made websocket subprotocols conform to spec

aiohttp/log.py

@@ -5,3 +5,4 @@
 client_log = logging.getLogger('aiohttp.client')
 internal_log = logging.getLogger('aiohttp.internal')
 server_log = logging.getLogger('aiohttp.server')
+websocket_log = logging.getLogger('aiohttp.websocket')

aiohttp/websocket.py

@@ -10,6 +10,7 @@
 import hashlib
 import struct
 from aiohttp import errors
+from aiohttp.log import websocket_log
 
 # Frame opcodes defined in the spec.
 OPCODE_CONTINUATION = 0x0
@@ -220,9 +221,9 @@ def do_handshake(method, headers, transport, protocols=()):
                 protocol = proto
                 break
         else:
-            raise errors.HttpBadRequest(
-                'Client protocols {!r} don’t overlap server-known ones {!r}'
-                .format(protocols, req_protocols))
+            websocket_log.warning(  # No overlap found: Return no protocol as per spec
+                'Client protocols %r don’t overlap server-known ones %r',
+                protocols, req_protocols)
 
     # check supported version
     version = headers.get('SEC-WEBSOCKET-VERSION')

tests/test_websocket.py

@@ -471,12 +471,21 @@ def test_handshake_protocol_agreement(self):
 
         self.assertEqual(protocol, best_proto)
 
-    def test_handshake_protocol_unsupported(self):
+    @unittest.mock.patch('aiohttp.websocket.websocket_log.warning')
+    def test_handshake_protocol_unsupported(self, m_websocket_warn):
+        '''Tests if a protocol mismatch handshake warns and returns None'''
+        warn_called = False
+        def websocket_warn(msg, *fmts):
+            nonlocal warn_called
+            warn_called = True
+        m_websocket_warn.side_effect = websocket_warn
+
         proto = 'chat'
         self.headers.extend(self.gen_ws_headers('test')[0])
 
-        self.assertRaises(
-            errors.HttpBadRequest,
-            websocket.do_handshake,
+        _, _, _, _, protocol = websocket.do_handshake(
             self.message.method, self.message.headers, self.transport,
             protocols=[proto])
+
+        self.assertTrue(warn_called, 'protocol mismatch didn’t warn')
+        self.assertIsNone(protocol)