network: Respond to messages before closing connections

This makes a connection tell the actor to stop the connection, instead
of stopping it itself. This is preferable, because other messages sent
to the actor that is not processed yet, may now send data to the client.

E.g. it makes this work:
$ echo status | nc localhost 6600

mopidy/utils/network.py

@@ -267,7 +267,8 @@ class Connection(object):
             return True
 
         if not data:
-            self.stop('Client most likely disconnected.')
+            self.actor_ref.tell({'close': True})
+            self.disable_recv()
             return True
 
         try:
@@ -348,6 +349,10 @@ class LineProtocol(pykka.ThreadingActor):
 
     def on_receive(self, message):
         """Handle messages with new data from server."""
+        if 'close' in message:
+            self.connection.stop('Client most likely disconnected.')
+            return
+
         if 'received' not in message:
             return
 

tests/utils/network/test_connection.py

@@ -416,7 +416,8 @@ class ConnectionTest(unittest.TestCase):
 
         self.assertTrue(network.Connection.recv_callback(
             self.mock, sentinel.fd, gobject.IO_IN))
-        self.mock.stop.assert_called_once_with(any_unicode)
+        self.mock.actor_ref.tell.assert_called_once_with({'close': True})
+        self.mock.disable_recv.assert_called_once_with()
 
     def test_recv_callback_recoverable_error(self):
         self.mock.sock = Mock(spec=socket.SocketType)

tests/utils/network/test_lineprotocol.py

@@ -8,6 +8,8 @@ import unittest
 
 from mopidy.utils import network
 
+from tests import any_unicode
+
 
 class LineProtocolTest(unittest.TestCase):
     def setUp(self):
@@ -33,6 +35,14 @@ class LineProtocolTest(unittest.TestCase):
         network.LineProtocol.__init__(self.mock, sentinel.connection)
         self.assertEqual(delimiter, self.mock.delimiter)
 
+    def test_on_receive_close_calls_stop(self):
+        self.mock.connection = Mock(spec=network.Connection)
+        self.mock.recv_buffer = ''
+        self.mock.parse_lines.return_value = []
+
+        network.LineProtocol.on_receive(self.mock, {'close': True})
+        self.mock.connection.stop.assert_called_once_with(any_unicode)
+
     def test_on_receive_no_new_lines_adds_to_recv_buffer(self):
         self.mock.connection = Mock(spec=network.Connection)
         self.mock.recv_buffer = ''