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/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,
+    },
 }