Ticket #7398: ease-custom-cache-backends-with-documentation.diff

django/core/cache/__init__.py

@@ -20 +20 @@
 from django.core.cache.backends.base import InvalidCacheBackendError
 
 BACKENDS = {
-    # name for use in settings file --> name of module in "backends" directory
-    'memcached': 'memcached',
-    'locmem': 'locmem',
-    'file': 'filebased',
-    'db': 'db',
-    'dummy': 'dummy',
+    # name for use in settings file --> path to the backend module
+    'memcached': 'django.core.cache.backends.memcached',
+    'locmem': 'django.core.cache.backends.locmem',
+    'file': 'django.core.cache.backends.filebased',
+    'db': 'django.core.cache.backends.db',
+    'dummy': 'django.core.cache.backends.dummy',
 }
 
+if hasattr(settings, "CACHE_BACKEND_MODULES"):
+    BACKENDS.update(settings.CACHE_BACKEND_MODULES)
+
 DEPRECATED_BACKENDS = {
     # deprecated backend --> replacement module
     'simple': 'locmem',
@@ -57 +60 @@
     if host.endswith('/'):
         host = host[:-1]
 
-    cache_class = getattr(__import__('django.core.cache.backends.%s' % BACKENDS[scheme], {}, {}, ['']), 'CacheClass')
+    cache_class = getattr(__import__(BACKENDS[scheme], {}, {}, ['']), 'CacheClass')
     return cache_class(host, params)
 
 cache = get_cache(settings.CACHE_BACKEND)

docs/settings.txt

@@ -256 +256 @@
 
 The cache backend to use. See the `cache docs`_.
 
+CACHE_BACKEND_MODULES
+---------------------
+
+**New in Django development version**
+
+Default: Not defined.
+
+A dictionary of cache backend import paths, keyed by a string
+identifier for use in ``CACHE_BACKEND``. These are added to the
+build-in backends. For example, to define a 'penandpaper' backend,
+use::
+
+    CACHE_BACKEND_MODULES = { 'penandpaper' : 'path.to.penandpaper_backend' }
+
+Reference this module in CACHE_BACKEND as ``'penandpaper://'``. Note
+that build-in backends can be replaced by overwriting them in this
+variable.
+
 CACHE_MIDDLEWARE_KEY_PREFIX
 ---------------------------