routers - swinton/django-rest-framework GitHub Wiki
Resource routing allows you to quickly declare all of the common routes for a given resourceful controller. Instead of declaring separate routes for your index... a resourceful route declares them in a single line of code.
Some Web frameworks such as Rails provide functionality for automatically determining how the URLs for an application should be mapped to the logic that deals with handling incoming requests.
REST framework adds support for automatic URL routing to Django, and provides you with a simple, quick and consistent way of wiring your view logic to a set of URLs.
Here's an example of a simple URL conf, that uses SimpleRouter
.
from rest_framework import routers
router = routers.SimpleRouter()
router.register(r'users', UserViewSet)
router.register(r'accounts', AccountViewSet)
urlpatterns = router.urls
There are two mandatory arguments to the register()
method:
-
prefix
- The URL prefix to use for this set of routes. -
viewset
- The viewset class.
Optionally, you may also specify an additional argument:
-
base_name
- The base to use for the URL names that are created. If unset the basename will be automatically generated based on themodel
orqueryset
attribute on the viewset, if it has one. Note that if the viewset does not include amodel
orqueryset
attribute then you must setbase_name
when registering the viewset.
The example above would generate the following URL patterns:
- URL pattern:
^users/$
Name:'user-list'
- URL pattern:
^users/{pk}/$
Name:'user-detail'
- URL pattern:
^accounts/$
Name:'account-list'
- URL pattern:
^accounts/{pk}/$
Name:'account-detail'
Note: The base_name
argument is used to specify the initial part of the view name pattern. In the example above, that's the user
or account
part.
Typically you won't need to specify the base-name
argument, but if you have a viewset where you've defined a custom get_queryset
method, then the viewset may not have a .queryset
attribute set. If you try to register that viewset you'll see an error like this:
'base_name' argument not specified, and could not automatically determine the name from the viewset, as it does not have a '.queryset' attribute.
This means you'll need to explicitly set the base_name
argument when registering the viewset, as it could not be automatically determined from the model name.
Any methods on the viewset decorated with @detail_route
or @list_route
will also be routed.
For example, given a method like this on the UserViewSet
class:
from myapp.permissions import IsAdminOrIsSelf
from rest_framework.decorators import detail_route
class UserViewSet(ModelViewSet):
...
@detail_route(methods=['post'], permission_classes=[IsAdminOrIsSelf])
def set_password(self, request, pk=None):
...
The following URL pattern would additionally be generated:
- URL pattern:
^users/{pk}/set_password/$
Name:'user-set-password'
For more information see the viewset documentation on marking extra actions for routing.
This router includes routes for the standard set of list
, create
, retrieve
, update
, partial_update
and destroy
actions. The viewset can also mark additional methods to be routed, using the @detail_route
or @list_route
decorators.
URL Style | HTTP Method | Action | URL Name |
---|---|---|---|
{prefix}/ | GET | list | {basename}-list |
POST | create | ||
{prefix}/{methodname}/ | GET, or as specified by `methods` argument | `@list_route` decorated method | {basename}-{methodname} |
{prefix}/{lookup}/ | GET | retrieve | {basename}-detail |
PUT | update | ||
PATCH | partial_update | ||
DELETE | destroy | ||
{prefix}/{lookup}/{methodname}/ | GET, or as specified by `methods` argument | `@detail_route` decorated method | {basename}-{methodname} |
By default the URLs created by SimpleRouter
are appended with a trailing slash.
This behavior can be modified by setting the trailing_slash
argument to False
when instantiating the router. For example:
router = SimpleRouter(trailing_slash=False)
Trailing slashes are conventional in Django, but are not used by default in some other frameworks such as Rails. Which style you choose to use is largely a matter of preference, although some javascript frameworks may expect a particular routing style.
The router will match lookup values containing any characters except slashes and period characters. For a more restrictive (or lenient) lookup pattern, set the lookup_value_regex
attribute on the viewset. For example, you can limit the lookup to valid UUIDs:
class MyModelViewSet(mixins.RetrieveModelMixin, viewsets.GenericViewSet):
lookup_field = 'my_model_id'
lookup_value_regex = '[0-9a-f]{32}'
This router is similar to SimpleRouter
as above, but additionally includes a default API root view, that returns a response containing hyperlinks to all the list views. It also generates routes for optional .json
style format suffixes.
