def find_root(resource):
""" Find the root node in the resource tree to which ``resource``
belongs. Note that ``resource`` should be :term:`location`-aware.
Note that the root resource is available in the request object by
accessing the ``request.root`` attribute.
"""
for location in lineage(resource):
if location.__parent__ is None:
resource = location
break
return resource
def find_interface(resource, class_or_interface):
"""
Return the first resource found in the :term:`lineage` of ``resource``
which, a) if ``class_or_interface`` is a Python class object, is an
instance of the class or any subclass of that class or b) if
``class_or_interface`` is a :term:`interface`, provides the specified
interface. Return ``None`` if no resource providing ``interface_or_class``
can be found in the lineage. The ``resource`` passed in *must* be
:term:`location`-aware.
"""
if IInterface.providedBy(class_or_interface):
test = class_or_interface.providedBy
else:
test = lambda arg: isinstance(arg, class_or_interface)
for location in lineage(resource):
if test(location):
return location
def _resource_path_list(resource, *elements):
""" Implementation detail shared by resource_path and resource_path_tuple"""
path = [loc.__name__ or '' for loc in lineage(resource)]
path.reverse()
path.extend(elements)
return path
