Implement ASGI lifespan events to match Sanic listeners

examples/run_asgi.py

@@ -56,3 +56,33 @@ async def handler_stream(request):
         body = body.decode("utf-8").replace("1", "A")
         # await response.write(body)
     return stream(streaming)
+
+
+@app.listener("before_server_start")
+async def listener_before_server_start(*args, **kwargs):
+    print("before_server_start")
+
+
+@app.listener("after_server_start")
+async def listener_after_server_start(*args, **kwargs):
+    print("after_server_start")
+
+
+@app.listener("before_server_stop")
+async def listener_before_server_stop(*args, **kwargs):
+    print("before_server_stop")
+
+
+@app.listener("after_server_stop")
+async def listener_after_server_stop(*args, **kwargs):
+    print("after_server_stop")
+
+
+@app.middleware("request")
+async def print_on_request(request):
+    print("print_on_request")
+
+
+@app.middleware("response")
+async def print_on_response(request, response):
+    print("print_on_response")

sanic/asgi.py

@@ -1,11 +1,18 @@
-from typing import Any, Awaitable, Callable, MutableMapping, Union
 import asyncio
-from multidict import CIMultiDict
+import warnings
+
 from functools import partial
+from inspect import isawaitable
+from typing import Any, Awaitable, Callable, MutableMapping, Union
+
+from multidict import CIMultiDict
+
+from sanic.exceptions import InvalidUsage
 from sanic.request import Request
 from sanic.response import HTTPResponse, StreamingHTTPResponse
-from sanic.websocket import WebSocketConnection
 from sanic.server import StreamBuffer
+from sanic.websocket import WebSocketConnection
+
 
 ASGIScope = MutableMapping[str, Any]
 ASGIMessage = MutableMapping[str, Any]
@@ -20,30 +27,29 @@ class MockProtocol:
         self._not_paused.set()
         self._complete = asyncio.Event(loop=loop)
 
-    def pause_writing(self):
+    def pause_writing(self) -> None:
         self._not_paused.clear()
 
-    def resume_writing(self):
+    def resume_writing(self) -> None:
         self._not_paused.set()
 
-    async def complete(self):
+    async def complete(self) -> None:
         self._not_paused.set()
         await self.transport.send(
             {"type": "http.response.body", "body": b"", "more_body": False}
         )
 
     @property
-    def is_complete(self):
+    def is_complete(self) -> bool:
         return self._complete.is_set()
 
-    async def push_data(self, data):
+    async def push_data(self, data: bytes) -> None:
         if not self.is_complete:
             await self.transport.send(
                 {"type": "http.response.body", "body": data, "more_body": True}
             )
 
-    async def drain(self):
-        print("draining")
+    async def drain(self) -> None:
         await self._not_paused.wait()
 
 
@@ -57,7 +63,7 @@ class MockTransport:
         self._protocol = None
         self.loop = None
 
-    def get_protocol(self):
+    def get_protocol(self) -> MockProtocol:
         if not self._protocol:
             self._protocol = MockProtocol(self, self.loop)
         return self._protocol
@@ -69,7 +75,10 @@ class MockTransport:
             return self.scope.get("scheme") in ["https", "wss"]
 
     def get_websocket_connection(self) -> WebSocketConnection:
+        try:
             return self._websocket_connection
+        except AttributeError:
+            raise InvalidUsage("Improper websocket connection.")
 
     def create_websocket_connection(
         self, send: ASGISend, receive: ASGIReceive
@@ -77,19 +86,61 @@ class MockTransport:
         self._websocket_connection = WebSocketConnection(send, receive)
         return self._websocket_connection
 
-    def add_task(self):
+    def add_task(self) -> None:
         raise NotImplementedError
 
-    async def send(self, data):
-        print(">> sending. more:", data.get("more_body"))
+    async def send(self, data) -> None:
         # TODO:
         # - Validation on data and that it is formatted properly and is valid
         await self._send(data)
 
-    async def receive(self):
+    async def receive(self) -> ASGIMessage:
         return await self._receive()
 
 
+class Lifespan:
+    def __init__(self, asgi_app: "ASGIApp") -> None:
+        self.asgi_app = asgi_app
+
+    async def startup(self) -> None:
+        if self.asgi_app.sanic_app.listeners["before_server_start"]:
+            warnings.warn(
+                'You have set a listener for "before_server_start". In ASGI mode it will be ignored. Perhaps you want to run it "after_server_start" instead?'
+            )
+        if self.asgi_app.sanic_app.listeners["after_server_stop"]:
+            warnings.warn(
+                'You have set a listener for "after_server_stop". In ASGI mode it will be ignored. Perhaps you want to run it "before_server_stop" instead?'
+            )
+
+        for handler in self.asgi_app.sanic_app.listeners["after_server_start"]:
+            response = handler(
+                self.asgi_app.sanic_app, self.asgi_app.sanic_app.loop
+            )
+            if isawaitable(response):
+                await response
+
+    async def shutdown(self) -> None:
+        for handler in self.asgi_app.sanic_app.listeners["before_server_stop"]:
+            response = handler(
+                self.asgi_app.sanic_app, self.asgi_app.sanic_app.loop
+            )
+            if isawaitable(response):
+                await response
+
+    async def __call__(
+        self, scope: ASGIScope, receive: ASGIReceive, send: ASGISend
+    ) -> None:
+        message = await receive()
+        if message["type"] == "lifespan.startup":
+            await self.startup()
+            await send({"type": "lifespan.startup.complete"})
+
+        message = await receive()
+        if message["type"] == "lifespan.shutdown":
+            await self.shutdown()
+            await send({"type": "lifespan.shutdown.complete"})
+
+
 class ASGIApp:
     def __init__(self) -> None:
         self.ws = None
@@ -104,20 +155,24 @@ class ASGIApp:
         instance.transport.add_task = sanic_app.loop.create_task
         instance.transport.loop = sanic_app.loop
 
-        url_bytes = scope.get("root_path", "") + scope["path"]
-        url_bytes = url_bytes.encode("latin-1")
-        url_bytes += scope["query_string"]
         headers = CIMultiDict(
             [
                 (key.decode("latin-1"), value.decode("latin-1"))
                 for key, value in scope.get("headers", [])
             ]
         )
-
         instance.do_stream = (
             True if headers.get("expect") == "100-continue" else False
         )
 
+        if scope["type"] == "lifespan":
+            lifespan = Lifespan(instance)
+            await lifespan(scope, receive, send)
+        else:
+            url_bytes = scope.get("root_path", "") + scope["path"]
+            url_bytes = url_bytes.encode("latin-1")
+            url_bytes += scope["query_string"]
+
             if scope["type"] == "http":
                 version = scope["http_version"]
                 method = scope["method"]
@@ -135,7 +190,12 @@ class ASGIApp:
                 # - close connection
 
             instance.request = Request(
-            url_bytes, headers, version, method, instance.transport, sanic_app
+                url_bytes,
+                headers,
+                version,
+                method,
+                instance.transport,
+                sanic_app,
             )
 
             if sanic_app.is_request_stream:

sanic/testing.py

@@ -1,6 +1,6 @@
-import typing
-import types
 import asyncio
+import types
+import typing
 
 from json import JSONDecodeError
 from socket import socket