version bump and small fix, defaulting unknown version to zero instead of None

Author: smn

setup.py

@@ -5,7 +5,7 @@ def listify(filename):
 
 setup(
     name = "django-cache-sweeper",
-    version = "0.1.1",
+    version = "0.1.2",
     url = 'http://github.com/smn/django-cache-sweeper',
     license = 'BSD',
     description = "Lazy Django fragment cache sweeping",

src/cachesweeper/tests.py

@@ -18,18 +18,19 @@ def __init__(self, *args, **kwargs):
         super(FragmentCacheInvalidation, self).__init__(*args, **kwargs)
 
     def setUp(self):
-        pass
+        cache.clear()
 
     def tearDown(self):
         pass
 
     def test_version_at_creation(self):
         comment = Comment.objects.latest()
+        comment.like_it()
         version_cache_key = cache_token_key_for_record(comment)
         # the cache version token should be zero as we've just created the record
         # by loading the fixtures. At creation the cache version should be
         # zero
-        self.assertTrue(cache.get(version_cache_key))
+        self.assertEquals(cache.get(version_cache_key), 0)
 
     def test_version_after_save(self):
         # get the comment we want to invalidate the cache for
@@ -38,11 +39,9 @@ def test_version_after_save(self):
         version_cache_key = cache_token_key_for_record(comment)
         # get the original version, should be zero
         original_version = cache.get(version_cache_key, None)
-        self.assertNotEquals(original_version, None)
         # change the comment & save, should increment the version value in
         # memcached
         comment.like_it()
-        comment.save()
         # get the new version value for the comment
         new_version = cache.get(version_cache_key)
         self.assertNotEquals(original_version, new_version)
@@ -71,7 +70,6 @@ def test_fragment_cache_miss(self):
 
         # modifying the model should change the cache
         comment.like_it()
-        comment.save()
 
         # assert the changed cache key
         new_cache_key = generate_fragment_cache_key_for_record(comment, "comment.xml")
@@ -89,7 +87,14 @@ def test_modelsweeper_mixin(self):
         tmm.save()
         self.assertEquals(tmm.cachesweeper_version, 1)
 
-    def test_modelsweeper_attr(self):
-        tam = TestAttributeModel(text='testing text')
-        tam.save()
-        
+    def test_default_version_zero(self):
+        tmm = TestMixinModel(text='testing text')
+        tmm.save()
+        cache.delete(tmm.cachesweeper_version_key)
+        self.assertEquals(tmm.cachesweeper_version, 0)
+        tmm.save()
+        self.assertEquals(tmm.cachesweeper_version, 1)
+    
+    # def test_modelsweeper_manager(self):
+    #     tmm = TestManagerModel(text='testing text')
+    #     self.assertTrue(hasattr(tmm.cachesweeper,'cachesweeper'))

src/cachesweeper/utils.py

@@ -50,25 +50,34 @@ def update_cache_token_for_record_with_attribute(instance, token_attr):
     token_value = getattr(instance,token_attr)
     token_value_hash = md5_constructor(str(token_value)).hexdigest()
     cache.set(cache_key, token_value_hash, 0) # 0 = no time based expiry
+    return token_value_hash
 
 def update_cache_token_for_record_with_counter(instance):
     """
     Update the cache token with an internal memcached counter. 
     """
     cache_key = cache_token_key_for_record(instance)
     value = cache.get(cache_key)
-    if value == None or not isinstance(value, int):
+    if value == None:
         cache.set(cache_key, 0, 0) # 0 = no time based expiry
+        return 0
     else:
-        cache.incr(cache_key)
+        return cache.incr(cache_key)
 
 
 
 def generate_fragment_cache_key_for_record(record, *cache_keys):
     unique_fragment_key = u":".join(map(lambda key: urlquote(str(key)), cache_keys))
     unique_fragment_key_hash = md5_constructor(unique_fragment_key)
     record_version_key = cache_token_key_for_record(record)
-    record_current_version = cache.get(record_version_key)
+    record_current_version = cache.get(record_version_key, None)
+    
+    # cache miss for a record that hasn't been versioned yet or
+    # has been expired by memcached
+    if record_current_version == None:
+        cache.set(record_version_key, 0, 0)
+        record_current_version = 0
+    
     cache_key = 'cachesweeper.%s.%s.%s' % (
             record_version_key, 
             record_current_version,
@@ -97,5 +106,9 @@ def cachesweeper_version_key(self):
 
     @property
     def cachesweeper_version(self):
-        return cache.get(self.cachesweeper_version_key)
+        cached_version = cache.get(self.cachesweeper_version_key)
+        if cached_version is not None:
+            return cached_version
+        else:
+            return update_cache_token_for_record_with_counter(self)