def invalidate_cache(model_class, objects, **extra_keys):
"""
Flushes the cache of any cached objects associated with this instance.
Explicitly set a None value instead of just deleting so we don't have any race
conditions where:
Thread 1 -> Cache miss, get object from DB
Thread 2 -> Object saved, deleted from cache
Thread 1 -> Store (stale) object fetched from DB in cache
Five second should be more than enough time to prevent this from happening for
a web app.
"""
invalidation_dict = {}
accessor_set = cache_signals.get_global_signals(model_class)
for obj in objects:
for (accessor_path, lookup_type, negate) in accessor_set:
for value in get_values(obj, accessor_path):
invalidation_key = get_invalidation_key(
model_class._meta.db_table, accessor_path=accessor_path, negate=negate, value=value, save=False
)
invalidation_dict[invalidation_key] = None
invalidation_dict.update(cache.get_many(invalidation_dict.keys()))
cache_keys = set()
for obj_key, cache_key_list in invalidation_dict.iteritems():
if cache_key_list:
cache_keys.update(cache_key_list.split(","))
keys_to_invalidate = dict([(key, None) for key in chain(cache_keys, invalidation_dict.keys())])
keys_to_invalidate.update(extra_keys)
cache.set_many(keys_to_invalidate, 5)
cache.delete_many(keys_to_invalidate.keys())
def __iter__(self):
results = cache.get(self.result_key)
if results is not None:
for obj in results:
if RUNNING_TESTS:
obj = self._set_field(obj,'from_cache', True)
yield obj
raise StopIteration
results = []
cache_query = getattr(self.queryset, '_cache_query', False)
pk_name = self.queryset.model._meta.pk.name
self.queryset._fill_select_reverse_cache()
reversemapping_keys = self.queryset._reversemapping.keys()
reversemapping_keys.sort()
for obj in self.iterator():
for related_name in reversemapping_keys:
reversemap = self.queryset._target_maps[related_name]
related_split = related_name.split(LOOKUP_SEP)
for related_obj, related_field in self._nested_select_reverse(obj, related_split):
val = reversemap.get(get_values(related_obj, pk_name),[])
related_obj = self._set_field(related_obj, related_field, val)
if cache_query:
results.append(obj)
if RUNNING_TESTS:
obj = self._set_field(obj,'from_cache', False)
yield obj
if cache_query:
self.cache_results(results)
def __iter__(self):
cache_query = getattr(self.queryset, '_cache_query', False)
if cache_query:
results = cache.get(self.result_key)
if results is not None:
for obj in results:
if conf.CACHEBOT_DEBUG_RESULTS:
set_value(obj, 'from_cache', True)
yield obj
raise StopIteration
results = []
pk_name = self.queryset.model._meta.pk.name
self.queryset._fill_select_reverse_cache()
reversemapping_keys = self.queryset._reversemapping.keys()
reversemapping_keys.sort()
for obj in self.parent_class.iterator(self.queryset):
for related_name in reversemapping_keys:
reversemap = self.queryset._target_maps[related_name]
related_split = related_name.split(LOOKUP_SEP)
for related_obj, related_field in self._nested_select_reverse(obj, related_split):
val = reversemap.get(get_values(related_obj, pk_name),[])
set_value(related_obj, related_field, val)
if cache_query:
results.append(obj)
if conf.CACHEBOT_DEBUG_RESULTS:
set_value(obj, 'from_cache', False)
yield obj
if cache_query:
self.cache_results(results)
def get_invalidation_keys(self, results):
"""
Iterates through a list of results, and returns an invalidation key for each result. If the
query spans multiple tables, also return invalidation keys of any related rows.
"""
related_fields = self.queryset._related_fields
for obj in results:
for field, model_class in related_fields.iteritems():
pk_name = model_class._meta.pk.attname
cache_signals.register(model_class, pk_name, 'exact')
for value in get_values(obj, field):
invalidation_key = get_invalidation_key(
model_class._meta.db_table,
accessor_path = pk_name,
value = value)
yield invalidation_key
def get_invalidation_keys(self, results):
"""
Iterates through a list of results, and returns an invalidation key for each result. If the
query spans multiple tables, also return invalidation keys of any related rows.
"""
related_fields = self.queryset._related_fields
for obj in results:
for field, model_class in related_fields.iteritems():
pk_name = model_class._meta.pk.attname
cache_signals.register(model_class, pk_name, 'exact')
for value in get_values(obj, field):
invalidation_key = get_invalidation_key(
model_class._meta.db_table,
accessor_path = pk_name,
value = value)
yield invalidation_key
def invalidate_cache(model_class, objects, **extra_keys):
"""
Flushes the cache of any cached objects associated with this instance.
Explicitly set a None value instead of just deleting so we don't have any race
conditions where:
Thread 1 -> Cache miss, get object from DB
Thread 2 -> Object saved, deleted from cache
Thread 1 -> Store (stale) object fetched from DB in cache
Five second should be more than enough time to prevent this from happening for
a web app.
"""
invalidation_dict = {}
accessor_set = cache_signals.get_global_signals(model_class)
for obj in objects:
for (accessor_path, lookup_type, negate) in accessor_set:
if lookup_type != 'exact' or negate:
invalidation_key = get_invalidation_key(
model_class._meta.db_table,
accessor_path=accessor_path,
negate=negate,
value='')
invalidation_dict[invalidation_key] = None
else:
for value in get_values(obj, accessor_path):
invalidation_key = get_invalidation_key(
model_class._meta.db_table,
accessor_path=accessor_path,
negate=negate,
value=value)
invalidation_dict[invalidation_key] = None
if invalidation_dict:
invalidation_dict.update(cache.get_many(invalidation_dict.keys()))
cache_keys = set()
for obj_key, cache_key_list in invalidation_dict.iteritems():
if cache_key_list:
cache_keys.update(cache_key_list.split(','))
if cache_keys:
cache.set_many(dict([(key, None) for key in cache_keys]),
conf.CACHE_INVALIDATION_TIMEOUT)
invalidation_dict.update(extra_keys)
cache.delete_many(invalidation_dict.keys())
