Network Working Group Y. YONEYA
Internet-Draft JPRS
Intended status: Informational Feb 26, 2007
Expires: August 30, 2007
IRI recognition in Applications
draft-yoneya-iri-recognition-00.txt
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Copyright (C) The IETF Trust (2007).
Abstract
Nowadays access to the Internet is a part of daily life. Users see
URIs written in various ways on various media, recognize them as "the
Internet Addresses", and use them to access to the Internet. Many
application programs recognize URIs automatically and make links to
them, so the users can access to the URIs very easily. But, at this
moment, most of application programs can't recognize
Internationalized Domain Name (IDN) and Internationalized URI (IRI)
correctly, so users will feel stress when using IDNs and IRIs.
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Utilization of the IDNs and the IRIs are getting higher. Therefore,
improvement of the application programs are highly recommended. This
document is intended to be an application developpers' guideline for
recognizing and corresponding to IDNs/IRIs correctly.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Delimiting an IRI in Context . . . . . . . . . . . . . . . . . 3
3. Passing an IRI between applications . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
7. Change History . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. draft-yoneya-ima-downgrade: Version 00 . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 7
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1. Introduction
Since most of major Web browsers are compliant to Internationalized
Domain Name (IDN) [RFC3490] and Internationalized URI (IRI)
[RFC3987], utilization of the IDNs and the IRIs are getting higher.
However, IDN/IRI aware application programs (hereinafter,
applications) other than Web browsers are very few.
From users' point of view, applications recognizing IRIs in context
and taking appropriate action as well as performed for URIs are
prefered. For example, copy-and-paste the IRI from an application to
another application, click the IRI to invoke external application,
and so on. In principle, there is no difference between recognizing
URI and IRI. But, in reality, many applications can't recognize IRIs
although can recognize URIs.
General method for delimiting a URI in context is already defined in
the Appendix C. of [RFC3986]. To apply the method to IRIs in
applications, this document tries to clarify ambiguous point and
relations between caller and callee applications.
2. Delimiting an IRI in Context
In Appendix C. of [RFC3986], main points to delimit a URI are as
follows:
1. Wrap URI with double-quotes, e.g.
"http://www.example.com/"
2. Wrap URI with angle brackets, e.g.
<http://www.example.com/>
3. Delimit by using whitespace, e.g.
http://www.example.com/
The first two points are clear. When applications find a URI scheme
name with preceding double-quote or left angle bracket, then
applications search for corresponding double-quote or right angle
bracket and recognize the string within double-quotes or angle
brackets is a URI. Note that the double-quotes and the angle
brackets are not part of a URI. This method is also valid for an
IRI.
The last point is ambiguous to two things. The first one is the
definition of whitespace itself. In applications, characters marked
as White_Space in [PropList] defined by [Unicode] should be
recognized as whitespace. The seconde one is whether a URI have to
be wrapped by whitespaces. The beginning of a URI scheme name is
unambiguous, therefore, prepending whitespace is not necessary. When
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applications find a URI scheme name without preceding double-quote or
left angle bracket, then applications search for whitespace and
recognize the string terminated by whitespace is a URI. Note that
the whitespaces are not part of a URI. This method is also valid for
an IRI.
3. Passing an IRI between applications
IDNs and IRIs have its ASCII compatible encoding (hereinafter, ACE)
form according to its specification. For example, IDNs have Punycode
form, and IRIs have %-encoding form. Generally, when passing an IRI
as a protocol parameter between applications, it should be in ACE
form. But, there is a big difference between applications being able
to recognize IRIs and being able to convert IRIs to ACE form. At the
User Interface level, passing an IRIs in IRI form is more convenient.
For example, when copying the IRI which is recognized automatically
by an application and pasting to another application, it should be in
IRI form.
When an application passes an IRI to another application by users'
action such as link click, there might be some combinations.
Following is a matrix which describes combinations conceptually.
+-------------------------+
| Callee |
+--------------------------+-------------------------+
| | IDN/IRI |
| Caller +------+-----------+-------------+
| | Form | compliant | uncompliant |
+-----+-------------+------+-----------+-------------+
| | recognize | IRI | OK | NG |
| IDN +-------------+------+-----------+-------------+
| / | | IRI | OK | NG |
| IRI | compliant +------+-----------+-------------+
| | | ACE | OK | OK |
+-----+-------------+------+-----------+-------------+
passing form and access availability
For example, if caller application recognize IDN/IRI correctly
according to this document but does not compliant to IDN/IRI
standards, then it passes IRI to another (callee) application. The
callee application can access to the passed IRI if it is IDN/IRI
compliant, otherwise not.
Caller application does not know whether callee applications are IDN/
IRI compliant. But it can be assumed under certain circumstances.
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In general, the most probable callee application is the Web browser.
As described in Section 1, most of major Web browsers on PCs are IDN/
IRI compliant, so passing an IRI in IRI form is assumed to work.
Right now, there is no comprehensive list of circumstances, therefore
the assumption is an open issue.
4. Security Considerations
Without verifying IRI string well, it is dangerous to access
automatically recognized IRI. See the security considerations in
[RFC3490] and [RFC3986] for further information.
5. IANA Considerations
No IANA actions are required by this document.
6. Acknowledgements
The authors of normative references.
7. Change History
This section is used for tracking the update of this document. Will
be removed after finalize.
7.1. draft-yoneya-ima-downgrade: Version 00
o Initial version
8. Normative References
[PropList]
The Unicode Consortium, "PropList, Unicode Character
Database", 2006,
<http://www.unicode.org/Public/UNIDATA/PropList.txt>.
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
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[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
Identifiers (IRIs)", RFC 3987, January 2005.
[Unicode] The Unicode Consortium, "The Unicode Standard, Version
5.0", 2006, <http://www.unicode.org/>.
Author's Address
Yoshiro YONEYA
JPRS
Chiyoda First Bldg. East 13F, 3-8-1 Nishi-Kanda
Chiyoda-ku, Tokyo 101-0065
Japan
Phone: +81 3 5215 8451
Email: yone@jprs.co.jp
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