282 lines
11 KiB
TeX
282 lines
11 KiB
TeX
\section{\module{nntplib} ---
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NNTP protocol client}
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\declaremodule{standard}{nntplib}
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\modulesynopsis{NNTP protocol client (requires sockets).}
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\indexii{NNTP}{protocol}
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\index{Network News Transfer Protocol}
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This module defines the class \class{NNTP} which implements the client
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side of the NNTP protocol. It can be used to implement a news reader
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or poster, or automated news processors. For more information on NNTP
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(Network News Transfer Protocol), see Internet \rfc{977}.
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Here are two small examples of how it can be used. To list some
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statistics about a newsgroup and print the subjects of the last 10
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articles:
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\begin{verbatim}
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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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...
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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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>>> s.quit()
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'205 news.cwi.nl closing connection. Goodbye.'
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\end{verbatim}
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To post an article from a file (this assumes that the article has
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valid headers):
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\begin{verbatim}
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>>> s = NNTP('news.cwi.nl')
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>>> f = open('/tmp/article')
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>>> s.post(f)
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'240 Article posted successfully.'
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>>> s.quit()
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'205 news.cwi.nl closing connection. Goodbye.'
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\end{verbatim}
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The module itself defines the following items:
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\begin{classdesc}{NNTP}{host\optional{, port
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\optional{, user\optional{, password
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\optional{, readermode}}}}}
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Return a new instance of the \class{NNTP} class, representing a
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connection to the NNTP server running on host \var{host}, listening at
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port \var{port}. The default \var{port} is 119. If the optional
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\var{user} and \var{password} are provided, the
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\samp{AUTHINFO USER} and \samp{AUTHINFO PASS} commands are used to
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identify and authenticate the user to the server. If the optional
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flag \var{readermode} is true, then a \samp{mode reader} command is
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sent before authentication is performed. Reader mode is sometimes
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necessary if you are connecting to an NNTP server on the local machine
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and intend to call reader-specific commands, such as \samp{group}. If
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you get unexpected \code{NNTPPermanentError}s, you might need to set
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\var{readermode}. \var{readermode} defaults to \code{None}.
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\end{classdesc}
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\begin{classdesc}{NNTPError}{}
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Derived from the standard exception \code{Exception}, this is the base
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class for all exceptions raised by the \code{nntplib} module.
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\end{classdesc}
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\begin{classdesc}{NNTPReplyError}{}
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Exception raised when an unexpected reply is received from the
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server. For backwards compatibility, the exception \code{error_reply}
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is equivalent to this class.
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\end{classdesc}
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\begin{classdesc}{NNTPTemporaryError}{}
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Exception raised when an error code in the range 400--499 is
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received. For backwards compatibility, the exception
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\code{error_temp} is equivalent to this class.
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\end{classdesc}
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\begin{classdesc}{NNTPPermanentError}{}
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Exception raised when an error code in the range 500--599 is
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received. For backwards compatibility, the exception
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\code{error_perm} is equivalent to this class.
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\end{classdesc}
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\begin{classdesc}{NNTPProtocolError}{}
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Exception raised when a reply is received from the server that does
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not begin with a digit in the range 1--5. For backwards
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compatibility, the exception \code{error_proto} is equivalent to this
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class.
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\end{classdesc}
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\begin{classdesc}{NNTPDataError}{}
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Exception raised when there is some error in the response data. For
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backwards compatibility, the exception \code{error_data} is
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equivalent to this class.
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\end{classdesc}
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\subsection{NNTP Objects \label{nntp-objects}}
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NNTP instances have the following methods. The \var{response} that is
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returned as the first item in the return tuple of almost all methods
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is the server's response: a string beginning with a three-digit code.
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If the server's response indicates an error, the method raises one of
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the above exceptions.
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\begin{methoddesc}{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
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information that may be relevant to the user.)
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\end{methoddesc}
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\begin{methoddesc}{set_debuglevel}{level}
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Set the instance's debugging level. This controls the amount of
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debugging output printed. The default, \code{0}, produces no debugging
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output. A value of \code{1} produces a moderate amount of debugging
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output, generally a single line per request or response. A value of
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\code{2} or higher produces the maximum amount of debugging output,
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logging each line sent and received on the connection (including
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message text).
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\end{methoddesc}
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\begin{methoddesc}{newgroups}{date, time}
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Send a \samp{NEWGROUPS} command. The \var{date} argument should be a
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string of the form \code{'\var{yy}\var{mm}\var{dd}'} indicating the
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date, and \var{time} should be a string of the form
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\code{'\var{hh}\var{mm}\var{ss}'} indicating the time. Return a pair
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\code{(\var{response}, \var{groups})} where \var{groups} is a list of
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group names that are new since the given date and time.
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\end{methoddesc}
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\begin{methoddesc}{newnews}{group, date, time}
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Send a \samp{NEWNEWS} command. Here, \var{group} is a group name or
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\code{'*'}, and \var{date} and \var{time} have the same meaning as for
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\method{newgroups()}. Return a pair \code{(\var{response},
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\var{articles})} where \var{articles} is a list of article ids.
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\end{methoddesc}
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\begin{methoddesc}{list}{}
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Send a \samp{LIST} command. Return a pair \code{(\var{response},
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\var{list})} where \var{list} is a list of tuples. Each tuple has the
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form \code{(\var{group}, \var{last}, \var{first}, \var{flag})}, where
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\var{group} is a group name, \var{last} and \var{first} are the last
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and first article numbers (as strings), and \var{flag} is
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\code{'y'} if posting is allowed, \code{'n'} if not, and \code{'m'} if
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the newsgroup is moderated. (Note the ordering: \var{last},
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\var{first}.)
