Fixed #8261 -- ModelAdmin hook for customising the "show on site" button

``ModelAdmin.view_on_site`` defines wether to show a link to the object on the
admin detail page. If ``True``, cleverness (i.e. ``Model.get_absolute_url``) is
used to get the url. If it's a callable, the callable is called with the object
as the only parameter. If ``False``, not link is displayed.

With the aim of maitaining backwards compatibility, ``True`` is the default.

django/contrib/admin/helpers.py

@@ -202,9 +202,10 @@ class InlineAdminFormSet(object):
 
     def __iter__(self):
         for form, original in zip(self.formset.initial_forms, self.formset.get_queryset()):
+            view_on_site_url = self.opts.get_view_on_site_url(original)
             yield InlineAdminForm(self.formset, form, self.fieldsets,
                 self.prepopulated_fields, original, self.readonly_fields,
-                model_admin=self.opts)
+                model_admin=self.opts, view_on_site_url=view_on_site_url)
         for form in self.formset.extra_forms:
             yield InlineAdminForm(self.formset, form, self.fieldsets,
                 self.prepopulated_fields, None, self.readonly_fields,
@@ -242,13 +243,14 @@ class InlineAdminForm(AdminForm):
     A wrapper around an inline form for use in the admin system.
     """
     def __init__(self, formset, form, fieldsets, prepopulated_fields, original,
-      readonly_fields=None, model_admin=None):
+      readonly_fields=None, model_admin=None, view_on_site_url=None):
         self.formset = formset
         self.model_admin = model_admin
         self.original = original
         if original is not None:
             self.original_content_type_id = ContentType.objects.get_for_model(original).pk
-        self.show_url = original and hasattr(original, 'get_absolute_url')
+        self.show_url = original and view_on_site_url is not None
+        self.absolute_url = view_on_site_url
         super(InlineAdminForm, self).__init__(form, fieldsets, prepopulated_fields,
             readonly_fields, model_admin)
 

django/contrib/admin/options.py

@@ -98,6 +98,7 @@ class BaseModelAdmin(six.with_metaclass(RenameBaseModelAdminMethods)):
     formfield_overrides = {}
     readonly_fields = ()
     ordering = None
+    view_on_site = True
 
     # validation
     validator_class = validation.BaseValidator
@@ -243,6 +244,19 @@ class BaseModelAdmin(six.with_metaclass(RenameBaseModelAdminMethods)):
 
         return db_field.formfield(**kwargs)
 
+    def get_view_on_site_url(self, obj=None):
+        if obj is None or not self.view_on_site:
+            return None
+
+        if callable(self.view_on_site):
+            return self.view_on_site(obj)
+        elif self.view_on_site:
+            # use the ContentType lookup if view_on_site is True
+            return reverse('admin:view_on_site', kwargs={
+                'content_type_id': ContentType.objects.get_for_model(obj).pk,
+                'object_id': obj.pk
+            })
+
     @property
     def declared_fieldsets(self):
         warnings.warn(
@@ -971,6 +985,7 @@ class ModelAdmin(BaseModelAdmin):
         app_label = opts.app_label
         preserved_filters = self.get_preserved_filters(request)
         form_url = add_preserved_filters({'preserved_filters': preserved_filters, 'opts': opts}, form_url)
+        view_on_site_url = self.get_view_on_site_url(obj)
         context.update({
             'add': add,
             'change': change,
@@ -978,7 +993,8 @@ class ModelAdmin(BaseModelAdmin):
             'has_change_permission': self.has_change_permission(request, obj),
             'has_delete_permission': self.has_delete_permission(request, obj),
             'has_file_field': True,  # FIXME - this should check if form or formsets have a FileField,
-            'has_absolute_url': hasattr(self.model, 'get_absolute_url'),
+            'has_absolute_url': view_on_site_url is not None,
+            'absolute_url': view_on_site_url,
             'form_url': form_url,
             'opts': opts,
             'content_type_id': ContentType.objects.get_for_model(self.model).id,

