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