URL Style | HTTP Method | Action | URL Name |
---|---|---|---|
[.format] | GET | automatically generated root view | api-root |
{prefix}/[.format] | GET | list | {basename}-list |
POST | create | ||
{prefix}/{methodname}/[.format] | GET, or as specified by `methods` argument | `@list_route` decorated method | {basename}-{methodname} |
{prefix}/{lookup}/[.format] | GET | retrieve | {basename}-detail |
PUT | update | ||
PATCH | partial_update | ||
DELETE | destroy | ||
{prefix}/{lookup}/{methodname}/[.format] | GET, or as specified by `methods` argument | `@detail_route` decorated method | {basename}-{methodname} |
As with SimpleRouter
the trailing slashes on the URL routes can be removed by setting the trailing_slash
argument to False
when instantiating the router.
router = DefaultRouter(trailing_slash=False)
Implementing a custom router isn't something you'd need to do very often, but it can be useful if you have specific requirements about how the your URLs for your API are structured. Doing so allows you to encapsulate the URL structure in a reusable way that ensures you don't have to write your URL patterns explicitly for each new view.
The simplest way to implement a custom router is to subclass one of the existing router classes. The .routes
attribute is used to template the URL patterns that will be mapped to each viewset. The .routes
attribute is a list of Route
named tuples.
The arguments to the Route
named tuple are:
url: A string representing the URL to be routed. May include the following format strings:
-
{prefix}
- The URL prefix to use for this set of routes. -
{lookup}
- The lookup field used to match against a single instance. -
{trailing_slash}
- Either a '/' or an empty string, depending on thetrailing_slash
argument.
mapping: A mapping of HTTP method names to the view methods
name: The name of the URL as used in reverse
calls. May include the following format string:
-
{basename}
- The base to use for the URL names that are created.
initkwargs: A dictionary of any additional arguments that should be passed when instantiating the view. Note that the suffix
argument is reserved for identifying the viewset type, used when generating the view name and breadcrumb links.
You can also customize how the @list_route
and @detail_route
decorators are routed.
To route either or both of these decorators, include a DynamicListRoute
and/or DynamicDetailRoute
named tuple in the .routes
list.
The arguments to DynamicListRoute
and DynamicDetailRoute
are:
url: A string representing the URL to be routed. May include the same format strings as Route
, and additionally accepts the {methodname}
and {methodnamehyphen}
format strings.
name: The name of the URL as used in reverse
calls. May include the following format strings: {basename}
, {methodname}
and {methodnamehyphen}
.
initkwargs: A dictionary of any additional arguments that should be passed when instantiating the view.
The following example will only route to the list
and retrieve
actions, and does not use the trailing slash convention.
from rest_framework.routers import Route, DynamicDetailRoute, SimpleRouter
class CustomReadOnlyRouter(SimpleRouter):
"""
A router for read-only APIs, which doesn't use trailing slashes.
"""
routes = [
Route(
url=r'^{prefix}$',
mapping={'get': 'list'},
name='{basename}-list',
initkwargs={'suffix': 'List'}
),
Route(
url=r'^{prefix}/{lookup}$',
mapping={'get': 'retrieve'},
name='{basename}-detail',
initkwargs={'suffix': 'Detail'}
),
DynamicDetailRoute(
url=r'^{prefix}/{lookup}/{methodnamehyphen}$',
name='{basename}-{methodnamehyphen}',
initkwargs={}
)
]
Let's take a look at the routes our CustomReadOnlyRouter
would generate for a simple viewset.
views.py
:
class UserViewSet(viewsets.ReadOnlyModelViewSet):
"""
A viewset that provides the standard actions
"""
queryset = User.objects.all()
serializer_class = UserSerializer
lookup_field = 'username'
@detail_route()
def group_names(self, request):
"""
Returns a list of all the group names that the given
user belongs to.
"""
user = self.get_object()
groups = user.groups.all()
return Response([group.name for group in groups])
urls.py
:
router = CustomReadOnlyRouter()
router.register('users', UserViewSet)
urlpatterns = router.urls
The following mappings would be generated...
URL | HTTP Method | Action | URL Name |
---|---|---|---|
/users | GET | list | user-list |
/users/{username} | GET | retrieve | user-detail |
/users/{username}/group-names | GET | group_names | user-group-names |
For another example of setting the .routes
attribute, see the source code for the SimpleRouter
class.
If you want to provide totally custom behavior, you can override BaseRouter
and override the get_urls(self)
method. The method should inspect the registered viewsets and return a list of URL patterns. The registered prefix, viewset and basename tuples may be inspected by accessing the self.registry
attribute.
You may also want to override the get_default_base_name(self, viewset)
method, or else always explicitly set the base_name
argument when registering your viewsets with the router.
The following third party packages are also available.
The drf-nested-routers package provides routers and relationship fields for working with nested resources.
The wq.db package provides an advanced Router class (and singleton instance) that extends DefaultRouter
with a register_model()
API. Much like Django's admin.site.register
, the only required argument to app.router.register_model
is a model class. Reasonable defaults for a url prefix and viewset will be inferred from the model and global configuration.
from wq.db.rest import app
from myapp.models import MyModel
app.router.register_model(MyModel)
The DRF-extensions
package provides routers for creating nested viewsets, collection level controllers with customizable endpoint names.