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                 if value is None:
 125                         self.object_ids = ""
 126                         return
 127                 if not isinstance(value, models.query.QuerySet):
 128                         raise TypeError("Value must be a QuerySet.")
 129                 self.content_type = ContentType.objects.get_for_model(value.model)
 130                 self.object_ids = ','.join([`value` for value in value.values_list('id', flat=True)])
 131
 132         value = property(get_value, set_value)
 133
 134         def value_formfield(self, form_class=forms.ModelMultipleChoiceField, **kwargs):
 135                 if self.content_type is None:
 136                         return None
 137                 kwargs.update({'initial': self.get_object_id_list(), 'required': False})
 138                 return form_class(self.content_type.model_class()._default_manager.all(), **kwargs)
 139
 140         def apply_data(self, cleaned_data):
 141                 if 'value' in cleaned_data and cleaned_data['value'] is not None:
 142                         self.value = cleaned_data['value']
 143                 else:
 144                         self.content_type = cleaned_data.get('content_type', None)
 145                         # If there is no value set in the cleaned data, clear the stored value.
 146                         self.object_ids = ""
 147
 148         class Meta:
 149                 app_label = 'philo'
 150
 151
 152 class Attribute(models.Model):
 153         entity_content_type = models.ForeignKey(ContentType, related_name='attribute_entity_set', verbose_name='Entity type')
 154         entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID')
 155         entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
 156
 157         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)
 158         value_object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True)
 159         value = generic.GenericForeignKey('value_content_type', 'value_object_id')
 160
 161         key = models.CharField(max_length=255)
 162
 163         def __unicode__(self):
 164                 return u'"%s": %s' % (self.key, self.value)
 165
 166         class Meta:
 167                 app_label = 'philo'
 168                 unique_together = (('key', 'entity_content_type', 'entity_object_id'), ('value_content_type', 'value_object_id'))
 169
 170
 171 class QuerySetMapper(object, DictMixin):
 172         def __init__(self, queryset, passthrough=None):
 173                 self.queryset = queryset
 174                 self.passthrough = passthrough
 175
 176         def __getitem__(self, key):
 177                 try:
 178                         value = self.queryset.get(key__exact=key).value
 179                 except ObjectDoesNotExist:
 180                         if self.passthrough is not None:
 181                                 return self.passthrough.__getitem__(key)
 182                         raise KeyError
 183                 else:
 184                         if value is not None:
 185                                 return value.value
 186                         return value
 187
 188         def keys(self):
 189                 keys = set(self.queryset.values_list('key', flat=True).distinct())
 190                 if self.passthrough is not None:
 191                         keys |= set(self.passthrough.keys())
 192                 return list(keys)
 193
 194
 195 class EntityOptions(object):
 196         def __init__(self, options):
 197                 if options is not None:
 198                         for key, value in options.__dict__.items():
 199                                 setattr(self, key, value)
 200                 if not hasattr(self, 'proxy_fields'):
 201                         self.proxy_fields = []
 202
 203         def add_proxy_field(self, proxy_field):
 204                 self.proxy_fields.append(proxy_field)
 205
 206
 207 class EntityBase(models.base.ModelBase):
 208         def __new__(cls, name, bases, attrs):
 209                 new = super(EntityBase, cls).__new__(cls, name, bases, attrs)
 210                 entity_options = attrs.pop('EntityMeta', None)
 211                 setattr(new, '_entity_meta', EntityOptions(entity_options))
 212                 entity_class_prepared.send(sender=new)
 213                 return new
 214
 215
 216 class Entity(models.Model):
 217         __metaclass__ = EntityBase
 218
 219         attribute_set = generic.GenericRelation(Attribute, content_type_field='entity_content_type', object_id_field='entity_object_id')
 220
 221         @property
 222         def attributes(self):
 223                 return QuerySetMapper(self.attribute_set)
 224
 225         @property
 226         def _added_attribute_registry(self):
 227                 if not hasattr(self, '_real_added_attribute_registry'):
 228                         self._real_added_attribute_registry = {}
 229                 return self._real_added_attribute_registry
