No, they don't decode first, but they do convert the Path -> 26char appid-charset/mpdecimal.  It really doesn't matter what the content is, as long as its somewhat consistent.  I could be returning a hardcoded id here.  I could move the decode bit out of the helper so that I can make the decision here.  Doing that would also mean I don't need to handle the case of name not being valid base64.