X-Git-Url: http://git.ithinksw.org/philo.git/blobdiff_plain/afd4b528f146e68d31315df32dbab94a9c2d7f0f..38c4439877b4551c9197b848b8b4f98b215f659b:/models/base.py

diff --git a/models/base.py b/models/base.py
index bd55e95..af1e880 100644
--- a/models/base.py
+++ b/models/base.py
@@ -1,454 +1,450 @@
-# encoding: utf-8
-from django.utils.translation import ugettext_lazy as _
-from django.contrib.auth.models import User, Group
-from django.contrib.contenttypes import generic
-from django.contrib.contenttypes.models import ContentType
+from django import forms
 from django.db import models
-from django.contrib.sites.models import Site
-from philo.utils import fattr
-from django.template import add_to_builtins as register_templatetags
-from django.template import Template as DjangoTemplate
-from django.template import TemplateDoesNotExist
-from django.template import Context, RequestContext
+from django.contrib.contenttypes.models import ContentType
+from django.contrib.contenttypes import generic
 from django.core.exceptions import ObjectDoesNotExist
+from django.core.validators import RegexValidator
 from django.utils import simplejson as json
+from django.utils.encoding import force_unicode
+from philo.exceptions import AncestorDoesNotExist
+from philo.models.fields import JSONField
+from philo.utils import ContentTypeRegistryLimiter, ContentTypeSubclassLimiter
+from philo.signals import entity_class_prepared
+from philo.validators import json_validator
 from UserDict import DictMixin
-from philo.templatetags.containers import ContainerNode
-from django.template.loader_tags import ExtendsNode, ConstantIncludeNode, IncludeNode
-from django.template.loader import get_template
-from django.http import Http404, HttpResponse, HttpResponseServerError, HttpResponseRedirect
-from django.core.servers.basehttp import FileWrapper
-from django.conf import settings
-from philo.validators import RedirectValidator
-
-
-def register_value_model(model):
-	pass
+from mptt.models import MPTTModel, MPTTModelBase, MPTTOptions
 
 
-def unregister_value_model(model):
-	pass
-
-
-class Attribute(models.Model):
-	entity_content_type = models.ForeignKey(ContentType, verbose_name='Entity type')
-	entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID')
-	entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
-	key = models.CharField(max_length=255)
-	json_value = models.TextField(verbose_name='Value (JSON)', help_text='This value must be valid JSON.')
-	
-	def get_value(self):
-		return json.loads(self.json_value)
-	
-	def set_value(self, value):
-		self.json_value = json.dumps(value)
-	
-	def delete_value(self):
-		self.json_value = json.dumps(None)
-	
-	value = property(get_value, set_value, delete_value)
+class Tag(models.Model):
+	name = models.CharField(max_length=255)
+	slug = models.SlugField(max_length=255, unique=True)
 	
 	def __unicode__(self):
-		return u'"%s": %s' % (self.key, self.value)
+		return self.name
 	
 	class Meta:
 		app_label = 'philo'
+		ordering = ('name',)
 
 
-class Relationship(models.Model):
-	entity_content_type = models.ForeignKey(ContentType, related_name='relationship_entity_set', verbose_name='Entity type')
-	entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID')
-	entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
-	key = models.CharField(max_length=255)
-	value_content_type = models.ForeignKey(ContentType, related_name='relationship_value_set', verbose_name='Value type')
-	value_object_id = models.PositiveIntegerField(verbose_name='Value ID')
-	value = generic.GenericForeignKey('value_content_type', 'value_object_id')
+class Titled(models.Model):
+	title = models.CharField(max_length=255)
+	slug = models.SlugField(max_length=255)
 	
 	def __unicode__(self):
-		return u'"%s": %s' % (self.key, self.value)
+		return self.title
 	
 	class Meta:
-		app_label = 'philo'
+		abstract = True
 
 
-class QuerySetMapper(object, DictMixin):
-	def __init__(self, queryset, passthrough=None):
-		self.queryset = queryset
-		self.passthrough = passthrough
-	def __getitem__(self, key):
-		try:
-			return self.queryset.get(key__exact=key).value
-		except ObjectDoesNotExist:
-			if self.passthrough:
-				return self.passthrough.__getitem__(key)
-			raise KeyError
-	def keys(self):
-		keys = set(self.queryset.values_list('key', flat=True).distinct())
-		if self.passthrough:
-			keys += set(self.passthrough.keys())
-		return list(keys)
+value_content_type_limiter = ContentTypeRegistryLimiter()
 
