Applications Area WG (APPSAWG) S. Moonesamy, Ed. Internet-Draft Intended Status: Informational Expires: December 9, 2012 June 7, 2012 The "about" URI Scheme draft-ietf-appsawg-about-uri-scheme-07 Abstract This document describes the "about" URI scheme, which is widely used by web browsers and some other applications to designate access to their internal resources, such as settings, application information, hidden built-in functionality, and so on. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2012 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 (http://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 Moonesamy Expires December 9, 2012 [Page 1]
INTERNET DRAFT The "about" URI Scheme June 7, 2012 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. URI Scheme Specification . . . . . . . . . . . . . . . . . . . 2 2.1. URI Scheme Syntax . . . . . . . . . . . . . . . . . . . . . 2 2.2. URI Scheme Semantics . . . . . . . . . . . . . . . . . . . 2 2.2.1. Well-known "about" URIs . . . . . . . . . . . . . . . . 3 2.3. Encoding Considerations . . . . . . . . . . . . . . . . . . 3 3. "about:blank" . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 5.1. URI Scheme Registration . . . . . . . . . . . . . . . . . . 4 5.2. A Registry for Well-known Tokens . . . . . . . . . . . . . 4 5.2.1. Registration procedure . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . . 6 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction This document describes the "about" Uniform Resource Identifier (URI) scheme. The "about" URI scheme is currently widely used by Web browsers to designate access to their internal resources such as settings, application information, so called "Easter eggs" (i.e. hidden feature or joke in an application). 2. URI Scheme Specification 2.1. URI Scheme Syntax The "about" URI syntactically conforms to the <about-uri> rule below, expressed using Augmented Backus-Naur Form (ABNF) [RFC5234]: about-uri = "about:" about-token [ about-query ] [ about-fragment ] about-token = *pchar about-query = "?" query about-fragment = "#" fragment pchar = <as specified in RFC 3986, Appendix A> query = <as specified in RFC 3986, Appendix A> fragment = <as specified in RFC 3986, Appendix A> 2.2. URI Scheme Semantics Moonesamy Expires December 9, 2012 [Page 2]
INTERNET DRAFT The "about" URI Scheme June 7, 2012 The resource which a particular "about" URI references is denoted by <about-token> part of the URI. It is not a hierarchical element for a naming authority. The <about-query> specifies additional information about its handling and/or the information that should be returned by the resource which the URI references. It is impossible to specify a binding between all the possible tokens and the semantics of "about" URIs that would contain such tokens. Therefore the resource referenced by the URI is generally considered as specific to a Web browser implementation. 2.2.1. Well-known "about" URIs Some <about-token>s have been reserved as the behavior when the resource is referenced is well-known (Well-known tokens). A well-known "about" URI is a URI that has a well-known token as its <about-token> part. It is recommended that such URIs be handled in accordance with the specification referenced in the Well-known Tokens registry (see Section 5.2). Well-known "about" URIs are intended to be registered when there is a need to codify the behavior of particular <about-token>. 2.3. Encoding Considerations "about" URIs are subject to encoding rules defined in RFC 3986 [RFC3986]. 3. "about:blank" This document defines one well-known token: "blank". The "about:blank" URI refers to a resource represented in the browser by a blank page. 4. Security Considerations Security considerations for URIs are discussed in Section 7 of RFC 3986 [RFC3986]. However, most of those provisions do not apply to the "about" URI scheme as they are mainly scoped to schemes used in the Internet. "about" URIs can sometimes refer to sensitive information, such as user passwords stored in a cache, or parameters that, if changed, could affect user's data. The application therefore needs to ensure that the user's data is secured and no threats are imposed Moonesamy Expires December 9, 2012 [Page 3]
INTERNET DRAFT The "about" URI Scheme June 7, 2012 by "about" URIs. 5. IANA Considerations 5.1. URI Scheme Registration The registration of the "about" URI scheme in the "URI Schemes" registry is requested. The information below is provided according to the guidelines from RFC 4395 [RFC4395]: URI scheme name: about Status: Permanent URI scheme syntax: see Section 2.1 of RFC xxxx URI scheme semantics: see Section 2.2 of RFC xxxx URI scheme encoding considerations: see Section 2.3 of RFC xxxx Applications that use the scheme: "about" URIs are predominantly used by Web browsers. Security considerations: see Section 4 of RFC xxxx Contact: IETF Applications Area Directors <app-ads@tools.ietf.org> Author/Change controller: IESG <iesg@ietf.org> (on behalf of the IETF) References: see Section 5 of RFC xxxx [RFC Editor: Please replace xxxx with assigned RFC number] 5.2. A Registry for Well-known Tokens This document creates the '"about" URI Well-known Tokens' registry. The registry entries consist of three fields: Well-known Token, Description and Reference. The Well-known Token field has to conform to <about-token> production defined in Section 2.1. The initial set of assignments is as follows: +--------------+------------------------------------+-------------+ | Well-known | Description | Reference | | Token | | | +------------------+--------------------------------+-------------+ | blank | The about:blank URI references a | RFC xxxx | Moonesamy Expires December 9, 2012 [Page 4]
INTERNET DRAFT The "about" URI Scheme June 7, 2012 | | blank page. | | +--------------+------------------------------------+-------------+ 5.2.1. Registration procedure The registration policy for this registry is "First Come First Served" as described in RFC 5226 [RFC5226]. The registrant of the token should provide the information mentioned in the following registration template: o Registered Token: The desired Well-known token to be used in "about" URIs. o Intended usage: A short description of how "about" URIs with the registered token is handled including information about the referenced resource. o Contact/Change controller: Person (including contact information) authorized to change this registration. o Specification: A stable reference to a document which specifies the registered "about" URI. The question of interoperability does not arise. The key motivation is to have a reference to a specification documenting well-known behavior of the "about" URI in Web browsers. As a rule of thumb if the behavior is common to two or more Web browser implementations it can be considered as well- known. An existing assignment may be duplicated if the registered token is used in more than one Web browser implementation. The following is a template for the "blank" token: o Registered Token: blank o Intended usage: The about:blank URI references a blank page. o Contact/Change controller: IESG <iesg@ietf.org> (on behalf of IETF). o Specification: RFC xxxx. [RFC Editor: Please replace xxxx with assigned RFC number] 6. References 6.1. Normative References [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, Moonesamy Expires December 9, 2012 [Page 5]
INTERNET DRAFT The "about" URI Scheme June 7, 2012 May 2008. [RFC5234] Crocker, D., Ed., and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. 6.2. Informative References [RFC4395] Hansen, T., Hardie, T., and L. Masinter, "Guidelines and Registration Procedures for New URI Schemes", BCP 35, RFC 4395, February 2006. Appendix A. Acknowledgments This document has been formed from the draft initially authored by Lachlan Hunt and Joseph Holsten. Additionally, the contributions of Frank Ellermann and Alexey Melnikov are gratefully acknowledged. Barry Leiba and Murray Kucherawy deserve a special credit for providing a great amount of text which has been used in this document. Lachlan Hunt and Mykyta Yevstifeyev edited previous versions of this document. Tim Bray and John Klensin provided suggestions about how to improve the document. Authors' Addresses S. Moonesamy (editor) 76, Ylang Ylang Avenue Quatre Bornes Mauritius EMail: sm+ietf@elandsys.com Moonesamy Expires December 9, 2012 [Page 6]