[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 06 07 08 09 10 11 RFC 5538

Network Working Group                                       F. Ellermann
Internet-Draft                                                     xyzzy
Updates: 1738 (if approved)                             October 22, 2006
Intended status: Standards Track
Expires: April 25, 2007


                     The news and nntp URI Schemes
                    draft-ellermann-news-nntp-uri-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 April 25, 2007.

Copyright Notice

   Copyright (C) The Internet Society (2006).













Ellermann                Expires April 25, 2007                 [Page 1]

Internet-Draft             News and nntp URIs               October 2006


Abstract

   This memo specifies the "news" and "nntp" Uniform Resource Identifier
   (URI) schemes that were originally defined in RFC 1738.  The purpose
   of this document is to allow RFC 1738 to be made obsolete while
   keeping the information about these schemes on standards track.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Background . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  nntp URIs  . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  news URIs  . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.3.  Query parts and fragments  . . . . . . . . . . . . . . . .  5
   3.  Syntax of nntp URIs  . . . . . . . . . . . . . . . . . . . . .  6
   4.  Syntax of news URIs  . . . . . . . . . . . . . . . . . . . . .  7
   5.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . .  9
   6.  Internationalization Considerations  . . . . . . . . . . . . . 10
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Appendix A.  Document History  . . . . . . . . . . . . . . . . . . 15
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
   Intellectual Property and Copyright Statements . . . . . . . . . . 17
























Ellermann                Expires April 25, 2007                 [Page 2]

Internet-Draft             News and nntp URIs               October 2006


1.  Introduction

   The first definition for many URI schemes appeared in [RFC1738].
   This memo extracts the "news" and "nntp" URI schemes from it to allow
   that material to remain on standards track if [RFC1738] is moved to
   "historic" status.  It belongs to a series of similar documents like
   [RFC4156], [RFC4157], [RFC4248], and [RFC4266] discussed on the
   <mailto:uri@w3.org> list.

   The definitions for the "news" and "nntp" URI schemes given here are
   updates from [RFC1738] based on modern usage of these schemes.

   [RFC3986] specifies how to define schemes for URIs, it also explains
   the term "Uniform Resource Locator" (URL).  The Network News Transfer
   Protocol (NNTP) is specified in [I-D.ietf-nntpext-base].  The Netnews
   Article Format is defined in [I-D.ietf-usefor-usefor].

   The key word "MUST" in this memo is to be interpreted as described in
   [RFC2119].  UTF-8 is specified in [RFC3629].  The syntax uses the
   ABNF defined in [RFC4234].































Ellermann                Expires April 25, 2007                 [Page 3]

Internet-Draft             News and nntp URIs               October 2006


2.  Background

   The "news" and "nntp" URI schemes identify resources on an NNTP
   server, individual articles, individual newsgroups, or sets of
   newsgroups.

   User agents like Web browsers supporting these schemes use the NNTP
   protocol to access the corresponding resources.  The details how they
   do this, e.g. employing a separate or integrated newsreader, depend
   on the implementation.  The default <port> associated with NNTP in
   [I-D.ietf-nntpext-base] is 119.

2.1.  nntp URIs

   The "nntp" URI scheme identifies articles in a newsgroup on a
   specific NNTP server.  In [RFC3986] terminology this means that
   "nntp" URIs have a non-empty <authority> component, there is no
   default <host> as for the "file" or "news" URI schemes.

   Netnews is typically distributed among several news servers, using
   the same newsgroup names, but local article numbers.  An article
   which might be available as number 10 in group "example" on server
   "news.example.com" has most likely a different number on any other
   server where the same article is (still) available.  Users allowed to
   read and post articles on one of "their" servers are typically not
   allowed to access articles on an "arbitrary" other server specified
   in an "nntp" URI.

   For these reasons the use of the "nntp" URI scheme is limited, and
   it's less widely supported by user agents than the similar "news" URI
   scheme.

2.2.  news URIs

   The "news" URI scheme identifies articles by their worldwide unique
   "Message-ID", independent of the server and the newsgroup.
   Newsreaders support access on articles by their "Message-ID", without
   the overhead for an URI scheme.  In simple cases they do this
   directly as NNTP client of a default or currently used server as
   configured by the user.  More general user agents use the "news" URI
   scheme to distinguish "Message-IDs" from similar constructs like
   other URI schemes in contexts like a plain text message body.

