Refactor how we get the default storage class

docs/configuration.rst

@@ -21,12 +21,23 @@ Settings
 
     :default: ``None``
 
+    Starting with Django 4.2, if you defined ``settings.STORAGES``: 
+    the Django storage backend alias to retrieve the storage instance defined
+    in your settings, as described in the `Django file storage documentation`_.
+    If no value is provided for ``IMAGEKIT_DEFAULT_FILE_STORAGE``, 
+    and none is specified by the spec definition, the ``default`` file storage 
+    will be used.
+
+    Before Django 4.2, or if ``settings.STORAGES`` is not defined: 
     The qualified class name of a Django storage backend to use to save the
     cached images. If no value is provided for ``IMAGEKIT_DEFAULT_FILE_STORAGE``,
     and none is specified by the spec definition, `your default file storage`__
     will be used.
 
 
+.. _`Django file storage documentation`: https://docs.djangoproject.com/en/dev/ref/files/storage/
+
+
 .. attribute:: IMAGEKIT_DEFAULT_CACHEFILE_BACKEND
 
     :default: ``'imagekit.cachefiles.backends.Simple'``
@@ -52,7 +63,7 @@ Settings
     The cache is then used to store information like the state of cached
     images (i.e. validated or not).
 
-.. _`Django cache section`: https://docs.djangoproject.com/en/1.8/topics/cache/#accessing-the-cache
+.. _`Django cache section`: https://docs.djangoproject.com/en/dev/topics/cache/#accessing-the-cache
 
 
 .. attribute:: IMAGEKIT_CACHE_TIMEOUT

imagekit/cachefiles/__init__.py

@@ -10,7 +10,9 @@
 from ..files import BaseIKFile
 from ..registry import generator_registry
 from ..signals import content_required, existence_required
-from ..utils import generate, get_by_qname, get_logger, get_singleton
+from ..utils import (
+    generate, get_by_qname, get_logger, get_singleton, get_storage
+)
 
 
 class ImageCacheFile(BaseIKFile, ImageFile):
@@ -44,8 +46,7 @@ def __init__(self, generator, name=None, storage=None, cachefile_backend=None, c
         self.name = name
 
         storage = (callable(storage) and storage()) or storage or \
-            getattr(generator, 'cachefile_storage', None) or get_singleton(
-            settings.IMAGEKIT_DEFAULT_FILE_STORAGE, 'file storage backend')
+            getattr(generator, 'cachefile_storage', None) or get_storage()
         self.cachefile_backend = (
             cachefile_backend
             or getattr(generator, 'cachefile_backend', None)
@@ -156,20 +157,14 @@ def __getstate__(self):
 
         # remove storage from state as some non-FileSystemStorage can't be
         # pickled
-        settings_storage = get_singleton(
-            settings.IMAGEKIT_DEFAULT_FILE_STORAGE,
-            'file storage backend'
-        )
+        settings_storage = get_storage()
         if state['storage'] == settings_storage:
             state.pop('storage')
         return state
 
     def __setstate__(self, state):
         if 'storage' not in state:
-            state['storage'] = get_singleton(
-                settings.IMAGEKIT_DEFAULT_FILE_STORAGE,
-                'file storage backend'
-            )
+            state['storage'] = get_storage()
         self.__dict__.update(state)
 
     def __repr__(self):

imagekit/conf.py

@@ -37,7 +37,9 @@ def configure_cache_timeout(self, value):
     def configure_default_file_storage(self, value):
         if value is None:
             try:
-                value = settings.STORAGES["default"]["BACKEND"]
-            except AttributeError:
-                value = settings.DEFAULT_FILE_STORAGE
+                from django.conf import DEFAULT_STORAGE_ALIAS
+            except ImportError:  # Django < 4.2
+                return settings.DEFAULT_FILE_STORAGE
+            else:
+                return DEFAULT_STORAGE_ALIAS
         return value

imagekit/utils.py

@@ -125,6 +125,22 @@ def get_cache():
     return caches[settings.IMAGEKIT_CACHE_BACKEND]
 
