zope DefaultPublishTraverse:publishTraverse

boboとは酔っ払ったという意味らしい。googleで調べてみるとtraverseをカスタマイズするための属性のようだ。千鳥足でtraverseするといったところか。

• A __bobo_traverse__ Example


• Override __bobo_traverse__ to provide custom URL lookup

    def publishTraverse(self, request, name):
        object = self.context
        URL=request['URL']

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

        

こちらはdelegateされているので何でもあり。なぜ__bobo_traverse_を使っていて、カスタムトラバース用のInterfaceが存在していないのだろう？（しているのかもしれないが）

        if hasattr(object,'__bobo_traverse__'):
            try:
                subobject=object.__bobo_traverse__(request, name)
                if type(subobject) is type(()) and len(subobject) > 1:
                    # Add additional parents into the path
                    # XXX There are no tests for this:
                    request['PARENTS'][-1:] = list(subobject[:-1])
                    object, subobject = subobject[-2:]            
            except (AttributeError, KeyError, NotFound), e:
                # Try to find a view
                subobject = queryMultiAdapter((object, request), Interface, name)                
                if subobject is not None:
                    # OFS.Application.__bobo_traverse__ calls
                    # REQUEST.RESPONSE.notFoundError which sets the HTTP
                    # status code to 404
                    request.response.setStatus(200)
                    # We don't need to do the docstring security check
                    # for views, so lets skip it and return the object here.
                    if IAcquirer.providedBy(subobject):
                        subobject = subobject.__of__(object)
                    return subobject
                # No view found. Reraise the error raised by __bobo_traverse__
                raise e

普通のケース。aq_baseはApp/Common.pyの中にある。

def aq_base(ob, getattr=getattr):
    # Return the aq_base of an object.
    return getattr(ob, 'aq_base', ob)

        else:
            # No __bobo_traverse__
            # Try with an unacquired attribute:
            if hasattr(aq_base(object), name):
                subobject = getattr(object, name)

aq_baseの意味するところがわからない。どういうプロトコルを構成しようとしているのだろうか？

            else:
                # We try to fall back to a view:
                subobject = queryMultiAdapter((object, request), Interface,
                                              name)
                if subobject is not None:
                    if IAcquirer.providedBy(subobject):
                        subobject = subobject.__of__(object)
                    return subobject
            
                # And lastly, of there is no view, try acquired attributes, but
                # only if there is no __bobo_traverse__:
                try:
                    subobject=getattr(object, name)
                    # Again, clear any error status created by __bobo_traverse__
                    # because we actually found something:
                    request.response.setStatus(200)
                    return subobject
                except AttributeError:
                    pass

                # Lastly we try with key access:
                try:
                    subobject = object[name]
                except TypeError: # unsubscriptable
                    raise KeyError(name)
                

コメントがすべて。問題はなぜそういうポリシーを採用しているかだ。次のコメントを読むと、2.2.2でmutableなやつのdocstringがどうのこうのと書いてある。おそらくは、adapter経由で意図していない公開が起こらない安全側に倒したのだろう。組み込み型はfile終わりのほうで列挙されている。

        # Ensure that the object has a docstring, or that the parent
        # object has a pseudo-docstring for the object. Objects that
        # have an empty or missing docstring are not published.
        doc = getattr(subobject, '__doc__', None)
        if doc is None:
            doc = getattr(object, '%s__doc__' % name, None)
        if not doc:
            raise Forbidden(
                "The object at %s has an empty or missing " \
                "docstring. Objects must have a docstring to be " \
                "published." % URL
                )

        # Hack for security: in Python 2.2.2, most built-in types
        # gained docstrings that they didn't have before. That caused
        # certain mutable types (dicts, lists) to become publishable
        # when they shouldn't be. The following check makes sure that
        # the right thing happens in both 2.2.2+ and earlier versions.

        if not typeCheck(subobject):
            raise Forbidden(
                "The object at %s is not publishable." % URL
                )

        return subobject