6.5. Normalization

No normalization procedures are needed.

6.3.7. CAL-UTC-OFFSET

This corresponds to the UTC-OFFSET value type in 3.3.14.

6.3.7.1. Value Name

CAL-UTC-OFFSET

6.3.7.2. Purpose

Representation of a UTC offset as described in [RFC5545].

6.3.7.3. Format Definition 

cal-utc-offset = sign iso-time-hour iso-time-minute [iso-time-second]

6.3.7.4. Description:

The value can be represented in two ways:

The PLUS SIGN character MUST be specified for positive UTC offsets (i.e., ahead of UTC). The HYPHEN-MINUS character MUST be specified for negative UTC offsets (i.e., behind of UTC).

The value of "-0000" and "-000000" are not allowed. The time-second, if present, MUST NOT be 60; if absent, it defaults to zero.

6.3.7.5. Example

The following UTC offsets are given for standard time for New York (five hours behind UTC) and Geneva (one hour ahead of UTC):

6.3.7.6. Normalization

No normalization procedures are needed.

6.3.8. ISO-DATE-TIME-COMPLETE

This corresponds to the TIMESTAMP value type in 4.3.5.

6.3.8.1. Value Name

ISO-DATE-TIME-COMPLETE

6.3.8.2. Purpose

A complete date and time of day combination as specified in 4.3.2

6.3.8.3. Format Definition 

iso-date-time  = iso-date "T" iso-time

6.3.8.4. Description

This value format accepts a complete date and time of day representation, specified in 4.3.2 "Complete representations".

The value can be represented in these ways:

6.3.8.5. Examples

6.3.8.6. Normalization

No normalization procedures are needed.

6.3.9. ISO-DATE-TIME-BASIC

This corresponds to the DATE-TIME value type in 3.3.5.

6.3.9.1. Value Name

ISO-DATE-TIME-BASIC

6.3.9.2. Purpose

A date and time of day combination without non-UTC timezone as specified in 4.3.2

6.3.9.3. Format Definition 

iso-date-time-no-zone  = iso-date "T" iso-time-basic

6.3.9.4. Description

This value format accepts a complete date and time of day representation, specified in 4.3.2 "Complete representations", identical with ISO-DATE-TIME-COMPLETE, except that the "utc-offset" portion is disallowed.

The value can be represented in these ways:

Due to the lack of "utc-offset", properties that use this value type SHOULD handle time zone information with other methods such as in property parameters, such as using the "TZID" property parameter defined in [RFC5545].

6.3.9.5. Examples

6.3.9.6. Normalization

No normalization procedures are needed.

6.3.10. ISO-DATE-TIME-FLEX

This corresponds to the DATE-TIME value type in 4.3.3.

6.3.10.1. Value Name

DATE-TIME-FLEX

6.3.10.2. Purpose

This value type defines a date and time of day combination as specified in 4.3 and 5.4.2 c).

6.3.10.3. Format Definition 

iso-date-time-flex = iso-date-time-flex-date "T" iso-date-time-flex-time

iso-date-time-flex-date = iso-date / iso-date-truncated
iso-date-time-flex-time = iso-time / iso-time-reduced

6.3.10.4. Description

This value format allows for the:

6.3.10.5. Examples

6.3.10.6. Normalization

No normalization procedures are needed.

6.3.11. ISO-DATE-AND-OR-TIME

This corresponds to the DATE-AND-OR-TIME value type in 4.3.4.

6.3.11.1. Value Name

ISO-DATE-AND-OR-TIME

6.3.11.2. Purpose

Representation of a ISO-DATE-FLEX, ISO-TIME-FLEX or an ISO-DATE-TIME-FLEX value.

6.3.11.3. Format Definition 

iso-date-and-or-time = iso-date-flex /
                       "T" iso-time-flex /
                       iso-date-time-flex

6.3.11.4. Description

This value format accepts values of ISO-DATE-FLEX, ISO-TIME-FLEX and ISO-DATE-TIME-FLEX.

A stand-alone ISO-TIME value MUST be preceded by a "T" for unambiguous interpretation.

6.3.11.5. Example

6.3.11.6. Normalization

No normalization procedures are needed.

6.3.12. ISO-DURATION-COMPLETE

This corresponds to the values accepted by "duration" as specified in [ISO.8601.2004].

