Merge pull request #10 from vdboor/master

Polymorphic admin interface

AUTHORS.rst

@@ -12,3 +12,4 @@ Contributors
 * Charles Leifer (python 2.4 compatibility)
 * Germán M. Bravo
 * Martin Brochhaus
+* Diederik van der Boor (polymorphic admin interface)

CHANGES.rst

@@ -3,6 +3,12 @@
 Changelog
 ++++++++++
 
+Juli 5, 2012, Polymorphic admin interface
+=========================================
+
+Added a polymorphic admin interface. The admin interface is able to add polymorphic models,
+and the admin edit screen also displays the custom fields of the polymorphic model.
+
 
 2011-12-20 Renaming, refactoring, new maintainer
 ================================================

DOCS.rst

@@ -153,6 +153,98 @@ In the examples below, these models are being used::
         field3 = models.CharField(max_length=10)
 
 
+Using polymorphic models in the admin interface
+-----------------------------------------------
+
+Naturally, it's possible to register individual polymorphic models in the Django admin interface.
+However, to use these models in a single cohesive interface, some extra base classes are available.
+
+The polymorphic admin interface works in a simple way:
+
+* The add screen gains an additional step where the desired child model is selected.
+* The edit screen displays the admin interface of the child model.
+* The list screen still displays all objects of the base class.
+
+The polymorphic admin is implemented via a parent admin that forwards the *edit* and *delete* views
+to the ``ModelAdmin`` of the derived child model. The *list* page is still implemented by the parent model admin.
+
+Both the parent model and child model need to have a ``ModelAdmin`` class.
+Only the ``ModelAdmin`` class of the parent/base model has to be registered in the Django admin site.
+
+The parent model
+~~~~~~~~~~~~~~~~
+
+The parent model needs to inherit ``PolymorphicParentModelAdmin``, and implement the following:
+
+* ``base_model`` should be set
+* ``child_models`` should be set, or:
+
+ * ``get_child_models()`` should return a list with (Model, ModelAdmin) tuple.
+
+The exact implementation can depend on the way your module is structured.
+For simple inheritance situations, ``child_models`` is best suited.
+For large applications, this leaves room for a plugin registration system.
+
+The child models
+~~~~~~~~~~~~~~~~
+
+The admin interface of the derived models should inherit from ``PolymorphicChildModelAdmin``.
+Again, ``base_model`` should be set in this class as well.
+This class implements the following features:
+
+* It corrects the breadcrumbs in the admin pages.
+* It extends the template lookup paths, to look for both the parent model and child model in the ``admin/app/model/change_form.html`` path.
+* It allows to set ``base_form`` so the derived class will automatically include other fields in the form.
+* It allows to set ``base_fieldsets`` so the derived class will automatically display any extra fields.
+
+By adding ``polymorphic`` to the ``INSTALLED_APPS``, the breadcrumbs will be
+fixed as well, to stay the same for all child models.
+
+The standard ``ModelAdmin`` attributes ``form`` and ``fieldsets`` should rather be avoided at the base class,
+because it will hide any additional fields which are defined in the derived model. Instead,
+use the ``base_form`` and ``base_fieldsets`` instead. The ``PolymorphicChildModelAdmin`` will
+automatically detect the additional fields that the child model has, display those in a separate fieldset.
+
+
+Example
+~~~~~~~
+
+::
+
+    from django.contrib import admin
+    from polymorphic.admin import PolymorphicParentModelAdmin, PolymorphicChildModelAdmin
+
+
+    class ModelAChildAdmin(PolymorphicChildModelAdmin):
+        """ Base admin class for all child models """
+        base_model = ModelA
+
+        # By using these `base_...` attributes instead of the regular ModelAdmin `form` and `fieldsets`,
+        # the additional fields of the child models are automatically added to the admin form.
+        base_form = ...
+        base_fieldsets = (
+            ...
+        )
+
+    class ModelBAdmin(ModelAChildAdmin):
+        # define custom features here
+
+    class ModelCAdmin(ModelBAdmin):
+        # define custom features here
+
+
+    class ModelAParentAdmin(PolymorphicParentModelAdmin):
+        """ The parent model admin """
+        base_model = ModelA
+        child_models = (
+            (ModelB, ModelBAdmin),
+            (ModelC, ModelCAdmin),
+        }
+
+    # Only the parent needs to be registered:
+    admin.site.register(ModelA, ModelAParentAdmin)
+
+
 Filtering for classes (equivalent to python's isinstance() ):
 -------------------------------------------------------------
 
@@ -504,9 +596,6 @@ Restrictions & Caveats
     ``extra()`` has one restriction: the resulting objects are required to have
     a unique primary key within the result set.
 
