One document matched: draft-ietf-json-rfc4627bis-02.xml
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<rfc
category="std"
docName="draft-ietf-json-rfc4627bis-02"
ipr="trust200902"
>
<front>
<title abbrev="JSON bis">The application/json Media Type for JavaScript Object Notation (JSON)</title>
<author fullname="Douglas Crockford" initials="D." surname="Crockford">
<organization>JSON.org</organization>
<address>
<email>douglas@crockford.com</email>
</address>
</author>
<date year="2013" month="June"/>
<area>Operations and Management</area>
<workgroup>Operations Area Working Group</workgroup>
<abstract>
<t>JavaScript Object Notation (JSON) is a lightweight, text-based,
language-independent data interchange format. It was derived from
the ECMAScript Programming Language Standard. JSON defines a small
set of formatting rules for the portable representation of structured
data.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>JavaScript Object Notation (JSON) is a text format for the
serialization of structured data. It is derived from the object
literals of JavaScript, as defined in the ECMAScript Programming
Language Standard, Third Edition <xref target="ECMA"/>.</t>
<t>JSON can represent four primitive types (strings, numbers, booleans,
and null) and two structured types (objects and arrays).</t>
<t>A string is a sequence of zero or more Unicode characters <xref target="UNICODE"/>.</t>
<t>An object is an unordered collection of zero or more name/value
pairs, where a name is a string and a value is a string, number,
boolean, null, object, or array.</t>
<t>An array is an ordered sequence of zero or more values.</t>
<t>The terms "object" and "array" come from the conventions of
JavaScript.</t>
<t>JSON's design goals were for it to be minimal, portable, textual, and
a subset of JavaScript.</t>
<section title="Conventions Used in This Document">
<t>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 <xref target="RFC2119" />.</t>
<t>The grammatical rules in this document are to be interpreted as
described in <xref target="RFC4234" />.</t>
</section>
<section title="Changes from RFC 4627">
<t>This section lists all changes between this document
and the text in RFC 4627.</t>
<t><list style="symbols">
<t>Applied errata #607 from RFC 4627 to correctly align the artwork for the definition of
"object".</t>
</list></t>
</section>
</section>
<section title="JSON Grammar">
<t>A JSON text is a sequence of tokens. The set of tokens includes six
structural characters, strings, numbers, and three literal names.</t>
<t>A JSON text is a serialized object or array.</t>
<figure><artwork>
JSON-text = object / array
</artwork></figure>
<t>These are the six structural characters:</t>
<figure><artwork>
begin-array = ws %x5B ws ; [ left square bracket
begin-object = ws %x7B ws ; { left curly bracket
end-array = ws %x5D ws ; ] right square bracket
end-object = ws %x7D ws ; } right curly bracket
name-separator = ws %x3A ws ; : colon
value-separator = ws %x2C ws ; , comma
</artwork></figure>
<t>Insignificant whitespace is allowed before or after any of the six
structural characters.</t>
<figure><artwork>
ws = *(
%x20 / ; Space
%x09 / ; Horizontal tab
%x0A / ; Line feed or New line
%x0D ; Carriage return
)
</artwork></figure>
<section title="Values">
<t>A JSON value MUST be an object, array, number, or string, or one of
the following three literal names:</t>
<figure><artwork>
false null true
</artwork></figure>
<t>The literal names MUST be lowercase. No other literal names are
allowed.</t>
<figure><artwork>
value = false / null / true / object / array / number / string
false = %x66.61.6c.73.65 ; false
null = %x6e.75.6c.6c ; null
true = %x74.72.75.65 ; true
</artwork></figure>
</section>
<section title="Objects">
<t>An object structure is represented as a pair of curly brackets
surrounding zero or more name/value pairs (or members). A name is a
string. A single colon comes after each name, separating the name
from the value. A single comma separates a value from a following
name. The names within an object SHOULD be unique.</t>
<figure><artwork>
object = begin-object [ member *( value-separator member ) ]
end-object
member = string name-separator value
</artwork></figure>
</section>
<section title="Arrays">
<t>An array structure is represented as square brackets surrounding zero
or more values (or elements). Elements are separated by commas.</t>
<figure><artwork>
array = begin-array [ value *( value-separator value ) ] end-array
</artwork></figure>
</section>
<section title="Numbers">
<t>The representation of numbers is similar to that used in most
programming languages. A number contains an integer component that
may be prefixed with an optional minus sign, which may be followed by
a fraction part and/or an exponent part.</t>
<t>Octal and hex forms are not allowed. Leading zeros are not allowed.</t>
<t>A fraction part is a decimal point followed by one or more digits.</t>
<t>An exponent part begins with the letter E in upper or lowercase,
which may be followed by a plus or minus sign. The E and optional
sign are followed by one or more digits.</t>
<t>Numeric values that cannot be represented as sequences of digits
(such as Infinity and NaN) are not permitted.</t>
<figure><artwork>
number = [ minus ] int [ frac ] [ exp ]
decimal-point = %x2E ; .