django/contrib/admin/templates/admin/change_form.html

@@ -32,7 +32,7 @@
         {% url opts|admin_urlname:'history' original.pk|admin_urlquote as history_url %}
         <a href="{% add_preserved_filters history_url %}" class="historylink">{% trans "History" %}</a>
     </li>
-    {% if has_absolute_url %}<li><a href="{% url 'admin:view_on_site' content_type_id original.pk %}" class="viewsitelink">{% trans "View on site" %}</a></li>{% endif%}
+    {% if has_absolute_url %}<li><a href="{{ absolute_url }}" class="viewsitelink">{% trans "View on site" %}</a></li>{% endif%}
     {% endblock %}
   </ul>
 {% endif %}{% endif %}

django/contrib/admin/templates/admin/edit_inline/stacked.html

@@ -6,7 +6,7 @@
 
 {% for inline_admin_form in inline_admin_formset %}<div class="inline-related{% if forloop.last %} empty-form last-related{% endif %}" id="{{ inline_admin_formset.formset.prefix }}-{% if not forloop.last %}{{ forloop.counter0 }}{% else %}empty{% endif %}">
   <h3><b>{{ inline_admin_formset.opts.verbose_name|capfirst }}:</b>&nbsp;<span class="inline_label">{% if inline_admin_form.original %}{{ inline_admin_form.original }}{% else %}#{{ forloop.counter }}{% endif %}</span>
-    {% if inline_admin_form.show_url %}<a href="{% url 'admin:view_on_site' inline_admin_form.original_content_type_id inline_admin_form.original.pk %}">{% trans "View on site" %}</a>{% endif %}
+      {% if inline_admin_form.show_url %}<a href="{{ inline_admin_form.absolute_url }}">{% trans "View on site" %}</a>{% endif %}
     {% if inline_admin_formset.formset.can_delete and inline_admin_form.original %}<span class="delete">{{ inline_admin_form.deletion_field.field }} {{ inline_admin_form.deletion_field.label_tag }}</span>{% endif %}
   </h3>
   {% if inline_admin_form.form.non_field_errors %}{{ inline_admin_form.form.non_field_errors }}{% endif %}

django/contrib/admin/templates/admin/edit_inline/tabular.html

@@ -27,7 +27,7 @@
         <td class="original">
           {% if inline_admin_form.original or inline_admin_form.show_url %}<p>
           {% if inline_admin_form.original %} {{ inline_admin_form.original }}{% endif %}
-          {% if inline_admin_form.show_url %}<a href="{% url 'admin:view_on_site' inline_admin_form.original_content_type_id inline_admin_form.original.pk %}">{% trans "View on site" %}</a>{% endif %}
+          {% if inline_admin_form.show_url %}<a href="{{ inline_admin_form.absolute_url }}">{% trans "View on site" %}</a>{% endif %}
             </p>{% endif %}
           {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
           {{ inline_admin_form.fk_field.field }}

django/contrib/admin/validation.py

@@ -164,6 +164,11 @@ class BaseValidator(object):
                 for idx, f in enumerate(val):
                     get_field(cls, model, "prepopulated_fields['%s'][%d]" % (field, idx), f)
 
+    def validate_view_on_site_url(self, cls, model):
+        if hasattr(cls, 'view_on_site'):
+            if not callable(cls.view_on_site) and not isinstance(cls.view_on_site, bool):
+                raise ImproperlyConfigured("%s.view_on_site is not a callable or a boolean value." % cls.__name__)
+
     def validate_ordering(self, cls, model):
         " Validate that ordering refers to existing fields or is random. "
         # ordering = None

docs/ref/contrib/admin/index.txt

@@ -1091,6 +1091,37 @@ subclass::
     :meth:`ModelAdmin.get_search_results` to provide additional or alternate
     search behavior.
 
