models/fields.py

   1 from django import forms
   2 from django.db import models
   3 from django.utils import simplejson as json
   4 from philo.forms.fields import JSONFormField
   5 from philo.validators import TemplateValidator, json_validator
   6
   7
   8 class TemplateField(models.TextField):
   9         def __init__(self, allow=None, disallow=None, secure=True, *args, **kwargs):
  10                 super(TemplateField, self).__init__(*args, **kwargs)
  11                 self.validators.append(TemplateValidator(allow, disallow, secure))
  12
  13
  14 class JSONDescriptor(object):
  15         def __init__(self, field):
  16                 self.field = field
  17
  18         def __get__(self, instance, owner):
  19                 if instance is None:
  20                         raise AttributeError # ?
  21
  22                 if self.field.name not in instance.__dict__:
  23                         json_string = getattr(instance, self.field.attname)
  24                         instance.__dict__[self.field.name] = json.loads(json_string)
  25
  26                 return instance.__dict__[self.field.name]
  27
  28         def __set__(self, instance, value):
  29                 instance.__dict__[self.field.name] = value
  30                 setattr(instance, self.field.attname, json.dumps(value))
  31
  32         def __delete__(self, instance):
  33                 del(instance.__dict__[self.field.name])
  34                 setattr(instance, self.field.attname, json.dumps(None))
  35
  36
  37 class JSONField(models.TextField):
  38         default_validators = [json_validator]
  39
  40         def get_attname(self):
  41                 return "%s_json" % self.name
  42
  43         def contribute_to_class(self, cls, name):
  44                 super(JSONField, self).contribute_to_class(cls, name)
  45                 setattr(cls, name, JSONDescriptor(self))
  46                 models.signals.pre_init.connect(self.fix_init_kwarg, sender=cls)
  47
  48         def fix_init_kwarg(self, sender, args, kwargs, **signal_kwargs):
  49                 if self.name in kwargs:
  50                         kwargs[self.attname] = json.dumps(kwargs.pop(self.name))
  51
  52         def formfield(self, *args, **kwargs):
  53                 kwargs["form_class"] = JSONFormField
  54                 return super(JSONField, self).formfield(*args, **kwargs)
  55
  56
  57 try:
  58         from south.modelsinspector import add_introspection_rules
  59 except ImportError:
  60         pass
  61 else:
  62         add_introspection_rules([], ["^philo\.models\.fields\.TemplateField"])
  63         add_introspection_rules([], ["^philo\.models\.fields\.JSONField"])