6.3.12.1. Value Name

ISO-DURATION-COMPLETE

6.3.12.2. Purpose

Representing a duration of time specified by 4.4.3.2 complete representation basic format.

6.3.12.3. Format Definition 


iso-duration-sign = ["+"] / "-"
iso-duration  = ( iso-duration-sign ) "P" iso-duration-value

iso-duration-value =  iso-duration-date / iso-duration-week

iso-duration-date   = iso-duration-day "T" iso-duration-time

iso-duration-week   = 1*DIGIT "W"

iso-duration-year   = 1*DIGIT "Y"
iso-duration-month  = 1*DIGIT "M"
iso-duration-day    = 1*DIGIT "D"

iso-duration-time   = iso-duration-hour iso-duration-minute
                      iso-duration-second

iso-duration-hour   = 1*DIGIT "H"
iso-duration-minute = 1*DIGIT "M"
iso-duration-second = 1*DIGIT "S"

6.3.12.4. Description

The value format is based on the complete representation basic format specified in 4.4.3.2.

It accepts the following formats ("nn" represents):

This format differs from the specification of 4.4.3.2 in the following areas:

In the case of discontinuities in the time scale, such as the change from standard time to daylight time and back, the computation of the exact duration requires the subtraction or addition of the change of duration of the discontinuity. Leap seconds MUST NOT be considered when computing an exact duration.

6.3.12.5. Examples

A duration of 15 days, 5 hours, and 20 seconds MAY be represented as

A duration of 7 weeks MAY be represented as:

6.3.12.6. Normalization

No normalization procedures are needed.

6.3.13. CAL-DURATION

This corresponds to the DURATION value type in 3.3.6.

6.3.13.1. Value Name

CAL-DURATION

6.3.13.2. Purpose

Representing a duration of time specified by 4.4.3.2 complete representation basic format, similar to ISO-DURATION, but with syntax tailored to calendaring.

6.3.13.3. Format Definition 

cal-duration         = cal-duration-sign cal-duration-no-sign
cal-duration-sign    = (["+"] / "-")
cal-duration-no-sign = "P" cal-duration-value

cal-duration-value   = ( cal-duration-date /
                         cal-duration-time /
                         cal-duration-week )

cal-duration-date   = cal-duration-day [cal-duration-time]

cal-duration-time   = "T" ( cal-duration-hour /
                            cal-duration-minute /
                            cal-duration-second )

cal-duration-week   = 1*DIGIT "W"
cal-duration-hour   = 1*DIGIT "H" [cal-duration-minute]
cal-duration-minute = 1*DIGIT "M" [cal-duration-second]
cal-duration-second = 1*DIGIT "S"
cal-duration-day    = 1*DIGIT "D"

6.3.13.4. Description

The value format is similar to ISO-DURATION and based on the complete representation basic format specified in 4.4.3.2, but given extra flexibility to calendaring usage.

It accepts the following formats ("nn" represents):

This format differs from the specification of 4.4.3.2 in the following areas:

In the case of discontinuities in the time scale, such as the change from standard time to daylight time and back, the computation of the exact duration requires the subtraction or addition of the change of duration of the discontinuity. Leap seconds MUST NOT be considered when computing an exact duration.

When computing an exact duration, the greatest order time components MUST be added first, that is, the number of days MUST be added first, followed by the number of hours, number of minutes, and number of seconds.

6.3.13.5. Example

A duration of 0 days, 0 hours, and 20 seconds SHOULD be represented as

P0DT0H0M20S

A duration of 15 days, 5 hours, and 3 hours SHOULD be represented as

P15DT5H3M

A duration of 15 days, 5 hours SHOULD be represented as

P15DT5H

A duration of 15 days SHOULD be represented as

P15D

A duration of 7 weeks SHOULD be represented as:

P7W

6.3.13.6. Normalization

No normalization procedures are needed.

6.3.14. ISO-INTERVAL

This corresponds to the values accepted by "time interval" as specified in [ISO.8601.2004].

6.3.14.1. Value Name

ISO-INTERVAL-COMPLETE

6.3.14.2. Purpose

Representation of a time interval.

6.3.14.3. Format Definition 

iso-interval     = iso-interval-explicit / iso-interval-start

iso-interval-explicit = iso-date-time "/" iso-date-time
iso-interval-start    = iso-date-time "/" iso-duration-no-sign

6.3.14.4. Description

This value format accepts a time interval representation, specified in 4.4 "Time Interval".

