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
from blog import views

urlpatterns = [
    url(r'^/$', views.apt_root),
    url(r'^comments/$', views.comment_list),
    url(r'^comments/(?P<pk>[0-9]+)/$', views.comment_detail)
]

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', '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 FORMAT_SUFFIX_KWARG setting.

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

Using with `i18n_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:

url patterns = [
    …
]

urlpatterns = i18n_patterns(
    format_suffix_patterns(urlpatterns, allowed=['json', 'html'])
)

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.

Format suffixes

format_suffix_patterns

Using with i18n_patterns

Accept headers vs. format suffixes

Using with `i18n_patterns`