def watch(self, call_on_created=None):
self._call_on_created = (self._call_on_created if
call_on_created is None else call_on_created)
# initialize investigator
self._investigator = Investigator(self.model, include=[self.attr])
# register the receivers
register_reciever(self.model, pre_save, self._pre_save_receiver)
register_reciever(self.model, post_save, self._post_save_receiver)
class ValueWatcher(WatcherBase):
"""
Watcher field for watching non relational field such as CharField.
"""
def __init__(self, model, attr, callback, call_on_created=True):
super(ValueWatcher, self).__init__(model, attr, callback)
self._call_on_created = call_on_created
def watch(self, call_on_created=None):
self._call_on_created = (self._call_on_created
if call_on_created is None
else call_on_created)
# initialize investigator
self._investigator = Investigator(self.model, include=[self.attr])
# register the receivers
register_reciever(self.model, pre_save,
self._pre_save_receiver)
register_reciever(self.model, post_save,
self._post_save_receiver)
def unwatch(self):
unregister_reciever(self.model, pre_save,
self._pre_save_receiver)
unregister_reciever(self.model, post_save,
self._post_save_receiver)
def _pre_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
self._investigator.prepare(instance)
def _post_save_receiver(self, sender, instance, created, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
if self._call_on_created and created:
self.call(instance)
# if investigator yield any field_name, call the callback
if any(self._investigator.investigate(instance)):
self.call(instance)
def watch(self, call_on_created=None, include=None, exclude=None):
self._call_on_created = (self._call_on_created if
call_on_created is None else call_on_created)
include = include or self.include
exclude = exclude or self.exclude
self._investigator = Investigator(self.related_model,
include=include,
exclude=exclude)
# register the receivers
register_reciever(self.model,
pre_save,
self._pre_save_receiver,
sender=self.related_model)
register_reciever(self.model,
post_save,
self._post_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
def watch(self, call_on_created=None):
self._call_on_created = (self._call_on_created
if call_on_created is None
else call_on_created)
# initialize investigator
self._investigator = Investigator(self.model, include=[self.attr])
# register the receivers
register_reciever(self.model, pre_save,
self._pre_save_receiver)
register_reciever(self.model, post_save,
self._post_save_receiver)
class ValueWatcher(WatcherBase):
"""
Watcher field for watching non relational field such as CharField.
"""
def __init__(self, model, attr, callback, call_on_created=True):
super(ValueWatcher, self).__init__(model, attr, callback)
self._call_on_created = call_on_created
def watch(self, call_on_created=None):
self._call_on_created = (self._call_on_created if
call_on_created is None else call_on_created)
# initialize investigator
self._investigator = Investigator(self.model, include=[self.attr])
# register the receivers
register_reciever(self.model, pre_save, self._pre_save_receiver)
register_reciever(self.model, post_save, self._post_save_receiver)
def unwatch(self):
unregister_reciever(self.model, pre_save, self._pre_save_receiver)
unregister_reciever(self.model, post_save, self._post_save_receiver)
def _pre_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
self._investigator.prepare(instance)
def _post_save_receiver(self, sender, instance, created, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
if self._call_on_created and created:
self.call(instance)
# if investigator yield any field_name, call the callback
if any(self._investigator.investigate(instance)):
self.call(instance)
def watch(self, call_on_created=None, include=None, exclude=None):
self._call_on_created = (self._call_on_created
if call_on_created is None
else call_on_created)
include = include or self.include
exclude = exclude or self.exclude
self._investigator = Investigator(self.related_model,
include=include,
exclude=exclude)
# register the receivers
register_reciever(self.model, pre_save,
self._pre_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
class RelatedWatcherBase(WatcherBase):
"""
A base watcher field for relational field such as ForeignKey, ManyToMany
"""
def __init__(self, model, attr, callback,
call_on_created=True,
include=None, exclude=None):
"""
Construct watcher field
Args:
model (model): A target model class
attr (str): A name of attribute
callback (fn): A callback function
call_on_created (bool): Call callback when the new instance is
created
include (None, list, tuple): A related object field name list
which will be investigated to determine the modification
exclude (None, list, tuple): A related object field name list
which won't be investigated to determine the modification
"""
super(RelatedWatcherBase, self).__init__(model, attr, callback)
self.include = include
self.exclude = exclude
self._call_on_created = call_on_created
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def is_reversed(self):
return self.get_field().model != self._model
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def related_model(self):
field = self.get_field()
if self.is_reversed:
return field.model
