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_set = generic.GenericRelation('Attribute', content_type_field='value_content_type', object_id_field='value_object_id')
  50
  51         @property
  52         def attribute(self):
  53                 return self.attribute_set.all()[0]
  54
  55         def apply_data(self, data):
  56                 raise NotImplementedError
  57
  58         def value_formfield(self, **kwargs):
  59                 raise NotImplementedError
  60
  61         def __unicode__(self):
  62                 return unicode(self.value)
  63
  64         class Meta:
  65                 abstract = True
  66
  67
  68 attribute_value_limiter = ContentTypeSubclassLimiter(AttributeValue)
  69
  70
  71 class JSONValue(AttributeValue):
  72         value = JSONField() #verbose_name='Value (JSON)', help_text='This value must be valid JSON.')
  73
  74         def __unicode__(self):
  75                 return self.value_json
  76
  77         def value_formfield(self, **kwargs):
  78                 kwargs['initial'] = self.value_json
  79                 return self._meta.get_field('value').formfield(**kwargs)
  80
  81         def apply_data(self, cleaned_data):
  82                 self.value = cleaned_data.get('value', None)
  83
  84         class Meta:
  85                 app_label = 'philo'
  86
  87
  88 class ForeignKeyValue(AttributeValue):
  89         content_type = models.ForeignKey(ContentType, limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
  90         object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True)
  91         value = generic.GenericForeignKey()
  92
  93         def value_formfield(self, form_class=forms.ModelChoiceField, **kwargs):
  94                 if self.content_type is None:
  95                         return None
  96                 kwargs.update({'initial': self.object_id, 'required': False})
  97                 return form_class(self.content_type.model_class()._default_manager.all(), **kwargs)
  98
  99         def apply_data(self, cleaned_data):
 100                 if 'value' in cleaned_data and cleaned_data['value'] is not None:
 101                         self.value = cleaned_data['value']
 102                 else:
 103                         self.content_type = cleaned_data.get('content_type', None)
 104                         # If there is no value set in the cleaned data, clear the stored value.
 105                         self.object_id = None
 106
 107         class Meta:
 108                 app_label = 'philo'
 109
 110
 111 class ManyToManyValue(AttributeValue):
 112         content_type = models.ForeignKey(ContentType, limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
 113         values = models.ManyToManyField(ForeignKeyValue, blank=True, null=True)
 114
 115         def get_object_id_list(self):
 116                 if not self.values.count():
 117                         return []
 118                 else:
 119                         return self.values.values_list('object_id', flat=True)
 120
 121         def get_value(self):
 122                 if self.content_type is None:
 123                         return None
 124
 125                 return self.content_type.model_class()._default_manager.filter(id__in=self.get_object_id_list())
 126
 127         def set_value(self, value):
 128                 # Value is probably a queryset - but allow any iterable.
 129
 130                 # These lines shouldn't be necessary; however, if value is an EmptyQuerySet,
 131                 # the code won't work without them. Unclear why...
 132                 if not value:
 133                         value = []
 134
 135                 if isinstance(value, models.query.QuerySet):
 136                         value = value.values_list('id', flat=True)
 137
 138                 self.values.filter(~models.Q(object_id__in=value)).delete()
 139                 current = self.get_object_id_list()
 140
 141                 for v in value:
 142                         if v in current:
 143                                 continue
 144                         self.values.create(content_type=self.content_type, object_id=v)
 145
 146         value = property(get_value, set_value)
 147
 148         def value_formfield(self, form_class=forms.ModelMultipleChoiceField, **kwargs):
 149                 if self.content_type is None:
 150                         return None
 151                 kwargs.update({'initial': self.get_object_id_list(), 'required': False})
 152                 return form_class(self.content_type.model_class()._default_manager.all(), **kwargs)
 153
 154         def apply_data(self, cleaned_data):
 155                 if 'value' in cleaned_data and cleaned_data['value'] is not None:
 156                         self.value = cleaned_data['value']
 157                 else:
 158                         self.content_type = cleaned_data.get('content_type', None)
 159                         # If there is no value set in the cleaned data, clear the stored value.
