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{{Short description|Expanded set of characters on the URI protocol}}
⚫
The '''Internationalized Resource Identifier''' ('''IRI''') – is an [[Internet Standard|internet protocol standard]] which extends the [[ASCII]] characters subset of the [[Uniform Resource Identifier]] (URI) protocol.<ref name="gangemi">{{cite journal|last1=Gangemi|first1=Aldo|last2=Presutti|first2=Valentina|date=2006|title=The bourne identity of a web resource|url=http://ra.ethz.ch/CDstore/www2006/www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf|journal=Proceedings of Identity Reference and the Web Workshop (IRW)|series=Laboratory for Applied Ontology|location=Roma, Italy|publisher=National Research Council (ISTC-CNR)|page=3|quote=Notice that IRIs (Internationalized Resource Identifier) [11] are supposed to replace URIs in next future.}}</ref><ref>{{Cite web|url=https://tools.ietf.org/html/rfc3987#section-1.3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|date=|website=tools.ietf.org|language=en|archive-url=|archive-date=|dead-url=|access-date=2018-06-09|quote=This document defines a new protocol element, the Internationalized Resource Identifier (IRI), as a complement to the Uniform Resource Identifier (URI). An IRI is a sequence of characters from the Universal Character Set (Unicode/ISO 10646). A mapping from IRIs to URIs is defined, which means that IRIs can be used instead of URIs, where appropriate, to identify resources. The approach of defining a new protocol element was chosen instead of extending or changing the definition of URIs.}}</ref><ref>{{Cite web|url=https://tools.ietf.org/html/rfc3987#page-3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|date=|website=tools.ietf.org|publisher=|language=en|archive-url=|archive-date=|dead-url=|access-date=2018-06-09|quote=This document defines a new protocol element called Internationalized Resource Identifier (IRI) by extending the syntax of URIs to a much wider repertoire of characters. It also defines "internationalized" versions corresponding to other constructs from [RFC3986], such as URI references. The syntax of IRIs is defined in section 2, and the relationship between IRIs and URIs in section 3.}}</ref> It was defined by the [[Internet Engineering Task Force]] (IETF) in 2005 as a new internet standard to extend the existing URI scheme. The primary standard is defined by the RFC 3987.<ref>{{Cite web|url=http://tools.ietf.org/html/rfc3987|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|language=en|access-date=2018-06-09}}</ref><ref>{{Cite web|url=https://tools.ietf.org/html/rfc3987#section-1.3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|language=en|access-date=2018-06-09}}</ref> While URIs are limited to a subset of the ASCII character set, IRIs may contain characters from the [[Universal Character Set]] (Unicode/[[ISO 10646]]), including Chinese, Japanese [[kanji]], [[Korean alphabet|Korean]], and [[Cyrillic script|Cyrillic]] characters.
{{Infobox technology standard
| title = Internationalized Resource Identifier
| long_name = Internationalized Resource Identifier
| status = Proposed Standard
| year_started = {{Start date|2002|04|22|df=y}}
| first_published = {{Start date|2002|04|22|df=y}}
| version_date = {{Start date|2020|01|21|df=y}}
| authors = {{plainlist|
* Martin Dürst
* Michel Suignard
}}
| organization = [[Internet Engineering Task Force|{{abbr|IETF|Internet Engineering Task Force}}]]
| domain = [[Character encoding]]
| website = {{IETF RFC|3987}}
| abbreviation = IRI
| base_standards = {{plainlist|
* [[Internationalized domain name|{{abbr|IDNA|Internationalized Domain Names in Applications}}]]
* [[UTF-8]]
* [[Unicode_equivalence#Normalization|Unicode Normalization]] (UAX #15)
}}
}}

