models/base.py

   1 from django import forms
   2 from django.db import models
   3 from django.contrib.contenttypes.models import ContentType
   4 from django.contrib.contenttypes import generic
   5 from django.utils import simplejson as json
   6 from django.core.exceptions import ObjectDoesNotExist
   7 from philo.exceptions import AncestorDoesNotExist
   8 from philo.models.fields import JSONField
   9 from philo.utils import ContentTypeRegistryLimiter, ContentTypeSubclassLimiter
  10 from philo.signals import entity_class_prepared
  11 from philo.validators import json_validator
  12 from UserDict import DictMixin
  13
  14
  15 class Tag(models.Model):
  16         name = models.CharField(max_length=255)
  17         slug = models.SlugField(max_length=255, unique=True)
  18
  19         def __unicode__(self):
  20                 return self.name
  21
  22         class Meta:
  23                 app_label = 'philo'
  24
  25
  26 class Titled(models.Model):
  27         title = models.CharField(max_length=255)
  28         slug = models.SlugField(max_length=255)
  29
  30         def __unicode__(self):
  31                 return self.title
  32
  33         class Meta:
  34                 abstract = True
  35
  36
  37 value_content_type_limiter = ContentTypeRegistryLimiter()
  38
  39
  40 def register_value_model(model):
  41         value_content_type_limiter.register_class(model)
  42
  43
  44 def unregister_value_model(model):
  45         value_content_type_limiter.unregister_class(model)
  46
  47
  48 class AttributeValue(models.Model):
  49         attribute = generic.GenericRelation('Attribute', content_type_field='value_content_type', object_id_field='value_object_id')
  50         def apply_data(self, data):
  51                 raise NotImplementedError
  52
  53         def value_formfield(self, **kwargs):
  54                 raise NotImplementedError
  55
  56         def __unicode__(self):
  57                 return unicode(self.value)
  58
  59         class Meta:
  60                 abstract = True
  61
  62
  63 attribute_value_limiter = ContentTypeSubclassLimiter(AttributeValue)
  64
  65
  66 class JSONValue(AttributeValue):
  67         value = JSONField() #verbose_name='Value (JSON)', help_text='This value must be valid JSON.')
  68
  69         def __unicode__(self):
  70                 return self.value_json
  71
  72         def value_formfield(self, **kwargs):
  73                 kwargs['initial'] = self.value_json
  74                 return self._meta.get_field('value').formfield(**kwargs)
  75
  76         def apply_data(self, cleaned_data):
  77                 self.value = cleaned_data.get('value', None)
  78
  79         class Meta:
  80                 app_label = 'philo'
  81
  82
  83 class ForeignKeyValue(AttributeValue):
  84         content_type = models.ForeignKey(ContentType, related_name='foreign_key_value_set', limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
  85         object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True)
  86         value = generic.GenericForeignKey()
  87
  88         def value_formfield(self, form_class=forms.ModelChoiceField, **kwargs):
  89                 if self.content_type is None:
  90                         return None
  91                 kwargs.update({'initial': self.object_id, 'required': False})
  92                 return form_class(self.content_type.model_class()._default_manager.all(), **kwargs)
  93
  94         def apply_data(self, cleaned_data):
  95                 if 'value' in cleaned_data and cleaned_data['value'] is not None:
  96                         self.value = cleaned_data['value']
  97                 else:
  98                         self.content_type = cleaned_data.get('content_type', None)
  99                         # If there is no value set in the cleaned data, clear the stored value.
 100                         self.object_id = None
 101
 102         class Meta:
 103                 app_label = 'philo'
 104
 105
 106 class ManyToManyValue(AttributeValue):
 107         # TODO: Change object_ids to object_pks.
 108         content_type = models.ForeignKey(ContentType, related_name='many_to_many_value_set', limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
 109         object_ids = models.CommaSeparatedIntegerField(max_length=300, verbose_name='Value IDs', null=True, blank=True)
 110
 111         def get_object_id_list(self):
 112                 if not self.object_ids:
 113                         return []
 114                 else:
 115                         return self.object_ids.split(',')
 116
 117         def get_value(self):
 118                 if self.content_type is None:
 119                         return None
 120
 121                 return self.content_type.model_class()._default_manager.filter(id__in=self.get_object_id_list())
 122
 123         def set_value(self, value):
 124                 # Value is probably a queryset - but allow any iterable.