   The "news" URI scheme also allows to identify newsgroups or sets of
   newsgroups independent of a specific server.  For Netnews a group
   "example" has the same name on any server carrying this group, exotic
   cases involving gateways not withstanding.  To distinguish
   "Message-IDs" and newsgroup names the "news" URI scheme uses the "@"



Ellermann                Expires April 25, 2007                 [Page 4]

Internet-Draft             News and nntp URIs               October 2006


   between local part (left hand side) and domain part (right hand side)
   of "Message-IDs".

   [RFC1738] offered only one wildcard for sets of newsgropus in "news"
   URIs, a "*" used to refer to "all available newsgroups".  In common
   practice this was extended to varying degrees by some user agents, an
   NNTP extension known as <wildmat> specified in [RFC2980] and now part
   of the base NNTP specification allows pattern matching in the style
   of the "find" command.  For the purpose of this memo this means that
   some additional special characters have to be allowed in "news" URIs,
   some of them percent-encoded as required by the overall [RFC3986] URI
   syntax.  User agents and NNTP servers might not (yet) implement all
   parts of this new feature.

   Another commonly supported addition to the [RFC1738] syntax is the
   optional specification of a server at the begin of "news" URIs.  This
   optional <authority> component follows the overall [RFC3986] syntax
   preceded by a double slash "//" and terminated by the next slash "/",
   question mark "?", number sign "#", or the end of the URI.

2.3.  Query parts and fragments

   The "news" and "nntp" URI schemes don't specify a query part
   introduced by a question mark "?" or a fragment introduced by a
   number sign "#", but some implementations are known to use query
   parts internally to address MIME parts.

























Ellermann                Expires April 25, 2007                 [Page 5]

Internet-Draft             News and nntp URIs               October 2006


3.  Syntax of nntp URIs

   An "nntp" URI identifies an article by its number in a given
   newsgroup of a specified server. or it identifies the newsgroup
   without article number.

      nntpURL        = "nntp:" server "/" group [ "/" article-number ]
      server         = "//" authority                     ; see RFC 3986
      group          = 1*( group-char / pct-encoded )
      article-number = 1*16DIGIT
      group-char     = ( ALPHA / DIGIT / "-" / "+" / "_" / "." )

   In the form with an <article-number> the URL corresponds roughly to
   the content of an <xref> header field as specified in
   [I-D.ietf-usefor-usefor], replacing its more general
   <article-locator> by the <article-number> used with NNTP.

   A <newsgroup-name> as specified in [I-D.ietf-usefor-usefor] consists
   of dot-separated components.  Each component contains one or more
   letters, digits, "-" (hyphen-minus), "+", or "_" (underscore).  These
   characters can be directly used in a segment of a path in a [RFC3986]
   URI, no percent-encoding is necessary.  Example:

       nntp://news.server.example/example.group.this/12345

   A <wildmat-exact> newsgroup name as specified in
   [I-D.ietf-nntpext-base] allows (in theory) any <UTF8-non-ascii> and
   most printable US-ASCII characters excluding "!", "*", ",", "?", "[",
   "\", and "]".  To keep the syntax here simple all additional
   characters in an NNTP <wildmat-exact> not (yet) allowed in
   [I-D.ietf-usefor-usefor] are covered by <pct-encoded> as defined in
   [RFC3986], although percent-encoding is not strictly necessary for
   some of these additional characters like ":", ";", and "~".  Most of
   the additional characters have to be percent-encoded, example:

       nntp://wild.server.example/example.group.n%2Fa/12345

   In the form without <article-number> the URL identifies a single
   group on the specified server.  This is also possible with an
   equivalent "news" URL, and the latter is better supported by user
   agents, example:

       nntp://news.server.example/example.group.this
       news://news.server.example/example.group.this







Ellermann                Expires April 25, 2007                 [Page 6]

Internet-Draft             News and nntp URIs               October 2006


4.  Syntax of news URIs

   A "news" URI identifies an article by its unique "Message-ID", or it
   identifies a set of newsgroups.  Additionally it can specify a
   server, without it a configured default server for Netnews access is
   used.

