nntplib.py

mallet是自然语言处理、机器学习领域的一个开源项目。

"""An NNTP client class based on RFC 977: Network News Transfer Protocol.

Example:

>>> from nntplib import NNTP
>>> s = NNTP('news')
>>> 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 51 articles, range 5770 to 5821
>>> resp, subs = s.xhdr('subject', first + '-' + last)
>>> resp = s.quit()
>>>

Here 'resp' is the server response line.
Error responses are turned into exceptions.

To post an article from a file:
>>> f = open(filename, 'r') # file containing article, including header
>>> resp = s.post(f)
>>>

For descriptions of all methods, read the comments in the code below.
Note that all arguments and return values representing article numbers
are strings, not numbers, since they are rarely used for calculations.
"""

# RFC 977 by Brian Kantor and Phil Lapsley.
# xover, xgtitle, xpath, date methods by Kevan Heydon


# Imports
import re
import socket
import types

__all__ = ["NNTP","NNTPReplyError","NNTPTemporaryError",
           "NNTPPermanentError","NNTPProtocolError","NNTPDataError",
           "error_reply","error_temp","error_perm","error_proto",
           "error_data",]

# Exceptions raised when an error or invalid response is received
class NNTPError(Exception):
    """Base class for all nntplib exceptions"""
    def __init__(self, *args):
        apply(Exception.__init__, (self,)+args)
        try:
            self.response = args[0]
        except IndexError:
            self.response = 'No response given'

class NNTPReplyError(NNTPError):
    """Unexpected [123]xx reply"""
    pass

class NNTPTemporaryError(NNTPError):
    """4xx errors"""
    pass

class NNTPPermanentError(NNTPError):
    """5xx errors"""
    pass

class NNTPProtocolError(NNTPError):
    """Response does not begin with [1-5]"""
    pass

class NNTPDataError(NNTPError):
    """Error in response data"""
    pass

# for backwards compatibility
error_reply = NNTPReplyError
error_temp = NNTPTemporaryError
error_perm = NNTPPermanentError
error_proto = NNTPProtocolError
error_data = NNTPDataError



# Standard port used by NNTP servers
NNTP_PORT = 119


# Response numbers that are followed by additional text (e.g. article)
LONGRESP = ['100', '215', '220', '221', '222', '224', '230', '231', '282']


# Line terminators (we always output CRLF, but accept any of CRLF, CR, LF)
CRLF = '\r\n'



# The class itself
class NNTP:
    def __init__(self, host, port=NNTP_PORT, user=None, password=None,
                 readermode=None):
        """Initialize an instance.  Arguments:
        - host: hostname to connect to
        - port: port to connect to (default the standard NNTP port)
        - user: username to authenticate with
        - password: password to use with username
        - readermode: if true, send 'mode reader' command after
                      connecting.

        readermode is sometimes necessary if you are connecting to an
        NNTP server on the local machine and intend to call
        reader-specific comamnds, such as `group'.  If you get
        unexpected NNTPPermanentErrors, you might need to set
        readermode.
        """
        self.host = host
        self.port = port
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect((self.host, self.port))
        self.file = self.sock.makefile('rb')
        self.debugging = 0
        self.welcome = self.getresp()

        # 'mode reader' is sometimes necessary to enable 'reader' mode.
        # However, the order in which 'mode reader' and 'authinfo' need to
        # arrive differs between some NNTP servers. Try to send
        # 'mode reader', and if it fails with an authorization failed
        # error, try again after sending authinfo.
        readermode_afterauth = 0
        if readermode:
            try:
                self.welcome = self.shortcmd('mode reader')
            except NNTPPermanentError:
                # error 500, probably 'not implemented'
                pass
            except NNTPTemporaryError, e:
                if user and e.response[:3] == '480':
                    # Need authorization before 'mode reader'
                    readermode_afterauth = 1
                else:
                    raise
        if user:
            resp = self.shortcmd('authinfo user '+user)
            if resp[:3] == '381':
                if not password:
                    raise NNTPReplyError(resp)
                else:
                    resp = self.shortcmd(
                            'authinfo pass '+password)
                    if resp[:3] != '281':
                        raise NNTPPermanentError(resp)
            if readermode_afterauth:
                try:
                    self.welcome = self.shortcmd('mode reader')
                except NNTPPermanentError:
                    # error 500, probably 'not implemented'
                    pass


