Add signals before and after handler execution (#2540)

sanic/app.py

@@ -894,9 +894,19 @@ class Sanic(BaseSanic, RunnerMixin, metaclass=TouchUpMeta):
                     )
 
                 # Run response handler
+                await self.dispatch(
+                    "http.handler.before",
+                    inline=True,
+                    context={"request": request},
+                )
                 response = handler(request, **request.match_info)
                 if isawaitable(response):
                     response = await response
+                await self.dispatch(
+                    "http.handler.after",
+                    inline=True,
+                    context={"request": request},
+                )
 
             if request.responded:
                 if response is not None:

sanic/signals.py

@@ -30,6 +30,8 @@ class Event(Enum):
     HTTP_LIFECYCLE_RESPONSE = "http.lifecycle.response"
     HTTP_ROUTING_AFTER = "http.routing.after"
     HTTP_ROUTING_BEFORE = "http.routing.before"
+    HTTP_HANDLER_AFTER = "http.handler.after"
+    HTTP_HANDLER_BEFORE = "http.handler.before"
     HTTP_LIFECYCLE_SEND = "http.lifecycle.send"
     HTTP_MIDDLEWARE_AFTER = "http.middleware.after"
     HTTP_MIDDLEWARE_BEFORE = "http.middleware.before"
@@ -53,6 +55,8 @@ RESERVED_NAMESPACES = {
         Event.HTTP_LIFECYCLE_RESPONSE.value,
         Event.HTTP_ROUTING_AFTER.value,
         Event.HTTP_ROUTING_BEFORE.value,
+        Event.HTTP_HANDLER_AFTER.value,
+        Event.HTTP_HANDLER_BEFORE.value,
         Event.HTTP_LIFECYCLE_SEND.value,
         Event.HTTP_MIDDLEWARE_AFTER.value,
         Event.HTTP_MIDDLEWARE_BEFORE.value,

tests/test_asgi.py

@@ -531,6 +531,8 @@ async def test_signals_triggered(app):
         "http.lifecycle.handle",
         "http.routing.before",
         "http.routing.after",
+        "http.handler.before",
+        "http.handler.after",
         "http.lifecycle.response",
         # "http.lifecycle.send",
         # "http.lifecycle.complete",

tests/test_handler.py

@@ -0,0 +1,36 @@
+from sanic.app import Sanic
+from sanic.response import empty
+from sanic.signals import Event
+
+
+def test_handler_operation_order(app: Sanic):
+    operations = []
+
+    @app.on_request
+    async def on_request(_):
+        nonlocal operations
+        operations.append(1)
+
+    @app.on_response
+    async def on_response(*_):
+        nonlocal operations
+        operations.append(5)
+
+    @app.get("/")
+    async def handler(_):
+        nonlocal operations
+        operations.append(3)
+        return empty()
+
+    @app.signal(Event.HTTP_HANDLER_BEFORE)
+    async def handler_before(**_):
+        nonlocal operations
+        operations.append(2)
+
+    @app.signal(Event.HTTP_HANDLER_AFTER)
+    async def handler_after(**_):
+        nonlocal operations
+        operations.append(4)
+
+    app.test_client.get("/")
+    assert operations == [1, 2, 3, 4, 5]