The value can be represented by:

a) a start and an end;

c) a start and a duration;

d) a duration and an end.

In accordance with 4.4.4.5:

In accordance with 4.4.5:

6.3.14.5. Normalization

No normalization procedures are needed.

6.3.15. CAL-INTERVAL

This corresponds to the PERIOD value type in 3.3.9.

6.3.15.1. Value Name

CAL-INTERVAL

6.3.15.2. Purpose

Representation of a time interval for calendaring.

6.3.15.3. Format Definition 

cal-interval     = cal-interval-explicit / cal-interval-start

cal-interval-explicit = iso-date-time-no-zone "/" iso-date-time-no-zone
cal-interval-start    = iso-date-time-no-zone "/" cal-duration-no-sign

6.3.15.4. Description

This value format accepts a time interval representation, specified in 4.4. "Time Interval" tailored for calendaring purposes.

The value can be represented in two ways.

As an interval with start and end:

As an interval with start and duration (positive duration only):

In accordance with 4.4.5, representations for UTC included with the component preceding the solidus shall be assumed to apply to the component following the solidus, unless a corresponding alternative is included.

6.3.15.5. Examples

6.3.15.6. Normalization

No normalization procedures are needed.

6.4. Parameter Value Types

TODO: vFormat URI in parameter values should be wrapped with DQUOTES.

6.4.1. PARAM-VALUE

6.4.1.1. Value Name

PARAM-VALUE

6.4.1.2. Purpose

This parameter value type is the basic value type for parameter values.

6.4.1.3. Format Definition 

param-value   = paramtext / quoted-string

paramtext     = *SAFE-CHAR
quoted-string = DQUOTE *QSAFE-CHAR DQUOTE

QSAFE-CHAR    = WSP / %x21 / %x23-7E / NON-US-ASCII
    ; Any character except CONTROL and DQUOTE

SAFE-CHAR     = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E
             / NON-US-ASCII
    ; Any character except CONTROL, DQUOTE, ";", ":", ","

NON-US-ASCII  = UTF8-2 / UTF8-3 / UTF8-4
     ; UTF8-2, UTF8-3, and UTF8-4 are defined in [RFC3629]

CONTROL       = %x00-08 / %x0A-1F / %x7F
     ; All the controls except HTAB

6.4.1.4. Description

Values that contain the COLON, SEMICOLON, or COMMA character separators MUST be specified as quoted-string text values.

Property parameter values that contain the DQUOTE character MUST be escaped and specified as quoted-string text values.

Property parameter values that are not in quoted-strings are case-insensitive.

An intentional line break MUST be represented by the sequence of "\n" or "\N" (BACKSLASH followed by a LATIN SMALL LETTER N (U+006E) or a LATIN CAPITAL LETTER N (U+004E)).

6.4.1.5. Example

The value cid:part1.0001@example.org in the parameter ALTREP within a DESCRIPTION property in iCalendar can be specified like this:

DESCRIPTION;ALTREP="cid:part1.0001@example.org":The Fall'98 Wild
 Wizards Conference - - Las Vegas\, NV\, USA

6.4.1.6. Normalization

Values of the PARAM-VALUE parameter data type MUST convert all line breaks ("\n" or "\N") into the character sequence "\n" (BACKSLASH followed by a LATIN SMALL LETTER N (U+006E)).

If a value of the PARAM-VALUE type is specified as paramtext (i.e., not inside a quoted-string), the value should be down-cased.

6.4.2. Conversion Of Property Value Types

All vObject property value types are allowed in parameter values.

Two primitives are defined to convert property value types into an acceptable parameter value type within vFormat:

7. Normalization

A normalization procedure can be applied to vObjects (in its various representations) to make them compatible prior to comparison, allowing for consistent results. The result of normalization processing of a vObject, is an equivalent vObject described according to vFormat representation.

The normalization method has the following properties:

There are two levels of normalization.

7.1. Approach

The goals of the normalization procedure are:

7.2. Steps

In order to serialize a vObject into normalized vFormat syntax, one would directly serialize the vObject data model into vFormat syntax.

The steps are generally described below.