digit1-9 = %x31-39 ; 1-9
e = %x65 / %x45 ; e E
exp = e [ minus / plus ] 1*DIGIT
frac = decimal-point 1*DIGIT
int = zero / ( digit1-9 *DIGIT )
minus = %x2D ; -
plus = %x2B ; +
zero = %x30 ; 0
</artwork></figure>
</section>
<section title="Strings">
<t>The representation of strings is similar to conventions used in the C
family of programming languages. A string begins and ends with
quotation marks. All Unicode characters may be placed within the
quotation marks except for the characters that must be escaped:
quotation mark, reverse solidus, and the control characters (U+0000
through U+001F).</t>
<t>Any character may be escaped. If the character is in the Basic
Multilingual Plane (U+0000 through U+FFFF), then it may be
represented as a six-character sequence: a reverse solidus, followed
by the lowercase letter u, followed by four hexadecimal digits that
encode the character's code point. The hexadecimal letters A though
F can be upper or lowercase. So, for example, a string containing
only a single reverse solidus character may be represented as
"\u005C".</t>
<t>Alternatively, there are two-character sequence escape
representations of some popular characters. So, for example, a
string containing only a single reverse solidus character may be
represented more compactly as "\\".</t>
<t>To escape an extended character that is not in the Basic Multilingual
Plane, the character is represented as a twelve-character sequence,
encoding the UTF-16 surrogate pair. So, for example, a string
containing only the G clef character (U+1D11E) may be represented as
"\uD834\uDD1E".</t>
<figure><artwork>
string = quotation-mark *char quotation-mark
char = unescaped /
escape (
%x22 / ; " quotation mark U+0022
%x5C / ; \ reverse solidus U+005C
%x2F / ; / solidus U+002F
%x62 / ; b backspace U+0008
%x66 / ; f form feed U+000C
%x6E / ; n line feed U+000A
%x72 / ; r carriage return U+000D
%x74 / ; t tab U+0009
%x75 4HEXDIG ) ; uXXXX U+XXXX
escape = %x5C ; \
quotation-mark = %x22 ; "
unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
</artwork></figure>
</section>
</section>
<section title="Encoding">
<t>JSON text SHALL be encoded in Unicode. The default encoding is
UTF-8.</t>
<t>Since the first two characters of a JSON text will always be ASCII
characters [RFC0020], it is possible to determine whether an octet
stream is UTF-8, UTF-16 (BE or LE), or UTF-32 (BE or LE) by looking
at the pattern of nulls in the first four octets.</t>
<figure><artwork>
00 00 00 xx UTF-32BE
00 xx 00 xx UTF-16BE
xx 00 00 00 UTF-32LE
xx 00 xx 00 UTF-16LE
xx xx xx xx UTF-8
</artwork></figure>
</section>
<section title="Parsers">
<t>A JSON parser transforms a JSON text into another representation. A
JSON parser MUST accept all texts that conform to the JSON grammar.
A JSON parser MAY accept non-JSON forms or extensions.</t>
<t>An implementation may set limits on the size of texts that it
accepts. An implementation may set limits on the maximum depth of
nesting. An implementation may set limits on the range of numbers.
