Add '.basename' and '.reverse_action()' to ViewSet (#5648)

* Router sets 'basename' on ViewSet

* Add 'ViewSet.reverse_action()' method

* Test router setting initkwargs

Author: Ryan P Kilby

docs/api-guide/viewsets.md

@@ -159,6 +159,21 @@ These decorators will route `GET` requests by default, but may also accept other
 
 The two new actions will then be available at the urls `^users/{pk}/set_password/$` and `^users/{pk}/unset_password/$`
 
+## Reversing action URLs
+
+If you need to get the URL of an action, use the `.reverse_action()` method. This is a convenience wrapper for `reverse()`, automatically passing the view's `request` object and prepending the `url_name` with the `.basename` attribute.
+
+Note that the `basename` is provided by the router during `ViewSet` registration. If you are not using a router, then you must provide the `basename` argument to the `.as_view()` method.
+
+Using the example from the previous section:
+
+```python
+>>> view.reverse_action('set-password', args=['1'])
+'http://localhost:8000/api/users/1/set_password'
+```
+
+The `url_name` argument should match the same argument to the `@list_route` and `@detail_route` decorators. Additionally, this can be used to reverse the default `list` and `detail` routes.
+
 ---
 
 # API Reference

rest_framework/routers.py

@@ -278,7 +278,12 @@ def get_urls(self):
                 if not prefix and regex[:2] == '^/':
                     regex = '^' + regex[2:]
 
-                view = viewset.as_view(mapping, **route.initkwargs)
+                initkwargs = route.initkwargs.copy()
+                initkwargs.update({
+                    'basename': basename,
+                })
+
+                view = viewset.as_view(mapping, **initkwargs)
                 name = route.name.format(basename=basename)
                 ret.append(url(regex, view, name=name))
 

rest_framework/viewsets.py

@@ -24,6 +24,7 @@
 from django.views.decorators.csrf import csrf_exempt
 
 from rest_framework import generics, mixins, views
+from rest_framework.reverse import reverse
 
 
 class ViewSetMixin(object):
@@ -46,10 +47,14 @@ def as_view(cls, actions=None, **initkwargs):
         instantiated view, we need to totally reimplement `.as_view`,
         and slightly modify the view function that is created and returned.
         """
-        # The suffix initkwarg is reserved for identifying the viewset type
+        # The suffix initkwarg is reserved for displaying the viewset type.
         # eg. 'List' or 'Instance'.
         cls.suffix = None
 
+        # Setting a basename allows a view to reverse its action urls. This
+        # value is provided by the router through the initkwargs.
+        cls.basename = None
+
         # actions must not be empty
         if not actions:
             raise TypeError("The `actions` argument must be provided when "
@@ -121,6 +126,15 @@ def initialize_request(self, request, *args, **kwargs):
             self.action = self.action_map.get(method)
         return request
 
+    def reverse_action(self, url_name, *args, **kwargs):
+        """
+        Reverse the action for the given `url_name`.
+        """
+        url_name = '%s-%s' % (self.basename, url_name)
+        kwargs.setdefault('request', self.request)
+
+        return reverse(url_name, *args, **kwargs)
+
 
 class ViewSet(ViewSetMixin, views.APIView):
     """

tests/test_routers.py

@@ -7,6 +7,7 @@
 from django.core.exceptions import ImproperlyConfigured
 from django.db import models
 from django.test import TestCase, override_settings
+from django.urls import resolve
 
 from rest_framework import permissions, serializers, viewsets
 from rest_framework.compat import get_regex_pattern
@@ -435,3 +436,18 @@ def test_regex_url_path_detail(self):
         response = self.client.get('/regex/{}/detail/{}/'.format(pk, kwarg))
         assert response.status_code == 200
         assert json.loads(response.content.decode('utf-8')) == {'pk': pk, 'kwarg': kwarg}
+
+
+@override_settings(ROOT_URLCONF='tests.test_routers')
+class TestViewInitkwargs(TestCase):
+    def test_suffix(self):
+        match = resolve('/example/notes/')
+        initkwargs = match.func.initkwargs
+
+        assert initkwargs['suffix'] == 'List'
+
+    def test_basename(self):
+        match = resolve('/example/notes/')
+        initkwargs = match.func.initkwargs
+
+        assert initkwargs['basename'] == 'routertestmodel'

