- Fixed a bug at applying middlewares.

- Simplified decorators.
- Added test for event handler middlewares.

docs/index.rst

@@ -226,6 +226,10 @@ subset of them:
 * ``after_event(*args)`` is called after the event handler with the
   event name, the namespace and the list of values the event handler
   returned. It may alter that values eventually.
+* ``ignore_event`` is called before the middleware is applied to an
+  event handler with the event name and namespace as arguments. If its
+  return value resolves to ``True`` the middleware is not applied to that
+  particular event handler.
 
 If one of these methods returns something else than ``None``, execution
 is stopped at that point and the returned value is treated as if it was

socketio/__init__.py

@@ -5,6 +5,7 @@ from .pubsub_manager import PubSubManager
 from .kombu_manager import KombuManager
 from .redis_manager import RedisManager
 from .server import Server
+from .util import apply_middleware
 
 __all__ = [Middleware, Namespace, Server, BaseManager, PubSubManager,
-           KombuManager, RedisManager]
+           KombuManager, RedisManager, apply_middleware]

socketio/namespace.py

@@ -36,7 +36,8 @@ class Namespace(object):
                 # ...
 
         sio = socketio.Server()
-        sio.register_namespace("/chat", ChatNamespace)
+        ns = sio.register_namespace("/chat", ChatNamespace)
+        # ns now holds the instantiated ChatNamespace object
     """
 
     def __init__(self, name, server):
@@ -73,10 +74,7 @@ class Namespace(object):
             else:
                 continue
             if _event_name == event_name:
-                extra_middlewares = getattr(attr, '_sio_middlewares', [])
-                return util._apply_middlewares(
-                    self.middlewares + extra_middlewares, event_name,
-                    self.name, attr)
+                return attr
 
     @staticmethod
     def event_name(name):
@@ -86,14 +84,12 @@ class Namespace(object):
             def foo(self, sid, data):
                 return "received: %s" % data
 
-        Note that you must not add third-party decorators after the ones
-        provided by this library because you'll otherwise loose metadata
-        that this decorators create. You can add them before instead.
+        Ensure that you only add well-behaving decorators after this one
+        (meaning such that preserve attributes) because you'll loose them
+        otherwise.
         """
+        @util._simple_decorator
         def wrapper(handler):
-            def wrapped_handler(*args, **kwargs):
-                return handler(*args, **kwargs)
-            util._copy_sio_properties(handler, wrapped_handler)
-            wrapped_handler._sio_event_name = name
-            return wrapped_handler
+            handler._sio_event_name = name
+            return handler
         return wrapper

socketio/server.py

@@ -6,7 +6,6 @@ import six
 from . import base_manager
 from . import namespace as sio_namespace
 from . import packet
-from . import util
 
 
 class Server(object):
@@ -173,25 +172,6 @@ class Server(object):
         self.handlers[name] = namespace
         return namespace
 
-    def _get_event_handler(self, event, namespace):
-        """Returns the event handler for given ``event`` and ``namespace`` or
-        ``None``, if none exists.
-
-        :param event: The event name the handler is required for.
-        :param namespace: The Socket.IO namespace for the event.
-        """
-        handler = None
-        ns = self.handlers.get(namespace)
-        if isinstance(ns, sio_namespace.Namespace):
-            handler = ns._get_event_handler(event)
-        elif isinstance(ns, dict):
-            handler = ns.get(event)
-        if handler is not None:
-            extra_middlewares = getattr(handler, '_sio_middlewares', [])
-            return util._apply_middlewares(
-                self.middlewares + extra_middlewares, event, namespace,
-                handler)
-
     def emit(self, event, data=None, room=None, skip_sid=None, namespace=None,
              callback=None):
         """Emit a custom event to one or more connected clients.
@@ -466,10 +446,62 @@ class Server(object):
 
     def _trigger_event(self, event, namespace, *args):
         """Invoke an application event handler."""
-        handler = self._get_event_handler(event, namespace)
+        handler = None
+        middlewares = list(self.middlewares)
+        ns = self.handlers.get(namespace)
+        if isinstance(ns, sio_namespace.Namespace):
+            middlewares.extend(ns.middlewares)
+            handler = ns._get_event_handler(event)
+        elif isinstance(ns, dict):
+            handler = ns.get(event)
         if handler is not None:
+            middlewares.extend(getattr(handler, '_sio_middlewares', []))
+            handler = self._apply_middlewares(middlewares, event, namespace,
+                                              handler)
             return handler(*args)
 