-*   Django Admin Integration: There currently is no specific admin integration,
-    but it would most likely make sense to have one.
-
 *   Diamond shaped inheritance: There seems to be a general problem 
     with diamond shaped multiple model inheritance with Django models
     (tested with V1.1 - V1.3).

MANIFEST.in

@@ -2,4 +2,4 @@ include README.rst
 include LICENSE
 include DOCS.rst
 include CHANGES.rst
-
+recursive-include polymorphic/templates/ *.html

pexp/admin.py

@@ -0,0 +1,63 @@
+from django.contrib import admin
+from polymorphic.admin import PolymorphicParentModelAdmin, PolymorphicChildModelAdmin
+from pexp.models import *
+
+
+class ProjectChildAdmin(PolymorphicChildModelAdmin):
+    base_model = Project
+
+class ProjectAdmin(PolymorphicParentModelAdmin):
+    base_model = Project
+    child_models = (
+        (Project, ProjectChildAdmin),
+        (ArtProject, ProjectChildAdmin),
+        (ResearchProject, ProjectChildAdmin),
+    )
+
+admin.site.register(Project, ProjectAdmin)
+
+
+
+class ModelAChildAdmin(PolymorphicChildModelAdmin):
+    base_model = ModelA
+
+class ModelAAdmin(PolymorphicParentModelAdmin):
+    base_model = ModelA
+    child_models = (
+        (ModelA, ModelAChildAdmin),
+        (ModelB, ModelAChildAdmin),
+        (ModelC, ModelAChildAdmin),
+    )
+
+admin.site.register(ModelA, ModelAAdmin)
+
+
+if 'Model2A' in globals():
+    class Model2AChildAdmin(PolymorphicChildModelAdmin):
+        base_model = Model2A
+
+    class Model2AAdmin(PolymorphicParentModelAdmin):
+        base_model = Model2A
+        child_models = (
+            (Model2A, Model2AChildAdmin),
+            (Model2B, Model2AChildAdmin),
+            (Model2C, Model2AChildAdmin),
+        )
+
+    admin.site.register(Model2A, Model2AAdmin)
+
+
+if 'UUIDModelA' in globals():
+    class UUIDModelAChildAdmin(PolymorphicChildModelAdmin):
+        base_model = UUIDModelA
+
+    class UUIDModelAAdmin(PolymorphicParentModelAdmin):
+        base_model = UUIDModelA
+        child_models = (
+            (UUIDModelA, UUIDModelAChildAdmin),
+            (UUIDModelB, UUIDModelAChildAdmin),
+            (UUIDModelC, UUIDModelAChildAdmin),
+        )
+
+    admin.site.register(UUIDModelA, UUIDModelAAdmin)
+

