Re: Web spaces of strange topology. Where?

John Lindroth (lindroth@musc.edu)
Fri, 17 May 1996 10:37:46 -0500


> My question was approximately if anyone knows of a place where
>
> http://www.foo.com/x/y/../z isn't the same as
> http://www.foo.com/x/z
>
> The one thing that has come up that I would like to clarify, is I mean
> real URLs in real documents. I'm aware of things like ftp sites where
> you can't directly reverse a directory change.
>
> but I think I have never seen such a URL. If anyone knows that they don't
> exist I'd be interested... if anyone knows where they do exist I'd also
> be really interested. If the reason everyone is being quiet is because
> they've never seen this, then I'd like to know why Tim Bray (related, I
> think to one of the search engines. I've only got a quote in another
> message handy) said in a message a while ago (see the list archives) that
> knowing the real meaning of /xxxx/./../x/../y/ is a problem.

Michael,
I've been doing some internal documentation on url's and the
differences in absolute and relative references. And I think that in
a UNIX file system Tim's example may not necessarily be obvious. In
URL space, as long as none of the references (xxxx,x,y) are
cgi-scripts, you could say that /xxxx/./../x/../y/ is equal to /y/
If, however, x is a cgi script and ../y/ is the argument, then you've
got a problem. There is a script called w3-msql that allows embedding
database query statements in an html file, that would cause this type
of problem. I'll see if I can create one, as a test on my server.
-John

=============================================
John Lindroth lindroth@musc.edu
http://www.musc.edu/~lindroth
Center for Computing & Information Technology
Medical University of South Carolina
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Any opinions expressed are mine.
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