Add ability to restrict children.

Expanding on the already present can_have_children so that it can also be a list in addition to booleans. (Empty list == False, Non-empty == True) The list is list of values similar to those values accepted in a model ForeignKey. If it is a list it is changed into a list of the content type ids of the listed models. i.e. ["self", "app.Model", "Model", Model] With "self" referring to the model on which can_have_children is defined. "app.Model" is an app_label-model dot string. "Model" is a model in the current app. And the last is a Model class or Model instance.

polymorphic_tree/admin/parentadmin.py

@@ -129,19 +129,26 @@ def can_preview_object(self, node):
  return hasattr(node, 'get_absolute_url')
 
 
- def can_have_children(self, node):
+ def can_have_children(self, node, child=None, is_real=False):
  """
  Define whether a node can have children.
  """
  # Allow can_have_children to be either to be a property on the base class that always works.
  if not node.can_have_children:
  return False
 
- # or a static variable declared on the class (avoids need for downcasted models).
- NodeClass = node.get_real_instance_class()
- return bool(NodeClass.can_have_children)
-
-
+ # or an instance variable
+ Node = node if is_real else node.get_real_instance()
+ if Node.can_have_children:
+ if child is None:
+ return True # just interested in boolean
+ # if we have a child we should check if it is allowed
+ try:
+ iter(Node.can_have_children)
+ except TypeError:
+ return True # not a list, boolean true
+ return child.polymorphic_ctype_id in Node.can_have_children
+ return False
 
  # ---- Custom views ----
 
@@ -189,12 +196,23 @@ def api_node_moved_view(self, request):
  except self.model.DoesNotExist as e:
  return HttpResponseNotFound(json.dumps({'action': 'reload', 'error': str(e[0])}), content_type='application/json')
 
- if not self.can_have_children(target) and position == 'inside':
- return HttpResponse(json.dumps({
- 'action': 'reject',
- 'moved_id': moved_id,
- 'error': _(u'Cannot place \u2018{0}\u2019 below \u2018{1}\u2019; a {2} does not allow children!').format(moved, target, target._meta.verbose_name)
- }), content_type='application/json', status=409) # Conflict
+ if position == 'inside':
+ error = None
+ real_target = target.get_real_instance()
+ if not self.can_have_children(real_target, is_real=True):
+ error = _(u'Cannot place \u2018{0}\u2019 below \u2018{1}\u2019;'
+ u' a {2} does not allow children!').format(moved, target,
+ target._meta.verbose_name)
+ if not self.can_have_children(real_target, moved, is_real=True):
+ error = _(u'Cannot place \u2018{0}\u2019 below \u2018{1}\u2019;'
+ u' a {2} does not allow {3} as a child!').format(moved,
+ target, target._meta.verbose_name, moved._meta.verbose_name)
+ if error is not None:
+ return HttpResponse(json.dumps({
+ 'action': 'reject',
+ 'moved_id': moved_id,
+ 'error': error
+ }), content_type='application/json', status=409) # Conflict
  if moved.parent_id != previous_parent_id:
  return HttpResponse(json.dumps({
  'action': 'reload',

polymorphic_tree/models.py

@@ -1,8 +1,11 @@
 """
 Model that inherits from both Polymorphic and MPTT.
 """
+from __future__ import unicode_literals
 from future.utils import with_metaclass
 from future.utils.six import integer_types
+from future.builtins import str
+from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ValidationError
 from django.utils.translation import ugettext_lazy as _
 from mptt.models import MPTTModel, MPTTModelBase, TreeForeignKey
@@ -34,7 +37,9 @@ class PolymorphicTreeForeignKey(TreeForeignKey):
  A foreignkey that limits the node types the parent can be.
  """
  default_error_messages = {
- 'no_children_allowed': _("The selected node cannot have child nodes."),
+ 'no_children_allowed': _('The selected node cannot have child nodes.'),
+ 'child_not_allowed': _('Cannot place this page below '
+ '\u2018{0}\u2019; a {1} does not allow {2} as a child!')
  }
 
  def clean(self, value, model_instance):
@@ -50,13 +55,21 @@ def _validate_parent(self, parent, model_instance):
  # TODO: Improve this code, it's a bit of a hack now because the base model is not known in the NodeTypePool.
  base_model = _get_base_polymorphic_model(model_instance.__class__)
 
- # Get parent, TODO: needs to downcast here to read can_have_children.
- parent = base_model.objects.get(pk=parent)
+ parent = base_model.objects.get(pk=parent).get_real_instance()
  elif not isinstance(parent, PolymorphicMPTTModel):
  raise ValueError("Unknown parent value")
 
  if parent.can_have_children:
- return
+ try:
+ iter(parent.can_have_children)
+ except TypeError:
+ return # boolean True
+ if model_instance.polymorphic_ctype_id in parent.can_have_children:
+ return # child is allowed
+ raise ValidationError(
+ self.error_messages['child_not_allowed'].format(parent,
+ parent._meta.verbose_name,
+ model_instance._meta.verbose_name))
 
  raise ValidationError(self.error_messages['no_children_allowed'])
 