 
-class Entity(models.Model):
-	attribute_set = generic.GenericRelation(Attribute, content_type_field='entity_content_type', object_id_field='entity_object_id')
-	relationship_set = generic.GenericRelation(Relationship, content_type_field='entity_content_type', object_id_field='entity_object_id')
-	
-	@property
-	def attributes(self):
-		return QuerySetMapper(self.attribute_set)
-	
-	@property
-	def relationships(self):
-		return QuerySetMapper(self.relationship_set)
-	
-	class Meta:
-		abstract = True
-		app_label = 'philo'
+def register_value_model(model):
+	value_content_type_limiter.register_class(model)
 
 
-class Collection(models.Model):
-	name = models.CharField(max_length=255)
-	description = models.TextField(blank=True, null=True)
-	
-	@fattr(short_description='Members')
-	def get_count(self):
-		return self.members.count()
-	
-	def __unicode__(self):
-		return self.name
-	
-	class Meta:
-		app_label = 'philo'
+register_value_model(Tag)
 
 
-class CollectionMemberManager(models.Manager):
-	use_for_related_fields = True
-
-	def with_model(self, model):
-		return model._default_manager.filter(pk__in=self.filter(member_content_type=ContentType.objects.get_for_model(model)).values_list('member_object_id', flat=True))
+def unregister_value_model(model):
+	value_content_type_limiter.unregister_class(model)
 
 
-class CollectionMember(models.Model):
-	objects = CollectionMemberManager()
-	collection = models.ForeignKey(Collection, related_name='members')
-	index = models.PositiveIntegerField(verbose_name='Index', help_text='This will determine the ordering of the item within the collection. (Optional)', null=True, blank=True)
-	member_content_type = models.ForeignKey(ContentType, verbose_name='Member type')
-	member_object_id = models.PositiveIntegerField(verbose_name='Member ID')
-	member = generic.GenericForeignKey('member_content_type', 'member_object_id')
-	
-	def __unicode__(self):
-		return u'%s - %s' % (self.collection, self.member)
+class AttributeValue(models.Model):
+	attribute_set = generic.GenericRelation('Attribute', content_type_field='value_content_type', object_id_field='value_object_id')
 	
-	class Meta:
-		app_label = 'philo'
-
-
-class TreeManager(models.Manager):
-	use_for_related_fields = True
+	def set_value(self, value):
+		raise NotImplementedError
 	
-	def roots(self):
-		return self.filter(parent__isnull=True)
+	def value_formfields(self, **kwargs):
+		"""Define any formfields that would be used to construct an instance of this value."""
+		raise NotImplementedError
 	
-	def get_with_path(self, path, root=None, absolute_result=True, pathsep='/'):
-		"""
-		Returns the object with the path, or None if there is no object with that path,
-		unless absolute_result is set to False, in which case it returns a tuple containing
-		the deepest object found along the path, and the remainder of the path after that
-		object as a string (or None in the case that there is no remaining path).
-		"""
-		slugs = path.split(pathsep)
-		obj = root
-		remaining_slugs = list(slugs)
-		remainder = None
-		for slug in slugs:
-			remaining_slugs.remove(slug)
-			if slug: # ignore blank slugs, handles for multiple consecutive pathseps
-				try:
-					obj = self.get(slug__exact=slug, parent__exact=obj)
-				except self.model.DoesNotExist:
-					if absolute_result:
-						obj = None
-					remaining_slugs.insert(0, slug)
-					remainder = pathsep.join(remaining_slugs)
-					break
-		if obj:
-			if absolute_result:
-				return obj
-			else:
-				return (obj, remainder)
-		raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name)
-
-
-class TreeModel(models.Model):
-	objects = TreeManager()
-	parent = models.ForeignKey('self', related_name='children', null=True, blank=True)
-	slug = models.SlugField()
-	
-	def get_path(self, pathsep='/', field='slug'):
-		path = getattr(self, field, '?')
-		parent = self.parent
-		while parent:
-			path = getattr(parent, field, '?') + pathsep + path
-			parent = parent.parent
-		return path
-	path = property(get_path)
+	def construct_instance(self, **kwargs):
+		"""Apply cleaned data from the formfields generated by valid_formfields to oneself."""
+		raise NotImplementedError
 	
 	def __unicode__(self):
-		return self.path
+		return unicode(self.value)
 	
 	class Meta:
 		abstract = True
-		app_label = 'philo'
 
