🐛 Fix support for path parameters in WebSockets (#3879)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

fastapi/routing.py

@@ -297,14 +297,14 @@ class APIWebSocketRoute(routing.WebSocketRoute):
         self.path = path
         self.endpoint = endpoint
         self.name = get_name(endpoint) if name is None else name
-        self.dependant = get_dependant(path=path, call=self.endpoint)
+        self.path_regex, self.path_format, self.param_convertors = compile_path(path)
+        self.dependant = get_dependant(path=self.path_format, call=self.endpoint)
         self.app = websocket_session(
             get_websocket_app(
                 dependant=self.dependant,
                 dependency_overrides_provider=dependency_overrides_provider,
             )
         )
-        self.path_regex, self.path_format, self.param_convertors = compile_path(path)
 
     def matches(self, scope: Scope) -> Tuple[Match, Scope]:
         match, child_scope = super().matches(scope)

tests/test_ws_router.py

@@ -35,6 +35,14 @@ async def routerindex2(websocket: WebSocket):
     await websocket.close()
 
 
+@router.websocket("/router/{pathparam:path}")
+async def routerindexparams(websocket: WebSocket, pathparam: str, queryparam: str):
+    await websocket.accept()
+    await websocket.send_text(pathparam)
+    await websocket.send_text(queryparam)
+    await websocket.close()
+
+
 async def ws_dependency():
     return "Socket Dependency"
 
@@ -106,3 +114,14 @@ def test_router_ws_depends_with_override():
     app.dependency_overrides[ws_dependency] = lambda: "Override"
     with client.websocket_connect("/router-ws-depends/") as websocket:
         assert websocket.receive_text() == "Override"
+
+
+def test_router_with_params():
+    client = TestClient(app)
+    with client.websocket_connect(
+        "/router/path/to/file?queryparam=a_query_param"
+    ) as websocket:
+        data = websocket.receive_text()
+        assert data == "path/to/file"
+        data = websocket.receive_text()
+        assert data == "a_query_param"