0.2.5: add model_url.

1 files changed, 20 insertions, 3 deletions

diff --git a/repoze/bfg/traversal.py b/repoze/bfg/traversal.py
index d0e140375..c72c90e5e 100644
--- a/repoze/bfg/traversal.py
+++ b/repoze/bfg/traversal.py
@@ -1,4 +1,5 @@
 import urllib
+import urlparse
 
 from zope.interface import classProvides
 from zope.interface import implements
@@ -66,9 +67,25 @@ class ModelGraphTraverser(object):
         return ob, name, path
 
 def find_interface(context, interface):
-    """ Return an object providing 'interface' anywhere in the parent
-    chain of 'context' or None if no object providing that interface
-    can be found in the parent chain """
+    """ Return an object providing ``interface`` anywhere in the
+    parent chain of ``context`` or ``None`` if no object providing
+    that interface can be found in the parent chain"""
     for location in LocationIterator(context):
         if interface.providedBy(location):
             return location
+
+def model_url(model, request, *elements):
+    """ Return the absolute URL of the model object based on the
+    ``wsgi.url_scheme``, ``HTTP_HOST`` or ``SERVER_NAME`` in the
+    request, plus any ``SCRIPT_NAME``.  Any positional passed in as
+    ``elements`` will be joined by slashes and appended to the
+    generated URL.  The passed in elements are *not* URL-quoted.  The
+    ``model`` passed in must be :term:`location`-aware."""
+    rpath = []
+    for location in LocationIterator(model):
+        if location.__name__:
+            rpath.append(urllib.quote(location.__name__))
+    path = list(reversed(rpath))
+    path.extend(elements)
+    path = '/'.join(path)
+    return urlparse.urljoin(request.application_url, path)