disconnect reasons for client

src/socketio/async_client.py

@@ -398,8 +398,9 @@ class AsyncClient(base_client.BaseClient):
         if not self.connected:
             return
         namespace = namespace or '/'
-        await self._trigger_event('disconnect', namespace=namespace)
-        await self._trigger_event('__disconnect_final', namespace=namespace)
+        await self._trigger_event('disconnect', namespace,
+                                  self.reason.SERVER_DISCONNECT)
+        await self._trigger_event('__disconnect_final', namespace)
         if namespace in self.namespaces:
             del self.namespaces[namespace]
         if not self.namespaces:
@@ -461,12 +462,28 @@ class AsyncClient(base_client.BaseClient):
         handler, args = self._get_event_handler(event, namespace, args)
         if handler:
             if asyncio.iscoroutinefunction(handler):
+                try:
                     try:
                         ret = await handler(*args)
+                    except TypeError:
+                        # the legacy disconnect event does not take a reason
+                        # argument
+                        if event == 'disconnect':
+                            ret = await handler(*args[:-1])
+                        else:  # pragma: no cover
+                            raise
                 except asyncio.CancelledError:  # pragma: no cover
                     ret = None
             else:
+                try:
                     ret = handler(*args)
+                except TypeError:
+                    # the legacy disconnect event does not take a reason
+                    # argument
+                    if event == 'disconnect':
+                        ret = handler(*args[:-1])
+                    else:  # pragma: no cover
+                        raise
             return ret
 
         # or else, forward the event to a namepsace handler if one exists
@@ -566,16 +583,15 @@ class AsyncClient(base_client.BaseClient):
             else:
                 raise ValueError('Unknown packet type.')
 
-    async def _handle_eio_disconnect(self):
+    async def _handle_eio_disconnect(self, reason):
         """Handle the Engine.IO disconnection event."""
         self.logger.info('Engine.IO connection dropped')
         will_reconnect = self.reconnection and self.eio.state == 'connected'
         if self.connected:
             for n in self.namespaces:
-                await self._trigger_event('disconnect', namespace=n)
+                await self._trigger_event('disconnect', n, reason)
                 if not will_reconnect:
-                    await self._trigger_event('__disconnect_final',
-                                              namespace=n)
+                    await self._trigger_event('__disconnect_final', n)
             self.namespaces = {}
             self.connected = False
         self.callbacks = {}

src/socketio/async_namespace.py

@@ -46,7 +46,15 @@ class AsyncNamespace(base_namespace.BaseServerNamespace):
                 except asyncio.CancelledError:  # pragma: no cover
                     ret = None
             else:
+                try:
                     ret = handler(*args)
+                except TypeError:
+                    # legacy disconnect events do not have a reason
+                    # argument
+                    if event == 'disconnect':
+                        ret = handler(*args[:-1])
+                    else:  # pragma: no cover
+                        raise
             return ret
 
     async def emit(self, event, data=None, to=None, room=None, skip_sid=None,
@@ -206,12 +214,28 @@ class AsyncClientNamespace(base_namespace.BaseClientNamespace):
         if hasattr(self, handler_name):
             handler = getattr(self, handler_name)
             if asyncio.iscoroutinefunction(handler) is True:
+                try:
                     try:
                         ret = await handler(*args)
+                    except TypeError:
+                        # legacy disconnect events do not have a reason
+                        # argument
+                        if event == 'disconnect':
+                            ret = await handler(*args[:-1])
+                        else:  # pragma: no cover
+                            raise
                 except asyncio.CancelledError:  # pragma: no cover
                     ret = None
             else:
+                try:
                     ret = handler(*args)
+                except TypeError:
+                    # legacy disconnect events do not have a reason
+                    # argument
+                    if event == 'disconnect':
+                        ret = handler(*args[:-1])
+                    else:  # pragma: no cover
+                        raise
             return ret
 
     async def emit(self, event, data=None, namespace=None, callback=None):

src/socketio/base_client.py

@@ -289,7 +289,7 @@ class BaseClient:
     def _handle_eio_message(self, data):  # pragma: no cover
         raise NotImplementedError()
 
