===============
The news runner
===============

The news runner is the queue runner that gateways mailing list messages to an
NNTP newsgroup.  One of the most important things this runner does is prepare
the message for Usenet (yes, I know that NNTP is not Usenet, but this runner
was originally written to gate to Usenet, which has its own rules).

    >>> mlist = create_list('_xtest@example.com')
    >>> mlist.linked_newsgroup = 'comp.lang.python'

Some NNTP servers such as INN reject messages containing a set of prohibited
headers, so one of the things that the news runner does is remove these
prohibited headers.

    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... NNTP-Posting-Host: news.example.com
    ... NNTP-Posting-Date: today
    ... X-Trace: blah blah
    ... X-Complaints-To: abuse@dom.ain
    ... Xref: blah blah
    ... Xref: blah blah
    ... Date-Received: yesterday
    ... Posted: tomorrow
    ... Posting-Version: 99.99
    ... Relay-Version: 88.88
    ... Received: blah blah
    ...
    ... A message
    ... """)
    >>> msgdata = {}

    >>> from mailman.queue.news import prepare_message
    >>> prepare_message(mlist, msg, msgdata)
    >>> msgdata['prepped']
    True
    >>> print msg.as_string()
    From: aperson@example.com
    To: _xtest@example.com
    Newsgroups: comp.lang.python
    Message-ID: ...
    Lines: 1
    <BLANKLINE>
    A message
    <BLANKLINE>

Some NNTP servers will reject messages where certain headers are duplicated,
so the news runner must collapse or move these duplicate headers to an
X-Original-* header that the news server doesn't care about.

    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... To: two@example.com
    ... Cc: three@example.com
    ... Cc: four@example.com
    ... Cc: five@example.com
    ... Content-Transfer-Encoding: yes
    ... Content-Transfer-Encoding: no
    ... Content-Transfer-Encoding: maybe
    ...
    ... A message
    ... """)
    >>> msgdata = {}
    >>> prepare_message(mlist, msg, msgdata)
    >>> msgdata['prepped']
    True
    >>> print msg.as_string()
    From: aperson@example.com
    Newsgroups: comp.lang.python
    Message-ID: ...
    Lines: 1
    To: _xtest@example.com
    X-Original-To: two@example.com
    CC: three@example.com
    X-Original-CC: four@example.com
    X-Original-CC: five@example.com
    Content-Transfer-Encoding: yes
    X-Original-Content-Transfer-Encoding: no
    X-Original-Content-Transfer-Encoding: maybe
    <BLANKLINE>
    A message
    <BLANKLINE>

But if no headers are duplicated, then the news runner doesn't need to modify
the message.

    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... Cc: someother@example.com
    ... Content-Transfer-Encoding: yes
    ...
    ... A message
    ... """)
    >>> msgdata = {}
    >>> prepare_message(mlist, msg, msgdata)
    >>> msgdata['prepped']
    True
    >>> print msg.as_string()
    From: aperson@example.com
    To: _xtest@example.com
    Cc: someother@example.com
    Content-Transfer-Encoding: yes
    Newsgroups: comp.lang.python
    Message-ID: ...
    Lines: 1
    <BLANKLINE>
    A message
    <BLANKLINE>


Newsgroup moderation
====================

When the newsgroup is moderated, an Approved: header with the list's posting
address is added for the benefit of the Usenet system.

    >>> from mailman.interfaces.nntp import NewsModeration
    >>> mlist.news_moderation = NewsModeration.open_moderated
    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... Approved: this gets deleted
    ...
    ... """)
    >>> prepare_message(mlist, msg, {})
    >>> print msg['approved']
    _xtest@example.com

    >>> mlist.news_moderation = NewsModeration.moderated
    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... Approved: this gets deleted
    ...
    ... """)
    >>> prepare_message(mlist, msg, {})
    >>> print msg['approved']
    _xtest@example.com

But if the newsgroup is not moderated, the Approved: header is not changed.

    >>> mlist.news_moderation = NewsModeration.none
    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ... Approved: this doesn't get deleted
    ...
    ... """)
    >>> prepare_message(mlist, msg, {})
    >>> msg['approved']
    u"this doesn't get deleted"


XXX More of the NewsRunner should be tested.
