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Versions: 00 01 Draft is active
In: IS-review
Network Working Group                                        M. Karcz
INTERNET-DRAFT                                            Independent
Intended status: Experimental                         27 January 2012
Expires: 30 July 2012



                     Unified User-Agent String (UUAS)
                            draft-karcz-uuas-00


Abstract

   User-Agent is a header used by certain protocols, e.g. HTTP. Unified
   User-Agent String is intended to unification of that complicated
   strings.

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community. This memo does not specify an Internet standard of any
   kind. Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

   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."















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Copyright 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.

   This document may not be modified, and derivative works of it may not
   be created, except to format it for publication as an RFC or to
   translate it into languages other than English.

































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Table of Contents


   1. Introduction ................................................ 3
   2. Structure ................................................... 3
      2.1. Agent signature......................................... 3
         2.1.1. Agent identifier .................................. 4
         2.1.2. Agent Features .................................... 4
            2.1.2.1. Security level flag .......................... 4
            2.1.2.2. Operating system ............................. 5
            2.1.2.3. Hardware platform ............................ 5
            2.1.2.4. Client language .............................. 5
            2.1.2.5. Contact ...................................... 5
            2.1.2.6. Additional data .............................. 5
      2.2. Engine signature ....................................... 6
         2.2.1. Engine information ................................ 6
      2.3. ABNF definition of UUAS ................................ 7
   3. Security Considerations ..................................... 7
   4. References .................................................. 8
      4.1. Normative References ................................... 8
   Appendix A. Acknowledgments .................................... 9

1. Introduction

   So far 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).

2. Structure

   Unified User-Agent String is separated by space into two parts:

   o Agent signature (REQUIRED) - overview Section 2.1

   o Engine signature (OPTIONAL) - overview Section 2.2

   General ABNF notation of UUAS is:

         uuas = agent *1(SP engine)

   2.1. Agent signature

   In Unified User-Agent String signature contains two main parts
   separated by space:



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   o Agent identifier, containing name and version of Agent - Section
      2.1.1

   o Agent features, containing information about Agent platform. -
      Section 2.1.2

   General ABNF notation of Agent signature is:

        agent = agent_id SP agent_ft

2.1.1. Agent identifier

   Agent identifier contains two parts separated by a slash sign:

   o Agent name, e.g. "FooBrowser"

   o Agent version, e.g. "1.0"

   Characters allowed to use in Agent name are: small and capital
   letters and a minus sign. Characters allowed to use in Agent version
   are: digits, dot, a minus sign and small and capital letters.

2.1.2. Agent Features

   Data contained in Agent features are (in turn):

   1. Security level flag - Section 2.1.2.1

   2. Operating system - Section 2.1.2.2

   3. Hardware platform - Section 2.1.2.3

   4. Client language - Section 2.1.2.4

   5. OPTIONAL Contact - Section 2.1.2.5

   6. OPTIONAL Addition data - Section 2.1.2.6

   All of Agent features is contained in brackets. Data are separated by
   semicolon and space.

2.1.2.1. Security level flag

   Security level flag indicates client.s security level. This field may
   contain these values:

   o "N" - no encryption


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   o "I" - 40-bit encryption

   o "U" - encryption stronger than 40-bit.

2.1.2.2. Operating system

   Operating system field indicates client.s operating system, e.g.
   "Windows NT 6.1", "FreeBSD 8.7" or "Mac OS X 10.7".

   Characters allowed to be used in this field are: small and capital
   letters, digits, dot, a minus sign and space.

2.1.2.3. Hardware platform

   Hardware platform field indicates client.s processor.s Instruction
   Set Architecture, e.g. "i386", "ppc" or "m68k".

   Character allowed to be used in this field are: small and capital
   letters, digits, dot and a minus sign. Maximum length of this field
   is 10 characters.

2.1.2.4. Client language

   This field indicates client application.s language. It may contain
   language tags defined in [RFC5646].

2.1.2.5. Contact

   This field contains one HTTP URL and zero or more client application-
   related e-mail addresses.

   URL and e-mail addresses are preceded by a plus sign. All subfields
   are separated by a semicolon and a space.

   ABNF notation of this field is here:

     contact = curl *(break cemail)
     curl = plus <rfc1738-httpurl>
     cemail = plus <rfc5322-addr-spec>

2.1.2.6. Additional data

   Additional data field can contain any data. All subfields are
   separated by semicolon and space.

   Characters allowed to be used in this field are: characters x20-x24,
   x26-x27, x2A-x2E, x30-x3A, x3C-x7E and hexadecimal-defined characters


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   Hexadecimal-defined character ABNF notation is here:

     hexchar = %x25 2HEXDIG

   This is ABNF notation of Additional data (one):

     addit_data = break 1*adchar

   2.2. Engine signature

   Engine signature indicates information about basis of the client
   application, e.g. HTML rendering engine. This signature contains two
   parts separated by space:

   o Engine identifier - structure identical as in Agent identifier

   o OPTIONAL Engine information - Section 2.2.1

   ABNF notation of Engine signature is:

     engine = engine_id *1(SP engine_if)

2.2.1. Engine information

   This field contains contact information and/or other data about
   engine separated by semicolon and space.

   This is ABNF notation of Engine information:

     engine_if = obracket (1* adchar / contact) *addit_data cbracket


















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   2.3. ABNF definition of UUAS

      ; Unified User-Agent String general definition
      uuas = agent *1(SP engine)

      ; Agent signature definition
      agent = agent_id SP agent_ft
      agent_id = agent_nm slash agent_vr
      agent_nm = 1*nmchar
      agent_vr = 1*vrchar

      agent_ft = obracket security_flg break os break hwplatform break
                 language *1(break contact) *addit_data cbraket
      security_flg = %x4E / %x49 / %x55
      os = 1*(vrchar / SP)
      hwplatform = 1*10vrchar
      language = <rfc5646-Language-Tag>

      ; Non-required data definitions
      contact = curl *(break cemail)
      curl = plus <rfc1738-httpurl>
      cemail = plus <rfc5322-addr-spec>

      addit_data = break 1*adchar

      ; Engine signature definition
      engine = engine_id *1(SP engine_if)
      engine_id = agent_id
      engine_if = obracket (1*adchar / contact) *addit_data cbraket


      ; Additional definitions
      slash = %xF2
      obracket = %x28
      cbracket = %x29
      plus = %x2B

      break = %x3B SP
      hexchar = %x25 2HEXDIG

      nmchar = ALPHA / "-"
      vrchar = nmchar / DIGIT / "."
      adchar = %x20-24 / %x26-27 / %x2A-2E / %x30-3A / %x3C-7E / hexchar

3. Security Considerations

   Security is truly believed to be irrelevant to this document.


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4. References

   4.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5234] Crocker, D. and Overell, P., "Augmented BNF for Syntax
             Specifications: ABNF", RFC 5234, January 2008.

   [RFC2068] Fielding, R., Gettys, J., Mogul, J., Frystyk, H. and
             Berners-Lee, T., "Hypertext Transport Protocol - HTTP/1.1",
             January 1997

   [RFC5646] Phillips, A. and Davis, M., "Tags for Identifying
             Languages", September 2009

   [RFC5322] Resnick, P., "Internet Message Format", October 2008






























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Appendix A.                 Acknowledgments

   I would like to thank my English teacher, who devoted their time to
   conduct a linguistic revision of this Memo.

   This document was prepared using 2-Word-v2.0.template.dot.

Authors. Addresses

   Mateusz Karcz
   Independent
   18/6 Sambora Street
   83-110 Tczew
   Poland

   Email: sami.wiecie.kto@interia.eu
































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