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:mod:`nntplib` --- NNTP protocol client
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=======================================
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:synopsis: NNTP protocol client (requires sockets).
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single: Network News Transfer Protocol
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This module defines the class :class:`NNTP` which implements the client side of
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the NNTP protocol. It can be used to implement a news reader or poster, or
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automated news processors. For more information on NNTP (Network News Transfer
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Protocol), see Internet :rfc:`977`.
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Here are two small examples of how it can be used. To list some statistics
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about a newsgroup and print the subjects of the last 10 articles::
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>>> s = NNTP('news.cwi.nl')
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>>> resp, count, first, last, name = s.group('comp.lang.python')
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>>> print('Group', name, 'has', count, 'articles, range', first, 'to', last)
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Group comp.lang.python has 59 articles, range 3742 to 3803
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>>> resp, subs = s.xhdr('subject', first + '-' + last)
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>>> for id, sub in subs[-10:]: print(id, sub)
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3792 Re: Removing elements from a list while iterating...
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3793 Re: Who likes Info files?
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3794 Emacs and doc strings
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3795 a few questions about the Mac implementation
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3796 Re: executable python scripts
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3797 Re: executable python scripts
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3798 Re: a few questions about the Mac implementation
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3799 Re: PROPOSAL: A Generic Python Object Interface for Python C Modules
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3802 Re: executable python scripts
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3803 Re: \POSIX{} wait and SIGCHLD
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'205 news.cwi.nl closing connection. Goodbye.'
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To post an article from a file (this assumes that the article has valid
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>>> s = NNTP('news.cwi.nl')
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>>> f = open('/tmp/article')
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'240 Article posted successfully.'
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'205 news.cwi.nl closing connection. Goodbye.'
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The module itself defines the following items:
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.. class:: NNTP(host[, port [, user[, password [, readermode][, usenetrc]]]])
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Return a new instance of the :class:`NNTP` class, representing a connection
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to the NNTP server running on host *host*, listening at port *port*. The
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default *port* is 119. If the optional *user* and *password* are provided,
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or if suitable credentials are present in :file:`/.netrc` and the optional
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flag *usenetrc* is true (the default), the ``AUTHINFO USER`` and ``AUTHINFO
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PASS`` commands are used to identify and authenticate the user to the server.
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If the optional flag *readermode* is true, then a ``mode reader`` command is
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sent before authentication is performed. Reader mode is sometimes necessary
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if you are connecting to an NNTP server on the local machine and intend to
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call reader-specific commands, such as ``group``. If you get unexpected
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:exc:`NNTPPermanentError`\ s, you might need to set *readermode*.
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*readermode* defaults to ``None``. *usenetrc* defaults to ``True``.
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.. exception:: NNTPError
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Derived from the standard exception :exc:`Exception`, this is the base class for
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all exceptions raised by the :mod:`nntplib` module.
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.. exception:: NNTPReplyError
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Exception raised when an unexpected reply is received from the server. For
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backwards compatibility, the exception ``error_reply`` is equivalent to this
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.. exception:: NNTPTemporaryError
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Exception raised when an error code in the range 400--499 is received. For
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backwards compatibility, the exception ``error_temp`` is equivalent to this
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.. exception:: NNTPPermanentError
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Exception raised when an error code in the range 500--599 is received. For
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backwards compatibility, the exception ``error_perm`` is equivalent to this
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.. exception:: NNTPProtocolError
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Exception raised when a reply is received from the server that does not begin
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with a digit in the range 1--5. For backwards compatibility, the exception
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``error_proto`` is equivalent to this class.
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.. exception:: NNTPDataError
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Exception raised when there is some error in the response data. For backwards
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compatibility, the exception ``error_data`` is equivalent to this class.
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NNTP instances have the following methods. The *response* that is returned as
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the first item in the return tuple of almost all methods is the server's
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response: a string beginning with a three-digit code. If the server's response
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indicates an error, the method raises one of the above exceptions.
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.. method:: NNTP.getwelcome()
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Return the welcome message sent by the server in reply to the initial
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connection. (This message sometimes contains disclaimers or help information
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that may be relevant to the user.)
