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Re: Canonicalization xml:base processing

From: John Cowan <cowan@ccil.org>
Date: Thu, 18 May 2006 11:45:04 -0400
To: Konrad Lanz <Konrad.Lanz@iaik.tugraz.at>
Cc: Richard Tobin <richard@inf.ed.ac.uk>, "Grosso, Paul" <pgrosso@ptc.com>, public-xml-core-wg@w3.org
Message-ID: <20060518154504.GD27118@ccil.org>

Konrad Lanz scripsit:

> Up front I'd like to mention that after talking to Jose Kahan and 
> thinking about the issue for a little longer we'd still prefer to also 
> perform "dot and dot-dot canonicalization" (aka. remove_dot_segments). 
> It will allow the reuse of existing implementations for relative URI 
> resolution. More important from my point of view however is: "dot and 
> dot-dot canonicalization" allows to map more equivalent documents onto 
> the same serialized output and helps to avoid false negatives in XMLDSig.

Unfortunately doing so produces inaccurate results.  For example, suppose
the outermost xml:base value is "foo/bar/" and the next inner one is
"../../..".  Ordinary remove_dot_segments will reduce this to the null
string, but this is incorrect.

Leaving it as "foo/bar/../../.." produces the same result as in the
original context when applied to an equivalent base URI.  It is only
safe to remove dots when that base URI is fully available.

-- 
The man that wanders far                        cowan@ccil.org
from the walking tree                           http://www.ccil.org/~cowan
        --first line of a non-existent poem by:         John Cowan
Received on Thursday, 18 May 2006 15:45:18 GMT

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