Change WebSocket request handler to a mix-in

We can't get the inheritence right in non-trivial cases as a regular
base class, so change it to be a mix-in that is to be combined with
one of the existing request handlers from the Python library.

websockify/websocketserver.py

@@ -3,7 +3,7 @@
 '''
 Python WebSocket server base
 Copyright 2011 Joel Martin
-Copyright 2016 Pierre Ossman
+Copyright 2016-2018 Pierre Ossman
 Licensed under LGPL version 3 (see docs/LICENSE.LGPL-3)
 '''
 
@@ -17,14 +17,14 @@ except ImportError:
 
 from websockify.websocket import WebSocket, WebSocketWantReadError, WebSocketWantWriteError
 
-class WebSocketRequestHandler(BaseHTTPRequestHandler):
-    """WebSocket request handler base class.
+class WebSocketRequestHandlerMixIn:
+    """WebSocket request handler mix-in class
 
-    This class forms the base for a server that wishes to handle
-    WebSocket requests. It functions exactly as BastHTTPRequestHandler,
-    except that WebSocket requests are intercepted and the methods
-    handle_upgrade() and handle_websocket() are called. The standard
-    do_GET() will be called for normal requests.
+    This class modifies and existing request handler to handle
+    WebSocket requests. The request handler will continue to function
+    as before, except that WebSocket requests are intercepted and the
+    methods handle_upgrade() and handle_websocket() are called. The
+    standard do_GET() will be called for normal requests.
 
     The class instance SocketClass can be overridden with the class to
     use for the WebSocket connection.
@@ -32,9 +32,6 @@ class WebSocketRequestHandler(BaseHTTPRequestHandler):
 
     SocketClass = WebSocket
 
-    def __init__(self, request, client_address, server):
-        BaseHTTPRequestHandler.__init__(self, request, client_address, server)
-
     def handle_one_request(self):
         """Extended request handler
 
@@ -45,7 +42,12 @@ class WebSocketRequestHandler(BaseHTTPRequestHandler):
         self._real_do_GET = self.do_GET
         self.do_GET = self._websocket_do_GET
         try:
-            BaseHTTPRequestHandler.handle_one_request(self)
+            # super() only works for new style classes
+            if issubclass(WebSocketRequestHandlerMixIn, object):
+                super(WebSocketRequestHandlerMixIn, self).handle_one_request()
+            else:
+                # Assume handle_one_request() hasn't been overriden
+                BaseHTTPRequestHandler.handle_one_request(self)
         finally:
             self.do_GET = self._real_do_GET
 
@@ -93,5 +95,11 @@ class WebSocketRequestHandler(BaseHTTPRequestHandler):
         """
         pass
 
+# Convenient ready made classes
+
+class WebSocketRequestHandler(WebSocketRequestHandlerMixIn,
+                              BaseHTTPRequestHandler):
+    pass
+
 class WebSocketServer(HTTPServer):
     pass

websockify/websockifyserver.py

@@ -45,7 +45,7 @@ if sys.platform == 'win32':
     sys.exit("Windows is not supported at this time")
 
 from websockify.websocket import WebSocket, WebSocketWantReadError, WebSocketWantWriteError
-from websockify.websocketserver import WebSocketRequestHandler
+from websockify.websocketserver import WebSocketRequestHandlerMixIn
 
 class CompatibleWebSocket(WebSocket):
     def select_subprotocol(self, protocols):
@@ -56,7 +56,7 @@ class CompatibleWebSocket(WebSocket):
             return ''
 
 # HTTP handler with WebSocket upgrade support
-class WebSockifyRequestHandler(WebSocketRequestHandler, SimpleHTTPRequestHandler):
+class WebSockifyRequestHandler(WebSocketRequestHandlerMixIn, SimpleHTTPRequestHandler):
     """
     WebSocket Request Handler Class, derived from SimpleHTTPRequestHandler.
     Must be sub-classed with new_websocket_client method definition.
@@ -99,7 +99,7 @@ class WebSockifyRequestHandler(WebSocketRequestHandler, SimpleHTTPRequestHandler
         if self.logger is None:
             self.logger = WebSockifyServer.get_logger()
 
-        WebSocketRequestHandler.__init__(self, req, addr, server)
+        SimpleHTTPRequestHandler.__init__(self, req, addr, server)
 
     def log_message(self, format, *args):
         self.logger.info("%s - - [%s] %s" % (self.address_string(), self.log_date_time_string(), format % args))
@@ -221,7 +221,7 @@ class WebSockifyRequestHandler(WebSocketRequestHandler, SimpleHTTPRequestHandler
         self.validate_connection()
         self.auth_connection()
 
-        WebSocketRequestHandler.handle_upgrade(self)
+        WebSocketRequestHandlerMixIn.handle_upgrade(self)
 
     def handle_websocket(self):
         # Indicate to server that a Websocket upgrade was done
@@ -306,7 +306,7 @@ class WebSockifyRequestHandler(WebSocketRequestHandler, SimpleHTTPRequestHandler
         if self.rec:
             self.rec.write("'EOF'];\n")
             self.rec.close()
-        WebSocketRequestHandler.finish(self)
+        SimpleHTTPRequestHandler.finish(self)
 
     def handle(self):
         # When using run_once, we have a single process, so