polymorphic/admin.py

@@ -0,0 +1,466 @@
+"""
+ModelAdmin code to display polymorphic models.
+"""
+from django import forms
+from django.conf.urls.defaults import patterns, url
+from django.contrib import admin
+from django.contrib.admin.helpers import AdminForm, AdminErrorList
+from django.contrib.admin.sites import AdminSite
+from django.contrib.admin.widgets import AdminRadioSelect
+from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import PermissionDenied
+from django.core.urlresolvers import RegexURLResolver
+from django.http import Http404, HttpResponseRedirect
+from django.shortcuts import render_to_response
+from django.template.context import RequestContext
+from django.utils.encoding import force_unicode
+from django.utils.safestring import mark_safe
+from django.utils.translation import ugettext_lazy as _
+
+__all__ = ('PolymorphicModelChoiceForm', 'PolymorphicParentModelAdmin', 'PolymorphicChildModelAdmin')
+
+
+class RegistrationClosed(RuntimeError):
+    "The admin model can't be registered anymore at this point."
+    pass
+
+class ChildAdminNotRegistered(RuntimeError):
+    "The admin site for the model is not registered."
+    pass
+
+
+class PolymorphicModelChoiceForm(forms.Form):
+    """
+    The default form for the ``add_type_form``. Can be overwritten and replaced.
+    """
+    #: Define the label for the radiofield
+    type_label = _("Type")
+
+    ct_id = forms.ChoiceField(label=type_label, widget=AdminRadioSelect(attrs={'class': 'radiolist'}))
+
+    def __init__(self, *args, **kwargs):
+        # Allow to easily redefine the label (a commonly expected usecase)
+        super(PolymorphicModelChoiceForm, self).__init__(*args, **kwargs)
+        self.fields['ct_id'].label = self.type_label
+
+
+
+class PolymorphicParentModelAdmin(admin.ModelAdmin):
+    """
+    A admin interface that can displays different change/delete pages, depending on the polymorphic model.
+    To use this class, two variables need to be defined:
+
+    * :attr:`base_model` should
+    * :attr:`child_models` should be a list of (Model, Admin) tuples
+
+    Alternatively, the following methods can be implemented:
+
+    * :func:`get_child_models` should return a list of (Model, ModelAdmin) tuples
+    * optionally, :func:`get_child_type_choices` can be overwritten to refine the choices for the add dialog.
+
+    This class needs to be inherited by the model admin base class that is registered in the site.
+    The derived models should *not* register the ModelAdmin, but instead it should be returned by :func:`get_child_models`.
+    """
+
+    #: The base model that the class uses
+    base_model = None
+
+    #: The child models that should be displayed
+    child_models = None
+
+    #: Whether the list should be polymorphic too, leave to ``False`` to optimize
+    polymorphic_list = False
+
+    add_type_template = None
+    add_type_form = PolymorphicModelChoiceForm
+
+
+    def __init__(self, model, admin_site, *args, **kwargs):
+        super(PolymorphicParentModelAdmin, self).__init__(model, admin_site, *args, **kwargs)
+        self._child_admin_site = AdminSite(name=self.admin_site.name)
+        self._is_setup = False
+
+
+    def _lazy_setup(self):
+        if self._is_setup:
+            return
+
+        # By not having this in __init__() there is less stress on import dependencies as well,
+        # considering an advanced use cases where a plugin system scans for the child models.
+        child_models = self.get_child_models()
+        for Model, Admin in child_models:
+            self.register_child(Model, Admin)
+        self._child_models = dict(child_models)
+
+        # This is needed to deal with the improved ForeignKeyRawIdWidget in Django 1.4 and perhaps other widgets too.
+        # The ForeignKeyRawIdWidget checks whether the referenced model is registered in the admin, otherwise it displays itself as a textfield.
+        # As simple solution, just make sure all parent admin models are also know in the child admin site.
+        # This should be done after all parent models are registered off course.
+        complete_registry = self.admin_site._registry.copy()
+        complete_registry.update(self._child_admin_site._registry)
+
+        self._child_admin_site._registry = complete_registry
+        self._is_setup = True
+
+
+    def register_child(self, model, model_admin):
+        """
+        Register a model with admin to display.
+        """
+        # After the get_urls() is called, the URLs of the child model can't be exposed anymore to the Django URLconf,
+        # which also means that a "Save and continue editing" button won't work.
+        if self._is_setup:
+            raise RegistrationClosed("The admin model can't be registered anymore at this point.")
+
+        if not issubclass(model, self.base_model):
