Adds custom 'has_key' implementation using redis's 'exists' command.

redis_cache/cache.py

@@ -333,6 +333,13 @@ class CacheClass(BaseCache):
             return self._client.ttl(key)
         return 0
 
+    def has_key(self, key, version=None):
+        """
+        Returns True if the key is in the cache and has not expired.
+        """
+        key = self.make_key(key, version=version)
+        return self._client.exists(key)
+
 
 class RedisCache(CacheClass):
     """

tests/testapp/tests.py

@@ -418,6 +418,13 @@ class RedisCacheTests(TestCase):
         ttl = self.cache.ttl('does_not_exist')
         self.assertEqual(ttl, 0)
 
+    def test_has_key_with_no_key(self):
+        self.assertFalse(self.cache.has_key('does_not_exist'))
+
+    def test_has_key_with_key(self):
+        self.cache.set('a', 'a')
+        self.assertTrue(self.cache.has_key('a'))
+
 
 if __name__ == '__main__':
     import unittest