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.. method:: NNTP.set_debuglevel(level)
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Set the instance's debugging level. This controls the amount of debugging
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output printed. The default, ``0``, produces no debugging output. A value of
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``1`` produces a moderate amount of debugging output, generally a single line
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per request or response. A value of ``2`` or higher produces the maximum amount
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of debugging output, logging each line sent and received on the connection
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(including message text).
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.. method:: NNTP.newgroups(date, time, [file])
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Send a ``NEWGROUPS`` command. The *date* argument should be a string of the
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form ``'yymmdd'`` indicating the date, and *time* should be a string of the form
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``'hhmmss'`` indicating the time. Return a pair ``(response, groups)`` where
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*groups* is a list of group names that are new since the given date and time. If
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the *file* parameter is supplied, then the output of the ``NEWGROUPS`` command
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is stored in a file. If *file* is a string, then the method will open a file
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object with that name, write to it then close it. If *file* is a file object,
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then it will start calling :meth:`write` on it to store the lines of the command
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output. If *file* is supplied, then the returned *list* is an empty list.
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.. method:: NNTP.newnews(group, date, time, [file])
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Send a ``NEWNEWS`` command. Here, *group* is a group name or ``'*'``, and
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*date* and *time* have the same meaning as for :meth:`newgroups`. Return a pair
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``(response, articles)`` where *articles* is a list of message ids. If the
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*file* parameter is supplied, then the output of the ``NEWNEWS`` command is
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stored in a file. If *file* is a string, then the method will open a file
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object with that name, write to it then close it. If *file* is a file object,
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then it will start calling :meth:`write` on it to store the lines of the command
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output. If *file* is supplied, then the returned *list* is an empty list.
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.. method:: NNTP.list([file])
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Send a ``LIST`` command. Return a pair ``(response, list)`` where *list* is a
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list of tuples. Each tuple has the form ``(group, last, first, flag)``, where
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*group* is a group name, *last* and *first* are the last and first article
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numbers (as strings), and *flag* is ``'y'`` if posting is allowed, ``'n'`` if
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not, and ``'m'`` if the newsgroup is moderated. (Note the ordering: *last*,
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*first*.) If the *file* parameter is supplied, then the output of the ``LIST``
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command is stored in a file. If *file* is a string, then the method will open
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a file object with that name, write to it then close it. If *file* is a file
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object, then it will start calling :meth:`write` on it to store the lines of the
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command output. If *file* is supplied, then the returned *list* is an empty
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.. method:: NNTP.descriptions(grouppattern)
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Send a ``LIST NEWSGROUPS`` command, where *grouppattern* is a wildmat string as
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specified in RFC2980 (it's essentially the same as DOS or UNIX shell wildcard
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strings). Return a pair ``(response, list)``, where *list* is a list of tuples
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containing ``(name, title)``.
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.. method:: NNTP.description(group)
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Get a description for a single group *group*. If more than one group matches
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(if 'group' is a real wildmat string), return the first match. If no group
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matches, return an empty string.
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This elides the response code from the server. If the response code is needed,
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use :meth:`descriptions`.
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.. method:: NNTP.group(name)
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Send a ``GROUP`` command, where *name* is the group name. Return a tuple
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``(response, count, first, last, name)`` where *count* is the (estimated) number
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of articles in the group, *first* is the first article number in the group,
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*last* is the last article number in the group, and *name* is the group name.
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The numbers are returned as strings.
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.. method:: NNTP.help([file])
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Send a ``HELP`` command. Return a pair ``(response, list)`` where *list* is a
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list of help strings. If the *file* parameter is supplied, then the output of
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the ``HELP`` command is stored in a file. If *file* is a string, then the
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method will open a file object with that name, write to it then close it. If
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*file* is a file object, then it will start calling :meth:`write` on it to store
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the lines of the command output. If *file* is supplied, then the returned *list*
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.. method:: NNTP.stat(id)
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Send a ``STAT`` command, where *id* is the message id (enclosed in ``'<'`` and
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``'>'``) or an article number (as a string). Return a triple ``(response,
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number, id)`` where *number* is the article number (as a string) and *id* is the
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message id (enclosed in ``'<'`` and ``'>'``).
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.. method:: NNTP.next()
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Send a ``NEXT`` command. Return as for :meth:`stat`.
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.. method:: NNTP.last()
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Send a ``LAST`` command. Return as for :meth:`stat`.