-    def _handle_eio_disconnect(self):  # pragma: no cover
+    def _handle_eio_disconnect(self, reason):  # pragma: no cover
         raise NotImplementedError()
 
     def _engineio_client_class(self):  # pragma: no cover

src/socketio/client.py

@@ -377,8 +377,9 @@ class Client(base_client.BaseClient):
         if not self.connected:
             return
         namespace = namespace or '/'
-        self._trigger_event('disconnect', namespace=namespace)
-        self._trigger_event('__disconnect_final', namespace=namespace)
+        self._trigger_event('disconnect', namespace,
+                            self.reason.SERVER_DISCONNECT)
+        self._trigger_event('__disconnect_final', namespace)
         if namespace in self.namespaces:
             del self.namespaces[namespace]
         if not self.namespaces:
@@ -436,7 +437,14 @@ class Client(base_client.BaseClient):
         # first see if we have an explicit handler for the event
         handler, args = self._get_event_handler(event, namespace, args)
         if handler:
+            try:
                 return handler(*args)
+            except TypeError:
+                # the legacy disconnect event does not take a reason argument
+                if event == 'disconnect':
+                    return handler(*args[:-1])
+                else:  # pragma: no cover
+                    raise
 
         # or else, forward the event to a namespace handler if one exists
         handler, args = self._get_namespace_handler(namespace, args)
@@ -525,15 +533,15 @@ class Client(base_client.BaseClient):
             else:
                 raise ValueError('Unknown packet type.')
 
-    def _handle_eio_disconnect(self):
+    def _handle_eio_disconnect(self, reason):
         """Handle the Engine.IO disconnection event."""
         self.logger.info('Engine.IO connection dropped')
         will_reconnect = self.reconnection and self.eio.state == 'connected'
         if self.connected:
             for n in self.namespaces:
-                self._trigger_event('disconnect', namespace=n)
+                self._trigger_event('disconnect', n, reason)
                 if not will_reconnect:
-                    self._trigger_event('__disconnect_final', namespace=n)
+                    self._trigger_event('__disconnect_final', n)
             self.namespaces = {}
             self.connected = False
         self.callbacks = {}

src/socketio/namespace.py

@@ -161,7 +161,14 @@ class ClientNamespace(base_namespace.BaseClientNamespace):
         """
         handler_name = 'on_' + (event or '')
         if hasattr(self, handler_name):
+            try:
                 return getattr(self, handler_name)(*args)
+            except TypeError:
+                # legacy disconnect events do not have a reason argument
+                if event == 'disconnect':
+                    return getattr(self, handler_name)(*args[:-1])
+                else:  # pragma: no cover
+                    raise
 
     def emit(self, event, data=None, namespace=None, callback=None):
         """Emit a custom event to the server.

tests/async/test_client.py

@@ -578,11 +578,9 @@ class TestAsyncClient:
         c._trigger_event = mock.AsyncMock()
         await c._handle_disconnect('/')
         c._trigger_event.assert_any_await(
-            'disconnect', namespace='/'
-        )
-        c._trigger_event.assert_any_await(
-            '__disconnect_final', namespace='/'
+            'disconnect', '/', c.reason.SERVER_DISCONNECT
         )
+        c._trigger_event.assert_any_await('__disconnect_final', '/')
         assert not c.connected
         await c._handle_disconnect('/')
         assert c._trigger_event.await_count == 2
@@ -593,21 +591,15 @@ class TestAsyncClient:
         c.namespaces = {'/foo': '1', '/bar': '2'}
         c._trigger_event = mock.AsyncMock()
         await c._handle_disconnect('/foo')
-        c._trigger_event.assert_any_await(
-            'disconnect', namespace='/foo'
-        )
-        c._trigger_event.assert_any_await(
-            '__disconnect_final', namespace='/foo'
-        )
+        c._trigger_event.assert_any_await('disconnect', '/foo',
+                                          c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_await('__disconnect_final', '/foo')
         assert c.namespaces == {'/bar': '2'}
         assert c.connected
         await c._handle_disconnect('/bar')
-        c._trigger_event.assert_any_await(
-            'disconnect', namespace='/bar'
-        )
-        c._trigger_event.assert_any_await(
-            '__disconnect_final', namespace='/bar'
-        )
+        c._trigger_event.assert_any_await('disconnect', '/bar',
+                                          c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_await('__disconnect_final', '/bar')
         assert c.namespaces == {}
         assert not c.connected
 