 
+def get_storage():
+    try:
+        from django.core.files.storage import storages, InvalidStorageError
+    except ImportError:  # Django < 4.2
+        return get_singleton(
+            settings.IMAGEKIT_DEFAULT_FILE_STORAGE, 'file storage backend'
+        )
+    else:
+        try:
+            return storages[settings.IMAGEKIT_DEFAULT_FILE_STORAGE]
+        except InvalidStorageError:
+            return get_singleton(
+                settings.IMAGEKIT_DEFAULT_FILE_STORAGE, 'file storage backend'
+            )
+
+
 def sanitize_cache_key(key):
     if settings.IMAGEKIT_USE_MEMCACHED_SAFE_CACHE_KEY:
         # Memcached keys can't contain whitespace or control characters.

tests/test_settings.py

@@ -2,6 +2,7 @@
 from django.test import override_settings
 import pytest
 from imagekit.conf import ImageKitConf, settings
+from imagekit.utils import get_storage
 
 
 @pytest.mark.skipif(
@@ -17,7 +18,7 @@ def test_custom_storages():
         },
     ):
         conf = ImageKitConf()
-        assert conf.configure_default_file_storage(None) == "tests.utils.CustomStorage"
+        assert conf.configure_default_file_storage(None) == "default"
 
 
 @pytest.mark.skipif(
@@ -29,4 +30,45 @@ def test_custom_default_file_storage():
         # If we don’t remove this, Django 4.2 will keep the old value.
         del settings.STORAGES
         conf = ImageKitConf()
-        assert conf.configure_default_file_storage(None) == "tests.utils.CustomStorage"
+
+        if django.VERSION >= (4, 2):
+            assert conf.configure_default_file_storage(None) == "default"
+        else:
+            assert (
+                conf.configure_default_file_storage(None) == "tests.utils.CustomStorage"
+            )
+
+
+def test_get_storage_default():
+    from django.core.files.storage import FileSystemStorage
+
+    assert isinstance(get_storage(), FileSystemStorage)
+
+
+@pytest.mark.skipif(
+    django.VERSION >= (5, 1),
+    reason="DEFAULT_FILE_STORAGE is removed in Django 5.1.",
+)
+def test_get_storage_custom_path():
+    from tests.utils import CustomStorage
+
+    with override_settings(IMAGEKIT_DEFAULT_FILE_STORAGE="tests.utils.CustomStorage"):
+        assert isinstance(get_storage(), CustomStorage)
+
+
+@pytest.mark.skipif(
+    django.VERSION < (4, 2),
+    reason="STORAGES was introduced in Django 4.2",
+)
+def test_get_storage_custom_key():
+    from tests.utils import CustomStorage
+
+    with override_settings(
+        STORAGES={
+            "custom": {
+                "BACKEND": "tests.utils.CustomStorage",
+            }
+        },
+        IMAGEKIT_DEFAULT_FILE_STORAGE="custom",
+    ):
+        assert isinstance(get_storage(), CustomStorage)

tests/test_utils.py

@@ -0,0 +1,42 @@
+import django
+from django.test import override_settings
+import pytest
+from imagekit.utils import get_storage
+
+
+def test_get_storage_default():
+    from django.core.files.storage import default_storage
+
+    if django.VERSION >= (4, 2):
+        assert get_storage() == default_storage
+    else:
+        assert isinstance(get_storage(), type(default_storage._wrapped))
+
+
+@pytest.mark.skipif(
+    django.VERSION >= (5, 1),
+    reason="DEFAULT_FILE_STORAGE is removed in Django 5.1.",
+)
+def test_get_storage_custom_import_path():
+    from tests.utils import CustomStorage
+
+    with override_settings(IMAGEKIT_DEFAULT_FILE_STORAGE="tests.utils.CustomStorage"):
+        assert isinstance(get_storage(), CustomStorage)
+
+
+@pytest.mark.skipif(
+    django.VERSION < (4, 2),
+    reason="STORAGES was introduced in Django 4.2",
+)
+def test_get_storage_custom_key():
+    from tests.utils import CustomStorage
+
+    with override_settings(
+        STORAGES={
+            "custom": {
+                "BACKEND": "tests.utils.CustomStorage",
+            }
+        },
+        IMAGEKIT_DEFAULT_FILE_STORAGE="custom",
+    ):
+        assert isinstance(get_storage(), CustomStorage)