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.. method:: NNTP.head(id)
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Send a ``HEAD`` command, where *id* has the same meaning as for :meth:`stat`.
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Return a tuple ``(response, number, id, list)`` where the first three are the
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same as for :meth:`stat`, and *list* is a list of the article's headers (an
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uninterpreted list of lines, without trailing newlines).
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.. method:: NNTP.body(id,[file])
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Send a ``BODY`` command, where *id* has the same meaning as for :meth:`stat`.
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If the *file* parameter is supplied, then the body is stored in a file. If
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*file* is a string, then the method will open a file object with that name,
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write to it then close it. If *file* is a file object, then it will start
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calling :meth:`write` on it to store the lines of the body. Return as for
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:meth:`head`. If *file* is supplied, then the returned *list* is an empty list.
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.. method:: NNTP.article(id)
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Send an ``ARTICLE`` command, where *id* has the same meaning as for
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:meth:`stat`. Return as for :meth:`head`.
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.. method:: NNTP.slave()
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Send a ``SLAVE`` command. Return the server's *response*.
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.. method:: NNTP.xhdr(header, string, [file])
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Send an ``XHDR`` command. This command is not defined in the RFC but is a
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common extension. The *header* argument is a header keyword, e.g.
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``'subject'``. The *string* argument should have the form ``'first-last'``
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where *first* and *last* are the first and last article numbers to search.
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Return a pair ``(response, list)``, where *list* is a list of pairs ``(id,
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text)``, where *id* is an article number (as a string) and *text* is the text of
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the requested header for that article. If the *file* parameter is supplied, then
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the output of the ``XHDR`` command is stored in a file. If *file* is a string,
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then the method will open a file object with that name, write to it then close
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it. If *file* is a file object, then it will start calling :meth:`write` on it
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to store the lines of the command output. If *file* is supplied, then the
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returned *list* is an empty list.
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.. method:: NNTP.post(file)
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Post an article using the ``POST`` command. The *file* argument is an open file
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object which is read until EOF using its :meth:`readline` method. It should be
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a well-formed news article, including the required headers. The :meth:`post`
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method automatically escapes lines beginning with ``.``.
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.. method:: NNTP.ihave(id, file)
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Send an ``IHAVE`` command. *id* is a message id (enclosed in ``'<'`` and
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``'>'``). If the response is not an error, treat *file* exactly as for the
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.. method:: NNTP.date()
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Return a triple ``(response, date, time)``, containing the current date and time
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in a form suitable for the :meth:`newnews` and :meth:`newgroups` methods. This
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is an optional NNTP extension, and may not be supported by all servers.
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.. method:: NNTP.xgtitle(name, [file])
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Process an ``XGTITLE`` command, returning a pair ``(response, list)``, where
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*list* is a list of tuples containing ``(name, title)``. If the *file* parameter
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is supplied, then the output of the ``XGTITLE`` command is stored in a file.
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If *file* is a string, then the method will open a file object with that name,
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write to it then close it. If *file* is a file object, then it will start
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calling :meth:`write` on it to store the lines of the command output. If *file*
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is supplied, then the returned *list* is an empty list. This is an optional NNTP
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extension, and may not be supported by all servers.
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RFC2980 says "It is suggested that this extension be deprecated". Use
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:meth:`descriptions` or :meth:`description` instead.
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.. method:: NNTP.xover(start, end, [file])
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Return a pair ``(resp, list)``. *list* is a list of tuples, one for each
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article in the range delimited by the *start* and *end* article numbers. Each
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tuple is of the form ``(article number, subject, poster, date, id, references,
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size, lines)``. If the *file* parameter is supplied, then the output of the
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``XOVER`` command is stored in a file. If *file* is a string, then the method
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will open a file object with that name, write to it then close it. If *file*
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is a file object, then it will start calling :meth:`write` on it to store the
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lines of the command output. If *file* is supplied, then the returned *list* is
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an empty list. This is an optional NNTP extension, and may not be supported by
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.. method:: NNTP.xpath(id)
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Return a pair ``(resp, path)``, where *path* is the directory path to the
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article with message ID *id*. This is an optional NNTP extension, and may not
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be supported by all servers.
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.. method:: NNTP.quit()
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Send a ``QUIT`` command and close the connection. Once this method has been
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called, no other methods of the NNTP object should be called.