       newsURL        = "news:" [ server "/" ] ( article / newsgroups )
       article        = mid-left "@" mid-right
       newsgroups     = 1*( group-char / pct-encoded / "*" )

       mid-left       = 1*( mid-atext / "." /  ; <dot-atom-text>
                         "(" / ")" /           ; allowed sub-delims
                         "," / ";" /           ; allowed sub-delims
                         ":" /                 ; allowed pchar
                         "%22" /               ; encoded DQUOTE
                         "%3C" / "%40" /       ; encoded "<" / "@"
                         "%5B" / "%5D" /       ; encoded "[" / "]"
                         "%5C%5C" / "%5C%22" ) ; encoded "\\" / '\"'

       mid-atext      = ALPHA / DIGIT /        ; RFC 2822 <atext>
                        "!" / "$" /            ; allowed sub-delims
                        "&" / "'" /            ; allowed sub-delims
                        "*" / "+" / "=" /      ; allowed sub-delims
                        "-" / "_" / "~" /      ; allowed unreserved
                        "%23" / "%25" /        ; encoded "#" / "%"
                        "%2F" / "%3F" /        ; encoded "/" / "?"
                        "%5E" / "%60" /        ; encoded "^" / "`"
                        "%7B" / "%7C" /        ; encoded "{" / "|"
                        "%7D"                  ; encoded "}"

       mid-right      = 1*( mid-atext / "." /  ; <dot-atom-text>
                         "(" / ")" /           ; allowed sub-delims
                         "," / ";" /           ; allowed sub-delims
                         ":" /                 ; allowed pchar
                         "%22" /               ; encoded DQUOTE
                         "%3C" / "%40" /       ; encoded "<" / "@"
                         "%5B" / "%5D" /       ; encoded "[" / "]"
                         "%5C%5C" /            ; encoded "\\"
                         "%5C%5B" / "%5C%5D" ) ; encoded "\[" / "\]"


   The form identifying an <article> corresponds to the <msg-id-core> in
   [I-D.ietf-usefor-usefor], it's a "Message-ID" without angle brackets.
   Characters not directly allowed in this part of an [RFC3986] URI have
   to be percent-encoded, minimally anything that is not <unreserved>,
   no ":" (colon), and doesn't belong to the <sub-delims>.




Ellermann                Expires April 25, 2007                 [Page 7]

Internet-Draft             News and nntp URIs               October 2006


   Several details of a <msg-id-core> are omitted here, the syntax
   mainly shows which characters MUST be percent-encoded in a <mid-left>
   (local part) or <mid-right> (domain part).  Please note that "%3E" is
   not allowed, and "%5C" can only occur in certain combinations.
   Examples:

       news://server.example/ab.cd@example.com
       news:%22do..ts%22@example.com
       news:ab.cd@%5B2001:DB8::CD30%5D

   The form identifying <newsgroups> corresponds to the
   <wildmat-pattern> in [I-D.ietf-nntpext-base], a newsgroup name with
   wildcards "*" and "?".  Any "?" has to be be percent-encoded as "%3F"
   in this part of an URI.  Examples:

       news://news.server.example/*
       news://wild.server.example/example.group.th%3Fse
       news:example.group.*
       news:example.group.this

   Without wildcards this form of the URL identifies a single group, and
   user agents would typically try to present an overview of the
   articles available in this group, probably somehow limiting this
   overview to the newest unread articles up to a configured maximum.

   With wildcards user agents could try to list matching group names on
   the specified or default server.  Some user agents support only a
   single wildcard "*" or a specific <group> without wildcards.























Ellermann                Expires April 25, 2007                 [Page 8]

Internet-Draft             News and nntp URIs               October 2006


5.  Acknowledgments

   An Internet Draft by Alfred S. Gilman published 1998 introduced
   additions to the original [RFC1738] "news" URI scheme.  Some of these
   ideas are now widely supported and reflected by the revised "news"
   URI scheme specified here.

   Paul Hoffman started the series of Internet Drafts allowing to
   replace [RFC1738].  Charles Lindsey and Russ Allbery contributed all
   missing details about the "nntp" URI scheme.

   Bill Fenner's _xml2rfc validator_ and _ABNF checker_ were a great
   help in the creation of (not only) this memo.






