  1. Normalize the vObject
    1. Normalize properties
      i.
      Normalize property parameters
      A.
      Normalize property parameter types
      B.
      Normalize property parameter values
      I.
      Sort property parameter values alphabetically.
      II.
      Concatenate property parameter values.
      C.
      Normalize property parameter key: cast to uppercase.
      D.
      Concatenate string form of property parameter key, value type and values.
      ii.
      Normalize property values
    2. Normalize inner vObjects (sub-components)
      i.
      Perform the same function as (1)

7.3. Alternative vCard representations

The normalization procedure applies to alternative vObject representations as well, including:

To normalize a vObject provided in these representations, the vObject data should be first normalized in data model form according to Section 4, and then serialized into these representations.

8. Client Implementations Recommendations

A CUA SHOULD normalize the vObject upon modification of it.

9. CardDAV

9.1. Additional Server Semantics for PUT, COPY and MOVE

This specification creates an additional precondition and postcondition for the PUT, COPY, and MOVE methods when:

9.1.1. Provide Normalized Output

Certain servers perform silent changes or cleanups of client provided vCard data when stored as address object resources, such as the order of property parameters or scrubbed values.

The resulting vCard data stored on the server (and when returned back to the client) MAY end up different than that of the client without its knowledge. It is therefore necessary for the client to be reported on such modifications.

Additional Postcondition:

  (CARDDAV:resource-normalized): Convert to normalized format.

10. CalDAV

TODO.

11. Security Considerations

Security considerations around vObject formats in the following documents MUST be adhered to:

12. IANA Considerations

New vObject and vFormat specifications produced MUST adhere to the requirements, including the normalization process, described in this document, and any exceptions or further instructions for normalization MUST be described.

12.1. vObject Component Uniqueness Properties Registration Procedure

This section defines the process to register new or modified uniqueness properties for vObject components with IANA.

The IETF will create a mailing list, vobject@ietf.org, which can be used for public discussion of vObject elements prior to registration.

The registry policy is Specification Required; any newly proposed specification MUST be reviewed by the designated expert.

The registry SHOULD contain the following note:

Note: Experts are to verify that the proposed registration
*SHOULD* provide benefits for the wider vObject community,
and provides a publicly-available standard that can be implemented in
an interoperable way. References to IETF-published documents are
preferred. The "Reference" value should point to a document that
details the implementation of this property.

The registration procedure begins when a completed registration template, defined in the sections below, is sent to vobject@ietf.org and iana@iana.org.

The designated expert is expected to tell IANA and the submitter of the registration within two weeks whether the registration is approved, approved with minor changes, or rejected with cause. When a registration is rejected with cause, it can be re-submitted if the concerns listed in the cause are addressed. Decisions made by the designated expert can be appealed to the IESG Applications Area Director, then to the IESG. They follow the normal appeals procedure for IESG decisions.

12.1.1. Registration Template for vObject Component Uniqueness Properties

A registration for a vObject Component Uniqueness Property is defined by completing the following template.

Component

The name of the component.
Property

The property of the component that is used to uniquely identify the component it belongs to.
Scope

The uniqueness scope of the aforementioned property.
Reference

The document that defines the component syntax and the uniqueness identifying property. Generally, this is where the component was originally defined, but if the uniqueness property is defined in an extension document, a reference to the extension document SHOULD be given instead.
Description

Any special notes about the usage of the uniqueness identifying property, how it is to be used, etc.
Example(s)

One or more examples of instances of the component need to be specified.

12.1.2. Initial vObject Component Uniqueness Identifiers Registry

The IANA created and maintains this registry for vObject Component Uniqueness Identifiers with pointers to appropriate reference documents.

The following table has been used to initialize the registry.

Component Property Scope Reference
VCALENDAR UID Global 5.3
VCARD UID Global 6.7.6
VEVENT UID Global 3.6.1
VTODO UID Global 3.6.2
VJOURNAL UID Global 3.6.3
VFREEBUSY UID Global 3.6.4
VTIMEZONE TZID Global 3.6.5
STANDARD DTSTART Parent 3.6.5
DAYLIGHT DTSTART Parent 3.6.5
VALARM UID Global 4
VAVAILABILITY UID Global 3.1
AVAILABLE UID Global 3.1
VPOLL UID Parent 4.5.1
VVOTER VOTER Parent 4.5.2
VOTE POLL-ITEM-ID Parent 4.5.3

