Created JSON field, descriptor, and formfield to handle json storage on models unifor...

[philo.git] / models / fields.py

diff --git a/models/fields.py b/models/fields.py
index dbf1886..9483516 100644 (file)
--- a/models/fields.py
+++ b/models/fields.py
@@ -1,10 +1,10 @@
 from django.db import models
 from django import forms
-from django.core.exceptions import FieldError
+from django.core.exceptions import FieldError, ValidationError
+from django.utils import simplejson as json
 from django.utils.text import capfirst
-from philo.models.base import Entity
 from philo.signals import entity_class_prepared
-from philo.validators import TemplateValidator
+from philo.validators import TemplateValidator, json_validator
 
 
 __all__ = ('AttributeField', 'RelationshipField')
@@ -24,6 +24,7 @@ class EntityProxyField(object):
                setattr(sender, self.attname, self.descriptor_class(self))
        
        def contribute_to_class(self, cls, name):
+               from philo.models.base import Entity
                if issubclass(cls, Entity):
                        self.name = name
                        self.attname = name
@@ -152,9 +153,58 @@ class TemplateField(models.TextField):
                self.validators.append(TemplateValidator(allow, disallow, secure))
 
 
+class JSONFormField(forms.Field):
+       def clean(self, value):
+               try:
+                       return json.loads(value)
+               except Exception, e:
+                       raise ValidationError(u'JSON decode error: %s' % e)
+
+
+class JSONDescriptor(object):
+       def __init__(self, field):
+               self.field = field
+       
+       def __get__(self, instance, owner):
+               if instance is None:
+                       raise AttributeError # ?
+               
+               if self.field.name not in instance.__dict__:
+                       json_string = getattr(instance, self.field.attname)
+                       instance.__dict__[self.field.name] = json.loads(json_string)
+               
+               return instance.__dict__[self.field.name]
+       
+       def __set__(self, instance, value):
+               instance.__dict__[self.field.name] = value
+               setattr(instance, self.field.attname, json.dumps(value))
+       
+       def __delete__(self, instance):
+               del(instance.__dict__[self.field.name])
+               setattr(instance, self.field.attname, json.dumps(None))
+
+
+class JSONField(models.TextField):
+       def __init__(self, *args, **kwargs):
+               super(JSONField, self).__init__(*args, **kwargs)
+               self.validators.append(json_validator)
+       
+       def get_attname(self):
+               return "%s_json" % self.name
+       
+       def contribute_to_class(self, cls, name):
+               super(JSONField, self).contribute_to_class(cls, name)
+               setattr(cls, name, JSONDescriptor(self))
+       
+       def formfield(self, *args, **kwargs):
+               kwargs["form_class"] = JSONFormField
+               return super(JSONField, self).formfield(*args, **kwargs)
+
+
 try:
        from south.modelsinspector import add_introspection_rules
 except ImportError:
        pass
 else:
-       add_introspection_rules([], ["^philo\.models\.fields\.TemplateField"])
\ No newline at end of file
+       add_introspection_rules([], ["^philo\.models\.fields\.TemplateField"])
+       add_introspection_rules([], ["^philo\.models\.fields\.JSONField"])
\ No newline at end of file