+            raise TypeError("{0} should be a subclass of {1}".format(model.__name__, self.base_model.__name__))
+        if not issubclass(model_admin, admin.ModelAdmin):
+            raise TypeError("{0} should be a subclass of {1}".format(model_admin.__name__, admin.ModelAdmin.__name__))
+
+        self._child_admin_site.register(model, model_admin)
+
+
+    def get_child_models(self):
+        """
+        Return the derived model classes which this admin should handle.
+        This should return a list of tuples, exactly like :attr:`child_models` is.
+
+        The model classes can be retrieved as ``base_model.__subclasses__()``,
+        a setting in a config file, or a query of a plugin registration system at your option
+        """
+        if self.child_models is None:
+            raise NotImplementedError("Implement get_child_models() or child_models")
+
+        return self.child_models
+
+
+    def get_child_type_choices(self):
+        """
+        Return a list of polymorphic types which can be added.
+        """
+        choices = []
+        for model, _ in self.get_child_models():
+            ct = ContentType.objects.get_for_model(model)
+            choices.append((ct.id, model._meta.verbose_name))
+        return choices
+
+
+    def _get_real_admin(self, object_id):
+        obj = self.model.objects.non_polymorphic().values('polymorphic_ctype').get(pk=object_id)
+        return self._get_real_admin_by_ct(obj['polymorphic_ctype'])
+
+
+    def _get_real_admin_by_ct(self, ct_id):
+        try:
+            ct = ContentType.objects.get_for_id(ct_id)
+        except ContentType.DoesNotExist as e:
+            raise Http404(e)   # Handle invalid GET parameters
+
+        model_class = ct.model_class()
+        if not model_class:
+            raise Http404("No model found for '{0}.{1}'.".format(*ct.natural_key()))  # Handle model deletion
+
+        return self._get_real_admin_by_model(model_class)
+
+
+    def _get_real_admin_by_model(self, model_class):
+        # In case of a ?ct_id=### parameter, the view is already checked for permissions.
+        # Hence, make sure this is a derived object, or risk exposing other admin interfaces.
+        if model_class not in self._child_models:
+            raise PermissionDenied("Invalid model '{0}', it must be registered as child model.".format(model_class))
+
+        try:
+            # HACK: the only way to get the instance of an model admin,
+            # is to read the registry of the AdminSite.
+            return self._child_admin_site._registry[model_class]
+        except KeyError:
+            raise ChildAdminNotRegistered("No child admin site was registered for a '{0}' model.".format(model_class))
+
+
+    def queryset(self, request):
+        # optimize the list display.
+        qs = super(PolymorphicParentModelAdmin, self).queryset(request)
+        if not self.polymorphic_list:
+            qs = qs.non_polymorphic()
+        return qs
+
+
+    def add_view(self, request, form_url='', extra_context=None):
+        """Redirect the add view to the real admin."""
+        ct_id = int(request.GET.get('ct_id', 0))
+        if not ct_id:
+            # Display choices
+            return self.add_type_view(request)
+        else:
+            real_admin = self._get_real_admin_by_ct(ct_id)
+            return real_admin.add_view(request, form_url, extra_context)
+
+
+    def change_view(self, request, object_id, *args, **kwargs):
+        """Redirect the change view to the real admin."""
+        # between Django 1.3 and 1.4 this method signature differs. Hence the *args, **kwargs
+        real_admin = self._get_real_admin(object_id)
+        return real_admin.change_view(request, object_id, *args, **kwargs)
+
+
+    def delete_view(self, request, object_id, extra_context=None):
+        """Redirect the delete view to the real admin."""
+        real_admin = self._get_real_admin(object_id)
+        return real_admin.delete_view(request, object_id, extra_context)
+
+
+    def get_urls(self):
+        """
+        Expose the custom URLs for the subclasses and the URL resolver.
+        """
+        urls = super(PolymorphicParentModelAdmin, self).get_urls()
+        info = self.model._meta.app_label, self.model._meta.module_name
+
+        # Patch the change URL so it's not a big catch-all; allowing all custom URLs to be added to the end.
+        # The url needs to be recreated, patching url.regex is not an option Django 1.4's LocaleRegexProvider changed it.
+        new_change_url = url(r'^(\d+)/$', self.admin_site.admin_view(self.change_view), name='{0}_{1}_change'.format(*info))
+        for i, oldurl in enumerate(urls):
+            if oldurl.name == new_change_url.name:
+                urls[i] = new_change_url
+
+        # Define the catch-all for custom views
+        custom_urls = patterns('',
