637 lines
21 KiB
Python
637 lines
21 KiB
Python
"""An NNTP client class based on RFC 977: Network News Transfer Protocol.
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Example:
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>>> from nntplib import NNTP
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>>> s = NNTP('news')
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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 51 articles, range 5770 to 5821
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>>> resp, subs = s.xhdr('subject', first + '-' + last)
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>>> resp = s.quit()
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>>>
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Here 'resp' is the server response line.
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Error responses are turned into exceptions.
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To post an article from a file:
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>>> f = open(filename, 'r') # file containing article, including header
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>>> resp = s.post(f)
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>>>
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For descriptions of all methods, read the comments in the code below.
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Note that all arguments and return values representing article numbers
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are strings, not numbers, since they are rarely used for calculations.
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"""
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# RFC 977 by Brian Kantor and Phil Lapsley.
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# xover, xgtitle, xpath, date methods by Kevan Heydon
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# Imports
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import re
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import socket
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__all__ = ["NNTP","NNTPReplyError","NNTPTemporaryError",
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"NNTPPermanentError","NNTPProtocolError","NNTPDataError",
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"error_reply","error_temp","error_perm","error_proto",
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"error_data",]
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# maximal line length when calling readline(). This is to prevent
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# reading arbitrary length lines. RFC 3977 limits NNTP line length to
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# 512 characters, including CRLF. We have selected 2048 just to be on
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# the safe side.
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_MAXLINE = 2048
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# Exceptions raised when an error or invalid response is received
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class NNTPError(Exception):
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"""Base class for all nntplib exceptions"""
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def __init__(self, *args):
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Exception.__init__(self, *args)
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try:
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self.response = args[0]
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except IndexError:
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self.response = 'No response given'
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class NNTPReplyError(NNTPError):
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"""Unexpected [123]xx reply"""
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pass
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class NNTPTemporaryError(NNTPError):
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"""4xx errors"""
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pass
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class NNTPPermanentError(NNTPError):
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"""5xx errors"""
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pass
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class NNTPProtocolError(NNTPError):
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"""Response does not begin with [1-5]"""
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pass
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class NNTPDataError(NNTPError):
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"""Error in response data"""
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pass
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# for backwards compatibility
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error_reply = NNTPReplyError
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error_temp = NNTPTemporaryError
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error_perm = NNTPPermanentError
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error_proto = NNTPProtocolError
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error_data = NNTPDataError
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# Standard port used by NNTP servers
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NNTP_PORT = 119
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# Response numbers that are followed by additional text (e.g. article)
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LONGRESP = ['100', '215', '220', '221', '222', '224', '230', '231', '282']
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# Line terminators (we always output CRLF, but accept any of CRLF, CR, LF)
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CRLF = '\r\n'
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# The class itself
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class NNTP:
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def __init__(self, host, port=NNTP_PORT, user=None, password=None,
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readermode=None, usenetrc=True):
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"""Initialize an instance. Arguments:
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- host: hostname to connect to
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- port: port to connect to (default the standard NNTP port)
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- user: username to authenticate with
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- password: password to use with username
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- readermode: if true, send 'mode reader' command after
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connecting.
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readermode is sometimes necessary if you are connecting to an
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NNTP server on the local machine and intend to call
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reader-specific commands, such as `group'. If you get
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unexpected NNTPPermanentErrors, you might need to set
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readermode.
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"""
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self.host = host
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self.port = port
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self.sock = socket.create_connection((host, port))
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self.file = self.sock.makefile('rb')
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self.debugging = 0
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self.welcome = self.getresp()
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# 'mode reader' is sometimes necessary to enable 'reader' mode.
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# However, the order in which 'mode reader' and 'authinfo' need to
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# arrive differs between some NNTP servers. Try to send
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# 'mode reader', and if it fails with an authorization failed
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# error, try again after sending authinfo.
