django-cache-machine · blag · Jan 4, 2016 · Jan 4, 2016
diff --git a/README.rst b/README.rst
@@ -31,6 +31,58 @@ or `github <http://github.com/django-cache-machine/django-cache-machine>`_::
 
     pip install -e git://github.com/django-cache-machine/django-cache-machine.git#egg=django-cache-machine
 
+then add ``caching`` to your ``INSTALLED_APPS``.
+
+
+Configuration
+-------------
+
+To use Cache Machine with your own models, subclass from
+``caching.base.CachingMixin`` and use or subclass
+``caching.base.CachingManager`` for your manager instance.
+
+To use Cache Machine with arbitrary models specify the import string with the
+``CACHE_MACHINE_MODELS`` setting. This can also be used to register models
+automatically generated from``ManyToManyField``s by specifying the ``through``
+attribute on the ManyToManyField directly.
+
+Example:
+~~~~~~~~
+
+``yourapp/models.py``:
+
+    from django.db import models
+
+    class Thing(models.Model):
+        others = models.ManyToManyField('self')
+
+
+``anotherapp/models.py``:
+
+    from django.db import models
+
+    class OtherThing(models.Model):
+        # ...
+
+        objects = models.Manager()
+
+
+``settings.py``:
+
+    CACHE_MACHINE_MODELS = {
+        # Cache the automatically generated intermediate model for the ManyToManyField
+        'yourapp.models.Thing.others.through': {},
+
+        # Cache a model from another app
+        'anotherapp.models.OtherThing': {
+            # Options dictionary
+        }
+    }
+
+Right now the only available option is ``manager_name``, which you can use to
+cache only certain managers. This option defaults to ``objects``, so it can be
+safely omitted in almost all cases.
+
 
 Running Tests
 -------------

diff --git a/caching/__init__.py b/caching/__init__.py
@@ -2,3 +2,5 @@
 
 VERSION = ('0', '9', '1')
 __version__ = '.'.join(VERSION)
+
+default_app_config = 'caching.apps.CacheMachineConfig'
diff --git a/caching/apps.py b/caching/apps.py
@@ -0,0 +1,102 @@
+from importlib import import_module
+
+from django.apps import AppConfig, apps
+from django.db.models.manager import Manager
+
+from .base import CachingManager, CachingMixin
+from .config import settings
+
+
+class CacheMachineConfig(AppConfig):
+    name = 'caching'
+    verbose_name = 'Cache Machine'
+
+    def ready(self):
+        for model_path, model_options in settings.CACHE_MACHINE_MODELS.items():
+            model_parts = model_path.split('.')
+
+            # We use negative indexing so we can support contrib apps out of
+            # the box.
+            #
+            # Example:
+            #
+            #   'django.contrib.contenttypes.models.ContentType'
+            #
+            #   app_name: contenttypes
+            #   model_name: ContentType
+            #
+            app_name = model_parts[-3]
+            model_name = model_parts[-1]
+
+            # Support auto-generated through models for ManyToManyFields
+            #
+            # Example:
+            #
+            #   `models.py`:
+            #
+            #   class OtherThing(models.Model):
+            #       ...
+            #
+            #
+            #   class Thing(models.Model):
+            #       ...
+            #       other_things = models.ManyToManyField(OtherThing)
+            #
+            #
+            #   `settings.py`:
+            #
+            #   'testapp.models.TestThing.other_things.through'
+            #
+            #   app_name: testapp
+            #   model_name: Thing_other_things
+            #
+            if model_name == 'through':
+                _app, _, _model, _field = model_parts[-5:-1]
+                _Model = apps.get_model(_app, _model)
+
+                field = getattr(_Model, _field)
+
+                app_name = field.through.__module__.split('.')[-2]
+                model_name = field.through.__name__
+                Model = apps.get_model(app_name, model_name)
+
+                # Use CachingManager for automatically generated through models
+                #
+                # The related_manager_cls function in
+                # django/db/models/fields/related_descriptors.py
+                # uses model._default_manager.__class__, so we set that to an
+                # *instance* of CachingManager here
+                #
+                field.through._default_manager = CachingManager()
+            else:
+                # Grab the model
+                Model = getattr(import_module('{}.models'.format(app_name)), model_name)
+
+            # Add CachingMixin to the model's bases
+            if CachingMixin not in Model.__bases__:
+                Model.__bases__ = (CachingMixin,) + Model.__bases__
+
+            # Support arbitrarily-named managers
+            manager_name = model_options.get('manager_name', 'objects')
+
+            # model_manager is the *instance* of the manager
+            model_manager = getattr(Model, manager_name)
+
+            # ModelManager is the manager *class*
+            ModelManager = model_manager.__class__
+
+            # We have to specially handle boring managers; luckily, this is much
+            # more straightforward
+            if ModelManager == Manager:
+                model_manager.__class__ = CachingManager
+
+            elif not any(issubclass(Base, CachingManager) for Base in ModelManager.__bases__):
+                # Dynamically create a new type of manager with a CachingManager
+                # mixin and swap the model's manager's *type* out for it
+                new_bases = (CachingManager,) + ModelManager.__bases__
+
+                new_manager_type_name = 'Caching{}'.format(ModelManager.__name__)
+
+                NewManagerType = type(new_manager_type_name, new_bases, {})
+
+                model_manager.__class__ = NewManagerType
diff --git a/caching/config.py b/caching/config.py
@@ -11,6 +11,7 @@
 CACHE_INVALIDATE_ON_CREATE = getattr(settings, 'CACHE_INVALIDATE_ON_CREATE', None)
 CACHE_MACHINE_NO_INVALIDATION = getattr(settings, 'CACHE_MACHINE_NO_INVALIDATION', False)
 CACHE_MACHINE_USE_REDIS = getattr(settings, 'CACHE_MACHINE_USE_REDIS', False)
+CACHE_MACHINE_MODELS = getattr(settings, 'CACHE_MACHINE_MODELS', {})
 
 _invalidate_on_create_values = (None, WHOLE_MODEL)
 if CACHE_INVALIDATE_ON_CREATE not in _invalidate_on_create_values:
Original file line number	Diff line number	Diff line change
Expand Up		@@ -2,3 +2,5 @@

		VERSION = ('0', '9', '1')
		__version__ = '.'.join(VERSION)

		default_app_config = 'caching.apps.CacheMachineConfig'