blob: 000e77e0b78b6a4d3bf25296425e48842149c46e [file] [log] [blame]
import os
import sys
from django.db import models
from django.forms.models import model_to_dict
from django.core.urlresolvers import reverse
from django.forms.models import model_to_dict
from django.utils import timezone
from django.core.exceptions import PermissionDenied
import model_policy
try:
# This is a no-op if observer_disabled is set to 1 in the config file
from observer import *
except:
print >> sys.stderr, "import of observer failed! printing traceback and disabling observer:"
import traceback
traceback.print_exc()
# guard against something failing
def notify_observer(*args, **kwargs):
pass
# This manager will be inherited by all subclasses because
# the core model is abstract.
class PlCoreBaseDeletionManager(models.Manager):
def get_queryset(self):
parent=super(PlCoreBaseDeletionManager, self)
if hasattr(parent, "get_queryset"):
return parent.get_queryset().filter(deleted=True)
else:
return parent.get_query_set().filter(deleted=True)
# deprecated in django 1.7 in favor of get_queryset().
def get_query_set(self):
return self.get_queryset()
# This manager will be inherited by all subclasses because
# the core model is abstract.
class PlCoreBaseManager(models.Manager):
def get_queryset(self):
parent=super(PlCoreBaseManager, self)
if hasattr(parent, "get_queryset"):
return parent.get_queryset().filter(deleted=False)
else:
return parent.get_query_set().filter(deleted=False)
# deprecated in django 1.7 in favor of get_queryset().
def get_query_set(self):
return self.get_queryset()
class DiffModelMixIn:
# Provides useful methods for computing which objects in a model have
# changed. Make sure to do self._initial = self._dict in the __init__
# method.
# This is broken out of PlCoreBase into a Mixin so the User model can
# also make use of it.
@property
def _dict(self):
return model_to_dict(self, fields=[field.name for field in
self._meta.fields])
@property
def diff(self):
d1 = self._initial
d2 = self._dict
diffs = [(k, (v, d2[k])) for k, v in d1.items() if v != d2[k]]
return dict(diffs)
@property
def has_changed(self):
return bool(self.diff)
@property
def changed_fields(self):
return self.diff.keys()
def has_field_changed(self, field_name):
return field_name in self.diff.keys()
def get_field_diff(self, field_name):
return self.diff.get(field_name, None)
class PlCoreBase(models.Model, DiffModelMixIn):
objects = PlCoreBaseManager()
deleted_objects = PlCoreBaseDeletionManager()
# default values for created and updated are only there to keep evolution
# from failing.
created = models.DateTimeField(auto_now_add=True, default=timezone.now)
updated = models.DateTimeField(auto_now=True, default=timezone.now)
enacted = models.DateTimeField(null=True, default=None)
backend_status = models.CharField(max_length=140,
default="Provisioning in progress")
deleted = models.BooleanField(default=False)
class Meta:
# Changing abstract to False would require the managers of subclasses of
# PlCoreBase to be customized individually.
abstract = True
app_label = "core"
def __init__(self, *args, **kwargs):
super(PlCoreBase, self).__init__(*args, **kwargs)
self._initial = self._dict # for DiffModelMixIn
self.silent = False
def can_update(self, user):
if user.is_readonly:
return False
if user.is_admin:
return True
return False
def delete(self, *args, **kwds):
# so we have something to give the observer
purge = kwds.get('purge',False)
silent = kwds.get('silent',False)
try:
purge = purge or observer_disabled
except NameError:
pass
if (purge):
del kwds['purge']
super(PlCoreBase, self).delete(*args, **kwds)
else:
self.deleted = True
self.enacted=None
self.save(update_fields=['enacted','deleted'], silent=silent)
def save(self, *args, **kwargs):
# let the user specify silence as either a kwarg or an instance varible
silent = self.silent
if "silent" in kwargs:
silent=silent or kwargs.pop("silent")
super(PlCoreBase, self).save(*args, **kwargs)
# This is a no-op if observer_disabled is set
if not silent:
notify_observer()
self._initial = self._dict
def save_by_user(self, user, *args, **kwds):
if not self.can_update(user):
if getattr(self, "_cant_update_fieldName", None) is not None:
raise PermissionDenied("You do not have permission to update field %s on object %s" % (self._cant_update_fieldName, self.__class__.__name__))
else:
raise PermissionDenied("You do not have permission to update %s objects" % self.__class__.__name__)
self.save(*args, **kwds)
def delete_by_user(self, user, *args, **kwds):
if not self.can_update(user):
raise PermissionDenied("You do not have permission to delete %s objects" % self.__class__.__name__)
self.delete(*args, **kwds)
@classmethod
def select_by_user(cls, user):
# This should be overridden by descendant classes that want to perform
# filtering of visible objects by user.
return cls.objects.all()