Merge branch 'flexible_attributes'
[philo.git] / models / fields.py
1 from django.db import models
2 from django import forms
3 from django.core.exceptions import FieldError, ValidationError
4 from django.utils import simplejson as json
5 from django.utils.text import capfirst
6 from philo.signals import entity_class_prepared
7 from philo.validators import TemplateValidator, json_validator
8
9
10 __all__ = ('JSONAttribute', 'ForeignKeyAttribute', 'ManyToManyAttribute')
11
12
13 class EntityProxyField(object):
14         descriptor_class = None
15         
16         def __init__(self, *args, **kwargs):
17                 if self.descriptor_class is None:
18                         raise NotImplementedError('EntityProxyField subclasses must specify a descriptor_class.')
19                 self.verbose_name = kwargs.get('verbose_name', None)
20                 self.help_text = kwargs.get('help_text', None)
21         
22         def actually_contribute_to_class(self, sender, **kwargs):
23                 sender._entity_meta.add_proxy_field(self)
24                 setattr(sender, self.attname, self.descriptor_class(self))
25         
26         def contribute_to_class(self, cls, name):
27                 from philo.models.base import Entity
28                 if issubclass(cls, Entity):
29                         self.name = name
30                         self.attname = name
31                         if self.verbose_name is None and name:
32                                 self.verbose_name = name.replace('_', ' ')
33                         entity_class_prepared.connect(self.actually_contribute_to_class, sender=cls)
34                 else:
35                         raise FieldError('%s instances can only be declared on Entity subclasses.' % self.__class__.__name__)
36         
37         def formfield(self, *args, **kwargs):
38                 raise NotImplementedError('EntityProxyField subclasses must implement a formfield method.')
39         
40         def value_from_object(self, obj):
41                 return getattr(obj, self.attname)
42
43
44 class AttributeFieldDescriptor(object):
45         def __init__(self, field):
46                 self.field = field
47         
48         def __get__(self, instance, owner):
49                 if instance:
50                         if self.field.key in instance._added_attribute_registry:
51                                 return instance._added_attribute_registry[self.field.key]
52                         if self.field.key in instance._removed_attribute_registry:
53                                 return None
54                         try:
55                                 return instance.attributes[self.field.key]
56                         except KeyError:
57                                 return None
58                 else:
59                         raise AttributeError('The \'%s\' attribute can only be accessed from %s instances.' % (self.field.name, owner.__name__))
60         
61         def __set__(self, instance, value):
62                 raise NotImplementedError('AttributeFieldDescriptor subclasses must implement a __set__ method.')
63         
64         def __delete__(self, instance):
65                 if self.field.key in instance._added_attribute_registry:
66                         del instance._added_attribute_registry[self.field.key]
67                 instance._removed_attribute_registry.append(self.field.key)
68
69
70 class JSONAttributeDescriptor(AttributeFieldDescriptor):
71         def __set__(self, instance, value):
72                 if self.field.key in instance._removed_attribute_registry:
73                         instance._removed_attribute_registry.remove(self.field.key)
74                 instance._added_attribute_registry[self.field.key] = value
75
76
77 class ForeignKeyAttributeDescriptor(AttributeFieldDescriptor):
78         def __set__(self, instance, value):
79                 if isinstance(value, (models.Model, type(None))):
80                         if self.field.key in instance._removed_attribute_registry:
81                                 instance._removed_attribute_registry.remove(self.field.key)
82                         instance._added_attribute_registry[self.field.key] = value
83                 else:
84                         raise AttributeError('The \'%s\' attribute can only be set using existing Model objects.' % self.field.name)
85
86
87 class ManyToManyAttributeDescriptor(AttributeFieldDescriptor):
88         def __set__(self, instance, value):
89                 if isinstance(value, models.QuerySet):
90                         if self.field.key in instance._removed_attribute_registry:
91                                 instance._removed_attribute_registry.remove(self.field.key)
92                         instance._added_attribute_registry[self.field.key] = value
93                 else:
94                         raise AttributeError('The \'%s\' attribute can only be set to a QuerySet.' % self.field.name)
95