@@ -617,12 +609,9 @@ class TestAsyncClient:
         c.namespaces = {'/foo': '1', '/bar': '2'}
         c._trigger_event = mock.AsyncMock()
         await c._handle_disconnect('/baz')
-        c._trigger_event.assert_any_await(
-            'disconnect', namespace='/baz'
-        )
-        c._trigger_event.assert_any_await(
-            '__disconnect_final', namespace='/baz'
-        )
+        c._trigger_event.assert_any_await('disconnect', '/baz',
+                                          c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_await('__disconnect_final', '/baz')
         assert c.namespaces == {'/foo': '1', '/bar': '2'}
         assert c.connected
 
@@ -632,8 +621,9 @@ class TestAsyncClient:
         c.namespaces = {'/foo': '1', '/bar': '2'}
         c._trigger_event = mock.AsyncMock()
         await c._handle_disconnect('/')
-        c._trigger_event.assert_any_await('disconnect', namespace='/')
-        c._trigger_event.assert_any_await('__disconnect_final', namespace='/')
+        c._trigger_event.assert_any_await('disconnect', '/',
+                                          c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_await('__disconnect_final', '/')
         assert c.namespaces == {'/foo': '1', '/bar': '2'}
         assert c.connected
 
@@ -818,6 +808,26 @@ class TestAsyncClient:
         handler.assert_awaited_once_with(1, '2')
         catchall_handler.assert_awaited_once_with('bar', 1, '2', 3)
 
+    async def test_trigger_legacy_disconnect_event(self):
+        c = async_client.AsyncClient()
+
+        @c.on('disconnect')
+        def baz():
+            return 'baz'
+
+        r = await c._trigger_event('disconnect', '/', 'foo')
+        assert r == 'baz'
+
+    async def test_trigger_legacy_disconnect_event_async(self):
+        c = async_client.AsyncClient()
+
+        @c.on('disconnect')
+        async def baz():
+            return 'baz'
+
+        r = await c._trigger_event('disconnect', '/', 'foo')
+        assert r == 'baz'
+
     async def test_trigger_event_class_namespace(self):
         c = async_client.AsyncClient()
         result = []
@@ -1127,10 +1137,8 @@ class TestAsyncClient:
         c.start_background_task = mock.MagicMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        await c._handle_eio_disconnect()
-        c._trigger_event.assert_awaited_once_with(
-            'disconnect', namespace='/'
-        )
+        await c._handle_eio_disconnect('foo')
+        c._trigger_event.assert_awaited_once_with('disconnect', '/', 'foo')
         assert c.sid is None
         assert not c.connected
 
@@ -1141,9 +1149,13 @@ class TestAsyncClient:
         c._trigger_event = mock.AsyncMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        await c._handle_eio_disconnect()
-        c._trigger_event.assert_any_await('disconnect', namespace='/foo')
-        c._trigger_event.assert_any_await('disconnect', namespace='/bar')
+        await c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.assert_any_await('disconnect', '/foo',
+                                          c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.assert_any_await('disconnect', '/bar',
+                                          c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.asserT_any_await('disconnect', '/',
+                                          c.reason.CLIENT_DISCONNECT)
         assert c.sid is None
         assert not c.connected
 