+.. attribute:: ModelAdmin.view_on_site
+
+    .. versionadded:: 1.7
+
+    Set ``view_on_site`` to control whether or not to display the "View on site" link.
+    This link should bring you to a URL where you can display the saved object.
+
+    This value can be either a boolean flag or a callable. If ``True`` (the
+    default), the object's :meth:`~django.db.models.Model.get_absolute_url`
+    method will be used to generate the url.
+
+    If your model has a :meth:`~django.db.models.Model.get_absolute_url` method
+    but you don't want the "View on site" button to appear, you only need to set
+    ``view_on_site`` to ``False``::
+
+        from django.contrib import admin
+
+        class PersonAdmin(admin.ModelAdmin):
+            view_on_site = False
+
+    In case it is a callable, it accepts the model instance as a parameter.
+    For example::
+
+        from django.contrib import admin
+        from django.core.urlresolvers import reverse
+
+        class PersonAdmin(admin.ModelAdmin):
+            def view_on_site(self, obj):
+                return 'http://example.com' + reverse('person-detail',
+                                                      kwargs={'slug': obj.slug})
+
 Custom template options
 ~~~~~~~~~~~~~~~~~~~~~~~
 

docs/releases/1.7.txt

@@ -168,6 +168,10 @@ Minor features
   <django.contrib.admin.ModelAdmin.list_display_links>` ``= None`` to disable
   links on the change list page grid.
 
+* You may now specify :attr:`ModelAdmin.view_on_site
+  <django.contrib.admin.ModelAdmin.view_on_site>` to control whether or not to
+  display the "View on site" link.
+
 :mod:`django.contrib.auth`
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 

tests/admin_views/admin.py

@@ -31,7 +31,7 @@ from .models import (Article, Chapter, Account, Media, Child, Parent, Picture,
     AdminOrderedCallable, Report, Color2, UnorderedObject, MainPrepopulated,
     RelatedPrepopulated, UndeletableObject, UnchangeableObject, UserMessenger, Simple, Choice,
     ShortMessage, Telegram, FilteredManager, EmptyModelHidden,
-    EmptyModelVisible, EmptyModelMixin)
+    EmptyModelVisible, EmptyModelMixin, State, City, Restaurant, Worker)
 
 
 def callable_year(dt_value):
@@ -74,6 +74,7 @@ class ChapterXtra1Admin(admin.ModelAdmin):
 class ArticleAdmin(admin.ModelAdmin):
     list_display = ('content', 'date', callable_year, 'model_year', 'modeladmin_year')
     list_filter = ('date', 'section')
+    view_on_site = False
     fieldsets = (
         ('Some fields', {
             'classes': ('collapse',),
@@ -735,6 +736,35 @@ class EmptyModelMixinAdmin(admin.ModelAdmin):
     form = FormWithVisibleAndHiddenField
     fieldsets = EmptyModelVisibleAdmin.fieldsets
 
+class CityInlineAdmin(admin.TabularInline):
+    model = City
+    view_on_site = False
+
+class StateAdmin(admin.ModelAdmin):
+    inlines = [CityInlineAdmin]
+
+class RestaurantInlineAdmin(admin.TabularInline):
+    model = Restaurant
+    view_on_site = True
+
+class CityAdmin(admin.ModelAdmin):
+    inlines = [RestaurantInlineAdmin]
+    view_on_site = True
+
+class WorkerAdmin(admin.ModelAdmin):
+    def view_on_site(self, obj):
+        return '/worker/%s/%s/' % (obj.surname, obj.name)
+
+class WorkerInlineAdmin(admin.TabularInline):
+    model = Worker
+
+    def view_on_site(self, obj):
+        return '/worker_inline/%s/%s/' % (obj.surname, obj.name)
+
+class RestaurantAdmin(admin.ModelAdmin):
+    inlines = [WorkerInlineAdmin]
+    view_on_site = False
+
 site = admin.AdminSite(name="admin")
 site.register(Article, ArticleAdmin)
 site.register(CustomArticle, CustomArticleAdmin)
@@ -785,6 +815,10 @@ site.register(MainPrepopulated, MainPrepopulatedAdmin)
 site.register(UnorderedObject, UnorderedObjectAdmin)
 site.register(UndeletableObject, UndeletableObjectAdmin)
 site.register(UnchangeableObject, UnchangeableObjectAdmin)
+site.register(State, StateAdmin)
+site.register(City, CityAdmin)
+site.register(Restaurant, RestaurantAdmin)
+site.register(Worker, WorkerAdmin)
 
 # We intentionally register Promo and ChapterXtra1 but not Chapter nor ChapterXtra2.
 # That way we cover all four cases:

tests/admin_views/fixtures/admin-views-restaurants.xml