96
97 class AttributeField(EntityProxyField):
98         def contribute_to_class(self, cls, name):
99                 super(AttributeField, self).contribute_to_class(cls, name)
100                 if self.key is None:
101                         self.key = name
102
103
104 class JSONAttribute(AttributeField):
105         descriptor_class = JSONAttributeDescriptor
106         
107         def __init__(self, field_template=None, key=None, **kwargs):
108                 super(AttributeField, self).__init__(**kwargs)
109                 self.key = key
110                 if field_template is None:
111                         field_template = models.CharField(max_length=255)
112                 self.field_template = field_template
113         
114         def formfield(self, **kwargs):
115                 defaults = {'required': False, 'label': capfirst(self.verbose_name), 'help_text': self.help_text}
116                 defaults.update(kwargs)
117                 return self.field_template.formfield(**defaults)
118         
119         def value_from_object(self, obj):
120                 return getattr(obj, self.attname).value
121
122
123 class ForeignKeyAttribute(AttributeField):
124         descriptor_class = ForeignKeyAttributeDescriptor
125         
126         def __init__(self, model, limit_choices_to=None, key=None, **kwargs):
127                 super(ForeignKeyAttribute, self).__init__(**kwargs)
128                 self.key = key
129                 self.model = model
130                 if limit_choices_to is None:
131                         limit_choices_to = {}
132                 self.limit_choices_to = limit_choices_to
133         
134         def formfield(self, form_class=forms.ModelChoiceField, **kwargs):
135                 defaults = {'required': False, 'label': capfirst(self.verbose_name), 'help_text': self.help_text}
136                 defaults.update(kwargs)
137                 return form_class(self.model._default_manager.complex_filter(self.limit_choices_to), **defaults)
138         
139         def value_from_object(self, obj):
140                 relobj = super(ForeignKeyAttribute, self).value_from_object(obj).value
141                 return getattr(relobj, 'pk', None)
142
143
144 class ManyToManyAttribute(AttributeField):
145         descriptor_class = ManyToManyAttributeDescriptor
146         #FIXME: Add __init__ and formfield methods
147
148
149 class TemplateField(models.TextField):
150         def __init__(self, allow=None, disallow=None, secure=True, *args, **kwargs):
151                 super(TemplateField, self).__init__(*args, **kwargs)
152                 self.validators.append(TemplateValidator(allow, disallow, secure))
153
154
155 class JSONFormField(forms.Field):
156         def clean(self, value):
157                 try:
158                         return json.loads(value)
159                 except Exception, e:
160                         raise ValidationError(u'JSON decode error: %s' % e)
161
162
163 class JSONDescriptor(object):
164         def __init__(self, field):
165                 self.field = field
166         
167         def __get__(self, instance, owner):
168                 if instance is None:
169                         raise AttributeError # ?
170                 
171                 if self.field.name not in instance.__dict__:
172                         json_string = getattr(instance, self.field.attname)
173                         instance.__dict__[self.field.name] = json.loads(json_string)
174                 
175                 return instance.__dict__[self.field.name]
176         
177         def __set__(self, instance, value):
178                 instance.__dict__[self.field.name] = value
179                 setattr(instance, self.field.attname, json.dumps(value))
180         
181         def __delete__(self, instance):
182                 del(instance.__dict__[self.field.name])
183                 setattr(instance, self.field.attname, json.dumps(None))
184
185
186 class JSONField(models.TextField):
187         def __init__(self, *args, **kwargs):
188                 super(JSONField, self).__init__(*args, **kwargs)
189                 self.validators.append(json_validator)
190         
191         def get_attname(self):
192                 return "%s_json" % self.name
193         
194         def contribute_to_class(self, cls, name):
195                 super(JSONField, self).contribute_to_class(cls, name)
196                 setattr(cls, name, JSONDescriptor(self))
197         
198         def formfield(self, *args, **kwargs):
199                 kwargs["form_class"] = JSONFormField
200                 return super(JSONField, self).formfield(*args, **kwargs)
201
202
203 try:
204         from south.modelsinspector import add_introspection_rules
205 except ImportError:
206         pass
207 else:
208         add_introspection_rules([], ["^philo\.models\.fields\.TemplateField"])
209         add_introspection_rules([], ["^philo\.models\.fields\.JSONField"])