planetstack/core/models/plcorebase.py

   1 import os
   2 from django.db import models
   3 from django.forms.models import model_to_dict
   4 from django.core.urlresolvers import reverse
   5 from django.forms.models import model_to_dict
   6
   7 try:
   8     # This is a no-op if observer_disabled is set to 1 in the config file
   9     from observer import *
  10 except:
  11     print "import of observer failed! printing traceback and disabling observer:"
  12     import traceback
  13     traceback.print_exc()
  14
  15     # guard against something failing
  16     def notify_observer():
  17         pass
  18
  19 class PlCoreBase(models.Model):
  20
  21     created = models.DateTimeField(auto_now_add=True)
  22     updated = models.DateTimeField(auto_now=True)
  23     enacted = models.DateTimeField(null=True, default=None)
  24     backend_status = models.CharField(max_length=140,
  25                                       default="Provisioning in progress")
  26     deleted = models.BooleanField(default=False)
  27
  28     class Meta:
  29         abstract = True
  30         app_label = "core"
  31
  32     def __init__(self, *args, **kwargs):
  33         super(PlCoreBase, self).__init__(*args, **kwargs)
  34         self.__initial = self._dict
  35
  36     @property
  37     def diff(self):
  38         d1 = self.__initial
  39         d2 = self._dict
  40         diffs = [(k, (v, d2[k])) for k, v in d1.items() if v != d2[k]]
  41         return dict(diffs)
  42
  43     @property
  44     def has_changed(self):
  45         return bool(self.diff)
  46
  47     @property
  48     def changed_fields(self):
  49         return self.diff.keys()
  50
  51     def get_field_diff(self, field_name):
  52         return self.diff.get(field_name, None)
  53
  54     def can_update(self, user):
  55         if user.is_readonly:
  56             return False
  57         if user.is_admin:
  58             return True
  59         return False
  60
  61     def delete(self, *args, **kwds):
  62         # so we have something to give the observer
  63         pk = self.pk
  64         model_dict = model_to_dict(self)
  65         for (k,v) in model_dict.items():
  66             # things like datetime are not JSON serializable
  67             model_dict[k] = str(v)
  68
  69         super(PlCoreBase, self).delete(*args, **kwds)
  70
  71         # This is a no-op if observer_disabled is set
  72         notify_observer(model=self, delete=True, pk=pk, model_dict=model_dict)
  73
  74     def save(self, *args, **kwargs):
  75         super(PlCoreBase, self).save(*args, **kwargs)
  76
  77         # This is a no-op if observer_disabled is set
  78         notify_observer()
  79
  80         self.__initial = self._dict
  81
  82     def save_by_user(self, user, *args, **kwds):
  83         if self.can_update(user):
  84             self.save(*args, **kwds)
  85
  86     def delete_by_user(self, user, *args, **kwds):
  87         if self.can_update(user):
  88             self.delete(*args, **kwds)
  89
  90     @property
  91     def _dict(self):
  92         return model_to_dict(self, fields=[field.name for field in
  93                              self._meta.fields])
  94
  95
  96