Plone traversing and forbidden Zope ids

Question

Although you can generate by code contents with an id that starts with underscore , like " _foo " it seems that you can't traverse an item with this special id. Every attempt to access a content named that way using a browser lead to a NotFound error. Neither methods like __bobotraverse__ or __getitem__ are called, like if this limitation is checked very early.

How this limitation works and how can I change it? Can I access subobjects with a prefix underscore in the id?

Answer 1

Found inside the unrestrictedTraverse implementation from OFS.Traversable :

if name[0] == '_':
    # Never allowed in a URL.
    raise NotFound, name

...but this is not enough. There's another check similar to the ones notified by @Mathias inside ZPublisher.BaseRequest.DefaultPublishTraverse in the publishTraverse method.

if name[:1]=='_':
    raise Forbidden("Object name begins with an underscore at: %s" % URL)

The sad part is that is not simple to override this:

• the unrestrictedTraverse is called on the Plone site context (so I can't customize it only for my content type)
• the publishTraverse method is owned by the request implementation (maybe for this I can use ad custom publish traverser?)

The simplest way to fix this seems through monkeypatch.