[3.1.x] Fixed #31594 -- Added ASGIStaticFilesHandler.get_response_async().

Backport of 92309e53d9 from master

django/contrib/staticfiles/handlers.py

@@ -1,6 +1,8 @@
 from urllib.parse import urlparse
 from urllib.request import url2pathname
 
+from asgiref.sync import sync_to_async
+
 from django.conf import settings
 from django.contrib.staticfiles import utils
 from django.contrib.staticfiles.views import serve
@@ -52,6 +54,12 @@ class StaticFilesHandlerMixin:
         except Http404 as e:
             return response_for_exception(request, e)
 
+    async def get_response_async(self, request):
+        try:
+            return await sync_to_async(self.serve)(request)
+        except Http404 as e:
+            return await sync_to_async(response_for_exception)(request, e)
+
 
 class StaticFilesHandler(StaticFilesHandlerMixin, WSGIHandler):
     """

tests/asgi/project/static/file.txt

@@ -0,0 +1 @@
+test

tests/asgi/tests.py

@@ -1,18 +1,25 @@
 import asyncio
 import sys
 import threading
+from pathlib import Path
 from unittest import skipIf
 
 from asgiref.sync import SyncToAsync
 from asgiref.testing import ApplicationCommunicator
 
+from django.contrib.staticfiles.handlers import ASGIStaticFilesHandler
 from django.core.asgi import get_asgi_application
 from django.core.signals import request_finished, request_started
 from django.db import close_old_connections
-from django.test import AsyncRequestFactory, SimpleTestCase, override_settings
+from django.test import (
+    AsyncRequestFactory, SimpleTestCase, modify_settings, override_settings,
+)
+from django.utils.http import http_date
 
 from .urls import test_filename
 
+TEST_STATIC_ROOT = Path(__file__).parent / 'project' / 'static'
+
 
 @skipIf(sys.platform == 'win32' and (3, 8, 0) < sys.version_info < (3, 8, 1), 'https://bugs.python.org/issue38563')
 @override_settings(ROOT_URLCONF='asgi.urls')
@@ -79,6 +86,45 @@ class ASGITest(SimpleTestCase):
         # Allow response.close() to finish.
         await communicator.wait()
 
+    @modify_settings(INSTALLED_APPS={'append': 'django.contrib.staticfiles'})
+    @override_settings(
+        STATIC_URL='/static/',
+        STATIC_ROOT=TEST_STATIC_ROOT,
+        STATICFILES_DIRS=[TEST_STATIC_ROOT],
+        STATICFILES_FINDERS=[
+            'django.contrib.staticfiles.finders.FileSystemFinder',
+        ],
+    )
+    async def test_static_file_response(self):
+        application = ASGIStaticFilesHandler(get_asgi_application())
+        # Construct HTTP request.
+        scope = self.async_request_factory._base_scope(path='/static/file.txt')
+        communicator = ApplicationCommunicator(application, scope)
+        await communicator.send_input({'type': 'http.request'})
+        # Get the file content.
+        file_path = TEST_STATIC_ROOT / 'file.txt'
+        with open(file_path, 'rb') as test_file:
+            test_file_contents = test_file.read()
+        # Read the response.
+        stat = file_path.stat()
+        response_start = await communicator.receive_output()
+        self.assertEqual(response_start['type'], 'http.response.start')
+        self.assertEqual(response_start['status'], 200)
+        self.assertEqual(
+            set(response_start['headers']),
+            {
+                (b'Content-Length', str(len(test_file_contents)).encode('ascii')),
+                (b'Content-Type', b'text/plain'),
+                (b'Content-Disposition', b'inline; filename="file.txt"'),
+                (b'Last-Modified', http_date(stat.st_mtime).encode('ascii')),
+            },
+        )
+        response_body = await communicator.receive_output()
+        self.assertEqual(response_body['type'], 'http.response.body')
+        self.assertEqual(response_body['body'], test_file_contents)
+        # Allow response.close() to finish.
+        await communicator.wait()
+
     async def test_headers(self):
         application = get_asgi_application()
         communicator = ApplicationCommunicator(

tests/staticfiles_tests/test_handlers.py

@@ -0,0 +1,22 @@
+from django.contrib.staticfiles.handlers import ASGIStaticFilesHandler
+from django.core.handlers.asgi import ASGIHandler
+from django.test import AsyncRequestFactory
+
+from .cases import StaticFilesTestCase
+
+
+class TestASGIStaticFilesHandler(StaticFilesTestCase):
+    async_request_factory = AsyncRequestFactory()
+
+    async def test_get_async_response(self):
+        request = self.async_request_factory.get('/static/test/file.txt')
+        handler = ASGIStaticFilesHandler(ASGIHandler())
+        response = await handler.get_response_async(request)
+        response.close()
+        self.assertEqual(response.status_code, 200)
+
+    async def test_get_async_response_not_found(self):
+        request = self.async_request_factory.get('/static/test/not-found.txt')
+        handler = ASGIStaticFilesHandler(ASGIHandler())
+        response = await handler.get_response_async(request)
+        self.assertEqual(response.status_code, 404)