⚫
The '''Internationalized Resource Identifier''' ('''IRI''') is an [[Internet Standard|internet protocol standard]] which builds on the [[Uniform Resource Identifier]] (URI) protocol by greatly expanding the set of permitted characters.<ref name="gangemi">{{cite journal|last1=Gangemi|first1=Aldo|last2=Presutti|first2=Valentina|date=2006|title=The bourne identity of a web resource|url=http://ra.ethz.ch/CDstore/www2006/www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf|journal=Proceedings of Identity Reference and the Web Workshop (IRW)|series=Laboratory for Applied Ontology|page=3|quote=Notice that IRIs (Internationalized Resource Identifier) [11] are supposed to replace URIs in next future.}}</ref><ref>{{Cite journal|url=https://tools.ietf.org/html/rfc3987#section-1.3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|date=January 2005 |language=en|access-date=2018-06-09|quote=This document defines a new protocol element, the Internationalized Resource Identifier (IRI), as a complement to the Uniform Resource Identifier (URI). An IRI is a sequence of characters from the Universal Character Set (Unicode/ISO 10646). A mapping from IRIs to URIs is defined, which means that IRIs can be used instead of URIs, where appropriate, to identify resources. The approach of defining a new protocol element was chosen instead of extending or changing the definition of URIs.}}</ref><ref>{{Cite journal|url=https://tools.ietf.org/html/rfc3987#page-3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|date=January 2005 |language=en|access-date=2018-06-09|quote=This document defines a new protocol element called Internationalized Resource Identifier (IRI) by extending the syntax of URIs to a much wider repertoire of characters. It also defines "internationalized" versions corresponding to other constructs from [RFC3986], such as URI references. The syntax of IRIs is defined in section 2, and the relationship between IRIs and URIs in section 3.}}</ref> It was defined by the [[Internet Engineering Task Force]] (IETF) in 2005 in RFC 3987. While URIs are limited to a subset of the [[US-ASCII]] character set (characters outside that set must be mapped to octets according to some unspecified character encoding, then [[percent-encoding|percent-encoded]]), IRIs may additionally contain most characters from the [[Universal Character Set]] (Unicode/[[ISO 10646]]),<ref>{{Cite journal|url=http://tools.ietf.org/html/rfc3987|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|date=January 2005 |language=en|access-date=2018-06-09}}</ref><ref>{{Cite journal|url=https://tools.ietf.org/html/rfc3987#section-1.3|title=Internationalized Resource Identifiers (IRIs)|last=Suignard|first=Michel|website=tools.ietf.org|date=January 2005 |language=en|access-date=2018-06-09}}</ref> including [[Chinese characters| Chinese]], [[Japanese writing system|Japanese]], [[Korean alphabet|Korean]], and [[Cyrillic script|Cyrillic]] characters.


== Syntax ==
== Syntax ==
Line 5: Line 28:


== Compatibility ==
== Compatibility ==
IRIs are mapped to URIs to retain backwards-compatibility with systems that do not support the new format.<ref name=rfc3987>{{cite journal|last1=Duerst|first1=M.|title=RFC 3987|journal=Network Working Group|date=2005|volume=Standards Track|url=http://tools.ietf.org/html/rfc3987|accessdate=12 October 2014|publisher=Internet Engineering Task Force}}</ref>
IRIs are mapped to URIs to retain backwards-compatibility with systems that do not support the new format.<ref name=rfc3987>{{cite journal|last1=Duerst|first1=M.|title=RFC 3987|journal=Network Working Group|date=2005|volume=Standards Track|url=http://tools.ietf.org/html/rfc3987|access-date=12 October 2014}}</ref>


For applications and protocols that do not allow direct consumption of IRIs, the IRI should first be converted to Unicode using [[Unicode equivalence|canonical composition normalization (NFC)]], if not already in Unicode format.
For applications and protocols that do not allow direct consumption of IRIs, the IRI should first be converted to Unicode using [[Unicode equivalence|canonical composition normalization (NFC)]], if not already in Unicode format.
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ASCII code points that are invalid URI characters ''may'' be encoded the same way, depending on implementation.<ref name="rfc3987" />
ASCII code points that are invalid URI characters ''may'' be encoded the same way, depending on implementation.<ref name="rfc3987" />


This conversion is easily reversible; by definition, converting an IRI to an URI and back again will yield an IRI that is semantically equivalent to the original IRI, even though it may differ in exact representation.<ref>{{cite book|last1=Hendler|first1=Hrsg. Dieter Fensel; Hrsg. John Domingue; Hrsg. James A.|title=Handbook of Semantic Web Technologies|date=2010|publisher=Springer-Verlag GmbH|location=Berlin|isbn=978-3-540-92912-3|edition=1. Aufl.|url=https://books.google.com/books?id=sdEFvSb9WNsC&dq|accessdate=12 October 2014}}</ref>
This conversion is easily reversible; by definition, converting an IRI to an URI and back again will yield an IRI that is semantically equivalent to the original IRI, even though it may differ in exact representation.<ref>{{cite book|last1=Hendler|first1=Hrsg. Dieter Fensel; Hrsg. John Domingue; Hrsg. James A.|title=Handbook of Semantic Web Technologies|date=2010|publisher=Springer-Verlag GmbH|location=Berlin|isbn=978-3-540-92912-3|edition=1. Aufl.|url=https://books.google.com/books?id=sdEFvSb9WNsC|access-date=12 October 2014}}</ref>


Some protocols may impose further transformations; e.g. [[Punycode]] for [[Domain Name System|DNS]] labels.
Some protocols may impose further transformations; e.g. [[Punycode]] for [[Domain Name System|DNS]] labels.