@@ -1151,14 +1163,14 @@ class TestAsyncClient:
         c = async_client.AsyncClient(reconnection=True)
         c.start_background_task = mock.MagicMock()
         c.eio.state = 'connected'
-        await c._handle_eio_disconnect()
+        await c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
         c.start_background_task.assert_called_once_with(c._handle_reconnect)
 
     async def test_eio_disconnect_self_disconnect(self):
         c = async_client.AsyncClient(reconnection=True)
         c.start_background_task = mock.MagicMock()
         c.eio.state = 'disconnected'
-        await c._handle_eio_disconnect()
+        await c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
         c.start_background_task.assert_not_called()
 
     async def test_eio_disconnect_no_reconnect(self):
@@ -1169,13 +1181,10 @@ class TestAsyncClient:
         c.start_background_task = mock.MagicMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        await c._handle_eio_disconnect()
-        c._trigger_event.assert_any_await(
-            'disconnect', namespace='/'
-        )
-        c._trigger_event.assert_any_await(
-            '__disconnect_final', namespace='/'
-        )
+        await c._handle_eio_disconnect(c.reason.TRANSPORT_ERROR)
+        c._trigger_event.assert_any_await('disconnect', '/',
+                                          c.reason.TRANSPORT_ERROR)
+        c._trigger_event.assert_any_await('__disconnect_final', '/')
         assert c.sid is None
         assert not c.connected
         c.start_background_task.assert_not_called()

tests/async/test_namespace.py

@@ -19,13 +19,37 @@ class TestAsyncNamespace:
     async def test_disconnect_event(self):
         result = {}
 
+        class MyNamespace(async_namespace.AsyncNamespace):
+            async def on_disconnect(self, sid, reason):
+                result['result'] = (sid, reason)
+
+        ns = MyNamespace('/foo')
+        ns._set_server(mock.MagicMock())
+        _run(ns.trigger_event('disconnect', 'sid', 'foo'))
+        assert result['result'] == ('sid', 'foo')
+
+    def test_legacy_disconnect_event(self):
+        result = {}
+
+        class MyNamespace(async_namespace.AsyncNamespace):
+            def on_disconnect(self, sid):
+                result['result'] = sid
+
+        ns = MyNamespace('/foo')
+        ns._set_server(mock.MagicMock())
+        _run(ns.trigger_event('disconnect', 'sid', 'foo'))
+        assert result['result'] == 'sid'
+
+    def test_legacy_disconnect_event_async(self):
+        result = {}
+
         class MyNamespace(async_namespace.AsyncNamespace):
             async def on_disconnect(self, sid):
                 result['result'] = sid
 
         ns = MyNamespace('/foo')
         ns._set_server(mock.MagicMock())
-        await ns.trigger_event('disconnect', 'sid')
+        await ns.trigger_event('disconnect', 'sid', 'foo')
         assert result['result'] == 'sid'
 
     async def test_sync_event(self):
@@ -242,6 +266,42 @@ class TestAsyncNamespace:
         await ns.disconnect('sid', namespace='/bar')
         ns.server.disconnect.assert_awaited_with('sid', namespace='/bar')
 
+    async def test_disconnect_event(self):
+        result = {}
+
+        class MyNamespace(async_namespace.AsyncClientNamespace):
+            async def on_disconnect(self, reason):
+                result['result'] = reason
+
+        ns = MyNamespace('/foo')
+        ns._set_client(mock.MagicMock())
+        await ns.trigger_event('disconnect', 'foo')
+        assert result['result'] == 'foo'
+
+    async def test_legacy_disconnect_event_client(self):
+        result = {}
+
+        class MyNamespace(async_namespace.AsyncClientNamespace):
+            def on_disconnect(self):
+                result['result'] = 'ok'
+
+        ns = MyNamespace('/foo')
+        ns._set_client(mock.MagicMock())
+        await ns.trigger_event('disconnect', 'foo')
+        assert result['result'] == 'ok'
+
+    async def test_legacy_disconnect_event_client_async(self):
+        result = {}
+
+        class MyNamespace(async_namespace.AsyncClientNamespace):
+            async def on_disconnect(self):
+                result['result'] = 'ok'
+
+        ns = MyNamespace('/foo')
+        ns._set_client(mock.MagicMock())
+        await ns.trigger_event('disconnect', 'foo')
+        assert result['result'] == 'ok'
+
     async def test_sync_event_client(self):
         result = {}
 