tests/test_viewsets.py

@@ -1,7 +1,11 @@
-from django.test import TestCase
+from django.conf.urls import include, url
+from django.db import models
+from django.test import TestCase, override_settings
 
 from rest_framework import status
+from rest_framework.decorators import detail_route, list_route
 from rest_framework.response import Response
+from rest_framework.routers import SimpleRouter
 from rest_framework.test import APIRequestFactory
 from rest_framework.viewsets import GenericViewSet
 
@@ -22,6 +26,46 @@ def dummy(self, request, *args, **kwargs):
         return Response({'view': self})
 
 
+class Action(models.Model):
+    pass
+
+
+class ActionViewSet(GenericViewSet):
+    queryset = Action.objects.all()
+
+    def list(self, request, *args, **kwargs):
+        pass
+
+    def retrieve(self, request, *args, **kwargs):
+        pass
+
+    @list_route()
+    def list_action(self, request, *args, **kwargs):
+        pass
+
+    @list_route(url_name='list-custom')
+    def custom_list_action(self, request, *args, **kwargs):
+        pass
+
+    @detail_route()
+    def detail_action(self, request, *args, **kwargs):
+        pass
+
+    @detail_route(url_name='detail-custom')
+    def custom_detail_action(self, request, *args, **kwargs):
+        pass
+
+
+router = SimpleRouter()
+router.register(r'actions', ActionViewSet)
+router.register(r'actions-alt', ActionViewSet, base_name='actions-alt')
+
+
+urlpatterns = [
+    url(r'^api/', include(router.urls)),
+]
+
+
 class InitializeViewSetsTestCase(TestCase):
     def test_initialize_view_set_with_actions(self):
         request = factory.get('/', '', content_type='application/json')
@@ -65,3 +109,43 @@ def test_args_kwargs_request_action_map_on_self(self):
         for attribute in ('args', 'kwargs', 'request', 'action_map'):
             self.assertNotIn(attribute, dir(bare_view))
             self.assertIn(attribute, dir(view))
+
+
+@override_settings(ROOT_URLCONF='tests.test_viewsets')
+class ReverseActionTests(TestCase):
+    def test_default_basename(self):
+        view = ActionViewSet()
+        view.basename = router.get_default_base_name(ActionViewSet)
+        view.request = None
+
+        assert view.reverse_action('list') == '/api/actions/'
+        assert view.reverse_action('list-action') == '/api/actions/list_action/'
+        assert view.reverse_action('list-custom') == '/api/actions/custom_list_action/'
+
+        assert view.reverse_action('detail', args=['1']) == '/api/actions/1/'
+        assert view.reverse_action('detail-action', args=['1']) == '/api/actions/1/detail_action/'
+        assert view.reverse_action('detail-custom', args=['1']) == '/api/actions/1/custom_detail_action/'
+
+    def test_custom_basename(self):
+        view = ActionViewSet()
+        view.basename = 'actions-alt'
+        view.request = None
+
+        assert view.reverse_action('list') == '/api/actions-alt/'
+        assert view.reverse_action('list-action') == '/api/actions-alt/list_action/'
+        assert view.reverse_action('list-custom') == '/api/actions-alt/custom_list_action/'
+
+        assert view.reverse_action('detail', args=['1']) == '/api/actions-alt/1/'
+        assert view.reverse_action('detail-action', args=['1']) == '/api/actions-alt/1/detail_action/'
+        assert view.reverse_action('detail-custom', args=['1']) == '/api/actions-alt/1/custom_detail_action/'
+
+    def test_request_passing(self):
+        view = ActionViewSet()
+        view.basename = router.get_default_base_name(ActionViewSet)
+        view.request = factory.get('/')
+
+        # Passing the view's request object should result in an absolute URL.
+        assert view.reverse_action('list') == 'http://testserver/api/actions/'
+
+        # Users should be able to explicitly not pass the view's request.
+        assert view.reverse_action('list', request=None) == '/api/actions/'