An implementation may set limits on the length and character contents
of strings.</t>
</section>
<section title="Generators">
<t>A JSON generator produces JSON text. The resulting text MUST
strictly conform to the JSON grammar.</t>
</section>
<section title="IANA Considerations" anchor="ianacons">
<figure><artwork>
The MIME media type for JSON text is application/json.
Type name: application
Subtype name: json
Required parameters: n/a
Optional parameters: n/a
Encoding considerations: 8bit if UTF-8; binary if UTF-16 or UTF-32
JSON may be represented using UTF-8, UTF-16, or UTF-32. When JSON
is written in UTF-8, JSON is 8bit compatible. When JSON is
written in UTF-16 or UTF-32, the binary content-transfer-encoding
must be used.
Security considerations:
Generally there are security issues with scripting languages. JSON
is a subset of JavaScript, but it is a safe subset that excludes
assignment and invocation.
A JSON text can be safely passed into JavaScript's eval() function
(which compiles and executes a string) if all the characters not
enclosed in strings are in the set of characters that form JSON
tokens. This can be quickly determined in JavaScript with two
regular expressions and calls to the test and replace methods.
</artwork></figure>
<figure><artwork>
var my_JSON_object = !(/[^,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]/.test(
text.replace(/"(\\.|[^"\\])*"/g, ''))) &&
eval('(' + text + ')');
</artwork></figure>
<figure><artwork>
Interoperability considerations: n/a
Published specification: RFC 4627
Applications that use this media type:
JSON has been used to exchange data between applications written
in all of these programming languages: ActionScript, C, C#,
ColdFusion, Common Lisp, E, Erlang, Java, JavaScript, Lua,
Objective CAML, Perl, PHP, Python, Rebol, Ruby, and Scheme.
Additional information:
Magic number(s): n/a
File extension(s): .json
Macintosh file type code(s): TEXT
Person & email address to contact for further information:
Douglas Crockford
douglas@crockford.com
Intended usage: COMMON
Restrictions on usage: none
Author:
Douglas Crockford
douglas@crockford.com
Change controller:
Douglas Crockford
douglas@crockford.com
</artwork></figure>
</section>
<section title="Security Considerations">
<t>See Security Considerations in <xref target="ianacons"/>.</t>
</section>
<section title="Examples">
<t>This is a JSON object:</t>
<figure><artwork>
{
"Image": {
"Width": 800,
"Height": 600,
"Title": "View from 15th Floor",
"Thumbnail": {
"Url": "http://www.example.com/image/481989943",
"Height": 125,
"Width": "100"
},
"IDs": [116, 943, 234, 38793]
}
}
</artwork></figure>
<t>Its Image member is an object whose Thumbnail member is an object
and whose IDs member is an array of numbers.</t>
<t>This is a JSON array containing two objects:</t>
<figure><artwork>
[
{
"precision": "zip",
"Latitude": 37.7668,
"Longitude": -122.3959,
"Address": "",
"City": "SAN FRANCISCO",
"State": "CA",
"Zip": "94107",
"Country": "US"
},
{
"precision": "zip",
"Latitude": 37.371991,
"Longitude": -122.026020,
"Address": "",
"City": "SUNNYVALE",
"State": "CA",
"Zip": "94085",
"Country": "US"
}
]
</artwork></figure>
</section>
</middle>
<back>
<references title="Normative References">
<reference anchor="ECMA" target="http://www.ecma-international.org/publications/files/ecma-st/ECMA-262.pdf">
<front>
<title abbrev="ECMAScript 3rd">
ECMAScript Language Specification 3rd Edition
</title>
<author>
<organization>European Computer Manufacturers Association</organization>
<address />
</author>
<date month="December" year="1999"/>
</front>
</reference>
&RFC0020;
&RFC2119;
&RFC4234;
<reference anchor="UNICODE" target="http://www.unicode.org/versions/Unicode4.1.0/">
<front>
<title abbrev="Unicode 4.0">
The Unicode Standard, Version 4.0
</title>
<author>
<organization>The Unicode Consortium</organization>
<address />
</author>
<date year="2003"/>
</front>
</reference>
</references>
</back>
</rfc>
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