[1.1.X] Fixed #11012: don't needless convert cache values to unicode.

This means you can now successfully store binary blogs, such as compressed data,
in the cache.

Thanks to Matt Croydon for the final patch.

Backport of [12637] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12638 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/cache/backends/memcached.py

@@ -43,15 +43,9 @@ class CacheClass(BaseCache):
         val = self._cache.get(smart_str(key))
         if val is None:
             return default
-        else:
-            if isinstance(val, basestring):
-                return smart_unicode(val)
-            else:
         return val
 
     def set(self, key, value, timeout=0):
-        if isinstance(value, unicode):
-            value = value.encode('utf-8')
         self._cache.set(smart_str(key), value, self._get_memcache_timeout(timeout))
 
     def delete(self, key):

tests/regressiontests/cache/tests.py

@@ -278,6 +278,16 @@ class BaseCacheTests(object):
             self.cache.set(key, value)
             self.assertEqual(self.cache.get(key), value)
 
+    def test_binary_string(self):
+        # Binary strings should be cachable
+        from zlib import compress, decompress
+        value = 'value_to_be_compressed'
+        compressed_value = compress(value)
+        self.cache.set('binary1', compressed_value)
+        compressed_result = self.cache.get('binary1')
+        self.assertEqual(compressed_value, compressed_result)
+        self.assertEqual(value, decompress(compressed_result))
+
     def test_long_timeout(self):
         '''
         Using a timeout greater than 30 days makes memcached think