Note that the dev server is running in WSGI mode

[Matthew Pava]

With the mass adoption of async Django on the way, we need to provide a clearer warning in the development server that it is running in WSGI mode and not ASGI mode. I spent an hour troubleshooting a warning because I created a middleware that was async only. Only when I made it compatible for both async and sync modes did the warning go away.

Or we could just make the Django dev server default to ASGI mode.

Actual result:
The Django server displays this warning:
WARNING: This is a development server. Do not use it in a production setting. Use a production WSGI or ASGI server instead.
For more information on production servers see: ​https://docs.djangoproject.com/en/6.0/howto/deployment/

Desired result:
Revise it to something like:
WARNING: This is a development server that is running only in sync mode (WSGI). Only middleware that is compatible with sync mode (WSGI) will run properly. Do not use it in a production setting. Use a production WSGI or ASGI server instead.

[Jacob Walls]

In general, this seems fine to tweak. I checked Daphne's runserver output, and it looks like:

Starting ASGI/Daphne version 4.2.1 development server at http://127.0.0.1:8000/

So I'd be happy to change Django's to:

django/core/management/commands/runserver.py

@@ -184 +184 @@
         print(
             f"{now}\n"
             f"Django version {version}, using settings {settings.SETTINGS_MODULE!r}\n"
-            f"Starting development server at {self.protocol}://{addr}:{server_port}/\n"
+            f"Starting WSGI development server at {self.protocol}://{addr}:{server_port}/\n"
             f"Quit the server with {quit_command}.",
             file=self.stdout,
         )

However, mixing this information up with the security warning doesn't seem appropriate to me, nor taking a detour into middleware.

[Matthew Pava]

That's fine. Can we also update the middleware documentation with some note that the development server only supports sync middleware?
​https://docs.djangoproject.com/en/6.0/topics/http/middleware/

[Jacob Walls]

Either there or on the async support page seems reasonable.

[Muhammed irshad ismail]

Hi, I’d like to work on this by adding a documentation note about the
development server running in WSGI (sync) mode, as suggested above.

[jaffar Khan]

I created a PR on this Issue: ​https://github.com/django/django/pull/20588

[Jacob Walls]

On second look I'm less convinced of the need to add anything in the middlewares section. If you're expecting async requests, you're using an async development server (perhaps the one from Daphne).

[Jacob Walls <jacobtylerwalls@…>]

In 2e83eb5e:

Fixed #36776 -- Clarified dev server runs in WSGI mode.