def delete(self, key):
"""Delete an entity.
Delete an existing entity from the store.
key (unicode): the key of the entity that has to be deleted
raise (InvalidKey): if key isn't a unicode or if no entity
with that key is present in the store.
"""
if not isinstance(key, str) or key not in self._store:
raise InvalidKey("Key not in store.")
with LOCK:
# delete entity
old_value = self._store[key]
del self._store[key]
# enforce consistency
for depend in self._depends:
for o_key, o_value in list(iteritems(depend._store)):
if not o_value.consistent(self._all_stores):
depend.delete(o_key)
# notify callbacks
self._update_timestamp()
for callback in self._delete_callbacks:
callback(self.timestamp, key, old_value)
# reflect changes on the persistent storage
try:
os.remove(os.path.join(self._path, key + '.json'))
except OSError:
logger.error("Unable to delete entity", exc_info=True)
def retrieve(self, key):
"""Retrieve an entity.
Retrieve an existing entity from the store.
key (unicode): the key of the entity that has to be retrieved
raise (InvalidKey): if key isn't a unicode or if no entity
with that key is present in the store.
"""
if not isinstance(key, str) or key not in self._store:
raise InvalidKey("Key not in store.")
# retrieve entity
return self._store[key].get()
def update(self, key, data):
"""Update an entity.
Update an existing entity with the given key and the given
data.
key (unicode): the key of the entity that has to be updated
data (dict): the new properties of the entity
raise (InvalidKey): if key isn't a unicode or if no entity
with that key is present in the store.
raise (InvalidData): if data cannot be parsed, if it's missing
some properties or if properties are of the wrong type.
"""
if not isinstance(key, str) or key not in self._store:
raise InvalidKey("Key not in store.")
# update entity
with LOCK:
item = self._entity()
item.set(data)
if not item.consistent(self._all_stores):
raise InvalidData("Inconsistent data")
item.key = key
old_item = self._store[key]
self._store[key] = item
# notify callbacks
self._update_timestamp()
for callback in self._update_callbacks:
callback(self.timestamp, key, old_item, item)
# reflect changes on the persistent storage
try:
path = os.path.join(self._path, key + '.json')
if PY3:
with io.open(path, 'wt', encoding="utf-8") as rec:
json.dump(self._store[key].get(), rec)
else:
with io.open(path, 'wb') as rec:
json.dump(self._store[key].get(), rec)
except IOError:
logger.error("I/O error occured while updating entity",
exc_info=True)
def create(self, key, data):
"""Create a new entity.
Create a new entity with the given key and the given data.
key (unicode): the key with which the entity will be later
accessed
data (dict): the properties of the entity
raise (InvalidKey): if key isn't a unicode or if an entity
with the same key is already present in the store.
raise (InvalidData): if data cannot be parsed, if it's missing
some properties or if properties are of the wrong type.
"""
if not isinstance(key, str) or key in self._store:
raise InvalidKey("Key already in store.")
# create entity
with LOCK:
item = self._entity()
item.set(data)
if not item.consistent():
raise InvalidData("Inconsistent data")
item.key = key
self._store[key] = item
# notify callbacks
for callback in self._create_callbacks:
callback(key, item)
# reflect changes on the persistent storage
try:
path = os.path.join(self._path, key + '.json')
if PY3:
with io.open(path, 'wt', encoding="utf-8") as rec:
json.dump(self._store[key].get(), rec)
else:
with io.open(path, 'wb') as rec:
json.dump(self._store[key].get(), rec)
except IOError:
logger.error("I/O error occured while creating entity",
exc_info=True)