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readermode_afterauth = 0
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if readermode:
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try:
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self.welcome = self.shortcmd('mode reader')
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except NNTPPermanentError:
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# error 500, probably 'not implemented'
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pass
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except NNTPTemporaryError, e:
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if user and e.response[:3] == '480':
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# Need authorization before 'mode reader'
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readermode_afterauth = 1
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else:
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raise
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# If no login/password was specified, try to get them from ~/.netrc
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# Presume that if .netc has an entry, NNRP authentication is required.
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try:
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if usenetrc and not user:
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import netrc
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credentials = netrc.netrc()
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auth = credentials.authenticators(host)
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if auth:
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user = auth[0]
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password = auth[2]
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except IOError:
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pass
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# Perform NNRP authentication if needed.
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if user:
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resp = self.shortcmd('authinfo user '+user)
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if resp[:3] == '381':
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if not password:
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raise NNTPReplyError(resp)
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else:
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resp = self.shortcmd(
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'authinfo pass '+password)
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if resp[:3] != '281':
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raise NNTPPermanentError(resp)
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if readermode_afterauth:
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try:
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self.welcome = self.shortcmd('mode reader')
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except NNTPPermanentError:
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# error 500, probably 'not implemented'
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pass
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# Get the welcome message from the server
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# (this is read and squirreled away by __init__()).
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# If the response code is 200, posting is allowed;
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# if it 201, posting is not allowed
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def getwelcome(self):
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"""Get the welcome message from the server
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(this is read and squirreled away by __init__()).
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If the response code is 200, posting is allowed;
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if it 201, posting is not allowed."""
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if self.debugging: print '*welcome*', repr(self.welcome)
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return self.welcome
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def set_debuglevel(self, level):
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"""Set the debugging level. Argument 'level' means:
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0: no debugging output (default)
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1: print commands and responses but not body text etc.
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2: also print raw lines read and sent before stripping CR/LF"""
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self.debugging = level
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debug = set_debuglevel
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def putline(self, line):
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"""Internal: send one line to the server, appending CRLF."""
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line = line + CRLF
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if self.debugging > 1: print '*put*', repr(line)
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self.sock.sendall(line)
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def putcmd(self, line):
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"""Internal: send one command to the server (through putline())."""
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if self.debugging: print '*cmd*', repr(line)
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self.putline(line)
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def getline(self):
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"""Internal: return one line from the server, stripping CRLF.
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Raise EOFError if the connection is closed."""
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line = self.file.readline(_MAXLINE + 1)
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if len(line) > _MAXLINE:
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raise NNTPDataError('line too long')
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if self.debugging > 1:
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print '*get*', repr(line)
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if not line: raise EOFError
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if line[-2:] == CRLF: line = line[:-2]
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elif line[-1:] in CRLF: line = line[:-1]
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return line
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def getresp(self):
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"""Internal: get a response from the server.
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Raise various errors if the response indicates an error."""
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resp = self.getline()
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if self.debugging: print '*resp*', repr(resp)
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c = resp[:1]
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if c == '4':
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raise NNTPTemporaryError(resp)
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if c == '5':
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raise NNTPPermanentError(resp)
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if c not in '123':
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raise NNTPProtocolError(resp)
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return resp
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def getlongresp(self, file=None):
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"""Internal: get a response plus following text from the server.
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Raise various errors if the response indicates an error."""
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openedFile = None
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try:
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# If a string was passed then open a file with that name
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if isinstance(file, str):
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openedFile = file = open(file, "w")
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resp = self.getresp()
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if resp[:3] not in LONGRESP:
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raise NNTPReplyError(resp)
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list = []
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while 1:
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line = self.getline()
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if line == '.':
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break
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if line[:2] == '..':
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line = line[1:]
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if file:
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file.write(line + "\n")
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else:
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list.append(line)
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finally:
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# If this method created the file, then it must close it
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if openedFile:
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openedFile.close()
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return resp, list
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def shortcmd(self, line):
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"""Internal: send a command and get the response."""