 
-class TreeEntity(TreeModel, Entity):
-	@property
-	def attributes(self):
-		if self.parent:
-			return QuerySetMapper(self.attribute_set, passthrough=self.parent.attributes)
-		return super(TreeEntity, self).attributes
-	
-	@property
-	def relationships(self):
-		if self.parent:
-			return QuerySetMapper(self.relationship_set, passthrough=self.parent.relationships)
-		return super(TreeEntity, self).relationships
-	
-	class Meta:
-		abstract = True
-		app_label = 'philo'
+attribute_value_limiter = ContentTypeSubclassLimiter(AttributeValue)
 
 
-class InheritableTreeEntity(TreeEntity):
-	instance_type = models.ForeignKey(ContentType, editable=False)
+class JSONValue(AttributeValue):
+	value = JSONField(verbose_name='Value (JSON)', help_text='This value must be valid JSON.', default='null', db_index=True)
 	
-	def save(self, force_insert=False, force_update=False):
-		if not hasattr(self, 'instance_type_ptr'):
-			self.instance_type = ContentType.objects.get_for_model(self.__class__)
-		super(InheritableTreeEntity, self).save(force_insert, force_update)
+	def __unicode__(self):
+		return force_unicode(self.value)
 	
-	@property
-	def instance(self):
-		try:
-			return self.instance_type.get_object_for_this_type(id=self.id)
-		except:
-			return None
+	def value_formfields(self):
+		kwargs = {'initial': self.value_json}
+		field = self._meta.get_field('value')
+		return {field.name: field.formfield(**kwargs)}
 	
-	def get_path(self, pathsep='/', field='slug'):
-		path = getattr(self.instance, field, getattr(self.instance, 'slug', '?'))
-		parent = self.parent
-		while parent:
-			path = getattr(parent.instance, field, getattr(parent.instance, 'slug', '?')) + pathsep + path
-			parent = parent.parent
-		return path
-	path = property(get_path)
+	def construct_instance(self, **kwargs):
+		field_name = self._meta.get_field('value').name
+		self.set_value(kwargs.pop(field_name, None))
 	
-	@property
-	def attributes(self):
-		if self.parent:
-			return QuerySetMapper(self.instance.attribute_set, passthrough=self.parent.instance.attributes)
-		return QuerySetMapper(self.instance.attribute_set)
-
-	@property
-	def relationships(self):
-		if self.parent:
-			return QuerySetMapper(self.instance.relationship_set, passthrough=self.parent.instance.relationships)
-		return QuerySetMapper(self.instance.relationship_set)
+	def set_value(self, value):
+		self.value = value
 	
 	class Meta:
-		abstract = True
 		app_label = 'philo'
 
 
-class Node(InheritableTreeEntity):
-	accepts_subpath = False
+class ForeignKeyValue(AttributeValue):
+	content_type = models.ForeignKey(ContentType, limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
+	object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True, db_index=True)
+	value = generic.GenericForeignKey()
 	
-	def render_to_response(self, request, path=None, subpath=None):
-		return HttpResponseServerError()
+	def value_formfields(self):
+		field = self._meta.get_field('content_type')
+		fields = {field.name: field.formfield(initial=getattr(self.content_type, 'pk', None))}
 		
-	class Meta:
-		unique_together = (('parent', 'slug'),)
-		app_label = 'philo'
-
-
-class MultiNode(Node):
-	accepts_subpath = True
+		if self.content_type:
+			kwargs = {
+				'initial': self.object_id,
+				'required': False,
+				'queryset': self.content_type.model_class()._default_manager.all()
+			}
+			fields['value'] = forms.ModelChoiceField(**kwargs)
+		return fields
+	
+	def construct_instance(self, **kwargs):
+		field_name = self._meta.get_field('content_type').name
+		ct = kwargs.pop(field_name, None)
+		if ct is None or ct != self.content_type:
+			self.object_id = None
+			self.content_type = ct
+		else:
+			value = kwargs.pop('value', None)
+			self.set_value(value)
+			if value is None:
+				self.content_type = ct
 	
