Merge pull request #268 from carlosfunk/cache-key-helpers

Cache key helper functions

docs/install.rst

@@ -212,6 +212,24 @@ If you put this in the same Django project, you can make a new ``settings_public
 
 Or you can create a completely separate project for the main website.
 
+Caching
+-------
+
+To enable tenant aware caching you can set the `KEY_FUNCTION <https://docs.djangoproject.com/en/1.8/ref/settings/#std:setting-CACHES-KEY_FUNCTION>`_ setting to use the provided ``make_key`` helper function which
+adds the tenants ``schema_name`` as the first key prefix.
+
+.. code-block:: python
+
+    CACHES = {
+        "default": {
+            ...
+            'KEY_FUNCTION': 'tenant_schemas.cache.make_key',
+            'REVERSE_KEY_FUNCTION': 'tenant_schemas.cache.reverse_key',
+        },
+    }
+
+The ``REVERSE_KEY_FUNCTION`` setting is only required if you are using the `django-redis <https://github.com/niwinz/django-redis>`_ cache backend.
+
 Configuring your Apache Server (optional)
 =========================================
 Here's how you can configure your Apache server to route all subdomains to your django project so you don't have to setup any subdomains manually.
@@ -238,3 +256,4 @@ formats using `Sphinx <http://pypi.python.org/pypi/Sphinx>`_. To get started
     make html
 
 This creates the documentation in HTML format at ``docs/_build/html``.
+

tenant_schemas/cache.py

@@ -0,0 +1,20 @@
+from django.db import connection
+
+
+def make_key(key, key_prefix, version):
+    """
+    Tenant aware function to generate a cache key.
+
+    Constructs the key used by all other methods. Prepends the tenant
+    `schema_name` and `key_prefix'.
+    """
+    return '%s:%s:%s:%s' % (connection.schema_name, key_prefix, version, key)
+
+
+def reverse_key(key):
+    """
+    Tenant aware function to reverse a cache key.
+
+    Required for django-redis REVERSE_KEY_FUNCTION setting.
+    """
+    return key.split(':', 3)[3]

tenant_schemas/tests/__init__.py

@@ -1,2 +1,3 @@
 from test_routes import *
 from test_tenants import *
+from test_cache import *

tenant_schemas/tests/test_cache.py

@@ -0,0 +1,13 @@
+from tenant_schemas.cache import make_key, reverse_key
+from tenant_schemas.test.cases import TenantTestCase
+
+
+class CacheHelperTestCase(TenantTestCase):
+    def test_make_key(self):
+        key = make_key(key='foo', key_prefix='', version=1)
+        tenant_prefix = key.split(':')[0]
+        self.assertEqual(self.tenant.schema_name, tenant_prefix)
+
+    def test_reverse_key(self):
+        key = 'foo'
+        self.assertEqual(key, reverse_key(make_key(key=key, key_prefix='', version=1)))