replace version identifier and require user action

test/test_upgrade.py

@@ -407,6 +407,35 @@ def test_wrong_method(self):
         event = next(ws.events())
         assert isinstance(event, ConnectionFailed)
 
+    @pytest.mark.parametrize('versions', [
+        b'',
+        b'12',
+        b'14',
+        b'10,11,12',
+        b'10, 11, 12',
+        b'10-12',
+    ])
+    def test_unsupported_version(self, versions):
+        test_host = 'frob.nitz'
+        test_path = '/fnord'
+
+        ws = WSConnection(SERVER)
+
+        nonce = bytes(random.getrandbits(8) for x in range(0, 16))
+        nonce = base64.b64encode(nonce)
+
+        request = b'GET ' + test_path.encode('ascii') + b' HTTP/1.1\r\n'
+        request += b'Host: ' + test_host.encode('ascii') + b'\r\n'
+        request += b'Connection: Upgrade\r\n'
+        request += b'Upgrade: WebSocket\r\n'
+        request += b'Sec-WebSocket-Version: ' + versions + b'\r\n'
+        request += b'Sec-WebSocket-Key: ' + nonce + b'\r\n'
+        request += b'\r\n'
+
+        ws.receive_bytes(request)
+        event = next(ws.events())
+        assert isinstance(event, ConnectionFailed)
+
     def test_bad_connection(self):
         test_host = 'frob.nitz'
         test_path = '/fnord'

wsproto/connection.py

@@ -25,6 +25,8 @@
 # RFC6455, Section 1.3 - Opening Handshake
 ACCEPT_GUID = b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
 
+# RFC6455, Section 4.2.1/6 - Reading the Client's Opening Handshake
+WEBSOCKET_VERSION = '13'
 
 class ConnectionState(Enum):
     """
@@ -109,8 +111,6 @@ def __init__(self, conn_type, host=None, resource=None, extensions=None,
         self.subprotocols = subprotocols or []
         self.extensions = extensions or []
 
-        self.version = b'13'
-
         self._state = ConnectionState.CONNECTING
         self._close_reason = None
 
@@ -141,7 +141,7 @@ def initiate_connection(self):
             b"Upgrade": b'WebSocket',
             b"Connection": b'Upgrade',
             b"Sec-WebSocket-Key": self._nonce,
-            b"Sec-WebSocket-Version": self.version,
+            b"Sec-WebSocket-Version": WEBSOCKET_VERSION,
         }
 
         if self.subprotocols:
@@ -378,8 +378,10 @@ def _process_connection_request(self, event):
         if b'sec-websocket-version' not in headers:
             return ConnectionFailed(CloseReason.PROTOCOL_ERROR,
                                     "Missing Sec-WebSocket-Version header")
-        # XX FIXME: need to check Sec-Websocket-Version, and respond with a
-        # 400 if it's not what we expect
+        versions = _split_comma_header(headers[b'sec-websocket-version'])
+        if WEBSOCKET_VERSION not in versions:
+            return ConnectionFailed(CloseReason.PROTOCOL_ERROR,
+                                    "Unsupported Sec-WebSocket-Version")
 
         if b'sec-websocket-protocol' in headers:
             proposed_subprotocols = _split_comma_header(

wsproto/events.py

@@ -49,6 +49,11 @@ def __repr__(self):
 
 
 class ConnectionFailed(ConnectionClosed):
+    """
+    The ConnectionFailed event is fired when the upgrade handshake failed.
+    Users must handle this error by appropriate responses to deal with the
+    connection, e.g., sending a 400 HTTP response for a failed client handshake.
+    """
     pass