planetstack/model_policy.py

   1 from django.db.models.signals import post_save
   2 from django.dispatch import receiver
   3 import pdb
   4 from core.models import *
   5 from dependency_walker import *
   6 import model_policies
   7
   8 modelPolicyEnabled = True
   9
  10 def EnableModelPolicy(x):
  11     global modelPolicyEnabled
  12     modelPolicyEnabled = x
  13
  14 def update_dep(d, o):
  15         try:
  16                 if (d.updated < o.updated):
  17                         d.save(update_fields=['updated'])
  18         except AttributeError,e:
  19                 pdb.set_trace()
  20                 raise e
  21
  22 def delete_if_inactive(d, o):
  23         #print "Deleting %s (%s)"%(d,d.__class__.__name__)
  24         d.delete()
  25         return
  26
  27 @receiver(post_save)
  28 def post_save_handler(sender, instance, **kwargs):
  29         if not modelPolicyEnabled:
  30             return
  31
  32         sender_name = sender.__name__
  33         policy_name = 'model_policy_%s'%sender_name
  34
  35         if (not kwargs['update_fields']):
  36                 # Automatic dirtying
  37                 walk_inv_deps(update_dep, instance)
  38
  39                 try:
  40                         policy_handler = getattr(model_policies, policy_name, None)
  41                         if policy_handler is not None:
  42                                 policy_handler.handle(instance)
  43                 except:
  44                         pass
  45         elif 'deleted' in kwargs['update_fields']:
  46                 walk_inv_deps(delete_if_inactive, instance)
  47