GitHub Django REST framework

urlpatterns.py

Format suffixes

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.

format_suffix_patterns

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.

Arguments:

  • 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.

Example:

from rest_framework.urlpatterns import format_suffix_patterns

urlpatterns = patterns('blog.views',
    url(r'^/$', 'api_root'),
    url(r'^comment/$', 'comment_root'),
    url(r'^comment/(?P<pk>[0-9]+)/$', 'comment_instance')
)

urlpatterns = format_suffix_patterns(urlpatterns, allowed=['json', 'html'])

When using format_suffix_patterns, you must make sure to add the 'format' keyword argument to the corresponding views. For example.

@api_view(('GET',))
def api_root(request, format=None):
    # do stuff...

The name of the kwarg used may be modified by using the FORMAT_SUFFIX_KWARG setting.

Also note that format_suffix_patterns does not support descending into include URL patterns.

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.