 160                         self.value = []
 161
 162         class Meta:
 163                 app_label = 'philo'
 164
 165
 166 class Attribute(models.Model):
 167         entity_content_type = models.ForeignKey(ContentType, related_name='attribute_entity_set', verbose_name='Entity type')
 168         entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID')
 169         entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
 170
 171         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)
 172         value_object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True)
 173         value = generic.GenericForeignKey('value_content_type', 'value_object_id')
 174
 175         key = models.CharField(max_length=255)
 176
 177         def __unicode__(self):
 178                 return u'"%s": %s' % (self.key, self.value)
 179
 180         class Meta:
 181                 app_label = 'philo'
 182                 unique_together = (('key', 'entity_content_type', 'entity_object_id'), ('value_content_type', 'value_object_id'))
 183
 184
 185 class QuerySetMapper(object, DictMixin):
 186         def __init__(self, queryset, passthrough=None):
 187                 self.queryset = queryset
 188                 self.passthrough = passthrough
 189
 190         def __getitem__(self, key):
 191                 try:
 192                         value = self.queryset.get(key__exact=key).value
 193                 except ObjectDoesNotExist:
 194                         if self.passthrough is not None:
 195                                 return self.passthrough.__getitem__(key)
 196                         raise KeyError
 197                 else:
 198                         if value is not None:
 199                                 return value.value
 200                         return value
 201
 202         def keys(self):
 203                 keys = set(self.queryset.values_list('key', flat=True).distinct())
 204                 if self.passthrough is not None:
 205                         keys |= set(self.passthrough.keys())
 206                 return list(keys)
 207
 208
 209 class EntityOptions(object):
 210         def __init__(self, options):
 211                 if options is not None:
 212                         for key, value in options.__dict__.items():
 213                                 setattr(self, key, value)
 214                 if not hasattr(self, 'proxy_fields'):
 215                         self.proxy_fields = []
 216
 217         def add_proxy_field(self, proxy_field):
 218                 self.proxy_fields.append(proxy_field)
 219
 220
 221 class EntityBase(models.base.ModelBase):
 222         def __new__(cls, name, bases, attrs):
 223                 new = super(EntityBase, cls).__new__(cls, name, bases, attrs)
 224                 entity_options = attrs.pop('EntityMeta', None)
 225                 setattr(new, '_entity_meta', EntityOptions(entity_options))
 226                 entity_class_prepared.send(sender=new)
 227                 return new
 228
 229
 230 class Entity(models.Model):
 231         __metaclass__ = EntityBase
 232
 233         attribute_set = generic.GenericRelation(Attribute, content_type_field='entity_content_type', object_id_field='entity_object_id')
 234
 235         @property
 236         def attributes(self):
 237                 return QuerySetMapper(self.attribute_set.all())
 238
 239         @property
 240         def _added_attribute_registry(self):
 241                 if not hasattr(self, '_real_added_attribute_registry'):
 242                         self._real_added_attribute_registry = {}
 243                 return self._real_added_attribute_registry
 244
 245         @property
 246         def _removed_attribute_registry(self):
 247                 if not hasattr(self, '_real_removed_attribute_registry'):
 248                         self._real_removed_attribute_registry = []
 249                 return self._real_removed_attribute_registry
 250
 251         def save(self, *args, **kwargs):
 252                 super(Entity, self).save(*args, **kwargs)
 253
 254                 for key in self._removed_attribute_registry:
 255                         self.attribute_set.filter(key__exact=key).delete()
 256                 del self._removed_attribute_registry[:]
 257
 258                 for field, value in self._added_attribute_registry.items():
 259                         try:
 260                                 attribute = self.attribute_set.get(key__exact=field.key)
 261                         except Attribute.DoesNotExist:
 262                                 attribute = Attribute()
 263                                 attribute.entity = self
 264                                 attribute.key = field.key
 265
 266                         field.set_attribute_value(attribute, value)
 267                         attribute.save()
 268                 self._added_attribute_registry.clear()
 269
 270         class Meta:
 271                 abstract = True
 272
 273
 274 class TreeManager(models.Manager):
 275         use_for_related_fields = True
 276
 277         def roots(self):
 278                 return self.filter(parent__isnull=True)
 279
 280         def get_with_path(self, path, root=None, absolute_result=True, pathsep='/'):
 281                 """
 282                 Returns the object with the path, or None if there is no object with that path,
 283                 unless absolute_result is set to False, in which case it returns a tuple containing
 284                 the deepest object found along the path, and the remainder of the path after that
 285                 object as a string (or None in the case that there is no remaining path).
 286                 """
 287                 slugs = path.split(pathsep)
 288                 obj = root
 289                 remaining_slugs = list(slugs)
 290                 remainder = None
 291                 for slug in slugs:
 292                         remaining_slugs.remove(slug)
 293                         if slug: # ignore blank slugs, handles for multiple consecutive pathseps
 294                                 try:
 295                                         obj = self.get(slug__exact=slug, parent__exact=obj)
 296                                 except self.model.DoesNotExist:
 297                                         if absolute_result:
 298                                                 obj = None
 299                                         remaining_slugs.insert(0, slug)
 300                                         remainder = pathsep.join(remaining_slugs)
 301                                         break
 302                 if obj:
 303                         if absolute_result:
 304                                 return obj
 305                         else:
 306                                 return (obj, remainder)
 307                 raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name)
 308
 309
 310 class TreeModel(models.Model):
 311         objects = TreeManager()
 312         parent = models.ForeignKey('self', related_name='children', null=True, blank=True)
 313         slug = models.SlugField(max_length=255)
 314
 315         def has_ancestor(self, ancestor):
 316                 parent = self
 317                 while parent:
 318                         if parent == ancestor:
 319                                 return True
 320                         parent = parent.parent
 321                 return False
 322
 323         def get_path(self, root=None, pathsep='/', field='slug'):
 324                 if root is not None and not self.has_ancestor(root):
 325                         raise AncestorDoesNotExist(root)
 326
 327                 path = getattr(self, field, '?')
 328                 parent = self.parent
 329                 while parent and parent != root:
 330                         path = getattr(parent, field, '?') + pathsep + path
 331                         parent = parent.parent
 332                 return path
 333         path = property(get_path)
 334
 335         def __unicode__(self):
 336                 return self.path
 337
 338         class Meta:
 339                 unique_together = (('parent', 'slug'),)
 340                 abstract = True
 341
 342
 343 class TreeEntity(Entity, TreeModel):
 344         @property
 345         def attributes(self):
 346                 if self.parent:
 347                         return QuerySetMapper(self.attribute_set.all(), passthrough=self.parent.attributes)
 348                 return super(TreeEntity, self).attributes
 349
 350         class Meta:
 351                 abstract = True