Fix ASGI compatibility on Python 3.12

CHANGELOG.rst

@@ -2,6 +2,8 @@
 Changelog
 =========
 
+* Fix ASGI compatibility on Python 3.12.
+
 1.7.0 (2023-10-11)
 ------------------
 

pyproject.toml

@@ -36,6 +36,7 @@ classifiers = [
   "Typing :: Typed",
 ]
 dependencies = [
+  "asgiref>=3.6",
   "Django>=3.2",
   "minify-html",
 ]

src/django_minify_html/middleware.py

@@ -1,10 +1,11 @@
 from __future__ import annotations
 
-import asyncio
 from typing import Awaitable
 from typing import Callable
 
 import minify_html
+from asgiref.sync import iscoroutinefunction
+from asgiref.sync import markcoroutinefunction
 from django.http import HttpRequest
 from django.http import HttpResponse
 from django.http.response import HttpResponseBase
@@ -22,19 +23,17 @@ def __init__(
         ),
     ) -> None:
         self.get_response = get_response
-        if asyncio.iscoroutinefunction(self.get_response):
+        self.async_mode = iscoroutinefunction(self.get_response)
+
+        if self.async_mode:
             # Mark the class as async-capable, but do the actual switch
             # inside __call__ to avoid swapping out dunder methods
-            self._is_coroutine = (
-                asyncio.coroutines._is_coroutine  # type: ignore [attr-defined]
-            )
-        else:
-            self._is_coroutine = None
+            markcoroutinefunction(self)
 
     def __call__(
         self, request: HttpRequest
     ) -> HttpResponseBase | Awaitable[HttpResponseBase]:
-        if self._is_coroutine:
+        if self.async_mode:
             return self.__acall__(request)
         response = self.get_response(request)
         assert isinstance(response, HttpResponseBase)