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self.putcmd(line)
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return self.getresp()
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def longcmd(self, line, file=None):
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"""Internal: send a command and get the response plus following text."""
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self.putcmd(line)
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return self.getlongresp(file)
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def newgroups(self, date, time, file=None):
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"""Process a NEWGROUPS command. Arguments:
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- date: string 'yymmdd' indicating the date
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- time: string 'hhmmss' indicating the time
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Return:
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- resp: server response if successful
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- list: list of newsgroup names"""
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return self.longcmd('NEWGROUPS ' + date + ' ' + time, file)
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def newnews(self, group, date, time, file=None):
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"""Process a NEWNEWS command. Arguments:
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- group: group name or '*'
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- date: string 'yymmdd' indicating the date
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- time: string 'hhmmss' indicating the time
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Return:
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- resp: server response if successful
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- list: list of message ids"""
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cmd = 'NEWNEWS ' + group + ' ' + date + ' ' + time
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return self.longcmd(cmd, file)
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def list(self, file=None):
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"""Process a LIST command. Return:
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- resp: server response if successful
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- list: list of (group, last, first, flag) (strings)"""
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resp, list = self.longcmd('LIST', file)
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for i in range(len(list)):
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# Parse lines into "group last first flag"
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list[i] = tuple(list[i].split())
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return resp, list
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def description(self, group):
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"""Get a description for a single group. If more than one
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group matches ('group' is a pattern), return the first. If no
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group matches, return an empty string.
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This elides the response code from the server, since it can
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only be '215' or '285' (for xgtitle) anyway. If the response
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code is needed, use the 'descriptions' method.
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NOTE: This neither checks for a wildcard in 'group' nor does
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it check whether the group actually exists."""
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resp, lines = self.descriptions(group)
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if len(lines) == 0:
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return ""
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else:
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return lines[0][1]
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def descriptions(self, group_pattern):
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"""Get descriptions for a range of groups."""
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line_pat = re.compile("^(?P<group>[^ \t]+)[ \t]+(.*)$")
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# Try the more std (acc. to RFC2980) LIST NEWSGROUPS first
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resp, raw_lines = self.longcmd('LIST NEWSGROUPS ' + group_pattern)
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if resp[:3] != "215":
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# Now the deprecated XGTITLE. This either raises an error
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# or succeeds with the same output structure as LIST
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# NEWSGROUPS.
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resp, raw_lines = self.longcmd('XGTITLE ' + group_pattern)
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lines = []
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for raw_line in raw_lines:
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match = line_pat.search(raw_line.strip())
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if match:
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lines.append(match.group(1, 2))
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return resp, lines
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def group(self, name):
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"""Process a GROUP command. Argument:
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- group: the group name
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Returns:
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- resp: server response if successful
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- count: number of articles (string)
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- first: first article number (string)
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- last: last article number (string)
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- name: the group name"""
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resp = self.shortcmd('GROUP ' + name)
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if resp[:3] != '211':
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raise NNTPReplyError(resp)
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words = resp.split()
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count = first = last = 0
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n = len(words)
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if n > 1:
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count = words[1]
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if n > 2:
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first = words[2]
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if n > 3:
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last = words[3]
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if n > 4:
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name = words[4].lower()
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return resp, count, first, last, name
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def help(self, file=None):
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"""Process a HELP command. Returns:
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- resp: server response if successful
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- list: list of strings"""
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return self.longcmd('HELP',file)
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def statparse(self, resp):
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"""Internal: parse the response of a STAT, NEXT or LAST command."""
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if resp[:2] != '22':
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raise NNTPReplyError(resp)
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words = resp.split()
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nr = 0
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id = ''
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n = len(words)
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if n > 1:
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nr = words[1]
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if n > 2:
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id = words[2]
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return resp, nr, id
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def statcmd(self, line):
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"""Internal: process a STAT, NEXT or LAST command."""
