Unified User-Agent String
draft-karcz-uuas-01
Independent M. Karcz
Internet-Draft UKLO Tczew
Updates: 7231 (if approved) November 10, 2014
Intended status: Experimental
Expires: May 14, 2015
Unified User-Agent String
draft-karcz-uuas-01
Abstract
User-Agent is a HTTP request-header field. It contains information
about the user agent originating the request, which is often used by
servers to help identify the scope of reported interoperability
problems, to work around or tailor responses to avoid particular user
agent limitations, and for analytics regarding browser or operating
system use. Over the years contents of this field got complicated
and ambiguous. That was the reaction for sending altered version of
websites to web browsers other than popular ones. During the
development of the WWW, authors of the new web browsers used to
construct User-Agent strings similar to Netscape's one. Nowadays
contents of the User-Agent field are much longer than 15 years ago.
This Memo proposes the Uniform User-Agent String as a way to simplify
the User-Agent field contents, while maintaining the previous
possibility of their use.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on May 14, 2015.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conformance . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 3
1.2.1. Whitespaces . . . . . . . . . . . . . . . . . . . . . 3
2. Use of the User-Agent strings . . . . . . . . . . . . . . . . 3
3. Definition of Proposed Format . . . . . . . . . . . . . . . . 3
3.1. Standard String . . . . . . . . . . . . . . . . . . . . . 4
3.2. Regular String . . . . . . . . . . . . . . . . . . . . . 4
3.3. Web Browser String . . . . . . . . . . . . . . . . . . . 5
4. ABNF Definition of UUAS . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Nowadays User-Agent strings are long, complicated and often
ambiguous. (e.g. "Mozilla/4.0 (compatible; MSIE 6.0; X11; Linux
i686; en) Opera 8.01" - it is Opera Browser, but it can be read as
Internet Explorer or Netscape Navigator.) This document specifies a
new, easy and clear format of Unified User-Agent String (UUAS), which
allows simple distinction between user agents, maintaining most of
the features of the existing solutions.
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1.1. Conformance
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].
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