13. Mapping Of Data Value Types For Existing RFCs

13.1. RFC 6350

Data Type Original Data Type
BOOLEAN BOOLEAN
ISO-DATE-FLEX DATE
ISO-DATE-AND-OR-TIME DATE-AND-OR-TIME
ISO-DATE-TIME-FLEX DATE-TIME
FLOAT FLOAT
INTEGER-64 INTEGER
LANGUAGE-TAG LANGUAGE-TAG
TEXT TEXT
ISO-TIME-FLEX TIME
ISO-TIME-COMPLETE TIMESTAMP
URI URI
ISO-UTC-OFFSET UTC-OFFSET

13.2. RFC 5545

Data Type Original Data Type
BINARY BINARY
BOOLEAN BOOLEAN
URI CAL-ADDRESS
ISO-DATE-COMPLETE DATE
ISO-DATE-TIME-BASIC DATE-TIME
CAL-DURATION DURATION
FLOAT FLOAT
INTEGER-32 INTEGER
CAL-DURATION PERIOD
TEXT TEXT
ISO-TIME-BASIC TIME
URI URI
CAL-UTC-OFFSET UTC-OFFSET
RECURMAP Section 13.2.1 RECUR

13.2.1. RECURMAP

RECURMAP is shown here instead of within the tables due to space constraints.

It is defined to be:

RECURMAP = MAP(
  KEYVALUE(FREQ, TEXT),
  KEYVALUE(UNTIL, ISO-DATE-COMPLETE / ISO-DATE-TIME-BASIC),
  KEYVALUE(COUNT, INTEGER),
  KEYVALUE(INTERVAL, INTEGER),
  KEYVALUE(BYSECOND, LIST(INTEGER)),
  KEYVALUE(BYMINUTE, LIST(INTEGER)),
  KEYVALUE(BYHOUR, LIST(INTEGER)),
  KEYVALUE(BYDAY, LIST(INTEGER)),
  KEYVALUE(BYMONTHDAY, LIST(INTEGER)),
  KEYVALUE(BYYEARDAY, LIST(INTEGER)),
  KEYVALUE(BYWEEKNO, LIST(INTEGER)),
  KEYVALUE(BYMONTH, LIST(INTEGER)),
  KEYVALUE(BYSETPOS, INTEGER),
  KEYVALUE(WKST, TEXT)
)

14. Mapping Of Component Property Value Types For Existing RFCs

14.1. VCARD Component (RFC 6350)

Properties with the default data type as TEXT.

Property Default Data Type Alt. Data Types Original Data Type
BEGIN TEXT 1\*TEXT
END TEXT 1\*TEXT
KIND TEXT 1\*TEXT
XML TEXT 1\*TEXT
FN TEXT 1\*TEXT
BDAY ISO-DATE-AND-OR-TIME TEXT 1\*date-and-or-time, 1\*text
ANNIVERSARY ISO-DATE-AND-OR-TIME TEXT 1\*date-and-or-time, 1\*text
EMAIL TEXT 1\*TEXT,
TZ TEXT URI, ISO-UTC-OFFSET 1\*TEXT, URI, UTC-OFFSET
TITLE TEXT 1\*TEXT
ROLE TEXT 1\*TEXT
NOTE TEXT 1\*TEXT
PRODID TEXT 1\*TEXT
VERSION TEXT 1\*TEXT

Properties with the default data type as URI.

Property Default Data Type Alt. Data Types Original Data Type
TEL URI TEXT 1\*text, URI
SOURCE URI URI
PHOTO URI URI
IMPP URI URI
GEO URI URI
LOGO URI URI
MEMBER URI URI
RELATED URI TEXT URI, 1\*text
UID URI URI, 1\*text
KEY URI URI, 1\*text
SOUND URI URI
URL URI URI
FBURL URI URI
CALADRURI URI URI
CALURI URI URI

Properties with FIELDSET.

Property Default Data Type Alt. Data Types Original Data Type
N FIELDSET(5\*LIST(TEXT)) TEXT
GENDER FIELDSET(2\*TEXT) TEXT
ADR FIELDSET(7\*LIST(TEXT)) TEXT
ORG FIELDSET(1\*TEXT) TEXT
CLIENTPIDMAP FIELDSET(INTEGER-64, URI) TEXT

Properties with LIST.

Property Default Data Type Alt. Data Types Original Data Type
NICKNAME LIST(TEXT) TEXT
CATEGORIES LIST(TEXT) TEXT

Properties with ISO-DATE-AND-OR-TIME.

