21.11. nntplib — NNTP protocol client

This module defines the class NNTP which implements the client side of the NNTP protocol. It can be used to implement a news reader or poster, or automated news processors. For more information on NNTP (Network News Transfer Protocol), see Internet RFC 977.

Here are two small examples of how it can be used. To list some statistics about a newsgroup and print the subjects of the last 10 articles:

>>> s = NNTP('news.cwi.nl')
>>> resp, count, first, last, name = s.group('comp.lang.python')
>>> print 'Group', name, 'has', count, 'articles, range', first, 'to', last
Group comp.lang.python has 59 articles, range 3742 to 3803
>>> resp, subs = s.xhdr('subject', first + '-' + last)
>>> for id, sub in subs[-10:]: print id, sub
...
3792 Re: Removing elements from a list while iterating...
3793 Re: Who likes Info files?
3794 Emacs and doc strings
3795 a few questions about the Mac implementation
3796 Re: executable python scripts
3797 Re: executable python scripts
3798 Re: a few questions about the Mac implementation
3799 Re: PROPOSAL: A Generic Python Object Interface for Python C Modules
3802 Re: executable python scripts
3803 Re: \POSIX{} wait and SIGCHLD
>>> s.quit()
'205 news.cwi.nl closing connection.  Goodbye.'

To post an article from a file (this assumes that the article has valid headers):

>>> s = NNTP('news.cwi.nl')
>>> f = open('/tmp/article')
>>> s.post(f)
'240 Article posted successfully.'
>>> s.quit()
'205 news.cwi.nl closing connection.  Goodbye.'

The module itself defines the following items:

class nntplib.NNTP(host[, port[, user[, password[, readermode][, usenetrc]]]])

Return a new instance of the NNTP class, representing a connection to the NNTP server running on host host, listening at port port. The default port is 119. If the optional user and password are provided, or if suitable credentials are present in /.netrc and the optional flag usenetrc is true (the default), the AUTHINFO USER and AUTHINFO PASS commands are used to identify and authenticate the user to the server. If the optional flag readermode is true, then a mode reader command is sent before authentication is performed. Reader mode is sometimes necessary if you are connecting to an NNTP server on the local machine and intend to call reader-specific commands, such as group. If you get unexpected NNTPPermanentErrors, you might need to set readermode. readermode defaults to None. usenetrc defaults to True.

Changed in version 2.4: usenetrc argument added.

exception nntplib.NNTPError

Derived from the standard exception Exception, this is the base class for all exceptions raised by the nntplib module.

exception nntplib.NNTPReplyError

Exception raised when an unexpected reply is received from the server. For backwards compatibility, the exception error_reply is equivalent to this class.

exception nntplib.NNTPTemporaryError

Exception raised when an error code in the range 400–499 is received. For backwards compatibility, the exception error_temp is equivalent to this class.

exception nntplib.NNTPPermanentError

Exception raised when an error code in the range 500–599 is received. For backwards compatibility, the exception error_perm is equivalent to this class.

exception nntplib.NNTPProtocolError

Exception raised when a reply is received from the server that does not begin with a digit in the range 1–5. For backwards compatibility, the exception error_proto is equivalent to this class.

exception nntplib.NNTPDataError

Exception raised when there is some error in the response data. For backwards compatibility, the exception error_data is equivalent to this class.

21.11.1. NNTP Objects

NNTP instances have the following methods. The response that is returned as the first item in the return tuple of almost all methods is the server’s response: a string beginning with a three-digit code. If the server’s response indicates an error, the method raises one of the above exceptions.

NNTP.getwelcome()

Return the welcome message sent by the server in reply to the initial connection. (This message sometimes contains disclaimers or help information that may be relevant to the user.)

NNTP.set_debuglevel(level)

Set the instance’s debugging level. This controls the amount of debugging output printed. The default, 0, produces no debugging output. A value of 1 produces a moderate amount of debugging output, generally a single line per request or response. A value of 2 or higher produces the maximum amount of debugging output, logging each line sent and received on the connection (including message text).

NNTP.newgroups(date, time[, file])

Send a NEWGROUPS command. The date argument should be a string of the form 'yymmdd' indicating the date, and time should be a string of the form 'hhmmss' indicating the time. Return a pair (response, groups) where groups is a list of group names that are new since the given date and time. If the file parameter is supplied, then the output of the NEWGROUPS command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list.

NNTP.newnews(group, date, time[, file])

Send a NEWNEWS command. Here, group is a group name or '*', and date and time have the same meaning as for newgroups(). Return a pair (response, articles) where articles is a list of message ids. If the file parameter is supplied, then the output of the NEWNEWS command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list.

