doc/core/examples/courier.py

   1 #!/usr/bin/env python
   2
   3 # Copyright (c) Twisted Matrix Laboratories.
   4 # See LICENSE for details.
   5
   6 """
   7 Example of a interfacing to Courier's mail filter interface.
   8 """
   9
  10 LOGFILE = '/tmp/filter.log'
  11
  12 # Setup log file
  13 from twisted.python import log
  14 log.startLogging(open(LOGFILE, 'a'))
  15 import sys
  16 sys.stderr = log.logfile
  17
  18 # Twisted imports
  19 from twisted.internet import reactor, stdio
  20 from twisted.internet.protocol import Protocol, Factory
  21 from twisted.protocols import basic
  22
  23 FILTERS='/var/lib/courier/filters'
  24 ALLFILTERS='/var/lib/courier/allfilters'
  25 FILTERNAME='twistedfilter'
  26
  27 import os, os.path
  28 from syslog import syslog, openlog, LOG_MAIL
  29 from rfc822 import Message
  30
  31 def trace_dump():
  32     t,v,tb = sys.exc_info()
  33     openlog(FILTERNAME, 0, LOG_MAIL)
  34     syslog('Unhandled exception: %s - %s' % (v, t))
  35     while tb:
  36         syslog('Trace: %s:%s %s' % (tb.tb_frame.f_code.co_filename,tb.tb_frame.f_code.co_name,tb.tb_lineno))
  37         tb = tb.tb_next
  38     # just to be safe
  39     del tb
  40
  41 def safe_del(file):
  42     try:
  43         if os.path.isdir(file):
  44             os.removedirs(file)
  45         else:
  46             os.remove(file)
  47     except OSError:
  48         pass
  49
  50
  51 class DieWhenLost(Protocol):
  52     def connectionLost(self, reason=None):
  53         reactor.stop()
  54
  55
  56 class MailProcessor(basic.LineReceiver):
  57     """I process a mail message.
  58
  59     Override filterMessage to do any filtering you want."""
  60     messageFilename = None
  61     delimiter = '\n'
  62
  63     def connectionMade(self):
  64         log.msg('Connection from %r' % self.transport)
  65         self.state = 'connected'
  66         self.metaInfo = []
  67
  68     def lineReceived(self, line):
  69         if self.state == 'connected':
  70             self.messageFilename = line
  71             self.state = 'gotMessageFilename'
  72         if self.state == 'gotMessageFilename':
  73             if line:
  74                 self.metaInfo.append(line)
  75             else:
  76                 if not self.metaInfo:
  77                     self.transport.loseConnection()
  78                     return
  79                 self.filterMessage()
  80
  81     def filterMessage(self):
  82         """Override this.
  83
  84         A trivial example is included.
  85         """
  86         try:
  87             m = Message(open(self.messageFilename))
  88             self.sendLine('200 Ok')
  89         except:
  90             trace_dump()
  91             self.sendLine('435 %s processing error' % FILTERNAME)
  92
  93
  94 def main():
  95     # Listen on the UNIX socket
  96     f = Factory()
  97     f.protocol = MailProcessor
  98     safe_del('%s/%s' % (ALLFILTERS, FILTERNAME))
  99     reactor.listenUNIX('%s/%s' % (ALLFILTERS, FILTERNAME), f, 10)
 100
 101     # Once started, close fd 3 to let Courier know we're ready
 102     reactor.callLater(0, os.close, 3)
 103
 104     # When stdin is closed, it's time to exit.
 105     s = stdio.StandardIO(DieWhenLost())
 106
 107     # Go!
 108     reactor.run()
 109
 110 if __name__ == '__main__':
 111     main()