Property Default Data Type Alt. Data Types Original Data Type
BDAY ISO-DATE-AND-OR-TIME TEXT date-and-or-time, text
ANNIVERSARY ISO-DATE-AND-OR-TIME TEXT date-and-or-time, text

Properties with ISO-DATE-TIME-COMPLETE.

Property Default Data Type Alt. Data Types Original Data Type
REV ISO-DATE-TIME-COMPLETE timestamp

Properties with LANGUAGE-TAG.

Property Default Data Type Alt. Data Types Original Data Type
LANG LANGUAGE-TAG language-tag

14.2. VCALENDAR Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
PRODID TEXT 1\*TEXT
VERSION TEXT 1\*TEXT
CALSCALE TEXT 1\*TEXT
METHOD TEXT 1\*TEXT
IANA-REGed/X- TEXT 1\*TEXT

14.3. VEVENT Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
DTSTAMP ISO-DATE-TIME-BASIC DATE-TIME
UID TEXT 1\*TEXT
DTSTART ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
CLASS TEXT 1\*TEXT
CREATED ISO-DATE-TIME-BASIC DATE-TIME
DESCRIPTION TEXT 1\*TEXT
GEO FIELDSET(2\*FLOAT) FLOAT ";" FLOAT
LAST-MODIFIED ISO-DATE-TIME-BASIC DATE-TIME
LOCATION TEXT 1\*TEXT
ORGANIZER URI cal-address
PRIORITY INTEGER-32 INTEGER
SEQUENCE INTEGER-32 INTEGER
STATUS TEXT 1\*TEXT
SUMMARY TEXT 1\*TEXT
TRANSP TEXT 1\*TEXT
URL URI URI
RECURRENCE-ID ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
RRULE RECURMAP Section 13.2.1 RECUR
DTEND ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
DURATION DURATION DURATION
ATTACH URI BINARY URI, BINARY
ATTENDEE URI cal-address
CATEGORIES LIST(TEXT) TEXT
COMMENT TEXT 1\*TEXT
CONTACT TEXT 1\*TEXT
EXDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE ) DATE-TIME, DATE
RELATED-TO TEXT 1\*TEXT
RESOURCES LIST(TEXT) TEXT
RDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE / CAL-INTERVAL) DATE-TIME, DATE, PERIOD
IANA-REGed/X- TEXT 1\*TEXT

14.4. VTODO Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
DTSTAMP ISO-DATE-TIME-BASIC DATE-TIME
UID TEXT 1\*TEXT
CLASS TEXT 1\*TEXT
CREATED ISO-DATE-TIME-BASIC DATE-TIME
COMPLETED ISO-DATE-TIME-BASIC DATE-TIME
DESCRIPTION TEXT 1\*TEXT
DTSTART ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
GEO FIELDSET(2\*FLOAT) FLOAT ";" FLOAT
LAST-MODIFIED ISO-DATE-TIME-BASIC DATE-TIME
LOCATION TEXT 1\*TEXT
ORGANIZER URI cal-address
PRIORITY INTEGER-32 INTEGER
SEQUENCE INTEGER-32 INTEGER
STATUS TEXT 1\*TEXT
SUMMARY TEXT 1\*TEXT
URL URI URI
RRULE RECURMAP Section 13.2.1 RECUR
DUE ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
DURATION DURATION DURATION
ATTACH URI BINARY URI, BINARY
ATTENDEE URI cal-address
CATEGORIES LIST(TEXT) TEXT
COMMENT TEXT 1\*TEXT
CONTACT TEXT 1\*TEXT
EXDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE ) DATE-TIME, DATE
REQUEST-STATUS TEXT 1\*TEXT
RELATED-TO TEXT 1\*TEXT
RESOURCES LIST(TEXT) TEXT
RDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE / CAL-INTERVAL) DATE-TIME, DATE, PERIOD
IANA-REGed/X- TEXT 1\*TEXT

