core, memory, plugins, stdui, frontends: look for DNS SRV records when server is not specified:

- fix bug 3
    - modify "Connection" params:
          - rename "Server" to "Force server" and "Port" to "Force port"
          - set the default value to empty string for both

src/core/constants.py

@@ -40,6 +40,9 @@ class Const(object):
     NO_SECURITY_LIMIT = -1
     INDIVIDUAL = "individual"
     GENERAL = "general"
+    # Parameters related to connection
+    FORCE_SERVER_PARAM = "Force server"
+    FORCE_PORT_PARAM = "Force port"
     # Parameters related to encryption
     PROFILE_PASS_PATH = ('General', 'Password')
     MEMORY_CRYPTO_NAMESPACE = 'crypto'  # for the private persistent binary dict

src/core/sat_main.py

@@ -220,7 +220,7 @@ class SAT(service.Service):
     def _connectXMPPClient(self, profile):
         """This part is called from asyncConnect when we have loaded individual parameters from memory"""
         try:
-            port = int(self.memory.getParamA("Port", "Connection", profile_key=profile))
+            port = int(self.memory.getParamA(C.FORCE_PORT_PARAM, "Connection", profile_key=profile))
         except ValueError:
             log.error(_("Can't parse port value, using default value"))
             port = 5222
@@ -228,7 +228,7 @@ class SAT(service.Service):
         password = yield self.memory.asyncGetParamA("Password", "Connection", profile_key=profile)
         current = self.profiles[profile] = xmpp.SatXMPPClient(self, profile,
             jid.JID(self.memory.getParamA("JabberID", "Connection", profile_key=profile)),
-            password, self.memory.getParamA("Server", "Connection", profile_key=profile), port)
+            password, self.memory.getParamA(C.FORCE_SERVER_PARAM, "Connection", profile_key=profile), port)
 
         current.messageProt = xmpp.SatMessageProtocol(self)
         current.messageProt.setHandlerParent(current)

src/core/xmpp.py

@@ -37,7 +37,9 @@ class SatXMPPClient(client.XMPPClient):
     implements(iwokkel.IDisco)
 
     def __init__(self, host_app, profile, user_jid, password, host=None, port=5222):
-        client.XMPPClient.__init__(self, user_jid, password, host, port)
+        # XXX: DNS SRV records are checked when the host is not specified.
+        # If no SRV record is found, the host is directly extracted from the JID.
+        client.XMPPClient.__init__(self, user_jid, password, host or None, port or 5222)
         self.factory.clientConnectionLost = self.connectionLost
         self.__connected = False
         self.profile = profile