@@ -73,6 +86,37 @@ class PolymorphicMPTTModel(with_metaclass(PolymorphicMPTTModelBase, MPTTModel, P
  # Django fields
  _default_manager = PolymorphicMPTTModelManager()
 
+ def __init__(self, *args, **kwargs):
+ super(PolymorphicMPTTModel, self).__init__(*args, **kwargs)
+ try:
+ iterator = iter(self.can_have_children)
+ except TypeError:
+ pass # can_have_children is not an iterable
+ else:
+ new_children = []
+ for child in iterator:
+ if isinstance(unicode(child), str):
+ child = unicode(child).lower()
+ # write self to refer to self
+ if child == 'self':
+ ct_id = self.polymorphic_ctype_id
+ else:
+ # either the name of a model in this app
+ # or the full app.model dot string
+ # just like a foreign key
+ try:
+ app_label, model = child.rsplit('.', 1)
+ except ValueError:
+ app_label = self._meta.app_label
+ model = child
+ ct_id = ContentType.objects.get(app_label=app_label,
+ model=model).id
+ else:
+ # pass in a model class
+ ct_id = ContentType.objects.get_for_model(child).id
+ new_children.append(ct_id)
+ self.can_have_children = new_children
+
  class Meta:
  abstract = True
  ordering = ('lft',)

polymorphic_tree/templates/admin/polymorphic_tree/jstree_list_results.html

@@ -44,9 +44,8 @@
  /*
  * This code is currently inline because it is generated using various template variables and translation messages.
  */
-
  var data = [{% adminlist_recursetree cl %}{% with is_leaf=node.is_leaf_node %}
- {id: {{ node.pk }}, classes: 'nodetype-{{ node|real_model_name|lower }}', can_have_children: {{ node.can_have_children|yesno:'true,false' }}, label: '<div class="col-primary{% if is_leaf %} leaf{% endif %}"><div class="col first-column"><a href="{{ change_url }}"{% if cl.is_popup %} onclick="opener.dismissRelatedLookupPopup(window, {{ node.pk }}); return false;"{% endif %}>{{ first_column|escapejs }}</a></div></div>{% if other_columns %}<div class="col-metadata">{% for name, repr in other_columns %}<div class="col col-{{ name }}">{{ repr|escapejs }}</div>{% endfor %}</div>{% endif %}'{% if not is_leaf %},
+ {id: {{ node.pk }}, ct: {{ node.polymorphic_ctype_id }}, classes: 'nodetype-{{ ct.model|lower }}', can_have_children: {{ node.get_real_instance.can_have_children|yesnolist:"true,false" }}, label: '<div class="col-primary{% if is_leaf %} leaf{% endif %}"><div class="col first-column"><a href="{{ change_url }}"{% if cl.is_popup %} onclick="opener.dismissRelatedLookupPopup(window, {{ node.pk }}); return false;"{% endif %}>{{ first_column|escapejs }}</a></div></div>{% if other_columns %}<div class="col-metadata">{% for name, repr in other_columns %}<div class="col col-{{ name }}">{{ repr|escapejs }}</div>{% endfor %}</div>{% endif %}'{% if not is_leaf %},
  children: [ {{ children }}
  ]{% endif %}},{% endwith %}{% endadminlist_recursetree %}
  null // for MSIE
@@ -64,9 +63,12 @@
  $div.append(contents);
  }
 
- function onCanMoveTo(moved_node, target_node, position)
- {
- return ( target_node.can_have_children || position != 'inside' );
+ function onCanMoveTo(moved_node, target_node, position) {
+ var can_have_children = target_node.can_have_children;
+ if (Object.prototype.toString.call(can_have_children) === '[object Array]'){
+ can_have_children = jQuery.inArray(moved_node.ct, can_have_children) > -1;
+ }
+ return ( can_have_children || position != 'inside' );
  }
 
  var tree = jQuery("#js-result-list").tree({

polymorphic_tree/templatetags/polymorphic_tree_admin_tags.py

@@ -2,13 +2,22 @@
 from django.contrib.admin.views.main import ChangeList
 from django.contrib.contenttypes.models import ContentType
 from django.template import Library, Node, TemplateSyntaxError, Variable
+from django.template.defaultfilters import yesno
 from django.utils.safestring import mark_safe
 from mptt.templatetags.mptt_tags import cache_tree_children
 from polymorphic_tree.templatetags.stylable_admin_list import stylable_column_repr
 
 
 register = Library()
 
+@register.filter
+def yesnolist(value, arg=None):
+ try:
+ iter(value)
+ except TypeError:
+ return yesno(value, arg)
+ return value
+
 
 @register.filter
 def real_model_name(node):