Network Working Group J. Gregorio, Ed.
Internet-Draft
Intended status: Standards Track M. Hadley, Ed.
Expires: January 10, 2008 Sun Microsystems
M. Nottingham, Ed.
D. Orchard
BEA Systems, Inc.
July 9, 2007
URI Template
draft-gregorio-uritemplate-01
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 10, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
URI Templates are strings that can be transformed into URIs after
embedded variables are substituted. This document defines the syntax
and processing of URI Templates.
Gregorio, et al. Expires January 10, 2008 [Page 1]
Internet-Draft URI Template July 2007
Editorial Note
To provide feedback on this Internet-Draft, join the W3C URI mailing
list (http://lists.w3.org/Archives/Public/uri/) [1].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. URI Template . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Template Variables . . . . . . . . . . . . . . . . . . . . 4
3.2. URI Template Substitution . . . . . . . . . . . . . . . . . 4
3.3. Using URI Templates . . . . . . . . . . . . . . . . . . . . 5
3.3.1. Examples . . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6. Normative References . . . . . . . . . . . . . . . . . . . . . 7
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . . 7
Appendix B. Revision History . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . . . 9
Gregorio, et al. Expires January 10, 2008 [Page 2]
Internet-Draft URI Template July 2007
1. Introduction
URI Templates are strings that contain embedded variables that are
transformed into URIs after embedded variables are substituted.
This is useful when it's necessary to convey the structure of a URI
in a well-defined way. For example, documentation of an interface
exposed by a Web site might use a template to show people how to find
information about a user;
http://www.example.com/users/{userid}
URI Templates can also be thought of as the basis of a machine-
readable forms language; by allowing clients to form their own
identifiers based on templates given to them by the URI's authority,
it's possible to construct dynamic systems that use more of the URI
than traditional HTML forms are able to. For example,
http://www.example.org/products/{upc}/buyers?page={page_num}
Finally, URI Templates can be used to compose URI-centric protocols
without impinging on authorities' control of their URIs. For
example, there are many emerging conventions for passing around login
information between sites using URIs. Forcing people to use a well-
known query parameter isn't good practice, but using a URI parameter
allows different sites to specify local ways of conveying the same
information;
http://login.example.org/login?back={return-uri}
http://auth.example.com/userauth;{return-uri}
This specification defines the basic syntax and processing of URI
Templates. Each application of URI Templates will need to define its
own profile of this specification that indicates what template
variables are available, how to convey them to clients, and what
their appropriate use is in that context.
2. Notational Conventions
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 [RFC2119].
This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC4234]. See [RFC3986] for the definitions of the URI-
reference, reserved, and unreserved rules.
Gregorio, et al. Expires January 10, 2008 [Page 3]
Internet-Draft URI Template July 2007
3. URI Template
A URI Template is a sequence of characters that contains one or more
embedded template variables, see Section 3.1. A URI Template becomes
a URI when the template variables are substituted with their values
(see Section 3.2). For example:
http://example.com/widgets/{widget_id}
If the value of the widget_id variable is "xyzzy", the resulting URI
after substitution is:
http://example.com/widgets/xyzzy
3.1. Template Variables
Template variables are the parameterized components of a URI
Template. A template variable MUST match the template-var rule.
template-char = unreserved
template-name = 1*template-char
template-var = "{" template-name "}"
3.2. URI Template Substitution
Evaluating a URI Template ("substitution") consists of replacing all
template variables with their respective string values.
During substitution, the string value of a template variable MUST
have any characters that do not match the reserved or unreserved
rules (i.e., those characters not legal in URIs without percent
encoding) percent-encoded, as per [RFC3986], section 2.1. Specific
applications of URI Templates MAY specify additional constraints and
encoding rules in addition to this.
Any number of template variables MAY appear in a URI Template; a
single template-name MAY appear multiple times.