 230
 231         @property
 232         def _removed_attribute_registry(self):
 233                 if not hasattr(self, '_real_removed_attribute_registry'):
 234                         self._real_removed_attribute_registry = []
 235                 return self._real_removed_attribute_registry
 236
 237         def save(self, *args, **kwargs):
 238                 super(Entity, self).save(*args, **kwargs)
 239
 240                 for key in self._removed_attribute_registry:
 241                         self.attribute_set.filter(key__exact=key).delete()
 242                 del self._removed_attribute_registry[:]
 243
 244                 for field, value in self._added_attribute_registry.items():
 245                         try:
 246                                 attribute = self.attribute_set.get(key__exact=field.key)
 247                         except Attribute.DoesNotExist:
 248                                 attribute = Attribute()
 249                                 attribute.entity = self
 250                                 attribute.key = field.key
 251
 252                         field.set_attribute_value(attribute, value)
 253                         attribute.save()
 254                 self._added_attribute_registry.clear()
 255
 256         class Meta:
 257                 abstract = True
 258
 259
 260 class TreeManager(models.Manager):
 261         use_for_related_fields = True
 262
 263         def roots(self):
 264                 return self.filter(parent__isnull=True)
 265
 266         def get_with_path(self, path, root=None, absolute_result=True, pathsep='/'):
 267                 """
 268                 Returns the object with the path, or None if there is no object with that path,
 269                 unless absolute_result is set to False, in which case it returns a tuple containing
 270                 the deepest object found along the path, and the remainder of the path after that
 271                 object as a string (or None in the case that there is no remaining path).
 272                 """
 273                 slugs = path.split(pathsep)
 274                 obj = root
 275                 remaining_slugs = list(slugs)
 276                 remainder = None
 277                 for slug in slugs:
 278                         remaining_slugs.remove(slug)
 279                         if slug: # ignore blank slugs, handles for multiple consecutive pathseps
 280                                 try:
 281                                         obj = self.get(slug__exact=slug, parent__exact=obj)
 282                                 except self.model.DoesNotExist:
 283                                         if absolute_result:
 284                                                 obj = None
 285                                         remaining_slugs.insert(0, slug)
 286                                         remainder = pathsep.join(remaining_slugs)
 287                                         break
 288                 if obj:
 289                         if absolute_result:
 290                                 return obj
 291                         else:
 292                                 return (obj, remainder)
 293                 raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name)
 294
 295
 296 class TreeModel(models.Model):
 297         objects = TreeManager()
 298         parent = models.ForeignKey('self', related_name='children', null=True, blank=True)
 299         slug = models.SlugField(max_length=255)
 300
 301         def has_ancestor(self, ancestor):
 302                 parent = self
 303                 while parent:
 304                         if parent == ancestor:
 305                                 return True
 306                         parent = parent.parent
 307                 return False
 308
 309         def get_path(self, root=None, pathsep='/', field='slug'):
 310                 if root is not None and not self.has_ancestor(root):
 311                         raise AncestorDoesNotExist(root)
 312
 313                 path = getattr(self, field, '?')
 314                 parent = self.parent
 315                 while parent and parent != root:
 316                         path = getattr(parent, field, '?') + pathsep + path
 317                         parent = parent.parent
 318                 return path
 319         path = property(get_path)
 320
 321         def __unicode__(self):
 322                 return self.path
 323
 324         class Meta:
 325                 unique_together = (('parent', 'slug'),)
 326                 abstract = True
 327
 328
 329 class TreeEntity(Entity, TreeModel):
 330         @property
 331         def attributes(self):
 332                 if self.parent:
 333                         return QuerySetMapper(self.attribute_set, passthrough=self.parent.attributes)
 334                 return super(TreeEntity, self).attributes
 335
 336         class Meta:
 337                 abstract = True