"""A POP3 client class.

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

# Author: David Ascher <david_ascher@brown.edu>
# [heavily stealing from nntplib.py]
# Updated: Piers Lauder <piers@cs.su.oz.au> [Jul '97]
# String method conversion and test jig improvements by ESR, February 2001.
# Added the POP3_SSL class. Methods loosely based on IMAP_SSL. Hector Urtubia <urtubia@mrbook.org> Aug 2003

# 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

# POP SSL PORT
POP3_SSL_PORT = 995

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

# maximal line length when calling readline(). This is to prevent
# reading arbitrary length lines. RFC 1939 limits POP3 line length to
# 512 characters, including CRLF. We have selected 2048 just to be on
# the safe side.
_MAXLINE = 2048


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
mailbox.

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

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


def __init__(self, host, port=POP3_PORT,
timeout=socket._GLOBAL_DEFAULT_TIMEOUT):
self.host = host
self.port = port
self.sock = socket.create_connection((host, port), timeout)
self.file = self.sock.makefile('rb')
self._debugging = 0
self.welcome = self._getresp()


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


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

def _putcmd(self, line):
if self._debugging: print '*cmd*', repr(line)
self._putline(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(_MAXLINE + 1)
if len(line) > _MAXLINE:
raise error_proto('line too long')
if self._debugging > 1: print '*get*', repr(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*', repr(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
list.append(line)
line, o = self._getline()
return resp, list, octets


# Internal: send a command and get the response

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


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

def _longcmd(self, line):
self._putcmd(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*', repr(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', ...], octets].

Result when a message number argument is given is a
single response: the "scan listing" for that message.
"""
if which is not None:
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):
"""Unmark all messages marked for deletion."""
return self._shortcmd('RSET')


def quit(self):
"""Signoff: commit changes on server, unlock mailbox, close connection."""
try:
resp = self._shortcmd('QUIT')
except error_proto, val:
resp = val
self.file.close()
self.sock.close()
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(br'\+OK.[^<]*(<.*>)')

def apop(self, user, secret):
"""Authorisation

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

Args:
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 hashlib
digest = hashlib.md5(m.group(1)+secret).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 is not None:
return self._shortcmd('UIDL %s' % which)
return self._longcmd('UIDL')

try:
import ssl
except ImportError:
pass
else:

class POP3_SSL(POP3):
"""POP3 client class over SSL connection

Instantiate with: POP3_SSL(hostname, port=995, keyfile=None, certfile=None)

hostname - the hostname of the pop3 over ssl server
port - port number
keyfile - PEM formatted file that contains your private key
certfile - PEM formatted certificate chain file

See the methods of the parent class POP3 for more documentation.
"""

def __init__(self, host, port = POP3_SSL_PORT, keyfile = None, certfile = None):
self.host = host
self.port = port
self.keyfile = keyfile
self.certfile = certfile
self.buffer = ""
msg = "getaddrinfo returns an empty list"
self.sock = None
for res in socket.getaddrinfo(self.host, self.port, 0, socket.SOCK_STREAM):
af, socktype, proto, canonname, sa = res
try:
self.sock = socket.socket(af, socktype, proto)
self.sock.connect(sa)
except socket.error, msg:
if self.sock:
self.sock.close()
self.sock = None
continue
break
if not self.sock:
raise socket.error, msg
self.file = self.sock.makefile('rb')
self.sslobj = ssl.wrap_socket(self.sock, self.keyfile, self.certfile)
self._debugging = 0
self.welcome = self._getresp()

def _fillBuffer(self):
localbuf = self.sslobj.read()
if len(localbuf) == 0:
raise error_proto('-ERR EOF')
self.buffer += localbuf

def _getline(self):
line = ""
renewline = re.compile(r'.*?\n')
match = renewline.match(self.buffer)
while not match:
self._fillBuffer()
if len(self.buffer) > _MAXLINE:
raise error_proto('line too long')
match = renewline.match(self.buffer)
line = match.group(0)
self.buffer = renewline.sub('' ,self.buffer, 1)
if self._debugging > 1: print '*get*', repr(line)

octets = len(line)
if line[-2:] == CRLF:
return line[:-2], octets
if line[0] == CR:
return line[1:-1], octets
return line[:-1], octets

def _putline(self, line):
if self._debugging > 1: print '*put*', repr(line)
line += CRLF
bytes = len(line)
while bytes > 0:
sent = self.sslobj.write(line)
if sent == bytes:
break # avoid copy
line = line[sent:]
bytes = bytes - sent

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

__all__.append("POP3_SSL")

if __name__ == "__main__":
import sys
a = POP3(sys.argv[1])
print a.getwelcome()
a.user(sys.argv[2])
a.pass_(sys.argv[3])
a.list()
(numMsgs, totalSize) = a.stat()
for i in range(1, numMsgs + 1):
(header, msg, octets) = a.retr(i)
print "Message %d:" % i
for line in msg:
print ' ' + line
print '-----------------------'
a.quit()