@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="utf-8"?>
+<django-objects version="1.0">
+    <object pk="1" model="admin_views.state">
+        <field type="CharField" name="name">New York</field>
+    </object>
+    <object pk="2" model="admin_views.state">
+        <field type="CharField" name="name">Illinois</field>
+    </object>
+    <object pk="3" model="admin_views.state">
+        <field type="CharField" name="name">California</field>
+    </object>
+    <object pk="1" model="admin_views.city">
+        <field to="admin_views.state" name="state" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">New York</field>
+    </object>
+    <object pk="2" model="admin_views.city">
+        <field to="admin_views.state" name="state" rel="ManyToOneRel">2</field>
+        <field type="CharField" name="name">Chicago</field>
+    </object>
+    <object pk="3" model="admin_views.city">
+        <field to="admin_views.state" name="state" rel="ManyToOneRel">3</field>
+        <field type="CharField" name="name">San Francisco</field>
+    </object>
+    <object pk="1" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">Italian Pizza</field>
+    </object>
+    <object pk="2" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">Boulevard</field>
+    </object>
+    <object pk="3" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">2</field>
+        <field type="CharField" name="name">Chinese Dinner</field>
+    </object>
+    <object pk="4" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">2</field>
+        <field type="CharField" name="name">Angels</field>
+    </object>
+    <object pk="5" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">2</field>
+        <field type="CharField" name="name">Take Away</field>
+    </object>
+    <object pk="6" model="admin_views.restaurant">
+        <field to="admin_views.city" name="city" rel="ManyToOneRel">3</field>
+        <field type="CharField" name="name">The Unknown Restaurant</field>
+    </object>
+    <object pk="1" model="admin_views.worker">
+        <field to="admin_views.restaurant" name="work_at" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">Mario</field>
+        <field type="CharField" name="surname">Rossi</field>
+    </object>
+    <object pk="2" model="admin_views.worker">
+        <field to="admin_views.restaurant" name="work_at" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">Antonio</field>
+        <field type="CharField" name="surname">Bianchi</field>
+    </object>
+    <object pk="3" model="admin_views.worker">
+        <field to="admin_views.restaurant" name="work_at" rel="ManyToOneRel">1</field>
+        <field type="CharField" name="name">John</field>
+        <field type="CharField" name="surname">Doe</field>
+    </object>
+</django-objects>

tests/admin_views/models.py

@@ -717,3 +717,19 @@ class EmptyModelHidden(models.Model):
 
 class EmptyModelMixin(models.Model):
     """ See ticket #11277. """
+
+class State(models.Model):
+    name = models.CharField(max_length=100)
+
+class City(models.Model):
+    state = models.ForeignKey(State)
+    name = models.CharField(max_length=100)
+
+class Restaurant(models.Model):
+    city = models.ForeignKey(City)
+    name = models.CharField(max_length=100)
+
+class Worker(models.Model):
+    work_at = models.ForeignKey(Restaurant)
+    name = models.CharField(max_length=50)
+    surname = models.CharField(max_length=50)

tests/admin_views/tests.py

@@ -9,6 +9,7 @@ import unittest
 from django.conf import settings, global_settings
 from django.core import mail
 from django.core.files import temp as tempfile
+from django.core.exceptions import ImproperlyConfigured
 from django.core.urlresolvers import reverse, NoReverseMatch
 # Register auth models with the admin.
 from django.contrib.auth import get_permission_codename
@@ -48,8 +49,8 @@ from .models import (Article, BarAccount, CustomArticle, EmptyModel, FooAccount,
     AdminOrderedModelMethod, AdminOrderedAdminMethod, AdminOrderedCallable,
     Report, MainPrepopulated, RelatedPrepopulated, UnorderedObject,
     Simple, UndeletableObject, UnchangeableObject, Choice, ShortMessage,