+            url(r'^(?P<path>.+)$', self.admin_site.admin_view(self.subclass_view))
+        )
+
+        # At this point. all admin code needs to be known.
+        self._lazy_setup()
+
+        # Add reverse names for all polymorphic models, so the delete button and "save and add" just work.
+        # These definitions are masked by the definition above, since it needs special handling (and a ct_id parameter).
+        dummy_urls = []
+        for model, _ in self.get_child_models():
+            admin = self._get_real_admin_by_model(model)
+            dummy_urls += admin.get_urls()
+
+        return urls + custom_urls + dummy_urls
+
+
+    def subclass_view(self, request, path):
+        """
+        Forward any request to a custom view of the real admin.
+        """
+        ct_id = int(request.GET.get('ct_id', 0))
+        if not ct_id:
+            raise Http404("No ct_id parameter, unable to find admin subclass for path '{0}'.".format(path))
+
+        real_admin = self._get_real_admin_by_ct(ct_id)
+        resolver = RegexURLResolver('^', real_admin.urls)
+        resolvermatch = resolver.resolve(path)
+        if not resolvermatch:
+            raise Http404("No match for path '{0}' in admin subclass.".format(path))
+
+        return resolvermatch.func(request, *resolvermatch.args, **resolvermatch.kwargs)
+
+
+    def add_type_view(self, request, form_url=''):
+        """
+        Display a choice form to select which page type to add.
+        """
+        extra_qs = ''
+        if request.META['QUERY_STRING']:
+            extra_qs = '&' + request.META['QUERY_STRING']
+
+        choices = self.get_child_type_choices()
+        if len(choices) == 1:
+            return HttpResponseRedirect('?ct_id={0}{1}'.format(choices[0][0], extra_qs))
+
+        # Create form
+        form = self.add_type_form(
+            data=request.POST if request.method == 'POST' else None,
+            initial={'ct_id': choices[0][0]}
+        )
+        form.fields['ct_id'].choices = choices
+
+        if form.is_valid():
+            return HttpResponseRedirect('?ct_id={0}{1}'.format(form.cleaned_data['ct_id'], extra_qs))
+
+        # Wrap in all admin layout
+        fieldsets = ((None, {'fields': ('ct_id',)}),)
+        adminForm = AdminForm(form, fieldsets, {}, model_admin=self)
+        media = self.media + adminForm.media
+        opts = self.model._meta
+
+        context = {
+            'title': _('Add %s') % force_unicode(opts.verbose_name),
+            'adminform': adminForm,
+            'is_popup': "_popup" in request.REQUEST,
+            'media': mark_safe(media),
+            'errors': AdminErrorList(form, ()),
+            'app_label': opts.app_label,
+        }
+        return self.render_add_type_form(request, context, form_url)
+
+
+    def render_add_type_form(self, request, context, form_url=''):
+        """
+        Render the page type choice form.
+        """
+        opts = self.model._meta
+        app_label = opts.app_label
+        context.update({
+            'has_change_permission': self.has_change_permission(request),
+            'form_url': mark_safe(form_url),
+            'opts': opts,
+        })
+        if hasattr(self.admin_site, 'root_path'):
+            context['root_path'] = self.admin_site.root_path  # Django < 1.4
+        context_instance = RequestContext(request, current_app=self.admin_site.name)
+        return render_to_response(self.add_type_template or [
+            "admin/%s/%s/add_type_form.html" % (app_label, opts.object_name.lower()),
+            "admin/%s/add_type_form.html" % app_label,
+            "admin/polymorphic/add_type_form.html",  # added default here
+            "admin/add_type_form.html"
+        ], context, context_instance=context_instance)
+
+
+    @property
+    def change_list_template(self):
+        opts = self.model._meta
+        app_label = opts.app_label
+
+        # Pass the base options
+        base_opts = self.base_model._meta
+        base_app_label = base_opts.app_label
+
+        return [
+            "admin/%s/%s/change_list.html" % (app_label, opts.object_name.lower()),
+            "admin/%s/change_list.html" % app_label,
+            # Added base class:
+            "admin/%s/%s/change_list.html" % (base_app_label, base_opts.object_name.lower()),
+            "admin/%s/change_list.html" % base_app_label,
+            "admin/change_list.html"
+        ]
+
+
+
+class PolymorphicChildModelAdmin(admin.ModelAdmin):
+    """
+    The *optional* base class for the admin interface of derived models.
+
+    This base class defines some convenience behavior for the admin interface:
+
+    * It corrects the breadcrumbs in the admin pages.
+    * It adds the base model to the template lookup paths.
+    * It allows to set ``base_form`` so the derived class will automatically include other fields in the form.