    # Get the welcome message from the server
    # (this is read and squirreled away by __init__()).
    # If the response code is 200, posting is allowed;
    # if it 201, posting is not allowed

    def getwelcome(self):
        """Get the welcome message from the server
        (this is read and squirreled away by __init__()).
        If the response code is 200, posting is allowed;
        if it 201, posting is not allowed."""

        if self.debugging: print '*welcome*', `self.welcome`
        return self.welcome

    def set_debuglevel(self, level):
        """Set the debugging level.  Argument 'level' means:
        0: no debugging output (default)
        1: print commands and responses but not body text etc.
        2: also print raw lines read and sent before stripping CR/LF"""

        self.debugging = level
    debug = set_debuglevel

    def putline(self, line):
        """Internal: send one line to the server, appending CRLF."""
        line = line + CRLF
        if self.debugging > 1: print '*put*', `line`
        self.sock.sendall(line)

    def putcmd(self, line):
        """Internal: send one command to the server (through putline())."""
        if self.debugging: print '*cmd*', `line`
        self.putline(line)

    def getline(self):
        """Internal: return one line from the server, stripping CRLF.
        Raise EOFError if the connection is closed."""
        line = self.file.readline()
        if self.debugging > 1:
            print '*get*', `line`
        if not line: raise EOFError
        if line[-2:] == CRLF: line = line[:-2]
        elif line[-1:] in CRLF: line = line[:-1]
        return line

    def getresp(self):
        """Internal: get a response from the server.
        Raise various errors if the response indicates an error."""
        resp = self.getline()
        if self.debugging: print '*resp*', `resp`
        c = resp[:1]
        if c == '4':
            raise NNTPTemporaryError(resp)
        if c == '5':
            raise NNTPPermanentError(resp)
        if c not in '123':
            raise NNTPProtocolError(resp)
        return resp

    def getlongresp(self, file=None):
        """Internal: get a response plus following text from the server.
        Raise various errors if the response indicates an error."""

        openedFile = None
        try:
            # If a string was passed then open a file with that name
            if isinstance(file, types.StringType):
                openedFile = file = open(file, "w")

            resp = self.getresp()
            if resp[:3] not in LONGRESP:
                raise NNTPReplyError(resp)
            list = []
            while 1:
                line = self.getline()
                if line == '.':
                    break
                if line[:2] == '..':
                    line = line[1:]
                if file:
                    file.write(line + "\n")
                else:
                    list.append(line)
        finally:
            # If this method created the file, then it must close it
            if openedFile:
                openedFile.close()

        return resp, list

    def shortcmd(self, line):
        """Internal: send a command and get the response."""
        self.putcmd(line)
        return self.getresp()

    def longcmd(self, line, file=None):
        """Internal: send a command and get the response plus following text."""
        self.putcmd(line)
        return self.getlongresp(file)

    def newgroups(self, date, time):
        """Process a NEWGROUPS command.  Arguments:
        - date: string 'yymmdd' indicating the date
        - time: string 'hhmmss' indicating the time
        Return:
        - resp: server response if successful
        - list: list of newsgroup names"""

        return self.longcmd('NEWGROUPS ' + date + ' ' + time)

    def newnews(self, group, date, time):
        """Process a NEWNEWS command.  Arguments:
        - group: group name or '*'
        - date: string 'yymmdd' indicating the date
        - time: string 'hhmmss' indicating the time
        Return:
        - resp: server response if successful
        - list: list of article ids"""

        cmd = 'NEWNEWS ' + group + ' ' + date + ' ' + time
        return self.longcmd(cmd)

    def list(self):
        """Process a LIST command.  Return:
        - resp: server response if successful
        - list: list of (group, last, first, flag) (strings)"""

        resp, list = self.longcmd('LIST')
        for i in range(len(list)):
            # Parse lines into "group last first flag"
            list[i] = tuple(list[i].split())
        return resp, list

    def group(self, name):