[refactor] separate tcp map server code

Separate the common tcp map server code, used for both alias resolver and
recipient access checker, to its own file.

3 files changed, 140 insertions, 60 deletions

diff --git a/src/leap/mx/alias_resolver.py b/src/leap/mx/alias_resolver.py
index 4247b57..9206ffb 100644
--- a/src/leap/mx/alias_resolver.py
+++ b/src/leap/mx/alias_resolver.py
@@ -24,65 +24,49 @@ Test this with postmap -v -q "foo" tcp:localhost:4242
 TODO:
     o Look into using twisted.protocols.postfix.policies classes for
       controlling concurrent connections and throttling resource consumption.
+    o We should probably use twisted.mail.alias somehow.
 """
 
-try:
-    # TODO: we should probably use the system alias somehow
-    # from twisted.mail import alias
-    from twisted.protocols import postfix
-    from twisted.python import log
-    from twisted.internet import defer
-    from twisted.internet.protocol import ServerFactory
-except ImportError:
-    print "This software requires Twisted. Please see the README file"
-    print "for instructions on getting required dependencies."
 
+from twisted.protocols import postfix
 
-class LEAPPostFixTCPMapserver(postfix.PostfixTCPMapServer):
-    def _cbGot(self, value):
-        uuid, pubkey = value
-        if uuid is None:
-            self.sendCode(500, postfix.quote("NOT FOUND SRY"))
-        elif pubkey is None:
-            self.sendCode(400, postfix.quote("4.7.13 USER ACCOUNT DISABLED"))
-        else:
-            self.sendCode(200, postfix.quote(value))
-
+from leap.mx.tcp_map import LEAPostfixTCPMapServerFactory
+from leap.mx.tcp_map import TCP_MAP_CODE_SUCCESS
+from leap.mx.tcp_map import TCP_MAP_CODE_TEMPORARY_FAILURE
+from leap.mx.tcp_map import TCP_MAP_CODE_PERMANENT_FAILURE
 
-class AliasResolverFactory(ServerFactory):
 
-    protocol = LEAPPostFixTCPMapserver
+class LEAPPostfixTCPMapAliasServer(postfix.PostfixTCPMapServer):
+    """
+    A postfix tcp map alias resolver server.
+    """
 
-    def __init__(self, couchdb):
-        self._cdb = couchdb
-
-    def _to_str(self, result):
-        """
-        Properly encodes the result string if any.
+    def _cbGot(self, value):
         """
-        if isinstance(result, unicode):
-            result = result.encode("utf8")
-        if result is None:
-            log.msg("Result not found")
-        return result
+        Return a code and message depending on the result of the factory's
+        get().
 
-    def _getPubKey(self, uuid):
+        :param value: The uuid and public key.
+        :type value: list
+        """
+        uuid, pubkey = value
         if uuid is None:
-            return defer.succeed([None, None])
-        d = defer.gatherResults([
-            self._to_str(uuid),
-            self._cdb.getPubKey(uuid),
-        ])
-        return d
+            self.sendCode(
+                TCP_MAP_CODE_PERMANENT_FAILURE,
+                postfix.quote("NOT FOUND SRY"))
+        elif pubkey is None:
+            self.sendCode(
+                TCP_MAP_CODE_TEMPORARY_FAILURE,
+                postfix.quote("4.7.13 USER ACCOUNT DISABLED"))
+        else:
+            self.sendCode(
+                TCP_MAP_CODE_SUCCESS,
+                postfix.quote(uuid))
 
-    def get(self, key):
-        """
-        Looks up the passed key, but only up to the username id of the key.
 
-        At some point we will have to consider the domain part too.
-        """
-        log.msg("Query key: %s" % (key,))
-        d = self._cdb.queryByAddress(key)
-        d.addCallback(self._getPubKey)
-        d.addErrback(log.err)
-        return d
+class AliasResolverFactory(LEAPostfixTCPMapServerFactory):
+    """
+    A factory for postfix tcp map alias resolver servers.
+    """
+
+    protocol = LEAPPostfixTCPMapAliasServer
diff --git a/src/leap/mx/check_recipient_access.py b/src/leap/mx/check_recipient_access.py
index d4ae339..cf172c7 100644
--- a/src/leap/mx/check_recipient_access.py
+++ b/src/leap/mx/check_recipient_access.py
@@ -24,22 +24,42 @@ Test this with postmap -v -q "foo" tcp:localhost:2244
 
 from twisted.protocols import postfix
 
-from leap.mx.alias_resolver import AliasResolverFactory
+from leap.mx.tcp_map import LEAPPostfixTCPMapServerFactory
+from leap.mx.tcp_map import TCP_MAP_CODE_SUCCESS
+from leap.mx.tcp_map import TCP_MAP_CODE_TEMPORARY_FAILURE
+from leap.mx.tcp_map import TCP_MAP_CODE_PERMANENT_FAILURE
 