+    * It allows to set ``base_fieldsets`` so the derived class will automatically display any extra fields.
+
+    The ``base_model`` attribute must be set.
+    """
+    base_model = None
+    base_form = None
+    base_fieldsets = None
+    extra_fieldset_title = _("Contents")  # Default title for extra fieldset
+
+
+    def get_form(self, request, obj=None, **kwargs):
+        # The django admin validation requires the form to have a 'class Meta: model = ..'
+        # attribute, or it will complain that the fields are missing.
+        # However, this enforces all derived ModelAdmin classes to redefine the model as well,
+        # because they need to explicitly set the model again - it will stick with the base model.
+        #
+        # Instead, pass the form unchecked here, because the standard ModelForm will just work.
+        # If the derived class sets the model explicitly, respect that setting.
+        if not self.form:
+            kwargs['form'] = self.base_form
+        return super(PolymorphicChildModelAdmin, self).get_form(request, obj, **kwargs)
+
+
+    @property
+    def change_form_template(self):
+        opts = self.model._meta
+        app_label = opts.app_label
+
+        # Pass the base options
+        base_opts = self.base_model._meta
+        base_app_label = base_opts.app_label
+
+        return [
+            "admin/%s/%s/change_form.html" % (app_label, opts.object_name.lower()),
+            "admin/%s/change_form.html" % app_label,
+            # Added:
+            "admin/%s/%s/change_form.html" % (base_app_label, base_opts.object_name.lower()),
+            "admin/%s/change_form.html" % base_app_label,
+            "admin/polymorphic/change_form.html",
+            "admin/change_form.html"
+        ]
+
+
+    @property
+    def delete_confirmation_template(self):
+        opts = self.model._meta
+        app_label = opts.app_label
+
+        # Pass the base options
+        base_opts = self.base_model._meta
+        base_app_label = base_opts.app_label
+
+        return [
+            "admin/%s/%s/delete_confirmation.html" % (app_label, opts.object_name.lower()),
+            "admin/%s/delete_confirmation.html" % app_label,
+            # Added:
+            "admin/%s/%s/delete_confirmation.html" % (base_app_label, base_opts.object_name.lower()),
+            "admin/%s/delete_confirmation.html" % base_app_label,
+            "admin/polymorphic/delete_confirmation.html",
+            "admin/delete_confirmation.html"
+        ]
+
+
+    def render_change_form(self, request, context, add=False, change=False, form_url='', obj=None):
+        context.update({
+            'base_opts': self.base_model._meta,
+        })
+        return super(PolymorphicChildModelAdmin, self).render_change_form(request, context, add=add, change=change, form_url=form_url, obj=obj)
+
+
+    def delete_view(self, request, object_id, context=None):
+        extra_context = {
+            'base_opts': self.base_model._meta,
+        }
+        return super(PolymorphicChildModelAdmin, self).delete_view(request, object_id, extra_context)
+
+
+    # ---- Extra: improving the form/fieldset default display ----
+
+    def get_fieldsets(self, request, obj=None):
+        # If subclass declares fieldsets, this is respected
+        if self.declared_fieldsets or not self.base_fieldsets:
+            return super(PolymorphicChildModelAdmin, self).get_fieldsets(request, obj)
+
+        # Have a reasonable default fieldsets,
+        # where the subclass fields are automatically included.
+        other_fields = self.get_subclass_fields(request, obj)
+
+        if other_fields:
+            return (
+                self.base_fieldsets[0],
+                (self.extra_fieldset_title, {'fields': other_fields}),
+            ) + self.base_fieldsets[1:]
+        else:
+            return self.base_fieldsets
+
+
+    def get_subclass_fields(self, request, obj=None):
+        # Find out how many fields would really be on the form,
+        # if it weren't restricted by declared fields.
+        exclude = list(self.exclude or [])
+        exclude.extend(self.get_readonly_fields(request, obj))
+
+        # By not declaring the fields/form in the base class,
+        # get_form() will populate the form with all available fields.
+        form = self.get_form(request, obj, exclude=exclude)
+        subclass_fields = form.base_fields.keys() + list(self.get_readonly_fields(request, obj))
+
+        # Find which fields are not part of the common fields.
+        for fieldset in self.base_fieldsets:
+            for field in fieldset[1]['fields']:
+                try:
+                    subclass_fields.remove(field)
+                except ValueError:
+                    pass   # field not found in form, Django will raise exception later.
+        return subclass_fields