-	urlpatterns = []
-	
-	def render_to_response(self, request, path=None, subpath=None):
-		if not subpath:
-			subpath = ""
-		subpath = "/" + subpath
-		from django.core.urlresolvers import resolve
-		view, args, kwargs = resolve(subpath, urlconf=self)
-		return view(request, *args, **kwargs)
+	def set_value(self, value):
+		self.value = value
 	
 	class Meta:
-		abstract = True
 		app_label = 'philo'
 
 
-class Redirect(Node):
-	STATUS_CODES = (
-		(302, 'Temporary'),
-		(301, 'Permanent'),
-	)
-	target = models.CharField(max_length=200,validators=[RedirectValidator()])
-	status_code = models.IntegerField(choices=STATUS_CODES, default=302, verbose_name='redirect type')
+class ManyToManyValue(AttributeValue):
+	content_type = models.ForeignKey(ContentType, limit_choices_to=value_content_type_limiter, verbose_name='Value type', null=True, blank=True)
+	values = models.ManyToManyField(ForeignKeyValue, blank=True, null=True)
 	
-	def render_to_response(self, request, path=None, subpath=None):
-		response = HttpResponseRedirect(self.target)
-		response.status_code = self.status_code
-		return response
+	def get_object_ids(self):
+		return self.values.values_list('object_id', flat=True)
+	object_ids = property(get_object_ids)
 	
-	class Meta:
-		app_label = 'philo'
-
-
-class File(Node):
-	""" For storing arbitrary files """
-	mimetype = models.CharField(max_length=255)
-	file = models.FileField(upload_to='philo/files/%Y/%m/%d')
+	def set_value(self, value):
+		# Value must be a queryset. Watch out for ModelMultipleChoiceField;
+		# it returns its value as a list if empty.
+		
+		self.content_type = ContentType.objects.get_for_model(value.model)
+		
+		# Before we can fiddle with the many-to-many to foreignkeyvalues, we need
+		# a pk.
+		if self.pk is None:
+			self.save()
+		
+		object_ids = value.values_list('id', flat=True)
+		
+		# These lines shouldn't be necessary; however, if object_ids is an EmptyQuerySet,
+		# the code (specifically the object_id__in query) won't work without them. Unclear why...
+		# TODO: is this still the case?
+		if not object_ids:
+			self.values.all().delete()
+		else:
+			self.values.exclude(object_id__in=object_ids, content_type=self.content_type).delete()
+			
+			current_ids = self.object_ids
+			
+			for object_id in object_ids:
+				if object_id in current_ids:
+					continue
+				self.values.create(content_type=self.content_type, object_id=object_id)
 	
-	def render_to_response(self, request, path=None, subpath=None):
-		wrapper = FileWrapper(self.file)
-		response = HttpResponse(wrapper, content_type=self.mimetype)
-		response['Content-Length'] = self.file.size
-		return response
+	def get_value(self):
+		if self.content_type is None:
+			return None
+		
+		# HACK to be safely explicit until http://code.djangoproject.com/ticket/15145 is resolved
+		object_ids = self.object_ids
+		manager = self.content_type.model_class()._default_manager
+		if not object_ids:
+			return manager.none()
+		return manager.filter(id__in=self.object_ids)
+	
+	value = property(get_value, set_value)
+	
+	def value_formfields(self):
+		field = self._meta.get_field('content_type')
+		fields = {field.name: field.formfield(initial=getattr(self.content_type, 'pk', None))}
+		
+		if self.content_type:
+			kwargs = {
+				'initial': self.object_ids,
+				'required': False,
+				'queryset': self.content_type.model_class()._default_manager.all()
+			}
+			fields['value'] = forms.ModelMultipleChoiceField(**kwargs)
+		return fields
+	
+	def construct_instance(self, **kwargs):
+		field_name = self._meta.get_field('content_type').name
+		ct = kwargs.pop(field_name, None)
+		if ct is None or ct != self.content_type:
+			self.values.clear()
+			self.content_type = ct
+		else:
+			value = kwargs.get('value', None)
+			if not value:
+				value = self.content_type.model_class()._default_manager.none()
+			self.set_value(value)
+	construct_instance.alters_data = True
 	
 	class Meta:
 		app_label = 'philo'
 
