Fixed #30451 -- Added ASGI handler and coroutine-safety.

This adds an ASGI handler, asgi.py file for the default project layout,
a few async utilities and adds async-safety to many parts of Django.

1 files changed, 33 insertions, 8 deletions

diff --git a/django/contrib/staticfiles/handlers.py b/django/contrib/staticfiles/handlers.py
index b0aa66036d..711d8864ad 100644
--- a/django/contrib/staticfiles/handlers.py
+++ b/django/contrib/staticfiles/handlers.py
@@ -4,25 +4,20 @@ from urllib.request import url2pathname
 from django.conf import settings
 from django.contrib.staticfiles import utils
 from django.contrib.staticfiles.views import serve
+from django.core.handlers.asgi import ASGIHandler
 from django.core.handlers.exception import response_for_exception
 from django.core.handlers.wsgi import WSGIHandler, get_path_info
 from django.http import Http404
 
 
-class StaticFilesHandler(WSGIHandler):
+class StaticFilesHandlerMixin:
     """
-    WSGI middleware that intercepts calls to the static files directory, as
-    defined by the STATIC_URL setting, and serves those files.
+    Common methods used by WSGI and ASGI handlers.
     """
     # May be used to differentiate between handler types (e.g. in a
     # request_finished signal)
     handles_files = True
 
-    def __init__(self, application):
-        self.application = application
-        self.base_url = urlparse(self.get_base_url())
-        super().__init__()
-
     def load_middleware(self):
         # Middleware are already loaded for self.application; no need to reload
         # them for self.
@@ -57,7 +52,37 @@ class StaticFilesHandler(WSGIHandler):
         except Http404 as e:
             return response_for_exception(request, e)
 
+
+class StaticFilesHandler(StaticFilesHandlerMixin, WSGIHandler):
+    """
+    WSGI middleware that intercepts calls to the static files directory, as
+    defined by the STATIC_URL setting, and serves those files.
+    """
+    def __init__(self, application):
+        self.application = application
+        self.base_url = urlparse(self.get_base_url())
+        super().__init__()
+
     def __call__(self, environ, start_response):
         if not self._should_handle(get_path_info(environ)):
             return self.application(environ, start_response)
         return super().__call__(environ, start_response)
+
+
+class ASGIStaticFilesHandler(StaticFilesHandlerMixin, ASGIHandler):
+    """
+    ASGI application which wraps another and intercepts requests for static
+    files, passing them off to Django's static file serving.
+    """
+    def __init__(self, application):
+        self.application = application
+        self.base_url = urlparse(self.get_base_url())
+
+    async def __call__(self, scope, receive, send):
+        # Only even look at HTTP requests
+        if scope['type'] == 'http' and self._should_handle(scope['path']):
+            # Serve static content
+            # (the one thing super() doesn't do is __call__, apparently)
+            return await super().__call__(scope, receive, send)
+        # Hand off to the main app
+        return await self.application(scope, receive, send)