id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
31920	ASGI/ASYNC SessionMiddleware - SynchronousOnlyOperation exception if request.user is not unwrapped in sync code	Michael Galler	Jon Janzen	"
{{{
class AuthenticationMiddleware(MiddlewareMixin):
    def process_request(self, request):
        request.user = SimpleLazyObject(lambda: get_user(request))

}}}

AuthenticationMiddleware wraps the request.user in a SimpleLazyObject, so the Database Query is called lazy

If i start now a project via django-admin and I add a user and log in and request the following view:


{{{
from asgiref.sync import sync_to_async
from django.core.exceptions import SynchronousOnlyOperation
from django.http import HttpResponse


@sync_to_async
def get_user_from_request(request):
    return request.user if bool(request.user) else None


async def async_test(request):
    # CASE 1
    try:
        print(request.user.is_authenticated)
    except SynchronousOnlyOperation:
        print('error 1')

    # CASE 2
    try:
        user = await sync_to_async(request.user)
        print(user)
    except SynchronousOnlyOperation:
        print('error 2')

    # CASE 3
    try:
        user = await sync_to_async(request.user)()
        print(user)
    except SynchronousOnlyOperation:
        print('error 3')

    # CASE 4
    try:
        user = await sync_to_async(bool)(request.user)
        print(request.user)
    except SynchronousOnlyOperation:
        print('error 4')

    # CASE 5
    try:
        user = await get_user_from_request(request)
        print(user)
    except SynchronousOnlyOperation:
        print('error 5')

    return HttpResponse('Hello, async world!')

}}}

Only case 4 and 5 works, i find it a little awkward that i have to do one of this cases."	New feature	closed	contrib.sessions	3.1	Normal	fixed	async	Andrew Godwin Carlton Gibson Jon Janzen Adam Johnson	Ready for checkin	1	0	0	0	0	0