from __future__ import unicode_literals
from django.db.models.signals import pre_save, post_save, post_delete
from django.db.models import Model
class ActionslogModelRegistry(object):
"""
A registry that keeps track of the models that use actionslog to track changes.
"""
def __init__(self, create=True, update=True, delete=True, custom=None):
from actionslog.receivers import action_log_create, action_log_update, action_log_delete
self._registry = {}
self._signals = {}
if create:
self._signals[post_save] = action_log_create
if update:
self._signals[pre_save] = action_log_update
if delete:
self._signals[post_delete] = action_log_delete
if custom is not None:
self._signals.update(custom)
def register(self, model, include_fields=[], exclude_fields=[]):
"""
Register a model with actionslog. Actionslog will then track mutations on this model's instances.
:param model: The model to register.
:type model: Model
:param include_fields: The fields to include. Implicitly excludes all other fields.
:type include_fields: list
:param exclude_fields: The fields to exclude. Overrides the fields to include.
:type exclude_fields: list
"""
if issubclass(model, Model):
self._registry[model] = {
'include_fields': include_fields,
'exclude_fields': exclude_fields,
}
self._connect_signals(model)
else:
raise TypeError("Supplied model is not a valid model.")
def contains(self, model):
"""
Check if a model is registered with actionslog.
:param model: The model to check.
:type model: Model
:return: Whether the model has been registered.
:rtype: bool
"""
return model in self._registry
def unregister(self, model):
"""
Unregister a model with actionslog. This will not affect the database.
:param model: The model to unregister.
:type model: Model
"""
try:
del self._registry[model]
except KeyError:
pass
else:
self._disconnect_signals(model)
def _connect_signals(self, model):
"""
Connect signals for the model.
"""
for signal in self._signals:
receiver = self._signals[signal]
signal.connect(receiver, sender=model, dispatch_uid=self._dispatch_uid(signal, model))
def _disconnect_signals(self, model):
"""
Disconnect signals for the model.
"""
for signal, receiver in self._signals.items():
signal.disconnect(sender=model, dispatch_uid=self._dispatch_uid(signal, model))
def _dispatch_uid(self, signal, model):
"""
Generate a dispatch_uid.
"""
return (self.__class__, model, signal)
def get_model_fields(self, model):
return {
'include_fields': self._registry[model]['include_fields'],
'exclude_fields': self._registry[model]['exclude_fields'],
}
actionslog = ActionslogModelRegistry()