 125                 if isinstance(value, models.query.QuerySet):
 126                         value = value.values_list('id', flat=True)
 127
 128                 self.object_ids = ','.join([str(v) for v in value])
 129
 130         value = property(get_value, set_value)
 131
 132         def value_formfield(self, form_class=forms.ModelMultipleChoiceField, **kwargs):
 133                 if self.content_type is None:
 134                         return None
 135                 kwargs.update({'initial': self.get_object_id_list(), 'required': False})
 136                 return form_class(self.content_type.model_class()._default_manager.all(), **kwargs)
 137
 138         def apply_data(self, cleaned_data):
 139                 if 'value' in cleaned_data and cleaned_data['value'] is not None:
 140                         self.value = cleaned_data['value']
 141                 else:
 142                         self.content_type = cleaned_data.get('content_type', None)
 143                         # If there is no value set in the cleaned data, clear the stored value.
 144                         self.object_ids = ""
 145
 146         class Meta:
 147                 app_label = 'philo'
 148
 149
 150 class Attribute(models.Model):
 151         entity_content_type = models.ForeignKey(ContentType, related_name='attribute_entity_set', verbose_name='Entity type')
 152         entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID')
 153         entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
 154
 155         value_content_type = models.ForeignKey(ContentType, related_name='attribute_value_set', limit_choices_to=attribute_value_limiter, verbose_name='Value type', null=True, blank=True)
 156         value_object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True)
 157         value = generic.GenericForeignKey('value_content_type', 'value_object_id')
 158
 159         key = models.CharField(max_length=255)
 160
 161         def __unicode__(self):
 162                 return u'"%s": %s' % (self.key, self.value)
 163
 164         class Meta:
 165                 app_label = 'philo'
 166                 unique_together = (('key', 'entity_content_type', 'entity_object_id'), ('value_content_type', 'value_object_id'))
 167
 168
 169 class QuerySetMapper(object, DictMixin):
 170         def __init__(self, queryset, passthrough=None):
 171                 self.queryset = queryset
 172                 self.passthrough = passthrough
 173
 174         def __getitem__(self, key):
 175                 try:
 176                         value = self.queryset.get(key__exact=key).value
 177                 except ObjectDoesNotExist:
 178                         if self.passthrough is not None:
 179                                 return self.passthrough.__getitem__(key)
 180                         raise KeyError
 181                 else:
 182                         if value is not None:
 183                                 return value.value
 184                         return value
 185
 186         def keys(self):
 187                 keys = set(self.queryset.values_list('key', flat=True).distinct())
 188                 if self.passthrough is not None:
 189                         keys |= set(self.passthrough.keys())
 190                 return list(keys)
 191
 192
 193 class EntityOptions(object):
 194         def __init__(self, options):
 195                 if options is not None:
 196                         for key, value in options.__dict__.items():
 197                                 setattr(self, key, value)
 198                 if not hasattr(self, 'proxy_fields'):
 199                         self.proxy_fields = []
 200
 201         def add_proxy_field(self, proxy_field):
 202                 self.proxy_fields.append(proxy_field)
 203
 204
 205 class EntityBase(models.base.ModelBase):
 206         def __new__(cls, name, bases, attrs):
 207                 new = super(EntityBase, cls).__new__(cls, name, bases, attrs)
 208                 entity_options = attrs.pop('EntityMeta', None)
 209                 setattr(new, '_entity_meta', EntityOptions(entity_options))
 210                 entity_class_prepared.send(sender=new)
 211                 return new
 212
 213
 214 class Entity(models.Model):
 215         __metaclass__ = EntityBase
 216
 217         attribute_set = generic.GenericRelation(Attribute, content_type_field='entity_content_type', object_id_field='entity_object_id')
 218
 219         @property
 220         def attributes(self):
 221                 return QuerySetMapper(self.attribute_set)
 222
 223         @property
 224         def _added_attribute_registry(self):
 225                 if not hasattr(self, '_real_added_attribute_registry'):
 226                         self._real_added_attribute_registry = {}
 227                 return self._real_added_attribute_registry
 228
 229         @property
 230         def _removed_attribute_registry(self):
