Section 6.2.1 does not say that content negotiation should be used all the time.
— Roy Fielding, REST discuss mailing list
A common pattern for Web APIs is to use filename extensions on URLs to provide an endpoint for a given media type. For example, 'http://example.com/api/users.json' to serve a JSON representation.
Adding format-suffix patterns to each individual entry in the URLconf for your API is error-prone and non-DRY, so REST framework provides a shortcut to adding these patterns to your URLConf.
Signature: format_suffix_patterns(urlpatterns, suffix_required=False, allowed=None)
Returns a URL pattern list which includes format suffix patterns appended to each of the URL patterns provided.
- urlpatterns: Required. A URL pattern list.
- suffix_required: Optional. A boolean indicating if suffixes in the URLs should be optional or mandatory. Defaults to
False, meaning that suffixes are optional by default.
- allowed: Optional. A list or tuple of valid format suffixes. If not provided, a wildcard format suffix pattern will be used.
from rest_framework.urlpatterns import format_suffix_patterns from blog import views urlpatterns = [ path('', views.apt_root), path('comments/', views.comment_list), path('comments/<int:pk>/', views.comment_detail) ] urlpatterns = format_suffix_patterns(urlpatterns, allowed=['json', 'html'])
format_suffix_patterns, you must make sure to add the
'format' keyword argument to the corresponding views. For example:
@api_view(['GET', 'POST']) def comment_list(request, format=None): # do stuff...
Or with class-based views:
class CommentList(APIView): def get(self, request, format=None): # do stuff... def post(self, request, format=None): # do stuff...
The name of the kwarg used may be modified by using the
Also note that
format_suffix_patterns does not support descending into
include URL patterns.
If using the
i18n_patterns function provided by Django, as well as
format_suffix_patterns you should make sure that the
i18n_patterns function is applied as the final, or outermost function. For example:
urlpatterns = [ … ] urlpatterns = i18n_patterns( format_suffix_patterns(urlpatterns, allowed=['json', 'html']) )
Query parameter formats
An alternative to the format suffixes is to include the requested format in a query parameter. REST framework provides this option by default, and it is used in the browsable API to switch between differing available representations.
To select a representation using its short format, use the
format query parameter. For example:
The name of this query parameter can be modified using the
URL_FORMAT_OVERRIDE setting. Set the value to
None to disable this behavior.
Accept headers vs. format suffixes
There seems to be a view among some of the Web community that filename extensions are not a RESTful pattern, and that
HTTP Accept headers should always be used instead.
It is actually a misconception. For example, take the following quote from Roy Fielding discussing the relative merits of query parameter media-type indicators vs. file extension media-type indicators:
“That's why I always prefer extensions. Neither choice has anything to do with REST.” — Roy Fielding, REST discuss mailing list
The quote does not mention Accept headers, but it does make it clear that format suffixes should be considered an acceptable pattern.