Add support for async functions to decorator

Tries to add support for async functions to the decorator, but trips
over not having a failing test to fix.

Author: jsocol

.github/actions/test/action.yml

@@ -14,13 +14,23 @@ runs:
     with:
       python-version: ${{ inputs.python-version }}
 
-  - name: Install dependencies
+  - name: Update pip
     shell: sh
-    run: |
-      python -m pip install --upgrade pip
-      if [[ ${{ inputs.django-version }} != 'main' ]]; then pip install --pre -q "Django>=${{ inputs.django-version }},<${{ inputs.django-version }}.99"; fi
-      if [[ ${{ inputs.django-version }} == 'main' ]]; then pip install https://github.com/django/django/archive/main.tar.gz; fi
-      pip install flake8 django-redis pymemcache
+    run: python -m pip install --upgrade pip
+
+  - name: Install Django
+    shell: sh
+    run: python -m pip install "Django>=${{ inputs.django-version }},<${{ inputs.django-version }}.99"
+    if: ${{ inputs.django-version != 'main' }}
+
+  - name: Install Django main
+    shell: sh
+    run: python -m pip install https://github.com/django/django/archive/main.tar.gz
+    if: ${{ inputs.django-version == 'main' }}
+
+  - name: Install Django dependencies
+    shell: sh
+    run: pip install flake8 django-redis pymemcache
 
   - name: Test
     shell: sh

django_ratelimit/decorators.py

@@ -1,4 +1,10 @@
 from functools import wraps
+import django
+if django.VERSION >= (4, 1):
+    from asgiref.sync import iscoroutinefunction
+else:
+    def iscoroutinefunction(func):
+        return False
 
 from django.conf import settings
 from django.utils.module_loading import import_string
@@ -13,6 +19,23 @@
 
 def ratelimit(group=None, key=None, rate=None, method=ALL, block=True):
     def decorator(fn):
+        # if iscoroutinefunction(fn):
+        #     @wraps(fn)
+        #     async def _async_wrapped(request, *args, **kw):
+        #         old_limited = getattr(request, 'limited', False)
+        #         ratelimited = is_ratelimited(
+        #             request=request, group=group, fn=fn, key=key, rate=rate,
+        #             method=method, increment=True)
+        #         request.limited = ratelimited or old_limited
+        #         if ratelimited and block:
+        #             cls = getattr(
+        #                 settings, 'RATELIMIT_EXCEPTION_CLASS', Ratelimited)
+        #             if isinstance(cls, str):
+        #                 cls = import_string(cls)
+        #             raise cls()
+        #         return await fn(request, *args, **kw)
+        #     return _async_wrapped
+
         @wraps(fn)
         def _wrapped(request, *args, **kw):
             old_limited = getattr(request, 'limited', False)
@@ -23,7 +46,9 @@ def _wrapped(request, *args, **kw):
             if ratelimited and block:
                 cls = getattr(
                     settings, 'RATELIMIT_EXCEPTION_CLASS', Ratelimited)
-                raise (import_string(cls) if isinstance(cls, str) else cls)()
+                if isinstance(cls, str):
+                    cls = import_string(cls)
+                raise cls()
             return fn(request, *args, **kw)
         return _wrapped
     return decorator

django_ratelimit/tests.py

@@ -1,4 +1,8 @@
+import asyncio
+
+import django
 from functools import partial
+from unittest import skipIf
 
 from django.core.cache import cache, InvalidCacheBackendError
 from django.core.exceptions import ImproperlyConfigured
@@ -12,7 +16,10 @@
 from django_ratelimit.core import (get_usage, is_ratelimited,
                                    _split_rate, _get_ip)
 
-
+if django.VERSION >= (4, 1):
+    from asgiref.sync import iscoroutinefunction
+    from django.test import AsyncRequestFactory
+    arf = AsyncRequestFactory()
 rf = RequestFactory()
 
 
@@ -411,6 +418,26 @@ def view(request):
             req.META['REMOTE_ADDR'] = '2001:db9::1000'
             assert not view(req)
 
+    @skipIf(
+        django.VERSION < (4, 1),
+        reason="Async view support requires Django 4.1 or higher",
+    )
+    async def test_decorate_async_function(self):
+        @ratelimit(key='ip', rate='1/m', block=False)
+        async def view(request):
+            await asyncio.sleep(0)
+            return request.limited
+
+        req1 = arf.get('/')
+        req1.META['REMOTE_ADDR'] = '1.2.3.4'
+
+        req2 = arf.get('/')
+        req2.META['REMOTE_ADDR'] = '1.2.3.4'
+
+        assert iscoroutinefunction(view)
+        assert await view(req1) is False
+        assert await view(req2) is True
+
 
 class FunctionsTests(TestCase):
     def setUp(self):