Add ability to configure websocket message size when running as django dev server

daphne/http_protocol.py

@@ -77,9 +77,7 @@ def process(self):
                     return
                 for value in values:
                     if INVALID_HEADER_VALUE_BYTES.intersection(value):
-                        self.basic_error(
-                            400, b"Bad Request", "Invalid header value"
-                        )
+                        self.basic_error(400, b"Bad Request", "Invalid header value")
                         return
 
             # Get upgrade header

daphne/management/commands/runserver.py

@@ -73,6 +73,22 @@ def add_arguments(self, parser):
                 "seconds (default: 5)"
             ),
         )
+        parser.add_argument(
+            "--websocket-max-message-size",
+            type=int,
+            help="Maximum size, in bytes, of an incoming WebSocket message. "
+            "0 disables the limit (not recommended; allows unauthenticated "
+            "memory exhaustion).",
+            default=None,
+        )
+        parser.add_argument(
+            "--websocket-max-frame-size",
+            type=int,
+            help="Maximum size, in bytes, of a single incoming WebSocket frame. "
+            "0 disables the limit (not recommended; allows unauthenticated "
+            "memory exhaustion).",
+            default=None,
+        )
         if apps.is_installed("django.contrib.staticfiles"):
             parser.add_argument(
                 "--nostatic",
@@ -95,6 +111,17 @@ def handle(self, *args, **options):
             raise CommandError(
                 "You have not set ASGI_APPLICATION, which is needed to run the server."
             )
+        self.websocket_max_message_size = options.get("websocket_max_message_size")
+        if self.websocket_max_message_size is None:
+            self.websocket_max_message_size = getattr(
+                settings, "DAPHNE_WEBSOCKET_MAX_MESSAGE_SIZE", 1024 * 1024
+            )
+        self.websocket_max_frame_size = options.get("websocket_max_frame_size")
+        if self.websocket_max_frame_size is None:
+            self.websocket_max_frame_size = getattr(
+                settings, "DAPHNE_WEBSOCKET_MAX_FRAME_SIZE", 1024 * 1024
+            )
+
         # Dispatch upward
         super().handle(*args, **options)
 
@@ -145,6 +172,8 @@ def inner_run(self, *args, **options):
                 http_timeout=self.http_timeout,
                 root_path=getattr(settings, "FORCE_SCRIPT_NAME", "") or "",
                 websocket_handshake_timeout=self.websocket_handshake_timeout,
+                websocket_max_message_size=self.websocket_max_message_size,
+                websocket_max_frame_size=self.websocket_max_frame_size,
             ).run()
             logger.debug("Daphne exited")
         except KeyboardInterrupt:

tests/test_websocket.py

@@ -330,9 +330,7 @@ def test_websocket_max_message_size_allows_under_limit(self):
             sock, _ = self.websocket_handshake(test_app)
             _, messages = test_app.get_received()
             self.assert_valid_websocket_connect_message(messages[0])
-            test_app.add_send_messages(
-                [{"type": "websocket.send", "text": "ack"}]
-            )
+            test_app.add_send_messages([{"type": "websocket.send", "text": "ack"}])
             self.websocket_send_frame(sock, "x" * 16)
             assert self.websocket_receive_frame(sock) == "ack"
 
@@ -418,9 +416,7 @@ def test_websocket_upgrade_rejects_smuggled_headers(self):
         for byte in self.INVALID_BYTES:
             with self.subTest(byte=byte):
                 value = b"innocent" + byte + b"X-Secret-Auth: admin-token"
-                response = self.run_daphne_raw(
-                    self._websocket_upgrade_request(value)
-                )
+                response = self.run_daphne_raw(self._websocket_upgrade_request(value))
                 self.assertTrue(
                     response.startswith(b"HTTP/1.1 400"),
                     f"expected 400 for byte {byte!r}, got {response[:80]!r}",