tests/common/test_client.py

@@ -752,8 +752,9 @@ class TestClient:
         c.connected = True
         c._trigger_event = mock.MagicMock()
         c._handle_disconnect('/')
-        c._trigger_event.assert_any_call('disconnect', namespace='/')
-        c._trigger_event.assert_any_call('__disconnect_final', namespace='/')
+        c._trigger_event.assert_any_call('disconnect', '/',
+                                         c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_call('__disconnect_final', '/')
         assert not c.connected
         c._handle_disconnect('/')
         assert c._trigger_event.call_count == 2
@@ -764,21 +765,15 @@ class TestClient:
         c.namespaces = {'/foo': '1', '/bar': '2'}
         c._trigger_event = mock.MagicMock()
         c._handle_disconnect('/foo')
-        c._trigger_event.assert_any_call(
-            'disconnect', namespace='/foo'
-        )
-        c._trigger_event.assert_any_call(
-            '__disconnect_final', namespace='/foo'
-        )
+        c._trigger_event.assert_any_call('disconnect', '/foo',
+                                         c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_call('__disconnect_final', '/foo')
         assert c.namespaces == {'/bar': '2'}
         assert c.connected
         c._handle_disconnect('/bar')
-        c._trigger_event.assert_any_call(
-            'disconnect', namespace='/bar'
-        )
-        c._trigger_event.assert_any_call(
-            '__disconnect_final', namespace='/bar'
-        )
+        c._trigger_event.assert_any_call('disconnect', '/bar',
+                                         c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_call('__disconnect_final', '/bar')
         assert c.namespaces == {}
         assert not c.connected
 
@@ -788,12 +783,9 @@ class TestClient:
         c.namespaces = {'/foo': '1', '/bar': '2'}
         c._trigger_event = mock.MagicMock()
         c._handle_disconnect('/baz')
-        c._trigger_event.assert_any_call(
-            'disconnect', namespace='/baz'
-        )
-        c._trigger_event.assert_any_call(
-            '__disconnect_final', namespace='/baz'
-        )
+        c._trigger_event.assert_any_call('disconnect', '/baz',
+                                         c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_call('__disconnect_final', '/baz')
         assert c.namespaces == {'/foo': '1', '/bar': '2'}
         assert c.connected
 
@@ -804,8 +796,9 @@ class TestClient:
         c._trigger_event = mock.MagicMock()
         c._handle_disconnect('/')
         print(c._trigger_event.call_args_list)
-        c._trigger_event.assert_any_call('disconnect', namespace='/')
-        c._trigger_event.assert_any_call('__disconnect_final', namespace='/')
+        c._trigger_event.assert_any_call('disconnect', '/',
+                                         c.reason.SERVER_DISCONNECT)
+        c._trigger_event.assert_any_call('__disconnect_final', '/')
         assert c.namespaces == {'/foo': '1', '/bar': '2'}
         assert c.connected
 
@@ -1003,8 +996,8 @@ class TestClient:
             def on_connect(self, ns):
                 result['result'] = (ns,)
 
-            def on_disconnect(self, ns):
-                result['result'] = ('disconnect', ns)
+            def on_disconnect(self, ns, reason):
+                result['result'] = ('disconnect', ns, reason)
 
             def on_foo(self, ns, data):
                 result['result'] = (ns, data)
@@ -1025,8 +1018,8 @@ class TestClient:
         assert result['result'] == 'bar/foo'
         c._trigger_event('baz', '/foo', 'a', 'b')
         assert result['result'] == ('/foo', 'a', 'b')
-        c._trigger_event('disconnect', '/foo')
-        assert result['result'] == ('disconnect', '/foo')
+        c._trigger_event('disconnect', '/foo', 'bar')
+        assert result['result'] == ('disconnect', '/foo', 'bar')
 
     def test_trigger_event_class_namespace(self):
         c = client.Client()
@@ -1286,8 +1279,8 @@ class TestClient:
         c.start_background_task = mock.MagicMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        c._handle_eio_disconnect()
-        c._trigger_event.assert_called_once_with('disconnect', namespace='/')
+        c._handle_eio_disconnect('foo')
+        c._trigger_event.assert_called_once_with('disconnect', '/', 'foo')
         assert c.sid is None
         assert not c.connected
 
