1 files changed, 42 insertions, 0 deletions
diff --git a/rest_framework/urlpatterns.py b/rest_framework/urlpatterns.py
new file mode 100644
index 00000000..316ccd19
--- /dev/null
+++ b/rest_framework/urlpatterns.py
@@ -0,0 +1,42 @@
+from django.conf.urls.defaults import url
+from rest_framework.settings import api_settings
+
+
+def format_suffix_patterns(urlpatterns, suffix_required=False, allowed=None):
+    """
+    Supplement existing urlpatterns with corrosponding patterns that also
+    include a '.format' suffix.  Retains urlpattern ordering.
+
+    urlpatterns:
+        A list of URL patterns.
+
+    suffix_required:
+        If `True`, only suffixed URLs will be generated, and non-suffixed
+        URLs will not be used.  Defaults to `False`.
+
+    allowed:
+        An optional tuple/list of allowed suffixes.  eg ['json', 'api']
+        Defaults to `None`, which allows any suffix.
+    """
+    suffix_kwarg = api_settings.FORMAT_SUFFIX_KWARG
+    if allowed:
+        if len(allowed) == 1:
+            allowed_pattern = allowed[0]
+        else:
+            allowed_pattern = '(%s)' % '|'.join(allowed)
+        suffix_pattern = r'\.(?P<%s>%s)$' % (suffix_kwarg, allowed_pattern)
+    else:
+        suffix_pattern = r'\.(?P<%s>[a-z]+)$' % suffix_kwarg
+
+    ret = []
+    for urlpattern in urlpatterns:
+        # Form our complementing '.format' urlpattern
+        regex = urlpattern.regex.pattern.rstrip('$') + suffix_pattern
+        view = urlpattern._callback or urlpattern._callback_str
+        kwargs = urlpattern.default_args
+        name = urlpattern.name
+        # Add in both the existing and the new urlpattern
+        if not suffix_required:
+            ret.append(urlpattern)
+        ret.append(url(regex, view, kwargs, name))
+    return ret