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\end{methoddesc}
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\begin{methoddesc}{group}{name}
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Send a \samp{GROUP} command, where \var{name} is the group name.
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Return a tuple \code{(\var{response}, \var{count}, \var{first},
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\var{last}, \var{name})} where \var{count} is the (estimated) number
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of articles in the group, \var{first} is the first article number in
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the group, \var{last} is the last article number in the group, and
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\var{name} is the group name. The numbers are returned as strings.
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\end{methoddesc}
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\begin{methoddesc}{help}{}
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Send a \samp{HELP} command. Return a pair \code{(\var{response},
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\var{list})} where \var{list} is a list of help strings.
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\end{methoddesc}
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\begin{methoddesc}{stat}{id}
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Send a \samp{STAT} command, where \var{id} is the message id (enclosed
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in \character{<} and \character{>}) or an article number (as a string).
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Return a triple \code{(\var{response}, \var{number}, \var{id})} where
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\var{number} is the article number (as a string) and \var{id} is the
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article id (enclosed in \character{<} and \character{>}).
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\end{methoddesc}
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\begin{methoddesc}{next}{}
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Send a \samp{NEXT} command. Return as for \method{stat()}.
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\end{methoddesc}
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\begin{methoddesc}{last}{}
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Send a \samp{LAST} command. Return as for \method{stat()}.
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\end{methoddesc}
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\begin{methoddesc}{head}{id}
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Send a \samp{HEAD} command, where \var{id} has the same meaning as for
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\method{stat()}. Return a tuple
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\code{(\var{response}, \var{number}, \var{id}, \var{list})}
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where the first three are the same as for \method{stat()},
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and \var{list} is a list of the article's headers (an uninterpreted
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list of lines, without trailing newlines).
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\end{methoddesc}
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\begin{methoddesc}{body}{id,\optional{file}}
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Send a \samp{BODY} command, where \var{id} has the same meaning as for
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\method{stat()}. If the \var{file} parameter is supplied, then
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the body is stored in a file. If \var{file} is a string, then
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the method will open a file object with that name, write to it then close it.
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If \var{file} is a file object, then it will start calling
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\method{write()} on it to store the lines of the body.
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Return as for \method{head()}. If \var{file} is supplied. Then
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the returned \var{list} is an empty list.
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\end{methoddesc}
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\begin{methoddesc}{article}{id}
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Send an \samp{ARTICLE} command, where \var{id} has the same meaning as
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for \method{stat()}. Return as for \method{head()}.
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\end{methoddesc}
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\begin{methoddesc}{slave}{}
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Send a \samp{SLAVE} command. Return the server's \var{response}.
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\end{methoddesc}
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\begin{methoddesc}{xhdr}{header, string}
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Send an \samp{XHDR} command. This command is not defined in the RFC
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but is a common extension. The \var{header} argument is a header
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keyword, e.g. \code{'subject'}. The \var{string} argument should have
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the form \code{'\var{first}-\var{last}'} where \var{first} and
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\var{last} are the first and last article numbers to search. Return a
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pair \code{(\var{response}, \var{list})}, where \var{list} is a list of
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pairs \code{(\var{id}, \var{text})}, where \var{id} is an article id
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(as a string) and \var{text} is the text of the requested header for
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that article.
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\end{methoddesc}
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\begin{methoddesc}{post}{file}
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Post an article using the \samp{POST} command. The \var{file}
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argument is an open file object which is read until EOF using its
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\method{readline()} method. It should be a well-formed news article,
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including the required headers. The \method{post()} method
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automatically escapes lines beginning with \samp{.}.
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\end{methoddesc}
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\begin{methoddesc}{ihave}{id, file}
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Send an \samp{IHAVE} command. If the response is not an error, treat
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\var{file} exactly as for the \method{post()} method.
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\end{methoddesc}
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\begin{methoddesc}{date}{}
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Return a triple \code{(\var{response}, \var{date}, \var{time})},
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containing the current date and time in a form suitable for the
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\method{newnews()} and \method{newgroups()} methods.
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This is an optional NNTP extension, and may not be supported by all
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servers.
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\end{methoddesc}
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\begin{methoddesc}{xgtitle}{name}
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Process an \samp{XGTITLE} command, returning a pair \code{(\var{response},
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\var{list})}, where \var{list} is a list of tuples containing
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\code{(\var{name}, \var{title})}.
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% XXX huh? Should that be name, description?
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This is an optional NNTP extension, and may not be supported by all
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servers.
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\end{methoddesc}
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\begin{methoddesc}{xover}{start, end}
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Return a pair \code{(\var{resp}, \var{list})}. \var{list} is a list
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of tuples, one for each article in the range delimited by the \var{start}
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and \var{end} article numbers. Each tuple is of the form
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\code{(\var{article number}, \var{subject}, \var{poster}, \var{date},
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\var{id}, \var{references}, \var{size}, \var{lines})}.
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This is an optional NNTP extension, and may not be supported by all
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servers.
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\end{methoddesc}
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\begin{methoddesc}{xpath}{id}
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Return a pair \code{(\var{resp}, \var{path})}, where \var{path} is the
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directory path to the article with message ID \var{id}. This is an
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optional NNTP extension, and may not be supported by all servers.
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\end{methoddesc}
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\begin{methoddesc}{quit}{}
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Send a \samp{QUIT} command and close the connection. Once this method
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has been called, no other methods of the NNTP object should be called.
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\end{methoddesc}
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