NNTP.list([file])

Send a LIST command. Return a pair (response, list) where list is a list of tuples. Each tuple has the form (group, last, first, flag), where group is a group name, last and first are the last and first article numbers (as strings), and flag is 'y' if posting is allowed, 'n' if not, and 'm' if the newsgroup is moderated. (Note the ordering: last, first.) If the file parameter is supplied, then the output of the LIST command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list.

NNTP.descriptions(grouppattern)

Send a LIST NEWSGROUPS command, where grouppattern is a wildmat string as specified in RFC2980 (it’s essentially the same as DOS or UNIX shell wildcard strings). Return a pair (response, list), where list is a list of tuples containing (name, title).

New in version 2.4.

NNTP.description(group)

Get a description for a single group group. If more than one group matches (if ‘group’ is a real wildmat string), return the first match. If no group matches, return an empty string.

This elides the response code from the server. If the response code is needed, use descriptions().

New in version 2.4.

NNTP.group(name)

Send a GROUP command, where name is the group name. Return a tuple (response, count, first, last, name) where count is the (estimated) number of articles in the group, first is the first article number in the group, last is the last article number in the group, and name is the group name. The numbers are returned as strings.

NNTP.help([file])

Send a HELP command. Return a pair (response, list) where list is a list of help strings. If the file parameter is supplied, then the output of the HELP command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list.

NNTP.stat(id)

Send a STAT command, where id is the message id (enclosed in '<' and '>') or an article number (as a string). Return a triple (response, number, id) where number is the article number (as a string) and id is the message id (enclosed in '<' and '>').

NNTP.next()

Send a NEXT command. Return as for stat().

NNTP.last()

Send a LAST command. Return as for stat().

NNTP.head(id)

Send a HEAD command, where id has the same meaning as for stat(). Return a tuple (response, number, id, list) where the first three are the same as for stat(), and list is a list of the article’s headers (an uninterpreted list of lines, without trailing newlines).

NNTP.body(id[, file])

Send a BODY command, where id has the same meaning as for stat(). If the file parameter is supplied, then the body is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the body. Return as for head(). If file is supplied, then the returned list is an empty list.

NNTP.article(id)

Send an ARTICLE command, where id has the same meaning as for stat(). Return as for head().

NNTP.slave()

Send a SLAVE command. Return the server’s response.

NNTP.xhdr(header, string[, file])

Send an XHDR command. This command is not defined in the RFC but is a common extension. The header argument is a header keyword, e.g. 'subject'. The string argument should have the form 'first-last' where first and last are the first and last article numbers to search. Return a pair (response, list), where list is a list of pairs (id, text), where id is an article number (as a string) and text is the text of the requested header for that article. If the file parameter is supplied, then the output of the XHDR command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list.

NNTP.post(file)

Post an article using the POST command. The file argument is an open file object which is read until EOF using its readline() method. It should be a well-formed news article, including the required headers. The post() method automatically escapes lines beginning with ..

NNTP.ihave(id, file)

Send an IHAVE command. id is a message id (enclosed in '<' and '>'). If the response is not an error, treat file exactly as for the post() method.

NNTP.date()

Return a triple (response, date, time), containing the current date and time in a form suitable for the newnews() and newgroups() methods. This is an optional NNTP extension, and may not be supported by all servers.

NNTP.xgtitle(name[, file])

Process an XGTITLE command, returning a pair (response, list), where list is a list of tuples containing (name, title). If the file parameter is supplied, then the output of the XGTITLE command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list. This is an optional NNTP extension, and may not be supported by all servers.

RFC2980 says “It is suggested that this extension be deprecated”. Use descriptions() or description() instead.

NNTP.xover(start, end[, file])

Return a pair (resp, list). list is a list of tuples, one for each article in the range delimited by the start and end article numbers. Each tuple is of the form (article number, subject, poster, date, id, references, size, lines). If the file parameter is supplied, then the output of the XOVER command is stored in a file. If file is a string, then the method will open a file object with that name, write to it then close it. If file is a file object, then it will start calling write() on it to store the lines of the command output. If file is supplied, then the returned list is an empty list. This is an optional NNTP extension, and may not be supported by all servers.

NNTP.xpath(id)

Return a pair (resp, path), where path is the directory path to the article with message ID id. This is an optional NNTP extension, and may not be supported by all servers.

NNTP.quit()

Send a QUIT command and close the connection. Once this method has been called, no other methods of the NNTP object should be called.