philo/models/fields/__init__.py

   1 from django import forms
   2 from django.core.exceptions import ValidationError
   3 from django.core.validators import validate_slug
   4 from django.db import models
   5 from django.utils import simplejson as json
   6 from django.utils.text import capfirst
   7 from django.utils.translation import ugettext_lazy as _
   8
   9 from philo.forms.fields import JSONFormField
  10 from philo.validators import TemplateValidator, json_validator
  11 #from philo.models.fields.entities import *
  12
  13
  14 class TemplateField(models.TextField):
  15         """A :class:`TextField` which is validated with a :class:`.TemplateValidator`. ``allow``, ``disallow``, and ``secure`` will be passed into the validator's construction."""
  16         def __init__(self, allow=None, disallow=None, secure=True, *args, **kwargs):
  17                 super(TemplateField, self).__init__(*args, **kwargs)
  18                 self.validators.append(TemplateValidator(allow, disallow, secure))
  19
  20
  21 class JSONDescriptor(object):
  22         def __init__(self, field):
  23                 self.field = field
  24
  25         def __get__(self, instance, owner):
  26                 if instance is None:
  27                         raise AttributeError # ?
  28
  29                 if self.field.name not in instance.__dict__:
  30                         json_string = getattr(instance, self.field.attname)
  31                         instance.__dict__[self.field.name] = json.loads(json_string)
  32
  33                 return instance.__dict__[self.field.name]
  34
  35         def __set__(self, instance, value):
  36                 instance.__dict__[self.field.name] = value
  37                 setattr(instance, self.field.attname, json.dumps(value))
  38
  39         def __delete__(self, instance):
  40                 del(instance.__dict__[self.field.name])
  41                 setattr(instance, self.field.attname, json.dumps(None))
  42
  43
  44 class JSONField(models.TextField):
  45         """A :class:`TextField` which stores its value on the model instance as a python object and stores its value in the database as JSON. Validated with :func:`.json_validator`."""
  46         default_validators = [json_validator]
  47
  48         def get_attname(self):
  49                 return "%s_json" % self.name
  50
  51         def contribute_to_class(self, cls, name):
  52                 super(JSONField, self).contribute_to_class(cls, name)
  53                 setattr(cls, name, JSONDescriptor(self))
  54                 models.signals.pre_init.connect(self.fix_init_kwarg, sender=cls)
  55
  56         def fix_init_kwarg(self, sender, args, kwargs, **signal_kwargs):
  57                 # Anything passed in as self.name is assumed to come from a serializer and
  58                 # will be treated as a json string.
  59                 if self.name in kwargs:
  60                         value = kwargs.pop(self.name)
  61
  62                         # Hack to handle the xml serializer's handling of "null"
  63                         if value is None:
  64                                 value = 'null'
  65
  66                         kwargs[self.attname] = value
  67
  68         def formfield(self, *args, **kwargs):
  69                 kwargs["form_class"] = JSONFormField
  70                 return super(JSONField, self).formfield(*args, **kwargs)
  71
  72
  73 class SlugMultipleChoiceField(models.Field):
  74         """Stores a selection of multiple items with unique slugs in the form of a comma-separated list."""
  75         __metaclass__ = models.SubfieldBase
  76         description = _("Comma-separated slug field")
  77
  78         def get_internal_type(self):
  79                 return "TextField"
  80
  81         def to_python(self, value):
  82                 if not value:
  83                         return []
  84
  85                 if isinstance(value, list):
  86                         return value
  87
  88                 return value.split(',')
  89
  90         def get_prep_value(self, value):
  91                 return ','.join(value)
  92
  93         def formfield(self, **kwargs):
  94                 # This is necessary because django hard-codes TypedChoiceField for things with choices.
  95                 defaults = {
  96                         'widget': forms.CheckboxSelectMultiple,
  97                         'choices': self.get_choices(include_blank=False),
  98                         'label': capfirst(self.verbose_name),
  99                         'required': not self.blank,
 100                         'help_text': self.help_text
 101                 }
 102                 if self.has_default():
 103                         if callable(self.default):
 104                                 defaults['initial'] = self.default
 105                                 defaults['show_hidden_initial'] = True
 106                         else:
 107                                 defaults['initial'] = self.get_default()
 108
 109                 for k in kwargs.keys():
 110                         if k not in ('coerce', 'empty_value', 'choices', 'required',
 111                                                  'widget', 'label', 'initial', 'help_text',
 112                                                  'error_messages', 'show_hidden_initial'):
 113                                 del kwargs[k]
 114
 115                 defaults.update(kwargs)
 116                 form_class = forms.TypedMultipleChoiceField
 117                 return form_class(**defaults)
 118
 119         def validate(self, value, model_instance):
 120                 invalid_values = []
 121                 for val in value:
 122                         try:
 123                                 validate_slug(val)
 124                         except ValidationError:
 125                                 invalid_values.append(val)
 126
 127                 if invalid_values:
 128                         # should really make a custom message.
 129                         raise ValidationError(self.error_messages['invalid_choice'] % invalid_values)
 130
 131
 132 try:
 133         from south.modelsinspector import add_introspection_rules
 134 except ImportError:
 135         pass
 136 else:
 137         add_introspection_rules([], ["^philo\.models\.fields\.SlugMultipleChoiceField"])
 138         add_introspection_rules([], ["^philo\.models\.fields\.TemplateField"])
 139         add_introspection_rules([], ["^philo\.models\.fields\.JSONField"])