polymorphic/templates/admin/polymorphic/add_type_form.html

@@ -0,0 +1,43 @@
+{% extends "admin/change_form.html" %}
+{% load i18n admin_modify adminmedia %}
+{% load url from future %}
+
+{% block breadcrumbs %}{% if not is_popup %}
+<div class="breadcrumbs">
+     <a href="../../../">{% trans "Home" %}</a> &rsaquo;
+     <a href="../../">{{ app_label|capfirst|escape }}</a> &rsaquo;
+     {% if has_change_permission %}<a href="../">{{ opts.verbose_name_plural|capfirst }}</a>{% else %}{{ opts.verbose_name_plural|capfirst }}{% endif %} &rsaquo;
+     {% trans "Add" %} {{ opts.verbose_name }}
+</div>
+{% endif %}{% endblock %}
+
+{% block content %}<div id="content-main">
+<form action="{{ form_url }}" method="post" id="{{ opts.module_name }}_form">{% csrf_token %}{% block form_top %}{% endblock %}
+<div>
+{% if is_popup %}<input type="hidden" name="_popup" value="1" />{% endif %}
+
+{% if save_on_top %}
+    <div class="submit-row" {% if is_popup %}style="overflow: auto;"{% endif %}>
+        <input type="submit" value="{% trans 'Submit' %}" class="default" name="_save" />
+    </div>
+{% endif %}
+
+{% if errors %}
+    <p class="errornote">
+    {% blocktrans count errors|length as counter %}Please correct the error below.{% plural %}Please correct the errors below.{% endblocktrans %}
+    </p>
+    {{ adminform.form.non_field_errors }}
+{% endif %}
+
+{% for fieldset in adminform %}
+  {% include "admin/includes/fieldset.html" %}
+{% endfor %}
+
+<div class="submit-row" {% if is_popup %}style="overflow: auto;"{% endif %}>
+    <input type="submit" value="{% trans 'Submit' %}" class="default" name="_save" />
+</div>
+
+<script type="text/javascript">document.getElementById("{{ adminform.first_field.id_for_label }}").focus();</script>
+</div>
+</form></div>
+{% endblock %}

polymorphic/templates/admin/polymorphic/change_form.html

@@ -0,0 +1,12 @@
+{% extends "admin/change_form.html" %}
+{% load i18n polymorphic_admin_tags %}
+
+{# fix breadcrumb #}
+{% block breadcrumbs %}{% if not is_popup %}{% breadcrumb_scope base_opts %}
+<div class="breadcrumbs">
+     <a href="../../../">{% trans "Home" %}</a> &rsaquo;
+     <a href="../../">{{ app_label|capfirst|escape }}</a> &rsaquo;
+     {% if has_change_permission %}<a href="../">{{ opts.verbose_name_plural|capfirst }}</a>{% else %}{{ opts.verbose_name_plural|capfirst }}{% endif %} &rsaquo;
+     {% if add %}{% trans "Add" %} {{ opts.verbose_name }}{% else %}{{ original|truncatewords:"18" }}{% endif %}
+</div>
+{% endbreadcrumb_scope %}{% endif %}{% endblock %}

polymorphic/templates/admin/polymorphic/delete_confirmation.html

@@ -0,0 +1,12 @@
+{% extends "admin/delete_confirmation.html" %}
+{% load i18n polymorphic_admin_tags %}
+
+{% block breadcrumbs %}{% breadcrumb_scope base_opts %}
+<div class="breadcrumbs">
+     <a href="../../../../">{% trans "Home" %}</a> &rsaquo;
+     <a href="../../../">{{ app_label|capfirst|escape }}</a> &rsaquo;
+     <a href="../../">{{ opts.verbose_name_plural|capfirst }}</a> &rsaquo;
+     <a href="../">{{ object|truncatewords:"18" }}</a> &rsaquo;
+     {% trans 'Delete' %}
+</div>
+{% endbreadcrumb_scope %}{% endblock %}