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resp = self.shortcmd(line)
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return self.statparse(resp)
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def stat(self, id):
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"""Process a STAT command. Argument:
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- id: article number or message id
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Returns:
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- resp: server response if successful
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- nr: the article number
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- id: the message id"""
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return self.statcmd('STAT ' + id)
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def next(self):
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"""Process a NEXT command. No arguments. Return as for STAT."""
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return self.statcmd('NEXT')
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def last(self):
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"""Process a LAST command. No arguments. Return as for STAT."""
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return self.statcmd('LAST')
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def artcmd(self, line, file=None):
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"""Internal: process a HEAD, BODY or ARTICLE command."""
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resp, list = self.longcmd(line, file)
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resp, nr, id = self.statparse(resp)
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return resp, nr, id, list
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def head(self, id):
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"""Process a HEAD command. Argument:
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- id: article number or message id
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Returns:
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- resp: server response if successful
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- nr: article number
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- id: message id
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- list: the lines of the article's header"""
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return self.artcmd('HEAD ' + id)
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def body(self, id, file=None):
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"""Process a BODY command. Argument:
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- id: article number or message id
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- file: Filename string or file object to store the article in
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Returns:
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- resp: server response if successful
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- nr: article number
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- id: message id
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- list: the lines of the article's body or an empty list
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if file was used"""
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return self.artcmd('BODY ' + id, file)
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def article(self, id):
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"""Process an ARTICLE command. Argument:
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- id: article number or message id
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Returns:
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- resp: server response if successful
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- nr: article number
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- id: message id
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- list: the lines of the article"""
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return self.artcmd('ARTICLE ' + id)
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def slave(self):
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"""Process a SLAVE command. Returns:
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- resp: server response if successful"""
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return self.shortcmd('SLAVE')
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def xhdr(self, hdr, str, file=None):
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"""Process an XHDR command (optional server extension). Arguments:
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- hdr: the header type (e.g. 'subject')
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- str: an article nr, a message id, or a range nr1-nr2
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Returns:
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- resp: server response if successful
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- list: list of (nr, value) strings"""
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pat = re.compile('^([0-9]+) ?(.*)\n?')
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resp, lines = self.longcmd('XHDR ' + hdr + ' ' + str, file)
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for i in range(len(lines)):
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line = lines[i]
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m = pat.match(line)
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if m:
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lines[i] = m.group(1, 2)
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return resp, lines
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def xover(self, start, end, file=None):
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"""Process an XOVER command (optional server extension) Arguments:
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- start: start of range
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- end: end of range
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Returns:
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- resp: server response if successful
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- list: list of (art-nr, subject, poster, date,
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id, references, size, lines)"""
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resp, lines = self.longcmd('XOVER ' + start + '-' + end, file)
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xover_lines = []
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for line in lines:
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elem = line.split("\t")
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try:
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xover_lines.append((elem[0],
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elem[1],
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elem[2],
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elem[3],
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elem[4],
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elem[5].split(),
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elem[6],
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elem[7]))
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except IndexError:
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raise NNTPDataError(line)
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return resp,xover_lines
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def xgtitle(self, group, file=None):
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"""Process an XGTITLE command (optional server extension) Arguments:
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- group: group name wildcard (i.e. news.*)
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Returns:
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- resp: server response if successful
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- list: list of (name,title) strings"""
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line_pat = re.compile("^([^ \t]+)[ \t]+(.*)$")
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resp, raw_lines = self.longcmd('XGTITLE ' + group, file)
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lines = []
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for raw_line in raw_lines:
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match = line_pat.search(raw_line.strip())
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if match:
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lines.append(match.group(1, 2))
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return resp, lines
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def xpath(self,id):
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"""Process an XPATH command (optional server extension) Arguments:
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- id: Message id of article
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Returns:
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resp: server response if successful
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path: directory path to article"""
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resp = self.shortcmd("XPATH " + id)
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if resp[:3] != '223':
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raise NNTPReplyError(resp)
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try:
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[resp_num, path] = resp.split()
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except ValueError:
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raise NNTPReplyError(resp)
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else:
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return resp, path
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|
|
|
def date (self):
|
|
"""Process the DATE command. Arguments:
|
|
None
|
|
Returns:
|
|
resp: server response if successful
|
|
date: Date suitable for newnews/newgroups commands etc.