 
-class Template(TreeModel):
-	name = models.CharField(max_length=255)
-	documentation = models.TextField(null=True, blank=True)
-	mimetype = models.CharField(max_length=255, null=True, blank=True, help_text='Default: %s' % settings.DEFAULT_CONTENT_TYPE)
-	code = models.TextField(verbose_name='django template code')
-	
-	@property
-	def origin(self):
-		return 'philo.models.Template: ' + self.path
+class Attribute(models.Model):
+	entity_content_type = models.ForeignKey(ContentType, related_name='attribute_entity_set', verbose_name='Entity type')
+	entity_object_id = models.PositiveIntegerField(verbose_name='Entity ID', db_index=True)
+	entity = generic.GenericForeignKey('entity_content_type', 'entity_object_id')
 	
-	@property
-	def django_template(self):
-		return DjangoTemplate(self.code)
+	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)
+	value_object_id = models.PositiveIntegerField(verbose_name='Value ID', null=True, blank=True, db_index=True)
+	value = generic.GenericForeignKey('value_content_type', 'value_object_id')
 	
-	@property
-	def containers(self):
-		"""
-		Returns a tuple where the first item is a list of names of contentlets referenced by containers,
-		and the second item is a list of tuples of names and contenttypes of contentreferences referenced by containers.
-		This will break if there is a recursive extends or includes in the template code.
-		Due to the use of an empty Context, any extends or include tags with dynamic arguments probably won't work.
-		"""
-		def container_nodes(template):
-			def nodelist_container_nodes(nodelist):
-				nodes = []
-				for node in nodelist:
-					try:
-						for nodelist_name in ('nodelist', 'nodelist_loop', 'nodelist_empty', 'nodelist_true', 'nodelist_false', 'nodelist_main'):
-							if hasattr(node, nodelist_name):
-								nodes.extend(nodelist_container_nodes(getattr(node, nodelist_name)))
-						if isinstance(node, ContainerNode):
-							nodes.append(node)
-						elif isinstance(node, ExtendsNode):
-							extended_template = node.get_parent(Context())
-							if extended_template:
-								nodes.extend(container_nodes(extended_template))
-						elif isinstance(node, ConstantIncludeNode):
-							included_template = node.template
-							if included_template:
-								nodes.extend(container_nodes(included_template))
-						elif isinstance(node, IncludeNode):
-							included_template = get_template(node.template_name.resolve(Context()))
-							if included_template:
-								nodes.extend(container_nodes(included_template))
-					except:
-						pass # fail for this node
-				return nodes
-			return nodelist_container_nodes(template.nodelist)
-		all_nodes = container_nodes(self.django_template)
-		contentlet_node_names = set([node.name for node in all_nodes if not node.references])
-		contentreference_node_names = []
-		contentreference_node_specs = []
-		for node in all_nodes:
-			if node.references and node.name not in contentreference_node_names:
-				contentreference_node_specs.append((node.name, node.references))
-				contentreference_node_names.append(node.name)
-		return contentlet_node_names, contentreference_node_specs
+	key = models.CharField(max_length=255, validators=[RegexValidator("\w+")], help_text="Must contain one or more alphanumeric characters or underscores.", db_index=True)
 	
 	def __unicode__(self):
-		return self.get_path(u' › ', 'name')
-	
-	@staticmethod
-	@fattr(is_usable=True)
-	def loader(template_name, template_dirs=None): # load_template_source
-		try:
-			template = Template.objects.get_with_path(template_name)
-		except Template.DoesNotExist:
-			raise TemplateDoesNotExist(template_name)
-		return (template.code, template.origin)
+		return u'"%s": %s' % (self.key, self.value)
 	
 	class Meta:
 		app_label = 'philo'
+		unique_together = (('key', 'entity_content_type', 'entity_object_id'), ('value_content_type', 'value_object_id'))
 
 
-class Page(Node):
-	"""
-	Represents a page - something which is rendered according to a template. The page will have a number of related Contentlets depending on the template selected - but these will appear only after the page has been saved with that template.
-	"""
-	template = models.ForeignKey(Template, related_name='pages')
-	title = models.CharField(max_length=255)
+class QuerySetMapper(object, DictMixin):
+	def __init__(self, queryset, passthrough=None):
+		self.queryset = queryset
+		self.passthrough = passthrough
 	
