Proposal for a standardized LIST SUBSCRIPTIONS command

[Julien ÉLIE]

Hi,

In case you have any comments or special need on that command, do not
hesitate to speak up.
Expectations from news readers, how it can be used, implementation
on news servers, etc.

Usage

Syntax
LIST SUBSCRIPTIONS [wildmat]

Responses
215 Subscriptions list follows (multi-line)

Parameters
wildmat Groups of interest

Description

See Section 7.6.1 of [RFC3977] for general requirements of the LIST
command.

The subscriptions list is maintained by some NNTP servers to provide
the client with a list of recommended newsgroups.

The information is returned as a multi-line data block following the
215 response code. Each line of this list MUST consist of a
newsgroup name. There are no leading or trailing whitespaces in a
line.

The order of newsgroups in the list is significant: they are listed
by order of importance, the first newsgroup being the most important
to subscribe to.

The same newsgroup name SHOULD NOT appear twice in the output of this
command. The list SHOULD contain only newsgroups the news server
carries.

The subscriptions list is newsgroup-based, and a wildmat MAY be
specified, in which case the response is limited to only the groups,
if any, whose names match the wildmat. Note that the wildmat
argument is a new feature in this specification and servers that do
not support CAPABILITIES or do not advertise the SUBSCRIPTIONS
keyword in the LIST capability (and therefore do not conform to this
specification) are unlikely to support it.

The subscriptions list MAY be empty. If the server does not maintain
the information, a 503 response code MUST be returned.

The client MAY use this information the first time it connects to the
news server so as to initialize the list of default subscribed
newsgroups. This list should therefore contain groups intended for
new users on the news server or Usenet in general. For instance
newsgroups dedicated to testing, support, annoucement, or FAQs. The
client MAY present the groups in the order of appearance in the list
to the user. When the subscriptions list is maintained and non
empty, the news client SHOULD use it, instead of a hard-coded default
list, if any.

Examples

Example of output with no argument:

[C] CAPABILITIES
[S] 101 Capability list:
[S] VERSION 2
[S] READER
[S] LIST ACTIVE NEWSGROUPS SUBSCRIPTIONS
[S] .
[C] LIST SUBSCRIPTIONS
[S] 215 List of recommended newsgroups follows
[S] local.welcome
[S] local.test
[S] news.newusers.questions
[S] news.announce.newusers
[S] .

Example of output with a wildmat:

[C] LIST SUBSCRIPTIONS local.*
[S] 215 List of recommended newsgroups follows
[S] local.welcome
[S] local.test
[S] .

ABNF syntax

list-arguments =/ "SUBSCRIPTIONS" [WS wildmat]

list-content =/ list-subscriptions-content
list-subscriptions-content = *(newsgroup-name CRLF)

--
Julien ï¿œLIE

ￜ Et maintenant, passons ￜ table. Toi aussi, mon fils ! ￜ (Cￜsar)