Commit 1fc7c4ae authored by Russell Keith-Magee's avatar Russell Keith-Magee
Browse files

Fixed #14596 -- Light refactoring of the cache backends. 

 * Removes some code duplication,
 * Provides a convenient base class for db-like cache backends
 * Adds tests for an edge case of culling,
 * Marks the memcached tests as "skipped", rather than omitting them.

Thanks to Jonas H for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14434 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent ed51dd5d

django/core/cache/backends/base.py

+12 −0
Original line number Diff line number Diff line
@@ -22,6 +22,18 @@ class BaseCache(object): 
            timeout = 300

        self.default_timeout = timeout



        max_entries = params.get('max_entries', 300)

        try:

            self._max_entries = int(max_entries)

        except (ValueError, TypeError):

            self._max_entries = 300



        cull_frequency = params.get('cull_frequency', 3)

        try:

            self._cull_frequency = int(cull_frequency)

        except (ValueError, TypeError):

            self._cull_frequency = 3



    def add(self, key, value, timeout=None):

        """

        Set a value in the cache if the key does not already exist. If

django/core/cache/backends/db.py

+2 −12
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ class Options(object): 
        self.managed = True

        self.proxy = False



class CacheClass(BaseCache):

class BaseDatabaseCacheClass(BaseCache):

    def __init__(self, table, params):

        BaseCache.__init__(self, params)

        self._table = table
@@ -34,17 +34,7 @@ class CacheClass(BaseCache): 
            _meta = Options(table)

        self.cache_model_class = CacheEntry



        max_entries = params.get('max_entries', 300)

        try:

            self._max_entries = int(max_entries)

        except (ValueError, TypeError):

            self._max_entries = 300

        cull_frequency = params.get('cull_frequency', 3)

        try:

            self._cull_frequency = int(cull_frequency)

        except (ValueError, TypeError):

            self._cull_frequency = 3



class CacheClass(BaseDatabaseCacheClass):

    def get(self, key, default=None):

        self.validate_key(key)

        db = router.db_for_read(self.cache_model_class)

django/core/cache/backends/filebased.py

+0 −13
Original line number Diff line number Diff line
@@ -14,19 +14,6 @@ from django.utils.hashcompat import md5_constructor 
class CacheClass(BaseCache):

    def __init__(self, dir, params):

        BaseCache.__init__(self, params)



        max_entries = params.get('max_entries', 300)

        try:

            self._max_entries = int(max_entries)

        except (ValueError, TypeError):

            self._max_entries = 300



        cull_frequency = params.get('cull_frequency', 3)

        try:

            self._cull_frequency = int(cull_frequency)

        except (ValueError, TypeError):

            self._cull_frequency = 3



        self._dir = dir

        if not os.path.exists(self._dir):

            self._createdir()

django/core/cache/backends/locmem.py

+0 −13
Original line number Diff line number Diff line
@@ -14,19 +14,6 @@ class CacheClass(BaseCache): 
        BaseCache.__init__(self, params)

        self._cache = {}

        self._expire_info = {}



        max_entries = params.get('max_entries', 300)

        try:

            self._max_entries = int(max_entries)

        except (ValueError, TypeError):

            self._max_entries = 300



        cull_frequency = params.get('cull_frequency', 3)

        try:

            self._cull_frequency = int(cull_frequency)

        except (ValueError, TypeError):

            self._cull_frequency = 3



        self._lock = RWLock()



    def add(self, key, value, timeout=None):

tests/regressiontests/cache/tests.py

+26 −19
Original line number Diff line number Diff line
@@ -410,6 +410,10 @@ class DBCacheTests(unittest.TestCase, BaseCacheTests): 
    def test_cull(self):

        self.perform_cull_test(50, 29)



    def test_zero_cull(self):

        self.cache = get_cache('db://%s?max_entries=30&cull_frequency=0' % self._table_name)

        self.perform_cull_test(50, 18)



class LocMemCacheTests(unittest.TestCase, BaseCacheTests):

    def setUp(self):

        self.cache = get_cache('locmem://?max_entries=30')
@@ -417,11 +421,14 @@ class LocMemCacheTests(unittest.TestCase, BaseCacheTests): 
    def test_cull(self):

        self.perform_cull_test(50, 29)



    def test_zero_cull(self):

        self.cache = get_cache('locmem://?max_entries=30&cull_frequency=0')

        self.perform_cull_test(50, 19)



# memcached backend isn't guaranteed to be available.

# To check the memcached backend, the test settings file will

# need to contain a CACHE_BACKEND setting that points at

# your memcache server.

if settings.CACHE_BACKEND.startswith('memcached://'):

class MemcachedCacheTests(unittest.TestCase, BaseCacheTests):

    def setUp(self):

        self.cache = get_cache(settings.CACHE_BACKEND)
@@ -440,7 +447,7 @@ if settings.CACHE_BACKEND.startswith('memcached://'): 
        self.assertRaises(Exception, self.cache.set, 'key with spaces', 'value')

        # memcached limits key length to 250

        self.assertRaises(Exception, self.cache.set, 'a' * 251, 'value')



MemcachedCacheTests = unittest.skipUnless(settings.CACHE_BACKEND.startswith('memcached://'), "memcached not available")(MemcachedCacheTests)



class FileBasedCacheTests(unittest.TestCase, BaseCacheTests):

    """