Re: [xsl] document() function and error-handling

Subject: Re: [xsl] document() function and error-handling
From: Mark Carlson <carlsonm@xxxxxxxxxxxxxxxx>
Date: Thu, 03 Jan 2008 14:05:39 -0800
I ran into a similar problem where I have "placeholders" for links that should be created if the corresponding file exists but not if they don't. I decided to put in these placeholders so that I wouldn't have to go back in and update ca. 3,000 files one by one with the linking information. I currently only have access to MSXML XSLT parser 1.0 on the server so couldn't use doc-available function and MSXML doesn't support the "script" extension. My hypothetical workaround will be to create a separate "link base" document that my link points to. I will use XSLT 2.0 or another scripting language (JScript, VBScript, etc.) to generate an XML document that will determine which of the links are valid and which ones are not. Thus my XSLT document will query the link base document rather than querying the file directly. So your link could point to file "file1.xml" and you could have a "link base" version of that file on your server that could evaluate to true or false:

<?xml version="1.0"?>
<!-- This is file1.xml -->

Or you could have a list of valid links in one single XML document that only contains valid files that you could query:

<?xml version="1.0"?>
<!-- This is linkbase.xml -->

And then query that single file for whether it exists.

It's a bit of a hack, but if you are limited to MSXML 1.0, then it's a good workaround.

Mark Carlson
Computer Support Analyst
Special Collections Division
University of Washington Libraries
BOX 352900
Seattle, WA, 98195
(206) 543-1929

Scott Trenda wrote:
Quick question, might be specific to the MSXML XSLT processor.

I'm trying to reference two different files passed in as parameters to a transformation using the document() function. If the files are blank or valid URIs (the URI handling is correct), the transformation works as expected, but if the URI points to a non-existant file, MSXML errors out with code 0x800c0006: "The system cannot locate the object specified." I'm developing a central framework for several different applications, and I don't know if the application is actually going to create the file I'm trying to reference here. If it doesn't exist, I don't care, I just want to use it in the case that it does exist.

I've played around with some different scenarios in the stylesheet, and the error occurs any time I try to access the variable that contains the result of the document() function, even if I only want to check if it's non-empty. Is there any more graceful way (for MSXML, in particular) to handle the case where the URI passed to document() doesn't exist?

I've included the stylesheet I'm using at the bottom, just in case it helps.

~ Scott

<xsl:stylesheet version="1.0" xmlns:xsl=""; xmlns:encodingStyle=""; exclude-result-prefixes="encodingStyle">

            <xsl:param name="framework-map-file"/>
            <xsl:param name="app-map-file"      />

<xsl:output method="text" encoding="utf-8"/>

            <xsl:variable name="framework-maps" select="document($framework-map-file)"/>
            <xsl:variable name="app-maps"       select="document($app-map-file      )"/>
            <xsl:variable name="maps"           select="$framework-maps/*/map | $app-maps/*/map"/>

            <xsl:template match="*">
                        <xsl:variable name="var-name">
                                    <xsl:apply-templates select="." mode="name"/>
                        <xsl:for-each select="$maps[normalize-space(@new) = $var-name]">
                                   <xsl:value-of select="concat('&lt;webSet #', normalize-space(@old), '# = #', $var-name, '#&gt;&#10;')"/>
                        <xsl:apply-templates select="*"/>

            <xsl:template match="*" mode="name">
                        <xsl:apply-templates select="parent::*" mode="name"/>
                                    <xsl:when test="../@encodingStyle:arrayType">[<xsl:number/>]</xsl:when>
                                                <xsl:if test="parent::*">.</xsl:if>
                                                <xsl:value-of select="name()"/>


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