The result of substitution MUST match the URI-reference rule and
SHOULD also match any known rules for the scheme of the resulting
URI.
Typically, this is ensured by the definitions of the template
variables used. For example, they may specify that a variable's
value is not to contain certain characters, or that some characters
should be percent-encoded before substitution.
Gregorio, et al. Expires January 10, 2008 [Page 4]
Internet-Draft URI Template July 2007
3.3. Using URI Templates
Applications using URI Templates will typically need to specify a
number of things, including;
o The template to use.
o What template variables are available.
o For each of the variables;
* What characters are allowed in the template's value.
* What encodings should be applied to the value before
substitutions.
* How to handle errors such as the output of substitution being
an invalid URI.
URI Template processors SHOULD allow applications to indicate that;
o A variable's value is required to contain at least one character
o A variable's value is required to match one of a set of supplied
options
o A variable's value is to have all reserved characters, as per
RFC3986, percent-escaped before substitution
Processors MAY make additional options available.
3.3.1. Examples
Given the following template names and values:
+--------+--------------------------+
| Name | Value |
+--------+--------------------------+
| a | fred |
| b | barney |
| c | cheeseburger |
| d | one two three |
| e | 20% tricky |
| f | |
| 20 | this-is-spinal-tap |
| scheme | https |
| p | quote=to+be+or+not+to+be |
| q | hullo#world |
+--------+--------------------------+
Table 1
(Note that the name 'wilma' has not been defined, and the value of
'f' is the empty string.)
Gregorio, et al. Expires January 10, 2008 [Page 5]
Internet-Draft URI Template July 2007
The following URI Templates will be expanded as shown:
http://example.org/page1#{a}
http://example.org/page1#fred
http://example.org/{a}/{b}/
http://example.org/fred/barney/
http://example.org/{a}{b}/
http://example.org/fredbarney/
http://example.com/order/{c}/{c}/{c}/
http://example.com/order/cheeseburger/cheeseburger/cheeseburger/
http://example.org/{d}
http://example.org/one%20two%20three
http://example.org/{e}
http://example.org/20%25%20tricky
http://example.com/{f}/
http://example.com//
{scheme}://{20}.example.org?date={wilma}&option={a}
https://this-is-spinal-tap.example.org?date=&option=fred
http://example.org?{p}
http://example.org?quote=to+be+or+not+to+be
http://example.com/{q}
http://example.com/hullo#world
4. Security Considerations
A URI Template does not contain active or executable content. Other
security considerations are the same as those for URIs, see section 7
of RFC3986.
5. IANA Considerations
In common with RFC3986, URI scheme names form a registered namespace
that is managed by IANA according to the procedures defined in
[RFC4395]. No IANA actions are required by this document.
Gregorio, et al. Expires January 10, 2008 [Page 6]
Internet-Draft URI Template July 2007
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, October 2005.
[RFC4395] Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
Registration Procedures for New URI Schemes", BCP 115,
RFC 4395, February 2006.
[1] <http://lists.w3.org/Archives/Public/uri/>
Appendix A. Contributors
The following people made significant contributions to this
specification: DeWitt Clinton and James Snell.
Appendix B. Revision History
01
00 - Initial Revision.
Authors' Addresses
Joe Gregorio (editor)
Email: joe@bitworking.org
URI: http://bitworking.org/
Marc Hadley (editor)
Sun Microsystems
Email: Marc.Hadley@sun.com
URI: http://sun.com/
Gregorio, et al. Expires January 10, 2008 [Page 7]
Internet-Draft URI Template July 2007
Mark Nottingham (editor)
Email: mnot@pobox.com
URI: http://mnot.net/
David Orchard
BEA Systems, Inc.
Email: dorchard@bea.com
URI: http://bea.com/
Gregorio, et al. Expires January 10, 2008 [Page 8]
Internet-Draft URI Template July 2007
Full Copyright Statement
Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Gregorio, et al. Expires January 10, 2008 [Page 9]
