apps/sponsors/fields.py

   1 # -*- encoding: utf-8 -*-
   2 import datetime
   3
   4 from django.conf import settings
   5 from django.db import models
   6 from django import forms
   7 from django.utils import simplejson as json
   8
   9
  10 class JSONEncoder(json.JSONEncoder):
  11     def default(self, obj):
  12         if isinstance(obj, datetime.datetime):
  13             return obj.strftime('%Y-%m-%d %H:%M:%S')
  14         elif isinstance(obj, datetime.date):
  15             return obj.strftime('%Y-%m-%d')
  16         elif isinstance(obj, datetime.time):
  17             return obj.strftime('%H:%M:%S')
  18         return json.JSONEncoder.default(self, obj)
  19
  20
  21 def dumps(data):
  22     return JSONEncoder().encode(data)
  23
  24
  25 def loads(str):
  26     return json.loads(str, encoding=settings.DEFAULT_CHARSET)
  27
  28
  29 class JSONFormField(forms.CharField):
  30     widget = forms.Textarea
  31
  32     def clean(self, value):
  33         try:
  34             loads(value)
  35             return value
  36         except ValueError, e:
  37             raise forms.ValidationError('Enter a valid JSON value. Error: %s' % e)
  38
  39
  40 class JSONField(models.TextField):
  41     def formfield(self, **kwargs):
  42         defaults = {'form_class': JSONFormField}
  43         defaults.update(kwargs)
  44         return super(JSONField, self).formfield(**defaults)
  45
  46     def db_type(self):
  47         return 'text'
  48
  49     def get_internal_type(self):
  50         return 'TextField'
  51
  52     def contribute_to_class(self, cls, name):
  53         super(JSONField, self).contribute_to_class(cls, name)
  54
  55         def get_value(model_instance):
  56             return loads(getattr(model_instance, self.attname, None))
  57         setattr(cls, 'get_%s_value' % self.name, get_value)
  58
  59         def set_value(model_instance, json):
  60             return setattr(model_instance, self.attname, dumps(json))
  61         setattr(cls, 'set_%s_value' % self.name, set_value)