+    @staticmethod
+    def _apply_middlewares(middlewares, event, namespace, handler):
+        """Wraps the given handler with a wrapper that executes middlewares
+        before and after the real event handler."""
+
+        _middlewares = []
+        for middleware in middlewares:
+            if isinstance(middleware, type):
+                middleware = middleware()
+            if not hasattr(middleware, 'ignore_event') or \
+               not middleware.ignore_event(event, namespace):
+                _middlewares.append(middleware)
+        if not _middlewares:
+            return handler
+
+        def wrapped(*args):
+            args = list(args)
+
+            for middleware in _middlewares:
+                if hasattr(middleware, 'before_event'):
+                    result = middleware.before_event(event, namespace, args)
+                    if result is not None:
+                        return result
+
+            result = handler(*args)
+            if result is None:
+                data = []
+            elif isinstance(result, tuple):
+                data = list(result)
+            else:
+                data = [result]
+
+            for middleware in reversed(_middlewares):
+                if hasattr(middleware, 'after_event'):
+                    result = middleware.after_event(event, namespace, data)
+                    if result is not None:
+                        return result
+
+            return tuple(data)
+
+        return wrapped
+
     def _handle_eio_connect(self, sid, environ):
         """Handle the Engine.IO connection event."""
         self.environ[sid] = environ

socketio/util.py

@@ -1,48 +1,33 @@
-def _copy_sio_properties(from_func, to_func):
-    """Copies all properties starting with ``'_sio'`` from one function to
-    another."""
-    for key in dir(from_func):
-        if key.startswith('_sio'):
-            setattr(to_func, key, getattr(from_func, key))
-
-
-def _apply_middlewares(middlewares, event, namespace, handler):
-    """Wraps the given handler with a wrapper that executes middlewares
-    before and after the real event handler."""
-    if not middlewares:
-        return handler
-
-    def wrapped(*args):
-        _middlewares = []
-        for middleware in middlewares:
-            if isinstance(middleware, type):
-                _middlewares.append(middleware())
-            else:
-                _middlewares.append(middleware)
-
-        for middleware in _middlewares:
-            if hasattr(middleware, 'before_event'):
-                result = middleware.before_event(event, namespace, args)
-                if result is not None:
-                    return result
-
-        result = handler(*args)
-        if result is None:
-            data = []
-        elif isinstance(result, tuple):
-            data = list(result)
-        else:
-            data = [result]
-
-        for middleware in reversed(_middlewares):
-            if hasattr(middleware, 'after_event'):
-                result = middleware.after_event(event, namespace, data)
-                if result is not None:
-                    return result
+def _simple_decorator(decorator):
+    """This decorator can be used to turn simple functions
+    into well-behaved decorators, so long as the decorators
+    are fairly simple. If a decorator expects a function and
+    returns a function (no descriptors), and if it doesn't
+    modify function attributes or docstring, then it is
+    eligible to use this. Simply apply @_simple_decorator to
+    your decorator and it will automatically preserve the
+    docstring and function attributes of functions to which
+    it is applied.
+
+    Also preserves all properties starting with ``'_sio'``.
+    """
+    def copy_attrs(a, b):
+        """Copies attributes from a to b."""
+        for attr_name in ('__name__', '__doc__'):
+            if hasattr(a, attr_name):
+                setattr(b, attr_name, getattr(a, attr_name))
+        if hasattr(a, '__dict__') and hasattr(b, '__dict__'):
+            b.__dict__.update(a.__dict__)
 
-        return tuple(data)
+    def new_decorator(f):
+        g = decorator(f)
+        copy_attrs(f, g)
+        return g
 
-    return wrapped
+    # Now a few lines needed to make _simple_decorator itself
+    # be a well-behaved decorator.
+    copy_attrs(decorator, new_decorator)
+    return new_decorator
 
 
 def apply_middleware(middleware):
@@ -51,10 +36,11 @@ def apply_middleware(middleware):
 
     :param middleware: The middleware to add
 
-    Note that you must not add third-party decorators after the ones
-    provided by this library because you'll otherwise loose metadata
-    that this decorators create. You can add them before instead.
+    Ensure that you only add well-behaving decorators after this one
+    (meaning such that preserve attributes) because you'll loose them
+    otherwise.
     """
+    @_simple_decorator
     def wrapper(handler):
         if not hasattr(handler, '_sio_middlewares'):
             handler._sio_middlewares = []

tests/test_server.py

@@ -11,6 +11,7 @@ else:
 from socketio import namespace
 from socketio import packet
 from socketio import server
+from socketio import util
 
 
 @mock.patch('engineio.Server')
@@ -62,6 +63,97 @@ class TestServer(unittest.TestCase):
         self.assertIsNotNone(s.handlers['/ns']._get_event_handler('foo bar'))
         self.assertIsNone(s.handlers['/ns']._get_event_handler('abc'))
 
