Fixed #33738 -- Allowed handling ASGI http.disconnect in long-lived requests.

2 files changed, 27 insertions, 0 deletions

diff --git a/docs/releases/5.0.txt b/docs/releases/5.0.txt
index 6e911f471e..cc4fb69ee3 100644
--- a/docs/releases/5.0.txt
+++ b/docs/releases/5.0.txt
@@ -192,6 +192,13 @@ Minor features
 
 * ...
 
+Asynchronous views
+~~~~~~~~~~~~~~~~~~
+
+* Under ASGI, ``http.disconnect`` events are now handled. This allows views to
+  perform any necessary cleanup if a client disconnects before the response is
+  generated. See :ref:`async-handling-disconnect` for more details.
+
 Cache
 ~~~~~
 
diff --git a/docs/topics/async.txt b/docs/topics/async.txt
index 95d3435e07..5a2324af5e 100644
--- a/docs/topics/async.txt
+++ b/docs/topics/async.txt
@@ -136,6 +136,26 @@ a purely synchronous codebase under ASGI because the request-handling code is
 still all running asynchronously. In general you will only want to enable ASGI
 mode if you have asynchronous code in your project.
 
+.. _async-handling-disconnect:
+
+Handling disconnects
+--------------------
+
+.. versionadded:: 5.0
+
+For long-lived requests, a client may disconnect before the view returns a
+response. In this case, an ``asyncio.CancelledError`` will be raised in the
+view. You can catch this error and handle it if you need to perform any
+cleanup::
+
+    async def my_view(request):
+        try:
+            # Do some work
+            ...
+        except asyncio.CancelledError:
+            # Handle disconnect
+            raise
+
 .. _async-safety:
 
 Async safety