Ellermann                Expires April 25, 2007                 [Page 9]

Internet-Draft             News and nntp URIs               October 2006


6.  Internationalization Considerations

   The URI schemes were updated to support percent-encoded UTF-8
   characters in NNTP newsgroup names as specified in
   [I-D.ietf-nntpext-base] and [RFC3987].














































Ellermann                Expires April 25, 2007                [Page 10]

Internet-Draft             News and nntp URIs               October 2006


7.  Security Considerations

   There are many security considerations for URI schemes discussed in
   [RFC3986].  The NNTP protocol may use passwords in the clear for
   authentication, or offer no privacy, both of which are considered
   extremely unsafe in current practice.  Alternatives and further
   security considerations with respect to NNTP are discussed in
   [I-D.ietf-nntpext-authinfo].











































Ellermann                Expires April 25, 2007                [Page 11]

Internet-Draft             News and nntp URIs               October 2006


8.  IANA Considerations

   The IANA registry of URI schemes could be updated to point to this
   memo instead of [RFC1738] for the "news" and "nntp" URI schemes.















































Ellermann                Expires April 25, 2007                [Page 12]

Internet-Draft             News and nntp URIs               October 2006


9.  References

9.1.  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.

   [I-D.ietf-nntpext-base]
              Feather, C., "Network News Transfer Protocol",
              draft-ietf-nntpext-base-27 (work in progress), June 2005.

   [I-D.ietf-usefor-usefor]
              Lindsey, C., "Netnews Article Format",
              draft-ietf-usefor-usefor-10 (work in progress),
              September 2006.

9.2.  Informative References

   [RFC1738]  Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
              Resource Locators (URL)", RFC 1738, December 1994.

   [RFC2822]  Resnick, P., "Internet Message Format", RFC 2822,
              April 2001.

   [RFC2980]  Barber, S., "Common NNTP Extensions", RFC 2980,
              October 2000.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [RFC3987]  Duerst, M. and M. Suignard, "Internationalized Resource
              Identifiers (IRIs)", RFC 3987, January 2005.

   [RFC4156]  Hoffman, P., "The wais URI Scheme", RFC 4156, August 2005.

   [RFC4157]  Hoffman, P., "The prospero URI Scheme", RFC 4157,
              August 2005.

   [RFC4248]  Hoffman, P., "The telnet URI Scheme", RFC 4248,
              October 2005.




Ellermann                Expires April 25, 2007                [Page 13]

Internet-Draft             News and nntp URIs               October 2006


   [RFC4266]  Hoffman, P., "The gopher URI Scheme", RFC 4266,
              November 2005.

   [I-D.ietf-nntpext-authinfo]
              Vinocur, J., "NNTP Extension for Authentication",
              draft-ietf-nntpext-authinfo-10 (work in progress),
              August 2005.












































Ellermann                Expires April 25, 2007                [Page 14]

Internet-Draft             News and nntp URIs               October 2006


Appendix A.  Document History

   Note: This informative appendix should be removed during the final
   publication of the document.

   Changes in version 01:

   o  References of RFC 977 and RFC 2980 replaced by the now approved
      RFC977bis [I-D.ietf-nntpext-base]

   o  Security considerations updated with a reference to the now
      approved [I-D.ietf-nntpext-authinfo].

   o  References of RFC 1036 and [RFC2822] replaced by the last called
      [I-D.ietf-usefor-usefor].

   o  References of RFC 2396 removed, the jumps from [RFC1738] to
      [RFC3986] and from RFC 1036 to [I-D.ietf-usefor-usefor] are
      interesting enough without talking about intermediate steps.

   o  [RFC1738] has no <range> for the "nntp" URI scheme, and this memo
      isn't the place to invent new tricks for a rarely used scheme.

   Changes in version 00:

   o  Derived from [I-D.hoffman-news-nntp-uri-04] after discussions on
      the URI list.  At this time what's now known as the Netnews
      Article Formt [I-D.ietf-usefor-usefor] was still far from ready,
      and RFC977bis [I-D.ietf-nntpext-base] also not finished.






















Ellermann                Expires April 25, 2007                [Page 15]

Internet-Draft             News and nntp URIs               October 2006


Author's Address

   Frank Ellermann
   xyzzy
   Hamburg, Germany

   Email: nobody@xyzzy.claranet.de
   URI:   http://purl.net/xyzzy/











































Ellermann                Expires April 25, 2007                [Page 16]

Internet-Draft             News and nntp URIs               October 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   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 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.


Acknowledgments

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).  This document was produced
   using xml2rfc v1.32pre1 (of http://xml.resource.org/) from a source
   in RFC-2629 XML format.



Ellermann                Expires April 25, 2007                [Page 17]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/