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Re: [xsl] Document function -- document may not exist
Subject: Re: [xsl] Document function -- document may not exist
From: "G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 03 Jul 2002 17:06:32 -0400
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At 2002-07-03 15:44 -0500, mjyoungblut@xxxxxxx wrote:
I was wondering if there is a way of getting around the exception that is
thrown by most parsers if the document function is called for a file that
does not exist. I would just like to continue on in the processing. For
example, I would like to do something like the following:
<xsl:variable name="FILE_A" select="document('A.xml')"/>
<xsl:variable name="FILE_B" select="document('B.xml')"/>
<xsl:for-each select="$FILE_A">
<!-- If it exists, do some processing -->
...
</xsl:for-each>
<xsl:for-each select="$FILE_B">
<!-- Same.... -->
</xsl:for-each>
Is the above not working for you? When the document() function cannot find
the document the recovery is to return an empty node-set. Since you are
using the result in the <xsl:for-each>, if the result is empty then nothing
happens. It seems to me what you have above should work just fine.
I use this for the REST-based aggregation on my web site of the dates of
the public courses of those licensees of mine who license our material for
public deliveries:
(1) - if I get a non-empty node set for the URL my licensee gives me,
I synthesize a local backup copy of the document by using the
processor extension to write out a node tree as XML
(2) - if I get an empty node set for the URL my licensee gives me,
I pass the local backup copy of the document to the document()
function so at least I have the latest information that was
available from my licensee the last time it was successful
This means that whenever I build my schedule page listing all of my
licensees, I can build all of the information from the most recent
successful non-empty return value from the document() function, even if at
that point in time there is some reason I cannot reach the private web page
on my licensee's site.
This model has made the aggregation of information from multiple sources
using XSLT really straightforward and resilient.
I hope this helps.
.............. Ken
--
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G. Ken Holman mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd. http://www.CraneSoftwrights.com/s/
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