xml-dev - System identifiers and base URIs

[Norman Walsh <ndw@nwalsh.com>]

It's possible that the following question is concretely answered
somewhere, in which case a simple whack on the head would be
appreciated. :-)

Suppose I attempt to parse a document: http://foo.bar/baz.dtd and that
attempt results in a redirect to http://moo.goo/boo.dtd. RFC2396 makes it
clear that the resulting base URI is http://moo.goo/boo.dtd:

  5.1.3. Base URI from the Retrieval URI

     [...] Note that if the retrieval was the
     result of a redirected request, the last URI used (i.e., that which
     resulted in the actual retrieval of the document) is the base URI.

What isn't well defined, AFAICT, is what "redirected request" really
means.  Suppose that my parser has an SAX entityResolver installed and
the entity resolver (through means that I don't think are important to
this question) decides to perform the redirection. What is the base
URI of the resulting document?

To make things concrete, suppose I have a document with a DOCTYPE
declaration that references http://foo.bar/baz.dtd (and I'm doing a
validating parse). The parser attempts to open http://foo.bar/baz.dtd,
and the entity resolver opens and returns http://moo.goo/boo.dtd
instead.

Subsequently, the parser encounters a relative URI "somefile.ent" in
the DTD. It must calculate an absolute URI in order to open it.

Is the resulting absolute URI "http://foo.bar/somefile.ent" or
"http://moo.goo/somefile.ent"? Or is there not a definitive answer?

                                        Be seeing you,
                                          norm

-- 
Norman.Walsh@East.Sun.COM | Are you not the future of all the memories
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