-	def render_to_response(self, request, path=None, subpath=None):
-		return HttpResponse(self.template.django_template.render(RequestContext(request, {'page': self})), mimetype=self.template.mimetype)
+	def __getitem__(self, key):
+		try:
+			value = self.queryset.get(key__exact=key).value
+		except ObjectDoesNotExist:
+			if self.passthrough is not None:
+				return self.passthrough.__getitem__(key)
+			raise KeyError
+		else:
+			if value is not None:
+				return value.value
+			return value
 	
-	def __unicode__(self):
-		return self.get_path(u' › ', 'title')
+	def keys(self):
+		keys = set(self.queryset.values_list('key', flat=True).distinct())
+		if self.passthrough is not None:
+			keys |= set(self.passthrough.keys())
+		return list(keys)
+
+
+class EntityOptions(object):
+	def __init__(self, options):
+		if options is not None:
+			for key, value in options.__dict__.items():
+				setattr(self, key, value)
+		if not hasattr(self, 'proxy_fields'):
+			self.proxy_fields = []
 	
-	class Meta:
-		app_label = 'philo'
+	def add_proxy_field(self, proxy_field):
+		self.proxy_fields.append(proxy_field)
 
 
-# the following line enables the selection of a node as the root for a given django.contrib.sites Site object
-models.ForeignKey(Node, related_name='sites', null=True, blank=True).contribute_to_class(Site, 'root_node')
+class EntityBase(models.base.ModelBase):
+	def __new__(cls, name, bases, attrs):
+		entity_meta = attrs.pop('EntityMeta', None)
+		new = super(EntityBase, cls).__new__(cls, name, bases, attrs)
+		new.add_to_class('_entity_meta', EntityOptions(entity_meta))
+		entity_class_prepared.send(sender=new)
+		return new
 
 
-class Contentlet(models.Model):
-	page = models.ForeignKey(Page, related_name='contentlets')
-	name = models.CharField(max_length=255)
-	content = models.TextField()
-	dynamic = models.BooleanField(default=False)
+class Entity(models.Model):
+	__metaclass__ = EntityBase
 	
-	def __unicode__(self):
-		return self.name
+	attribute_set = generic.GenericRelation(Attribute, content_type_field='entity_content_type', object_id_field='entity_object_id')
+	
+	@property
+	def attributes(self):
+		return QuerySetMapper(self.attribute_set.all())
 	