polymorphic/templatetags/polymorphic_admin_tags.py

@@ -0,0 +1,52 @@
+from django.template import Library, Node, TemplateSyntaxError
+
+register = Library()
+
+
+class BreadcrumbScope(Node):
+    def __init__(self, base_opts, nodelist):
+        self.base_opts = base_opts
+        self.nodelist = nodelist   # Note, takes advantage of Node.child_nodelists
+
+    @classmethod
+    def parse(cls, parser, token):
+        bits = token.split_contents()
+        if len(bits) == 2:
+            (tagname, base_opts) = bits
+            base_opts = parser.compile_filter(base_opts)
+            nodelist = parser.parse(('endbreadcrumb_scope',))
+            parser.delete_first_token()
+
+            return cls(
+                base_opts=base_opts,
+                nodelist=nodelist
+            )
+        else:
+            raise TemplateSyntaxError("{0} tag expects 1 argument".format(token.contents[0]))
+
+
+    def render(self, context):
+        # app_label is really hard to overwrite in the standard Django ModelAdmin.
+        # To insert it in the template, the entire render_change_form() and delete_view() have to copied and adjusted.
+        # Instead, have an assignment tag that inserts that in the template.
+        base_opts = self.base_opts.resolve(context)
+        new_vars = {}
+        if base_opts and not isinstance(base_opts, basestring):
+            new_vars = {
+                'app_label': base_opts.app_label,  # What this is all about
+                'opts': base_opts,
+            }
+
+        new_scope = context.push()
+        new_scope.update(new_vars)
+        html = self.nodelist.render(context)
+        context.pop()
+        return html
+
+
+@register.tag
+def breadcrumb_scope(parser, token):
+    """
+    Easily allow the breadcrumb to be generated in the admin change templates.
+    """
+    return BreadcrumbScope.parse(parser, token)

settings.py

@@ -68,18 +68,20 @@ SECRET_KEY = 'nk=c&k+c&#+)8557)%&0auysdd3g^sfq6@rw8_x1k8)-p@y)!('
 
 # List of callables that know how to import templates from various sources.
 TEMPLATE_LOADERS = (
-    'django.template.loaders.filesystem.load_template_source',
-    'django.template.loaders.app_directories.load_template_source',
-#     'django.template.loaders.eggs.load_template_source',
+    'django.template.loaders.filesystem.Loader',
+    'django.template.loaders.app_directories.Loader',
 )
 
 MIDDLEWARE_CLASSES = (
     'django.middleware.common.CommonMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
 )
 
-ROOT_URLCONF = ''
+ROOT_URLCONF = 'urls'
+STATIC_URL = '/static/'
+ADMIN_MEDIA_PREFIX = '/static/admin/'  # 1.3 compatibility
 
 TEMPLATE_DIRS = (
     # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
@@ -88,10 +90,14 @@ TEMPLATE_DIRS = (
 )
 
 INSTALLED_APPS = (
-    #'django.contrib.auth',
+    'django.contrib.auth',
+    'django.contrib.admin',
     'django.contrib.contenttypes',
-    #'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.sessions',
+    'django.contrib.staticfiles',
+
     #'django.contrib.sites',
-    'polymorphic',      # only needed if you want to use polymorphic_dumpdata
+    'polymorphic',      # needed if you want to use the polymorphic admin
     'pexp',             # this Django app is for testing and experimentation; not needed otherwise
 )

setup.py

@@ -8,7 +8,11 @@ setup(
     author_email = 'bert.constantin@gmx.de',
     maintainer = 'Christopher Glass',
     maintainer_email = 'tribaal@gmail.com',
-    packages = [ 'polymorphic' ],
+    url = 'https://github.com/chrisglass/django_polymorphic',
+    packages = [
+        'polymorphic',
+        'polymorphic.templatetags',
+    ],
     classifiers=[
         'Framework :: Django',
         'Intended Audience :: Developers',

urls.py

@@ -0,0 +1,10 @@
+from django.conf import settings
+from django.conf.urls.defaults import patterns, include, url
+from django.conf.urls.static import static
+from django.contrib import admin
+
+admin.autodiscover()
+
+urlpatterns = patterns('',
+    url(r'^admin/', include(admin.site.urls)),
+)