+    def test_middleware(self, eio):
+        class MW:
+            def __init__(self):
+                self.ignore_event = mock.MagicMock(side_effect=100*[False])
+                self.before_event = mock.MagicMock(side_effect=100*[None])
+                self.after_event = mock.MagicMock(side_effect=100*[None])
+
+        mw1 = MW()
+        mw2 = MW()
+        mw3 = MW()
+        mw4 = MW()
+        mw4.ignore_event = mock.MagicMock(side_effect=[True]+100*[False])
+        mw4.before_event = mock.MagicMock(side_effect=['x']+100*[None])
+        mw4.after_event = mock.MagicMock(side_effect=['x']+100*[None])
+
+        class NS(namespace.Namespace):
+            def on_foo(self, sid):
+                pass
+
+            @namespace.Namespace.event_name('foo bar')
+            @util.apply_middleware(mw4)
+            def some_name(self, sid):
+                pass
+
+        s = server.Server()
+        s.middlewares.append(mw1)
+
+        @s.on('abc')
+        @util.apply_middleware(mw2)
+        def abc(sid):
+            pass
+
+        ns = s.register_namespace('/ns', NS)
+        ns.middlewares.append(mw3)
+
+        # only mw1 and mw3 should run completely
+        s._trigger_event('foo', '/ns', '123')
+        self.assertEqual(mw1.before_event.call_count, 1)
+        self.assertEqual(mw1.after_event.call_count, 1)
+        self.assertEqual(mw2.before_event.call_count, 0)
+        self.assertEqual(mw2.after_event.call_count, 0)
+        self.assertEqual(mw3.before_event.call_count, 1)
+        self.assertEqual(mw3.after_event.call_count, 1)
+        self.assertEqual(mw4.before_event.call_count, 0)
+        self.assertEqual(mw4.after_event.call_count, 0)
+
+        # only mw1 and mw3 should run completely, mw4 is enabled but ignored
+        s._trigger_event('foo bar', '/ns', '123')
+        self.assertEqual(mw1.before_event.call_count, 2)
+        self.assertEqual(mw1.after_event.call_count, 2)
+        self.assertEqual(mw2.before_event.call_count, 0)
+        self.assertEqual(mw2.after_event.call_count, 0)
+        self.assertEqual(mw3.before_event.call_count, 2)
+        self.assertEqual(mw3.after_event.call_count, 2)
+        self.assertEqual(mw4.before_event.call_count, 0)
+        self.assertEqual(mw4.after_event.call_count, 0)
+
+        # again, this time mw4 before_event should be triggered
+        s._trigger_event('foo bar', '/ns', '123')
+        self.assertEqual(mw1.before_event.call_count, 3)
+        self.assertEqual(mw1.after_event.call_count, 2)
+        self.assertEqual(mw2.before_event.call_count, 0)
+        self.assertEqual(mw2.after_event.call_count, 0)
+        self.assertEqual(mw3.before_event.call_count, 3)
+        self.assertEqual(mw3.after_event.call_count, 2)
+        self.assertEqual(mw4.before_event.call_count, 1)
+        self.assertEqual(mw4.after_event.call_count, 0)
+
+        # again, this time mw4 before + after_event should be triggered
+        # but after_event should abort execution
+        s._trigger_event('foo bar', '/ns', '123')
+        self.assertEqual(mw1.before_event.call_count, 4)
+        self.assertEqual(mw1.after_event.call_count, 2)
+        self.assertEqual(mw2.before_event.call_count, 0)
+        self.assertEqual(mw2.after_event.call_count, 0)
+        self.assertEqual(mw3.before_event.call_count, 4)
+        self.assertEqual(mw3.after_event.call_count, 2)
+        self.assertEqual(mw4.before_event.call_count, 2)
+        self.assertEqual(mw4.after_event.call_count, 1)
+
+        # only mw1 and mw2 should run completely
+        s._trigger_event('abc', '/', '123')
+        self.assertEqual(mw1.before_event.call_count, 5)
+        self.assertEqual(mw1.after_event.call_count, 3)
+        self.assertEqual(mw2.before_event.call_count, 1)
+        self.assertEqual(mw2.after_event.call_count, 1)
+        self.assertEqual(mw3.before_event.call_count, 4)
+        self.assertEqual(mw3.after_event.call_count, 2)
+        self.assertEqual(mw4.before_event.call_count, 2)
+        self.assertEqual(mw4.after_event.call_count, 1)
+
     def test_on_bad_event_name(self, eio):
         s = server.Server()
         self.assertRaises(ValueError, s.on, 'two-words')