 	class Meta:
-		app_label = 'philo'
+		abstract = True
 
 
-class ContentReference(models.Model):
-	page = models.ForeignKey(Page, related_name='contentreferences')
-	name = models.CharField(max_length=255)
-	content_type = models.ForeignKey(ContentType, verbose_name='Content type')
-	content_id = models.PositiveIntegerField(verbose_name='Content ID', blank=True, null=True)
-	content = generic.GenericForeignKey('content_type', 'content_id')
+class TreeManager(models.Manager):
+	use_for_related_fields = True
+	
+	def get_with_path(self, path, root=None, absolute_result=True, pathsep='/', field='slug'):
+		"""
+		Returns the object with the path, unless absolute_result is set to False, in which
+		case it returns a tuple containing the deepest object found along the path, and the
+		remainder of the path after that object as a string (or None if there is no remaining
+		path). Raises a DoesNotExist exception if no object is found with the given path.
+		
+		If the path you're searching for is known to exist, it is always faster to use
+		absolute_result=True - unless the path depth is over ~40, in which case the high cost
+		of the absolute query makes a binary search (i.e. non-absolute) faster.
+		"""
+		# Note: SQLite allows max of 64 tables in one join. That means the binary search will
+		# only work on paths with a max depth of 127 and the absolute fetch will only work
+		# to a max depth of (surprise!) 63. Although this could be handled, chances are your
+		# tree structure won't be that deep.
+		segments = path.split(pathsep)
+		
+		# Clean out blank segments. Handles multiple consecutive pathseps.
+		while True:
+			try:
+				segments.remove('')
+			except ValueError:
+				break
+		
+		# Special-case a lack of segments. No queries necessary.
+		if not segments:
+			if root is not None:
+				if absolute_result:
+					return root
+				return root, None
+			else:
+				raise self.model.DoesNotExist('%s matching query does not exist.' % self.model._meta.object_name)
+		
+		def make_query_kwargs(segments, root):
+			kwargs = {}
+			prefix = ""
+			revsegs = list(segments)
+			revsegs.reverse()
+			
+			for segment in revsegs:
+				kwargs["%s%s__exact" % (prefix, field)] = segment
+				prefix += "parent__"
+			
+			if prefix:
+				kwargs[prefix[:-2]] = root
+			
+			return kwargs
+		
+		def find_obj(segments, depth, deepest_found=None):
+			if deepest_found is None:
+				deepest_level = 0
+			elif root is None:
+				deepest_level = deepest_found.get_level() + 1
+			else:
+				deepest_level = deepest_found.get_level() - root.get_level()
+			try:
+				obj = self.get(**make_query_kwargs(segments[deepest_level:depth], deepest_found or root))
+			except self.model.DoesNotExist:
+				if not deepest_level and depth > 1:
+					# make sure there's a root node...
+					depth = 1
+				else:
+					# Try finding one with half the path since the deepest find.
+					depth = (deepest_level + depth)/2
+				
+				if deepest_level == depth:
+					# This should happen if nothing is found with any part of the given path.
+					if root is not None and deepest_found is None:
+						return root, pathsep.join(segments)
+					raise
+				
+				return find_obj(segments, depth, deepest_found)
+			else:
+				# Yay! Found one!
+				if root is None:
+					deepest_level = obj.get_level() + 1
+				else:
+					deepest_level = obj.get_level() - root.get_level()
+				
+				# Could there be a deeper one?
+				if obj.is_leaf_node():
+					return obj, pathsep.join(segments[deepest_level:]) or None
+				
+				depth += (len(segments) - depth)/2 or len(segments) - depth
+				
+				if depth > deepest_level + obj.get_descendant_count():
+					depth = deepest_level + obj.get_descendant_count()
+				
+				if deepest_level == depth:
+					return obj, pathsep.join(segments[deepest_level:]) or None
+				
+				try:
+					return find_obj(segments, depth, obj)
+				except self.model.DoesNotExist:
+					# Then this was the deepest.
+					return obj, pathsep.join(segments[deepest_level:])
+		
+		if absolute_result:
+			return self.get(**make_query_kwargs(segments, root))
+		
+		# Try a modified binary search algorithm. Feed the root in so that query complexity
+		# can be reduced. It might be possible to weight the search towards the beginning
+		# of the path, since short paths are more likely, but how far forward? It would
+		# need to shift depending on len(segments) - perhaps logarithmically?
+		return find_obj(segments, len(segments)/2 or len(segments))
+
+
+class TreeModel(MPTTModel):
+	objects = TreeManager()
+	parent = models.ForeignKey('self', related_name='children', null=True, blank=True)
+	slug = models.SlugField(max_length=255)
+	
+	def get_path(self, root=None, pathsep='/', field='slug'):
+		if root == self:
+			return ''
+		
+		if root is not None and not self.is_descendant_of(root):
+			raise AncestorDoesNotExist(root)
+		
+		qs = self.get_ancestors(include_self=True)
+		
+		if root is not None:
+			qs = qs.filter(**{'%s__gt' % self._mptt_meta.level_attr: root.get_level()})
+		
+		return pathsep.join([getattr(parent, field, '?') for parent in qs])
+	path = property(get_path)
 	
 	def __unicode__(self):
-		return self.name
+		return self.path
 	
 	class Meta:
-		app_label = 'philo'
+		unique_together = (('parent', 'slug'),)
+		abstract = True
 
 
-register_templatetags('philo.templatetags.containers')
+class TreeEntityBase(MPTTModelBase, EntityBase):
+	def __new__(meta, name, bases, attrs):
+		attrs['_mptt_meta'] = MPTTOptions(attrs.pop('MPTTMeta', None))
+		cls = EntityBase.__new__(meta, name, bases, attrs)
+		
+		return meta.register(cls)
 
 
-register_value_model(User)
-register_value_model(Group)
-register_value_model(Site)
-register_value_model(Collection)
-register_value_model(Template)
-register_value_model(Page)
+class TreeEntity(Entity, TreeModel):
+	__metaclass__ = TreeEntityBase
+	
+	@property
+	def attributes(self):
+		if self.parent:
+			return QuerySetMapper(self.attribute_set.all(), passthrough=self.parent.attributes)
+		return super(TreeEntity, self).attributes
+	
+	class Meta:
+		abstract = True
\ No newline at end of file