 231                 if not hasattr(self, '_real_removed_attribute_registry'):
 232                         self._real_removed_attribute_registry = []
 233                 return self._real_removed_attribute_registry
 234
 235         def save(self, *args, **kwargs):
 236                 super(Entity, self).save(*args, **kwargs)
 237
 238                 for key in self._removed_attribute_registry:
 239                         self.attribute_set.filter(key__exact=key).delete()
 240                 del self._removed_attribute_registry[:]
 241
 242                 for field, value in self._added_attribute_registry.items():
 243                         try:
 244                                 attribute = self.attribute_set.get(key__exact=field.key)
 245                         except Attribute.DoesNotExist:
 246                                 attribute = Attribute()
 247                                 attribute.entity = self
 248                                 attribute.key = field.key
 249
 250                         field.set_attribute_value(attribute, value)
 251                         attribute.save()
 252                 self._added_attribute_registry.clear()
 253
 254         class Meta:
 255                 abstract = True
 256
 257
 258 class TreeManager(models.Manager):
 259         use_for_related_fields = True
 260
 261         def roots(self):
 262                 return self.filter(parent__isnull=True)
 263
 264         def get_with_path(self, path, root=None, absolute_result=True, pathsep='/'):
 265                 """
 266                 Returns the object with the path, or None if there is no object with that path,
 267                 unless absolute_result is set to False, in which case it returns a tuple containing
 268                 the deepest object found along the path, and the remainder of the path after that
 269                 object as a string (or None in the case that there is no remaining path).
 270                 """
 271                 slugs = path.split(pathsep)
 272                 obj = root
 273                 remaining_slugs = list(slugs)
 274                 remainder = None
 275                 for slug in slugs:
 276                         remaining_slugs.remove(slug)
 277                         if slug: # ignore blank slugs, handles for multiple consecutive pathseps
 278                                 try:
 279                                         obj = self.get(slug__exact=slug, parent__exact=obj)
 280                                 except self.model.DoesNotExist:
 281                                         if absolute_result:
 282                                                 obj = None
 283                                         remaining_slugs.insert(0, slug)
 284                                         remainder = pathsep.join(remaining_slugs)
 285                                         break
 286                 if obj:
 287                         if absolute_result:
 288                                 return obj
 289                         else:
 290                                 return (obj, remainder)
 291                 raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name)
 292
 293
 294 class TreeModel(models.Model):
 295         objects = TreeManager()
 296         parent = models.ForeignKey('self', related_name='children', null=True, blank=True)
 297         slug = models.SlugField(max_length=255)
 298
 299         def has_ancestor(self, ancestor):
 300                 parent = self
 301                 while parent:
 302                         if parent == ancestor:
 303                                 return True
 304                         parent = parent.parent
 305                 return False
 306
 307         def get_path(self, root=None, pathsep='/', field='slug'):
 308                 if root is not None and not self.has_ancestor(root):
 309                         raise AncestorDoesNotExist(root)
 310
 311                 path = getattr(self, field, '?')
 312                 parent = self.parent
 313                 while parent and parent != root:
 314                         path = getattr(parent, field, '?') + pathsep + path
 315                         parent = parent.parent
 316                 return path
 317         path = property(get_path)
 318
 319         def __unicode__(self):
 320                 return self.path
 321
 322         class Meta:
 323                 unique_together = (('parent', 'slug'),)
 324                 abstract = True
 325
 326
 327 class TreeEntity(Entity, TreeModel):
 328         @property
 329         def attributes(self):
 330                 if self.parent:
 331                         return QuerySetMapper(self.attribute_set, passthrough=self.parent.attributes)
 332                 return super(TreeEntity, self).attributes
 333
 334         class Meta:
 335                 abstract = True