planetstack/core/models/plcorebase.py

   1 import datetime
   2 import os
   3 import sys
   4 from django.db import models
   5 from django.forms.models import model_to_dict
   6 from django.core.urlresolvers import reverse
   7 from django.forms.models import model_to_dict
   8
   9 try:
  10     # This is a no-op if observer_disabled is set to 1 in the config file
  11     from observer import *
  12 except:
  13     print >> sys.stderr, "import of observer failed! printing traceback and disabling observer:"
  14     import traceback
  15     traceback.print_exc()
  16
  17     # guard against something failing
  18     def notify_observer(*args, **kwargs):
  19         pass
  20
  21 class PlCoreBaseManager(models.Manager):
  22     def get_query_set(self):
  23         return super(PlCoreBaseManager, self).get_query_set().filter(deleted=False)
  24
  25     # default values for created and updated are only there to keep evolution
  26     # from failing.
  27 class PlCoreBase(models.Model):
  28     objects = PlCoreBaseManager()
  29     created = models.DateTimeField(auto_now_add=True, default=datetime.datetime.now())
  30     updated = models.DateTimeField(auto_now=True, default=datetime.datetime.now())
  31     enacted = models.DateTimeField(null=True, default=None)
  32     backend_status = models.CharField(max_length=140,
  33                                       default="Provisioning in progress")
  34     deleted = models.BooleanField(default=False)
  35
  36     class Meta:
  37         abstract = True
  38         app_label = "core"
  39
  40     def __init__(self, *args, **kwargs):
  41         super(PlCoreBase, self).__init__(*args, **kwargs)
  42         self.__initial = self._dict
  43
  44     @property
  45     def diff(self):
  46         d1 = self.__initial
  47         d2 = self._dict
  48         diffs = [(k, (v, d2[k])) for k, v in d1.items() if v != d2[k]]
  49         return dict(diffs)
  50
  51     @property
  52     def has_changed(self):
  53         return bool(self.diff)
  54
  55     @property
  56     def changed_fields(self):
  57         return self.diff.keys()
  58
  59     def get_field_diff(self, field_name):
  60         return self.diff.get(field_name, None)
  61
  62     def can_update(self, user):
  63         if user.is_readonly:
  64             return False
  65         if user.is_admin:
  66             return True
  67         return False
  68
  69     def delete(self, *args, **kwds):
  70         # so we have something to give the observer
  71         pk = self.pk
  72         model_dict = model_to_dict(self)
  73         for (k,v) in model_dict.items():
  74             # things like datetime are not JSON serializable
  75             model_dict[k] = str(v)
  76
  77         super(PlCoreBase, self).delete(*args, **kwds)
  78
  79         # This is a no-op if observer_disabled is set
  80         notify_observer(model=self, delete=True, pk=pk, model_dict=model_dict)
  81
  82     def save(self, *args, **kwargs):
  83         super(PlCoreBase, self).save(*args, **kwargs)
  84
  85         # This is a no-op if observer_disabled is set
  86         notify_observer()
  87
  88         self.__initial = self._dict
  89
  90     def save_by_user(self, user, *args, **kwds):
  91         if self.can_update(user):
  92             self.save(*args, **kwds)
  93
  94     def delete_by_user(self, user, *args, **kwds):
  95         if self.can_update(user):
  96             self.delete(*args, **kwds)
  97
  98     @property
  99     def _dict(self):
 100         return model_to_dict(self, fields=[field.name for field in
 101                              self._meta.fields])
 102
 103
 104