|
|
time: Time suitable for newnews/newgroups commands etc."""
|
|
|
|
resp = self.shortcmd("DATE")
|
|
if resp[:3] != '111':
|
|
raise NNTPReplyError(resp)
|
|
elem = resp.split()
|
|
if len(elem) != 2:
|
|
raise NNTPDataError(resp)
|
|
date = elem[1][2:8]
|
|
time = elem[1][-6:]
|
|
if len(date) != 6 or len(time) != 6:
|
|
raise NNTPDataError(resp)
|
|
return resp, date, time
|
|
|
|
|
|
def post(self, f):
|
|
"""Process a POST command. Arguments:
|
|
- f: file containing the article
|
|
Returns:
|
|
- resp: server response if successful"""
|
|
|
|
resp = self.shortcmd('POST')
|
|
# Raises error_??? if posting is not allowed
|
|
if resp[0] != '3':
|
|
raise NNTPReplyError(resp)
|
|
while 1:
|
|
line = f.readline()
|
|
if not line:
|
|
break
|
|
if line[-1] == '\n':
|
|
line = line[:-1]
|
|
if line[:1] == '.':
|
|
line = '.' + line
|
|
self.putline(line)
|
|
self.putline('.')
|
|
return self.getresp()
|
|
|
|
def ihave(self, id, f):
|
|
"""Process an IHAVE command. Arguments:
|
|
- id: message-id of the article
|
|
- f: file containing the article
|
|
Returns:
|
|
- resp: server response if successful
|
|
Note that if the server refuses the article an exception is raised."""
|
|
|
|
resp = self.shortcmd('IHAVE ' + id)
|
|
# Raises error_??? if the server already has it
|
|
if resp[0] != '3':
|
|
raise NNTPReplyError(resp)
|
|
while 1:
|
|
line = f.readline()
|
|
if not line:
|
|
break
|
|
if line[-1] == '\n':
|
|
line = line[:-1]
|
|
if line[:1] == '.':
|
|
line = '.' + line
|
|
self.putline(line)
|
|
self.putline('.')
|
|
return self.getresp()
|
|
|
|
def quit(self):
|
|
"""Process a QUIT command and close the socket. Returns:
|
|
- resp: server response if successful"""
|
|
|
|
resp = self.shortcmd('QUIT')
|
|
self.file.close()
|
|
self.sock.close()
|
|
del self.file, self.sock
|
|
return resp
|
|
|
|
|
|
# Test retrieval when run as a script.
|
|
# Assumption: if there's a local news server, it's called 'news'.
|
|
# Assumption: if user queries a remote news server, it's named
|
|
# in the environment variable NNTPSERVER (used by slrn and kin)
|
|
# and we want readermode off.
|
|
if __name__ == '__main__':
|
|
import os
|
|
newshost = 'news' and os.environ["NNTPSERVER"]
|
|
if newshost.find('.') == -1:
|
|
mode = 'readermode'
|
|
else:
|
|
mode = None
|
|
s = NNTP(newshost, readermode=mode)
|
|
resp, count, first, last, name = s.group('comp.lang.python')
|
|
print resp
|
|
print 'Group', name, 'has', count, 'articles, range', first, 'to', last
|
|
resp, subs = s.xhdr('subject', first + '-' + last)
|
|
print resp
|
|
for item in subs:
|
|
print "%7s %s" % item
|
|
resp = s.quit()
|
|
print resp
|