return field.related.parent_model
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def related_attr(self):
field = self.get_field()
if self.is_reversed:
return field.name
return field.related.get_accessor_name()
def watch(self, call_on_created=None, include=None, exclude=None):
self._call_on_created = (self._call_on_created
if call_on_created is None
else call_on_created)
include = include or self.include
exclude = exclude or self.exclude
self._investigator = Investigator(self.related_model,
include=include,
exclude=exclude)
# register the receivers
register_reciever(self.model, pre_save,
self._pre_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
def unwatch(self):
# unregister the receivers
unregister_reciever(self.model, pre_save,
self._pre_save_receiver)
unregister_reciever(self.model, post_save,
self._post_save_receiver)
unregister_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
def get_value(self, instance):
try:
return getattr(instance, self.related_attr, None)
except ObjectDoesNotExist:
return None
def get_values(self, instance):
value = self.get_value(instance)
if value is None:
return set()
if hasattr(value, 'iterator'):
value = value.iterator()
elif not hasattr(value, '__iter__'):
value = tuple([value])
return set(value)
def _pre_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
self._investigator.prepare(instance)
def _post_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
# get a reverse related objects from the instance
instance_cached = self._investigator.get_cached(instance.pk)
values_cached = self.get_values(instance_cached)
values_latest = self.get_values(instance)
object_set = values_cached | values_latest
if any(self._investigator.investigate(instance)):
for obj in object_set:
self.call(obj)
def _post_save_receiver_for_creation(self, sender, instance,
created, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
if self._call_on_created and created:
self.call(instance)
class RelatedWatcherBase(WatcherBase):
"""
A base watcher field for relational field such as ForeignKey, ManyToMany
"""
def __init__(self,
model,
attr,
callback,
call_on_created=True,
include=None,
exclude=None):
"""
Construct watcher field
Args:
model (model): A target model class
attr (str): A name of attribute
callback (fn): A callback function
call_on_created (bool): Call callback when the new instance is
created
include (None, list, tuple): A related object field name list
which will be investigated to determine the modification
exclude (None, list, tuple): A related object field name list
which won't be investigated to determine the modification
"""
super(RelatedWatcherBase, self).__init__(model, attr, callback)
self.include = include
self.exclude = exclude
self._call_on_created = call_on_created
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def is_reversed(self):
return self.get_field().model != self._model
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def related_model(self):
field = self.get_field()
if self.is_reversed:
return field.model
return field.related.parent_model
@property
@lru_cache(settings.OBSERVER_LRU_CACHE_SIZE)
def related_attr(self):
field = self.get_field()
if self.is_reversed:
return field.name
return field.related.get_accessor_name()
def watch(self, call_on_created=None, include=None, exclude=None):
self._call_on_created = (self._call_on_created if
call_on_created is None else call_on_created)
include = include or self.include
exclude = exclude or self.exclude
self._investigator = Investigator(self.related_model,
include=include,
exclude=exclude)
# register the receivers
register_reciever(self.model,
pre_save,
self._pre_save_receiver,
sender=self.related_model)
register_reciever(self.model,
post_save,
self._post_save_receiver,
sender=self.related_model)
register_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
def unwatch(self):
# unregister the receivers
unregister_reciever(self.model, pre_save, self._pre_save_receiver)
unregister_reciever(self.model, post_save, self._post_save_receiver)
unregister_reciever(self.model, post_save,
self._post_save_receiver_for_creation)
def get_value(self, instance):
try:
return getattr(instance, self.related_attr, None)
except ObjectDoesNotExist:
return None
def get_values(self, instance):
value = self.get_value(instance)
if value is None:
return set()
if hasattr(value, 'iterator'):
value = value.iterator()
elif not hasattr(value, '__iter__'):
value = tuple([value])
return set(value)
def _pre_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
self._investigator.prepare(instance)
def _post_save_receiver(self, sender, instance, **kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
# get a reverse related objects from the instance
instance_cached = self._investigator.get_cached(instance.pk)
values_cached = self.get_values(instance_cached)
values_latest = self.get_values(instance)
object_set = values_cached | values_latest
if any(self._investigator.investigate(instance)):
for obj in object_set:
self.call(obj)
def _post_save_receiver_for_creation(self, sender, instance, created,
**kwargs):
if kwargs.get('row', False):
# should not call any callback while it is called via fixtures or
# so on
return
if self._call_on_created and created:
self.call(instance)