-    Telegram, Pizza, Topping, FilteredManager)
+    Telegram, Pizza, Topping, FilteredManager, City, Restaurant, Worker)
-from .admin import site, site2
+from .admin import site, site2, CityAdmin
 
 
 ERROR_MESSAGE = "Please enter the correct username and password \
@@ -4597,3 +4598,87 @@ class TestLabelVisibility(TestCase):
 
     def assert_fieldline_hidden(self, response):
         self.assertContains(response, '<div class="form-row hidden')
+
+
+@override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
+class AdminViewOnSiteTest(TestCase):
+    urls = "admin_views.urls"
+    fixtures = ['admin-views-users.xml', 'admin-views-restaurants.xml']
+
+    def setUp(self):
+        self.client.login(username='super', password='secret')
+
+    def tearDown(self):
+        self.client.logout()
+
+    def test_validate(self):
+        "Ensure that the view_on_site value is either a boolean or a callable"
+        CityAdmin.view_on_site = True
+        CityAdmin.validate(City)
+        CityAdmin.view_on_site = False
+        CityAdmin.validate(City)
+        CityAdmin.view_on_site = lambda obj: obj.get_absolute_url()
+        CityAdmin.validate(City)
+        CityAdmin.view_on_site = []
+        with self.assertRaisesMessage(ImproperlyConfigured, 'CityAdmin.view_on_site is not a callable or a boolean value.'):
+            CityAdmin.validate(City)
+
+    def test_false(self):
+        "Ensure that the 'View on site' button is not displayed if view_on_site is False"
+        response = self.client.get('/test_admin/admin/admin_views/restaurant/1/')
+        content_type_pk = ContentType.objects.get_for_model(Restaurant).pk
+        self.assertNotContains(response,
+                               '"/test_admin/admin/r/%s/1/"' % content_type_pk,
+                               )
+
+    def test_true(self):
+        "Ensure that the default behaviour is followed if view_on_site is True"
+        response = self.client.get('/test_admin/admin/admin_views/city/1/')
+        content_type_pk = ContentType.objects.get_for_model(City).pk
+        self.assertContains(response,
+                            '"/test_admin/admin/r/%s/1/"' % content_type_pk,
+                            )
+
+    def test_callable(self):
+        "Ensure that the right link is displayed if view_on_site is a callable"
+        response = self.client.get('/test_admin/admin/admin_views/worker/1/')
+        worker = Worker.objects.get(pk=1)
+        self.assertContains(response,
+                            '"/worker/%s/%s/"' % (worker.surname, worker.name),
+                            )
+
+
+@override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
+class InlineAdminViewOnSiteTest(TestCase):
+    urls = "admin_views.urls"
+    fixtures = ['admin-views-users.xml', 'admin-views-restaurants.xml']
+
+    def setUp(self):
+        self.client.login(username='super', password='secret')
+
+    def tearDown(self):
+        self.client.logout()
+
+    def test_false(self):
+        "Ensure that the 'View on site' button is not displayed if view_on_site is False"
+        response = self.client.get('/test_admin/admin/admin_views/state/1/')
+        content_type_pk = ContentType.objects.get_for_model(City).pk
+        self.assertNotContains(response,
+                               '/test_admin/admin/r/%s/1/' % content_type_pk,
+                               )
+
+    def test_true(self):
+        "Ensure that the 'View on site' button is displayed if view_on_site is True"
+        response = self.client.get('/test_admin/admin/admin_views/city/1/')
+        content_type_pk = ContentType.objects.get_for_model(Restaurant).pk
+        self.assertContains(response,
+                            '/test_admin/admin/r/%s/1/' % content_type_pk,
+                            )
+
+    def test_callable(self):
+        "Ensure that the right link is displayed if view_on_site is a callable"
+        response = self.client.get('/test_admin/admin/admin_views/restaurant/1/')
+        worker = Worker.objects.get(pk=1)
+        self.assertContains(response,
+                            '"/worker_inline/%s/%s/"' % (worker.surname, worker.name),
+                            )