== Advantages ==
== Advantages ==
There are reasons to see URIs displayed in different languages; mostly, it makes it easier for users who are unfamiliar with the Latin (A-Z) alphabet. Assuming that it isn't too difficult for anyone to replicate arbitrary Unicode on their keyboards, this can make the [[URI]] system more accessible.<ref>{{cite web|last1=Clark|first1=Kendall|title=Internationalizing the URI|url=http://www.xml.com/pub/a/2003/05/07/deviant.html|publisher=O’Reilly Media, Inc.|accessdate=12 October 2014|date=2003-05-07}}</ref>
There are reasons to see URIs displayed in different languages; mostly, it makes it easier for users who are unfamiliar with the Latin (A–Z) alphabet. Assuming that it isn't too difficult for anyone to replicate arbitrary Unicode on their keyboards, this can make the [[URI]] system more accessible.<ref>{{cite web|last1=Clark|first1=Kendall|title=Internationalizing the URI|url=http://www.xml.com/pub/a/2003/05/07/deviant.html|publisher=O’Reilly Media, Inc.|access-date=12 October 2014|date=2003-05-07}}</ref>


== Disadvantages ==
== Disadvantages ==
Mixing IRIs and [[ASCII]] [[uniform resource identifier|URIs]] can make it much easier to execute [[phishing]] attacks that trick someone into believing they are on a different site that they really are. For example, one can replace an ASCII "a" in <code>www.myfictionalbank.com</code> with the Unicode look-alike "[[α]]" to give <code>www.myfictionαlbank.com</code> and point that IRI to a malicious site. This is known as an [[IDN homograph attack]].
Mixing IRIs and [[ASCII]] [[uniform resource identifier|URIs]] can make it much easier to execute [[phishing]] attacks that trick someone into believing they are on a different site than they really are. For example, one can replace an ASCII "a" in <code>www.myfictionalbank.com</code> with the Unicode look-alike "[[α]]" to give <code>www.myfictionαlbank.com</code> and point that IRI to a malicious site. This is known as an [[IDN homograph attack]].


While a URI does not provide people with a way to specify Web resources using their own alphabets, an IRI does not make clear how Web resources can be accessed with keyboards that are not capable of generating the requisite internationalized characters. This does mean that IRIs are now handled in a way very similar to many other software which might require the use of a non-keyboard [[input method]] when dealing with texts in various languages.
While a URI does not provide people with a way to specify web resources using their own alphabets, an IRI does not make clear how web resources can be accessed with keyboards that are not capable of generating the requisite internationalized characters. This means that IRIs are now handled in a way very similar to many other software which might require the use of a non-keyboard [[input method]] when dealing with texts in various languages.


== See also ==
== See also ==
Line 37: Line 60:


== External links ==
== External links ==
⚫
* [https://datatracker.ietf.org/doc/rfc3987/ RFC 3987: Proposed Standard of Internationalized Resource Identifiers (IRIs)]
* [http://www.w3.org/International/ W3C Internationalization Activity]
* [http://www.w3.org/International/ W3C Internationalization Activity]
* [https://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml#uri-schemes-3 IANA List of Registered URI Schemes]
⚫
* [http://tools.ietf.org/html/rfc3987 RFC 3987 : Proposed Standard of Internationalized Resource Identifiers (IRIs)]
* [http://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml#uri-schemes-3 IANA List of Registered URI Schemes]
* [https://www.w3.org/International/iri-edit/spec-use-survey.html Survey of use of IRIs in W3C Specs]


{{Semantic Web|state=collapsed}}
{{Semantic Web|state=collapsed}}
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[[Category:Application layer protocols]]
[[Category:Application layer protocols]]
[[Category:Emerging technologies]]
[[Category:Internet protocols]]
[[Category:Internet protocols]]
[[Category:Internet Standards]]
[[Category:Internet Standards]]

Latest revision as of 10:27, 12 December 2023

Internationalized Resource Identifier
Internationalized Resource Identifier
AbbreviationIRI
StatusProposed Standard
Year started22 April 2002 (2002-04-22)
First published22 April 2002 (2002-04-22)
Latest version21 January 2020 (2020-01-21)
OrganizationIETF
Authors
  • Martin Dürst
  • Michel Suignard
Base standards
DomainCharacter encoding
WebsiteRFC 3987

The Internationalized Resource Identifier (IRI) is an internet protocol standard which builds on the Uniform Resource Identifier (URI) protocol by greatly expanding the set of permitted characters.[1][2][3] It was defined by the Internet Engineering Task Force (IETF) in 2005 in RFC 3987. While URIs are limited to a subset of the US-ASCII character set (characters outside that set must be mapped to octets according to some unspecified character encoding, then percent-encoded), IRIs may additionally contain most characters from the Universal Character Set (Unicode/ISO 10646),[4][5] including Chinese, Japanese, Korean, and Cyrillic characters.

