def _mymodel_delete(sender, instance, **kwargs):
"""
When a PicklePersistedModel is deleted, also delete its pickle file
:param sender:
:param instance:
:param kwargs:
:return:
"""
if isinstance(instance, PicklePersistedModel):
filepath = pickle_path(instance.id, instance.__class__.__name__)
print('Delete {}'.format(filepath))
if os.path.isfile(filepath):
os.remove(filepath)
else:
warning('File {} doesnot exist.'.format(filepath))
def load(self):
"""
Load the persisted data on to the model from its pickle file
Not to be called when the model is being constructed
:return: None
"""
if self.id:
fpath = pickle_path(self.id, self.__class__.__name__)
if os.path.isfile(fpath):
with open(fpath, 'rb') as f:
mdict = pickle.load(f)
for attr in self._meta.attrs:
# _attr = '_{}'.format(attr)
setattr(self, attr, mdict[attr])
self._loaded = True
else:
warning('Can\'t restore data for {} #{}. File {} not found'
.format(self.__class__.__name__, self.id, fpath))
def save(self, *args, **kwargs):
"""
Save the object and then use its ID to store a pickle file contaning all the attrs as declared
Pickle file will be stored in user_data/pickle/<class name>/
:param args:
:param kwargs:
:return: None
"""
super(PicklePersistedModel, self).save(*args, **kwargs)
fpath = pickle_path(self.id, self.__class__.__name__)
ensure_parent_folder_exists(fpath)
mdict = {}
for attr in self._meta.attrs:
mdict[attr] = getattr(self, attr)
with open(fpath, 'wb') as f:
pickle.dump(mdict, f, pickle.HIGHEST_PROTOCOL)