 
-class LEAPPostFixTCPMapserverAccess(postfix.PostfixTCPMapServer):
+class LEAPPostFixTCPMapAccessServer(postfix.PostfixTCPMapServer):
+    """
+    A postfix tcp map recipient access checker server.
+    """
+
     def _cbGot(self, value):
-        # For more info, see:
-        # http://www.postfix.org/tcp_table.5.html
-        # http://www.postfix.org/access.5.html
+        """
+        Return a code and message depending on the result of the factory's
+        get().
+
+        For more info, see: http://www.postfix.org/access.5.html
+
+        :param value: The uuid and public key.
+        :type value: list
+        """
         uuid, pubkey = value
         if uuid is None:
-            self.sendCode(500, postfix.quote("REJECT"))
+            self.sendCode(
+                TCP_MAP_CODE_PERMANENT_FAILURE,
+                postfix.quote("REJECT"))
         elif pubkey is None:
-            self.sendCode(400, postfix.quote("4.7.13 USER ACCOUNT DISABLED"))
+            self.sendCode(
+                TCP_MAP_CODE_TEMPORARY_FAILURE,
+                postfix.quote("4.7.13 USER ACCOUNT DISABLED"))
         else:
-            self.sendCode(200, postfix.quote("OK"))
+            self.sendCode(
+                TCP_MAP_CODE_SUCCESS,
+                postfix.quote("OK"))
+
 
+class CheckRecipientAccessFactory(LEAPPostfixTCPMapServerFactory):
 
-class CheckRecipientAccessFactory(AliasResolverFactory):
-    protocol = LEAPPostFixTCPMapserverAccess
+    protocol = LEAPPostFixTCPMapAccessServer
diff --git a/src/leap/mx/tcp_map.py b/src/leap/mx/tcp_map.py
new file mode 100644
index 0000000..b7066ff
--- /dev/null
+++ b/src/leap/mx/tcp_map.py
@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+# -*- encoding: utf-8 -*-
+# tcpmap.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+from twisted.python import log
+from twisted.internet import defer
+from twisted.internet.protocol import ServerFactory
+
+
+# For info on codes, see: http://www.postfix.org/tcp_table.5.html
+TCP_MAP_CODE_SUCCESS = 200
+TCP_MAP_CODE_TEMPORARY_FAILURE = 400
+TCP_MAP_CODE_PERMANENT_FAILURE = 500
+
+
+class LEAPPostfixTCPMapServerFactory(ServerFactory):
+    """
+    A factory for postfix tcp map servers.
+    """
+
+    def __init__(self, couchdb):
+        """
+        Initialize the factory.
+
+        :param couchdb: A CouchDB client.
+        :type couchdb: leap.mx.couchdbhelper.ConnectedCouchDB
+        """
+        self._cdb = couchdb
+
+    def _getPubKey(self, uuid):
+        """
+        Look up PGP public key based on user uid.
+
+        :param uuid: The user uid.
+        :type uuid: str
+
+        :return: A deferred that is fired with the uuid and the public key, if
+                 available.
+        :rtype: DeferredList
+        """
+        if uuid is None:
+            return defer.succeed([None, None])
+        return defer.gatherResults([
+            defer.succeed(uuid),
+            self._cdb.getPubKey(uuid),
+        ])
+
+    def get(self, key):
+        """
+        Look up uuid based on key, only up to the username id of the key.
+
+        At some point we will have to consider the domain part too.
+
+        :param key: The lookup key.
+        :type key: str
+        """
+        log.msg("Query key: %s" % (key,))
+        d = self._cdb.queryByAddress(key)
+        d.addCallback(self._getPubKey)
+        d.addErrback(log.err)
+        return d