# Add an attribute for each agent (a 'bug') to keep track of the field valuesĬurrent_value = getattr( instance, field_name) Raise WatchException( ''%s' is not a field of '%s'' % ( field_name, model.

Raise WatchException( ''%s' is not a subclass of django.db.models.Model' % ( model. Known limitation: using the update method on a queryset will prevent django-spy from detecting the field value change (as the save method and related signals are not called)ĭef _init_( self, field_name, on_change, pre_save = True): Note that the callback function you pass in the agent definition will be passed exactly 3 arguments when called by spy: instance, old field value and new field value optional switch to have the callback called before (default) or after the instance is saved callback function to be called when the value of the field changes

name of the field to be watched/spied on The spy_on class decorator takes a list of Agent definitions. Print 'Changed book title (old: %s) (new: %s)' % (old_title, log_change)]) Sample usage (using the spy_on class decorator for models)ĭef log_change(book, old_title, new_title): signals import post_init, pre_save, post_saveįrom django.

Spy agent title