Add websocket.handler.before/after/exception signals.

sanic/app.py

@@ -1369,6 +1369,12 @@ class Sanic(
             protocol = request.transport.get_protocol()
             ws = await protocol.websocket_handshake(request, subprotocols)
 
+        await self.dispatch(
+            "websocket.handler.before",
+            inline=True,
+            context={"request": request, "websocket": ws},
+            fail_not_found=False,
+        )
         # schedule the application handler
         # its future is kept in self.websocket_tasks in case it
         # needs to be cancelled due to the server being stopped
@@ -1377,10 +1383,24 @@ class Sanic(
         cancelled = False
         try:
             await fut
+            await self.dispatch(
+                "websocket.handler.after",
+                inline=True,
+                context={"request": request, "websocket": ws},
+                reverse=True,
+                fail_not_found=False,
+            )
         except (CancelledError, ConnectionClosed):  # type: ignore
             cancelled = True
         except Exception as e:
             self.error_handler.log(request, e)
+            await self.dispatch(
+                "websocket.handler.exception",
+                inline=True,
+                context={"request": request, "websocket": ws, "exception": e},
+                reverse=True,
+                fail_not_found=False,
+            )
         finally:
             self.websocket_tasks.remove(fut)
             if cancelled:

sanic/response/types.py

@@ -24,6 +24,7 @@ from sanic.helpers import (
     Default,
     _default,
     has_message_body,
+    remove_entity_headers,
 )
 from sanic.http import Http
 
@@ -105,6 +106,9 @@ class BaseHTTPResponse:
         Returns:
             Iterator[Tuple[bytes, bytes]]: A list of header tuples encoded in bytes for sending
         """  # noqa: E501
+        # TODO: Make a blacklist set of header names and then filter with that
+        if self.status in (304, 412):  # Not Modified, Precondition Failed
+            self.headers = remove_entity_headers(self.headers)
         if has_message_body(self.status):
             self.headers.setdefault("content-type", self.content_type)
         # Encode headers into bytes

sanic/signals.py

@@ -38,6 +38,9 @@ class Event(Enum):
     HTTP_LIFECYCLE_SEND = "http.lifecycle.send"
     HTTP_MIDDLEWARE_AFTER = "http.middleware.after"
     HTTP_MIDDLEWARE_BEFORE = "http.middleware.before"
+    WEBSOCKET_HANDLER_AFTER = "websocket.handler.after"
+    WEBSOCKET_HANDLER_BEFORE = "websocket.handler.before"
+    WEBSOCKET_HANDLER_EXCEPTION = "websocket.handler.exception"
 
 
 RESERVED_NAMESPACES = {
@@ -65,6 +68,11 @@ RESERVED_NAMESPACES = {
         Event.HTTP_MIDDLEWARE_AFTER.value,
         Event.HTTP_MIDDLEWARE_BEFORE.value,
     ),
+    "websocket": {
+        Event.WEBSOCKET_HANDLER_AFTER.value,
+        Event.WEBSOCKET_HANDLER_BEFORE.value,
+        Event.WEBSOCKET_HANDLER_EXCEPTION.value,
+    },
 }
 
 

tests/test_response.py

@@ -178,10 +178,6 @@ def json_app(app):
     async def unmodified_handler(request: Request):
         return json(JSON_DATA, status=304)
 
-    @app.get("/precondition")
-    async def precondition_handler(request: Request):
-        return json(JSON_DATA, status=412)
-
     @app.delete("/")
     async def delete_handler(request: Request):
         return json(None, status=204)
@@ -197,10 +193,6 @@ def test_json_response(json_app):
     assert response.text == json_dumps(JSON_DATA)
     assert response.json == JSON_DATA
 
-    request, response = json_app.test_client.get("/precondition")
-    assert response.status == 412
-    assert response.json == JSON_DATA
-
 
 def test_no_content(json_app):
     request, response = json_app.test_client.get("/no-content")

tests/test_ws_handlers.py

@@ -54,3 +54,65 @@ def test_ws_handler_async_for(
     )
     assert ws_proxy.client_sent == ["test 1", "test 2", ""]
     assert ws_proxy.client_received == ["test 1", "test 2"]
+
+
+def signalapp(app):
+    @app.signal("websocket.handler.before")
+    async def ws_before(request: Request, websocket: Websocket):
+        app.ctx.seq.append("before")
+        print("before")
+        await websocket.send("before: " + await websocket.recv())
+        print("before2")
+
+    @app.signal("websocket.handler.after")
+    async def ws_after(request: Request, websocket: Websocket):
+        app.ctx.seq.append("after")
+        await websocket.send("after: " + await websocket.recv())
+        await websocket.recv()
+
+    @app.signal("websocket.handler.exception")
+    async def ws_exception(
+        request: Request, websocket: Websocket, exception: Exception
+    ):
+        app.ctx.seq.append("exception")
+        await websocket.send(f"exception: {exception}")
+        await websocket.recv()
+
+    @app.websocket("/ws")
+    async def ws_handler(request: Request, ws: Websocket):
+        app.ctx.seq.append("ws")
+
+    @app.websocket("/wserror")
+    async def ws_error(request: Request, ws: Websocket):
+        print("wserr")
+        app.ctx.seq.append("wserror")
+        raise Exception(await ws.recv())
+        print("wserr2")
+
+
+def test_ws_signals(
+    app: Sanic,
+    simple_ws_mimic_client: MimicClientType,
+):
+    signalapp(app)
+
+    app.ctx.seq = []
+    _, ws_proxy = app.test_client.websocket(
+        "/ws", mimic=simple_ws_mimic_client
+    )
+    assert ws_proxy.client_received == ["before: test 1", "after: test 2"]
+    assert app.ctx.seq == ["before", "ws", "after"]
+
+
+def test_ws_signals_exception(
+    app: Sanic,
+    simple_ws_mimic_client: MimicClientType,
+):
+    signalapp(app)
+
+    app.ctx.seq = []
+    _, ws_proxy = app.test_client.websocket(
+        "/wserror", mimic=simple_ws_mimic_client
+    )
+    assert ws_proxy.client_received == ["before: test 1", "exception: test 2"]
+    assert app.ctx.seq == ["before", "wserror", "exception"]