Syntax[edit]

IRIs extend URIs by using the Universal Character Set, where URIs were limited to ASCII, with far fewer characters. IRIs may be represented by a sequence of octets but by definition are defined as a sequence of characters, because IRIs may be spoken or written by hand.[6]

Compatibility[edit]

IRIs are mapped to URIs to retain backwards-compatibility with systems that do not support the new format.[6]

For applications and protocols that do not allow direct consumption of IRIs, the IRI should first be converted to Unicode using canonical composition normalization (NFC), if not already in Unicode format.

All non-ASCII code points in the IRI should next be encoded as UTF-8, and the resulting bytes percent-encoded, to produce a valid URI.

Example: The IRI https://en.wiktionary.org/wiki/Ῥόδος becomes the URI https://en.wiktionary.org/wiki/%E1%BF%AC%CF%8C%CE%B4%CE%BF%CF%82

ASCII code points that are invalid URI characters may be encoded the same way, depending on implementation.[6]

This conversion is easily reversible; by definition, converting an IRI to an URI and back again will yield an IRI that is semantically equivalent to the original IRI, even though it may differ in exact representation.[7]

Some protocols may impose further transformations; e.g. Punycode for DNS labels.

Advantages[edit]

There are reasons to see URIs displayed in different languages; mostly, it makes it easier for users who are unfamiliar with the Latin (A–Z) alphabet. Assuming that it isn't too difficult for anyone to replicate arbitrary Unicode on their keyboards, this can make the URI system more accessible.[8]

Disadvantages[edit]

Mixing IRIs and ASCII URIs can make it much easier to execute phishing attacks that trick someone into believing they are on a different site than they really are. For example, one can replace an ASCII "a" in www.myfictionalbank.com with the Unicode look-alike "α" to give www.myfictionαlbank.com and point that IRI to a malicious site. This is known as an IDN homograph attack.

While a URI does not provide people with a way to specify web resources using their own alphabets, an IRI does not make clear how web resources can be accessed with keyboards that are not capable of generating the requisite internationalized characters. This means that IRIs are now handled in a way very similar to many other software which might require the use of a non-keyboard input method when dealing with texts in various languages.

See also[edit]

References[edit]

  1. ^ Gangemi, Aldo; Presutti, Valentina (2006). "The bourne identity of a web resource" (PDF). Proceedings of Identity Reference and the Web Workshop (IRW). Laboratory for Applied Ontology: 3. Notice that IRIs (Internationalized Resource Identifier) [11] are supposed to replace URIs in next future.
  2. ^ Suignard, Michel (January 2005). "Internationalized Resource Identifiers (IRIs)". tools.ietf.org. Retrieved 2018-06-09. This document defines a new protocol element, the Internationalized Resource Identifier (IRI), as a complement to the Uniform Resource Identifier (URI). An IRI is a sequence of characters from the Universal Character Set (Unicode/ISO 10646). A mapping from IRIs to URIs is defined, which means that IRIs can be used instead of URIs, where appropriate, to identify resources. The approach of defining a new protocol element was chosen instead of extending or changing the definition of URIs.
  3. ^ Suignard, Michel (January 2005). "Internationalized Resource Identifiers (IRIs)". tools.ietf.org. Retrieved 2018-06-09. This document defines a new protocol element called Internationalized Resource Identifier (IRI) by extending the syntax of URIs to a much wider repertoire of characters. It also defines "internationalized" versions corresponding to other constructs from [RFC3986], such as URI references. The syntax of IRIs is defined in section 2, and the relationship between IRIs and URIs in section 3.
  4. ^ Suignard, Michel (January 2005). "Internationalized Resource Identifiers (IRIs)". tools.ietf.org. Retrieved 2018-06-09.
  5. ^ Suignard, Michel (January 2005). "Internationalized Resource Identifiers (IRIs)". tools.ietf.org. Retrieved 2018-06-09.
  6. ^ a b c Duerst, M. (2005). "RFC 3987". Network Working Group. Standards Track. Retrieved 12 October 2014.
  7. ^ Hendler, Hrsg. Dieter Fensel; Hrsg. John Domingue; Hrsg. James A. (2010). Handbook of Semantic Web Technologies (1. Aufl. ed.). Berlin: Springer-Verlag GmbH. ISBN 978-3-540-92912-3. Retrieved 12 October 2014.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. ^ Clark, Kendall (2003-05-07). "Internationalizing the URI". O’Reilly Media, Inc. Retrieved 12 October 2014.

External links[edit]

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