Rework Auth Plugins to Support HTTP Auth

This commit reworks auth plugins slightly to enable
support for HTTP authentication.  By raising an
AuthenticationError, auth plugins can now return
HTTP responses to the upgrade request (such as 401).

Related to kanaka/noVNC#522

tests/test_websocketproxy.py

@@ -106,11 +106,11 @@ class ProxyRequestHandlerTestCase(unittest.TestCase):
             def lookup(self, token):
                 return (self.source + token).split(',')
 
-        self.stubs.Set(websocketproxy.ProxyRequestHandler, 'do_proxy',
-                       lambda *args, **kwargs: None)
+        self.stubs.Set(websocketproxy.ProxyRequestHandler, 'send_auth_error',
+                       staticmethod(lambda *args, **kwargs: None))
 
         self.handler.server.token_plugin = TestPlugin("somehost,")
-        self.handler.new_websocket_client()
+        self.handler.validate_connection()
 
         self.assertEqual(self.handler.server.target_host, "somehost")
         self.assertEqual(self.handler.server.target_port, "blah")
@@ -119,9 +119,9 @@ class ProxyRequestHandlerTestCase(unittest.TestCase):
         class TestPlugin(auth_plugins.BasePlugin):
             def authenticate(self, headers, target_host, target_port):
                 if target_host == self.source:
-                    raise auth_plugins.AuthenticationError("some error")
+                    raise auth_plugins.AuthenticationError(response_msg="some_error")
 
-        self.stubs.Set(websocketproxy.ProxyRequestHandler, 'do_proxy',
+        self.stubs.Set(websocketproxy.ProxyRequestHandler, 'send_auth_error',
                        staticmethod(lambda *args, **kwargs: None))
 
         self.handler.server.auth_plugin = TestPlugin("somehost")
@@ -129,8 +129,8 @@ class ProxyRequestHandlerTestCase(unittest.TestCase):
         self.handler.server.target_port = "someport"
 
         self.assertRaises(auth_plugins.AuthenticationError,
-                          self.handler.new_websocket_client)
+                          self.handler.validate_connection)
 
         self.handler.server.target_host = "someotherhost"
-        self.handler.new_websocket_client()
+        self.handler.validate_connection()