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"""A POP3 client class.

Based on the J. Myers POP3 draft, Jan. 96

# Author: David Ascher <>
#         [heavily stealing from]
# Updated: Piers Lauder <> [Jul '97]
# String method conversion and test jig improvements by ESR, February 2001.

# Example (see the test function at the end of this file)

# Imports

import re, socket

__all__ = ["POP3","error_proto"]

# Exception raised when an error or invalid response is received:

class error_proto(Exception): pass

# Standard Port
POP3_PORT = 110

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

class POP3:

    """This class supports both the minimal and optional command sets.
    Arguments can be strings or integers (where appropriate)
    (e.g.: retr(1) and retr('1') both work equally well.

    Minimal Command Set:
            USER name               user(name)
            PASS string             pass_(string)
            STAT                    stat()
            LIST [msg]              list(msg = None)
            RETR msg                retr(msg)
            DELE msg                dele(msg)
            NOOP                    noop()
            RSET                    rset()
            QUIT                    quit()

    Optional Commands (some servers support these):
            RPOP name               rpop(name)
            APOP name digest        apop(name, digest)
            TOP msg n               top(msg, n)
            UIDL [msg]              uidl(msg = None)

    Raises one exception: 'error_proto'.

    Instantiate with:
            POP3(hostname, port=110)

    NB:     the POP protocol locks the mailbox from user
            authorization until QUIT, so be sure to get in, suck
            the messages, and quit, each time you access the

            POP is a line-based protocol, which means large mail
            messages consume lots of python cycles reading them

            If it's available on your mail server, use IMAP4
            instead, it doesn't suffer from the two problems

    def __init__(self, host, port = POP3_PORT): = host
        self.port = port
        msg = "getaddrinfo returns an empty list"
        for res in socket.getaddrinfo(, self.port, 0, socket.SOCK_STREAM):
            af, socktype, proto, canonname, sa = res
                self.sock = socket.socket(af, socktype, proto)
            except socket.error, msg:
                self.sock = None
        if not self.sock:
            raise socket.error, msg
        self.file = self.sock.makefile('rb')
        self._debugging = 0
        self.welcome = self._getresp()

    def _putline(self, line):
        #if self._debugging > 1: print '*put*', `line`
        self.sock.send('%s%s' % (line, CRLF))

    # Internal: send one command to the server (through _putline())

    def _putcmd(self, line):
        #if self._debugging: print '*cmd*', `line`

    # Internal: return one line from the server, stripping CRLF.
    # This is where all the CPU time of this module is consumed.
    # Raise error_proto('-ERR EOF') if the connection is closed.

    def _getline(self):
        line = self.file.readline()
        #if self._debugging > 1: print '*get*', `line`
        if not line: raise error_proto('-ERR EOF')
        octets = len(line)
        # server can send any combination of CR & LF
        # however, 'readline()' returns lines ending in LF
        # so only possibilities are ...LF, ...CRLF, CR...LF
        if line[-2:] == CRLF:
            return line[:-2], octets
        if line[0] == CR:
            return line[1:-1], octets
        return line[:-1], octets

    # Internal: get a response from the server.
    # Raise 'error_proto' if the response doesn't start with '+'.

    def _getresp(self):
        resp, o = self._getline()
        #if self._debugging > 1: print '*resp*', `resp`
        c = resp[:1]
        if c != '+':
            raise error_proto(resp)
        return resp

    # Internal: get a response plus following text from the server.

    def _getlongresp(self):
        resp = self._getresp()
        list = []; octets = 0
        line, o = self._getline()
        while line != '.':
            if line[:2] == '..':
                o = o-1
                line = line[1:]
            octets = octets + o
            line, o = self._getline()
        return resp, list, octets

    # Internal: send a command and get the response

    def _shortcmd(self, line):
        return self._getresp()

    # Internal: send a command and get the response plus following text

    def _longcmd(self, line):
        return self._getlongresp()

    # These can be useful:

    def getwelcome(self):
        return self.welcome

    def set_debuglevel(self, level):
        self._debugging = level

    # Here are all the POP commands:

    def user(self, user):
        """Send user name, return response

        (should indicate password required).
        return self._shortcmd('USER %s' % user)

    def pass_(self, pswd):
        """Send password, return response

        (response includes message count, mailbox size).

        NB: mailbox is locked by server from here to 'quit()'
        return self._shortcmd('PASS %s' % pswd)

    def stat(self):
        """Get mailbox status.

        Result is tuple of 2 ints (message count, mailbox size)
        retval = self._shortcmd('STAT')
        rets = retval.split()
        #if self._debugging: print '*stat*', `rets`
        numMessages = int(rets[1])
        sizeMessages = int(rets[2])
        return (numMessages, sizeMessages)

    def list(self, which=None):
        """Request listing, return result.

        Result without a message number argument is in form
        ['response', ['mesg_num octets', ...]].

        Result when a message number argument is given is a
        single response: the "scan listing" for that message.
        if which:
            return self._shortcmd('LIST %s' % which)
        return self._longcmd('LIST')

    def retr(self, which):
        """Retrieve whole message number 'which'.

        Result is in form ['response', ['line', ...], octets].
        return self._longcmd('RETR %s' % which)

    def dele(self, which):
        """Delete message number 'which'.

        Result is 'response'.
        return self._shortcmd('DELE %s' % which)

    def noop(self):
        """Does nothing.

        One supposes the response indicates the server is alive.
        return self._shortcmd('NOOP')

    def rset(self):
        """Not sure what this does."""
        return self._shortcmd('RSET')

    def quit(self):
        """Signoff: commit changes on server, unlock mailbox, close connection."""
            resp = self._shortcmd('QUIT')
        except error_proto, val:
            resp = val
        del self.file, self.sock
        return resp

    #__del__ = quit

    # optional commands:

    def rpop(self, user):
        """Not sure what this does."""
        return self._shortcmd('RPOP %s' % user)

    timestamp = re.compile(r'\+OK.*(<[^>]+>)')

    def apop(self, user, secret):

        - only possible if server has supplied a timestamp in initial greeting.

                user    - mailbox user;
                secret  - secret shared between client and server.

        NB: mailbox is locked by server from here to 'quit()'
        m = self.timestamp.match(self.welcome)
        if not m:
            raise error_proto('-ERR APOP not supported by server')
        import md5
        digest =
        digest = ''.join(map(lambda x:'%02x'%ord(x), digest))
        return self._shortcmd('APOP %s %s' % (user, digest))

    def top(self, which, howmuch):
        """Retrieve message header of message number 'which'
        and first 'howmuch' lines of message body.

        Result is in form ['response', ['line', ...], octets].
        return self._longcmd('TOP %s %s' % (which, howmuch))

    def uidl(self, which=None):
        """Return message digest (unique id) list.

        If 'which', result contains unique id for that message
        in the form 'response mesgnum uid', otherwise result is
        the list ['response', ['mesgnum uid', ...], octets]
        if which:
            return self._shortcmd('UIDL %s' % which)
        return self._longcmd('UIDL')

if __name__ == "__main__":
    import sys
    a = POP3(sys.argv[1])
    print a.getwelcome()
    (numMsgs, totalSize) = a.stat()
    for i in range(1, numMsgs + 1):
        (header, msg, octets) = a.retr(i)
        print "Message ", `i`, ':'
        for line in msg:
            print '   ' + line
        print '-----------------------'