Added /leap/mx/alias_resolver.py, which contains classes for creating a server

to resolve Postfix aliases.

1 files changed, 118 insertions, 0 deletions

diff --git a/leap/mx/alias_resolver.py b/leap/mx/alias_resolver.py
new file mode 100644
index 0000000..2263de5
--- /dev/null
+++ b/leap/mx/alias_resolver.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python
+# -*- encoding: utf-8 -*-
+'''
+alias_resolver.py
+=================
+Classes for resolving postfix aliases.
+
+@authors: Isis Agora Lovecruft
+@version: 0.0.1-beta
+@license: WTFPL see included LICENSE file
+@copyright: copyright 2013 Isis Agora Lovecruft
+'''
+
+import os
+
+from twisted.internet  import address
+from twisted.mail      import maildir
+from twisted.protocols import postfix
+
+from leap.mx import net, log
+
+
+def checkIPaddress(addr):
+    """
+    Check that a given string is a valid IPv4 or IPv6 address.
+
+    @param addr:
+        Any string defining an IP address, i.e. '0.0.0.0', '::1', or '1.2.3.4'.
+    @returns:
+        True if :param:`addr` defines a valid IPAddress, False otherwise.
+    """
+    import ipaddr
+
+    try:
+        check = ipaddr.IPAddress(addr)
+    except ValueError, ve:
+        log.warn(ve.message)
+        return False
+    else:
+        return True
+
+class PostfixAliasResolver(postfix.PostfixTCPMapServer):
+    """
+    Resolve postfix aliases, similarly to using "$ postmap -q <alias>".
+
+    This class starts a simple LineReceiver server which listens for a string
+    specifying an alias to look up, :param:`key`, and which will be used to
+    query the local Postfix server. You can test it with:
+
+        $ ./alias_resolver.py &
+        $ /usr/bin/postmap -q <key> tcp:localhost:4242
+
+    """
+    def __init__(self, *args, **kwargs):
+        """
+        Create a local LineReceiver server which listens for Postfix aliases
+        to resolve.
+        """
+        super(postfix.PostfixTCPMapServer, self).__init__(*args, **kwargs)
+
+class PostfixAliasResolverFactory(postfix.PostfixTCPMapDeferringDictServerFactory):
+    """
+    A Factory for creating PostfixAliasResolver servers, which handles inputs
+    and outputs, and keeps an in-memory mapping of Postfix aliases in the form
+    of a dict.
+
+    xxx fill me in
+
+    """
+    protocol = PostfixAliasResolver
+
+    def __init__(self, addr='127.0.0.1', port=4242, timeout=120, data=None):
+        """
+        Create a Factory which returns :class:`PostfixAliasResolver` servers.
+
+        @param addr:
+            (optional) A string giving the IP address of the Postfix server.
+            Default: '127.0.0.1'
+        @param port:
+            (optional) An integer that specifies the port number of the
+            Postfix server. Default: 4242
+        @param timeout:
+            (optional) An integer specifying the number of seconds to wait
+            until we should time out. Default: 120
+        @param data:
+            (optional) A dict to use to initialise or update the alias
+            mapping.
+        """
+        super(postfix.PostfixTCPMapDeferringDictServerFactory, 
+              self).__init__(data=data)
+        self.timeout = timeout
+        self.noisy = False ## xxx get config value
+
+        try:
+            assert isinstance(port, int), "Port number must be an integer"
+            assert isinstance(timeout, int), "Timeout must be an integer"
+        except AssertionError, ae:
+            raise SystemExit(ae.message)
+
+        if checkIPaddress(addr):
+            self.addr = address._IPAddress('TCP', addr, int(port))
+        else:
+            log.debug("Using default address for Postfix: 127.0.0.1:%s" % port)
+            self.addr = address._IPAddress('TCP', '127.0.0.1', int(port))
+
+    def buildProtocol(self):
+        """
+        Create an instance of the :class:`PostfixAliasResolver` server.
+        """
+        proto = self.protocol()
+        proto.timeout = self.timeout
+        proto.factory = self
+        return proto
+
+
+if __name__ == "__main__":
+
+    print "To test alias_resolver.py, please use /test/test_alias_resolver.py"