14.5. VJOURNAL Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
DTSTAMP ISO-DATE-TIME-BASIC DATE-TIME
UID TEXT 1\*TEXT
CLASS TEXT 1\*TEXT
CREATED ISO-DATE-TIME-BASIC DATE-TIME
DTSTART ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
LAST-MODIFIED ISO-DATE-TIME-BASIC DATE-TIME
ORGANIZER URI cal-address
SEQUENCE INTEGER-32 INTEGER
STATUS TEXT 1\*TEXT
SUMMARY TEXT 1\*TEXT
URL URI URI
RRULE RECURMAP Section 13.2.1 RECUR
ATTACH URI BINARY URI, BINARY
ATTENDEE URI cal-address
CATEGORIES LIST(TEXT) TEXT
COMMENT TEXT 1\*TEXT
CONTACT TEXT 1\*TEXT
DESCRIPTION TEXT 1\*TEXT
EXDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE ) DATE-TIME, DATE
RELATED-TO TEXT 1\*TEXT
RDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE / CAL-INTERVAL) DATE-TIME, DATE, PERIOD
REQUEST-STATUS TEXT 1\*TEXT
IANA-REGed/X- TEXT 1\*TEXT

14.6. VFREEBUSY Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
DTSTAMP ISO-DATE-TIME-BASIC DATE-TIME
UID TEXT 1\*TEXT
CONTACT TEXT 1\*TEXT
DTSTART ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
DTEND ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
ORGANIZER URI cal-address
URL URI URI
ATTENDEE URI cal-address
COMMENT TEXT 1\*TEXT
FREEBUSY LIST(CAL-INTERVAL) LIST(PERIOD)
REQUEST-STATUS TEXT 1\*TEXT
IANA-REGed/X- TEXT 1\*TEXT

14.7. VTIMEZONE Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
TZID TEXT 1\*TEXT
LAST-MODIFIED ISO-DATE-TIME-BASIC DATE-TIME
TZURL URI URI
IANA-REGed/X- TEXT 1\*TEXT

14.8. STANDARD / DAYLIGHT Components (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
DTSTART ISO-DATE-TIME-BASIC ISO-DATE-COMPLETE DATE-TIME, DATE
TZOFFSETFROM CAL-UTC-OFFSET UTC-OFFSET
TZOFFSETTO CAL-UTC-OFFSET UTC-OFFSET
RRULE RECURMAP Section 13.2.1 RECUR
COMMENT TEXT 1\*TEXT
RDATE LIST( ISO-DATE-TIME-BASIC / ISO-DATE-COMPLETE / CAL-INTERVAL) DATE-TIME, DATE, PERIOD
TZNAME TEXT 1\*TEXT
IANA-REGed/X- TEXT 1\*TEXT

14.9. VALARM Component (RFC 5545)

Property Default Data Type Alt. Data Types Original Data Type
ACTION TEXT 1\*TEXT
DESCRIPTION TEXT 1\*TEXT
SUMMARY TEXT 1\*TEXT
TRIGGER DURATION ISO-DATE-TIME-BASIC DURATION, DATE-TIME
DURATION DURATION DURATION
REPEAT INTEGER-32 INTEGER
ATTACH URI BINARY URI, BINARY
ATTENDEE URI cal-address
IANA-REGed/X- TEXT 1\*TEXT

15. Mapping Of Parameter Value Types For Existing RFCs

15.1. RFC 6350

Parameter Data Type
LANGUAGE LANGUAGE-TAG
VALUE TEXT
PREF INTEGER-64
ALTID TEXT
PID TEXT
TYPE LIST(TEXT)
MEDIATYPE TEXT
CALSCALE TEXT
SORT-AS LIST(TEXT)
GEO URI
TZ TEXT

15.2. RFC 5545

Parameter Data Type
ALTREP URI
CN TEXT
CUTYPE TEXT
DELEGATED-FROM URI
DELEGATED-TO URI
DIR URI
ENCODING TEXT
FMTTYPE TEXT
FBTYPE TEXT
LANGUAGE LANGUAGE-TAG
MEMBER LIST(URI)
PARTSTAT TEXT
RANGE TEXT
RELATED TEXT
RELTYPE TEXT
ROLE TEXT
RSVP BOOLEAN
SENT-BY URI
TZID TEXT
VALUE TEXT

16. References

16.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005.
[RFC5545] Desruisseaux, B., "Internet Calendaring and Scheduling Core Object Specification (iCalendar)", RFC 5545, DOI 10.17487/RFC5545, September 2009.
[RFC5646] Phillips, A. and M. Davis, "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009.
[RFC6350] Perreault, S., "vCard Format Specification", RFC 6350, DOI 10.17487/RFC6350, August 2011.
[RFC8126] Cotton, M., Leiba, B. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017.