@@ -1299,10 +1292,13 @@ class TestClient:
         c.start_background_task = mock.MagicMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        c._handle_eio_disconnect()
-        c._trigger_event.assert_any_call('disconnect', namespace='/foo')
-        c._trigger_event.assert_any_call('disconnect', namespace='/bar')
-        c._trigger_event.assert_any_call('disconnect', namespace='/')
+        c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.assert_any_call('disconnect', '/foo',
+                                         c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.assert_any_call('disconnect', '/bar',
+                                         c.reason.CLIENT_DISCONNECT)
+        c._trigger_event.assert_any_call('disconnect', '/',
+                                         c.reason.CLIENT_DISCONNECT)
         assert c.sid is None
         assert not c.connected
 
@@ -1310,14 +1306,14 @@ class TestClient:
         c = client.Client(reconnection=True)
         c.start_background_task = mock.MagicMock()
         c.eio.state = 'connected'
-        c._handle_eio_disconnect()
+        c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
         c.start_background_task.assert_called_once_with(c._handle_reconnect)
 
     def test_eio_disconnect_self_disconnect(self):
         c = client.Client(reconnection=True)
         c.start_background_task = mock.MagicMock()
         c.eio.state = 'disconnected'
-        c._handle_eio_disconnect()
+        c._handle_eio_disconnect(c.reason.CLIENT_DISCONNECT)
         c.start_background_task.assert_not_called()
 
     def test_eio_disconnect_no_reconnect(self):
@@ -1328,9 +1324,10 @@ class TestClient:
         c.start_background_task = mock.MagicMock()
         c.sid = 'foo'
         c.eio.state = 'connected'
-        c._handle_eio_disconnect()
-        c._trigger_event.assert_any_call('disconnect', namespace='/')
-        c._trigger_event.assert_any_call('__disconnect_final', namespace='/')
+        c._handle_eio_disconnect(c.reason.TRANSPORT_ERROR)
+        c._trigger_event.assert_any_call('disconnect', '/',
+                                         c.reason.TRANSPORT_ERROR)
+        c._trigger_event.assert_any_call('__disconnect_final', '/')
         assert c.sid is None
         assert not c.connected
         c.start_background_task.assert_not_called()

tests/common/test_namespace.py

@@ -19,13 +19,25 @@ class TestNamespace:
     def test_disconnect_event(self):
         result = {}
 
+        class MyNamespace(namespace.Namespace):
+            def on_disconnect(self, sid, reason):
+                result['result'] = (sid, reason)
+
+        ns = MyNamespace('/foo')
+        ns._set_server(mock.MagicMock())
+        ns.trigger_event('disconnect', 'sid', 'foo')
+        assert result['result'] == ('sid', 'foo')
+
+    def test_legacy_disconnect_event(self):
+        result = {}
+
         class MyNamespace(namespace.Namespace):
             def on_disconnect(self, sid):
                 result['result'] = sid
 
         ns = MyNamespace('/foo')
         ns._set_server(mock.MagicMock())
-        ns.trigger_event('disconnect', 'sid')
+        ns.trigger_event('disconnect', 'sid', 'foo')
         assert result['result'] == 'sid'
 
     def test_event(self):
@@ -216,6 +228,31 @@ class TestNamespace:
         ns.disconnect('sid', namespace='/bar')
         ns.server.disconnect.assert_called_with('sid', namespace='/bar')
 
+    def test_disconnect_event_client(self):
+        result = {}
+
+        class MyNamespace(namespace.ClientNamespace):
+            def on_disconnect(self, reason):
+                result['result'] = reason
+
+        ns = MyNamespace('/foo')
+        ns._set_client(mock.MagicMock())
+        ns.trigger_event('disconnect', 'foo')
+        assert result['result'] == 'foo'
+
+    def test_legacy_disconnect_event_client(self):
+        result = {}
+
+        class MyNamespace(namespace.ClientNamespace):
+            def on_disconnect(self):
+                result['result'] = 'ok'
+
+        ns = MyNamespace('/foo')
+        ns._set_client(mock.MagicMock())
+        ns.trigger_event('disconnect', 'foo')
+        assert result['result'] == 'ok'
+
+
     def test_event_not_found_client(self):
         result = {}