16.2. Informative References

[CALCONNECT-CALENDAR] The Calendaring and Scheduling Consortium, "CalConnect CALENDAR Technical Committee", April 2018.
[CALCONNECT-VCARD] The Calendaring and Scheduling Consortium, "CalConnect VCARD Technical Committee", April 2018.
[I-D.daboo-valarm-extensions] Daboo, C., "VALARM Extensions for iCalendar", Internet-Draft draft-daboo-valarm-extensions-04, June 2012.
[I-D.york-vpoll] York, E., Daboo, C. and M. Douglass, "VPOLL: Consensus Scheduling Component for iCalendar", Internet-Draft draft-york-vpoll-04, February 2017.
[IEEE.754.2008] Institute of Electrical and Electronics Engineers, "IEEE Standard 754, Standard for Binary Floating-Point Arithmetic", August 2008.
[ISO.8601.2000] ISO/IEC, "ISO 8601:2000, Data elements and interchange formats -- Information interchange -- Representation of dates and times", December 2000.
[ISO.8601.2004] ISO/IEC, "ISO 8601:2004, Data elements and interchange formats -- Information interchange -- Representation of dates and times", December 2004.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC Text on Security Considerations", BCP 72, RFC 3552, DOI 10.17487/RFC3552, July 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006.
[RFC4791] Daboo, C., Desruisseaux, B. and L. Dusseault, "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, DOI 10.17487/RFC4791, March 2007.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008.
[RFC5789] Dusseault, L. and J. Snell, "PATCH Method for HTTP", RFC 5789, DOI 10.17487/RFC5789, March 2010.
[RFC6321] Daboo, C., Douglass, M. and S. Lees, "xCal: The XML Format for iCalendar", RFC 6321, DOI 10.17487/RFC6321, August 2011.
[RFC6351] Perreault, S., "xCard: vCard XML Representation", RFC 6351, DOI 10.17487/RFC6351, August 2011.
[RFC6352] Daboo, C., "CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV)", RFC 6352, DOI 10.17487/RFC6352, August 2011.
[RFC7095] Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095, DOI 10.17487/RFC7095, January 2014.
[RFC7265] Kewisch, P., Daboo, C. and M. Douglass, "jCal: The JSON Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May 2014.
[RFC7953] Daboo, C. and M. Douglass, "Calendar Availability", RFC 7953, DOI 10.17487/RFC7953, August 2016.
[RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986, DOI 10.17487/RFC7986, October 2016.
[RFC8259] Bray, T., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017.
[vCard21] Internet Mail Consortium, "vCard - The Electronic Business Card Version 2.1", September 1996.
[VPATCH] Daboo, C. and K. Murchison, "The iCalendar VPATCH Component (draft)", October 2016.

Appendix A. Normalization Examples for vFormat

Original:

BEGIN:VOBJECT
PROPERTY1:10
PROPERTY2:20
END:VOBJECT

Normalized:

BEGIN:VOBJECT
PROPERTY1:10
PROPERTY2:20
END:VOBJECT

A.1. vCard

Original:

BEGIN:VCARD
VERSION:4.0
KIND:individual
FN:Martin Van Buren
N:Van Buren;Martin;;;Hon.
TEL;VALUE=uri;PREF=1;TYPE="voice";TYPE="home":tel:+1-888-888-8888;ext=8888
END:VCARD

Normalized:

BEGIN:VCARD
VERSION:4.0
KIND:individual
FN:Martin Van Buren
N:Van Buren;Martin;;;Hon.
TEL;VALUE=uri;PREF=1;TYPE="voice,home":tel:+1-888-888-8888;ext=8888
END:VCARD

Appendix B. Acknowledgements

The authors wish to thank their families and the following parties who helped this materialize and for their support of a better and vObject-enabled world:

This specification was developed by the CalConnect TC-VCARD committee.

Authors' Addresses

Ronald Henry Tse Ribose Suite 1111, 1 Pedder Street Central, Hong Kong EMail: ronald.tse@ribose.com URI: https://www.ribose.com
Peter Kwan Yu Tam Ribose Suite 1111, 1 Pedder Street Central, Hong Kong EMail: peter.tam@ribose.com URI: https://www.ribose.com
Cyrus Daboo Apple Inc. 1 Infinite Loop Cupertino, CA 95014 United States of America EMail: cyrus@daboo.name URI: https://www.apple.com
Kenneth Murchison FastMail Pty Ltd Level 2, 114 William Street Melbourne, VIC 3000 Australia EMail: murch@fastmailteam.com