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xsltxsl-fo

Can I include a variable inside a src attribute of an XSL-FO block?

We have 60-odd images that we want to include, and want to insert them into a doc using a variable name in the src attribute. Here is the code that currently isn't working:

Without XSL:-

<var name="Request.Data.Communication.AddressStructured.Sender.OrgId" type="string" />

<fo:block xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:fox="http://xmlgraphics.apache.org/fop/extensions" xmlns:svg="http://www.w3.org/2000/svg" xmlns:th="http://www.thunderhead.com/XSL/Extensions" font-family="Frutiger 45 Light">
  <fo:external-graphic content-height="30mm" content-width="100mm" src="cms:///Resources/Images/Request.Data.Communication.AddressStructured.Sender.OrgId.jpg" />

</fo:block>

With XSL:-

<xsl:block xmlns:xsl="http://www.w3.org/1999/XSL/Format" xmlns:fox="http://xmlgraphics.apache.org/fop/extensions" xmlns:svg="http://www.w3.org/2000/svg" 
<xsl:var name="Request.Data.Communication.AddressStructured.Sender.OrgId" select="Request.Data.Communication.AddressStructured.Sender.OrgId"/>

<fo:block xmlns:fo="http://www.w3.org/1999/XSL/Transform" xmlns:fox="http://xmlgraphics.apache.org/fop/extensions" xmlns:svg="http://www.w3.org/2000/svg" <fo:external-graphic content-height="30mm" content-width="100mm" src="cms:///Resources/Images/${Request.Data.Communication.AddressStructured.Sender.OrgId}.jpg" />

</fo:block>
</xsl:block>
Solution

  • You might want {$Request.Data.Communication.AddressStructured.Sender.OrgId} rather than ${Request.Data.Communication.AddressStructured.Sender.OrgId}, otherwise read on...

    Getting from your source XML to PDF output is a two-step process (unless, that is, you author documents directly in the XSL-FO vocabulary). The steps are:

    1. An XSLT transformation transforms your XML into XML in the XSL-FO vocabulary that an XSL Formatter understands
    2. An XSL Formatter formats the XSL-FO to make pages and outputs those pages as PDF, SVG, etc.

    This graphic from the XSL 1.1 Recommendation (https://www.w3.org/TR/xsl11/#d0e147) tries to illustrate the process:

    XSL involves transformation followed by formatting

    The XSLT stage has variables, but the XSL-FO stage does not. (You can write expressions for the value of (most) XSL-FO properties, but the expression language (see https://www.w3.org/TR/xsl11/#d0e5032) doesn't stretch to having variables.)

    So, in your XSLT stylesheet, you would have something like:

    {$Request.Data.Communication.AddressStructured.Sender.OrgId}.jpg

    where:

    • $Request.Data.Communication.AddressStructured.Sender.OrgId is a variable (or parameter) reference. We don't have enough information to know how you'd define the variable.
    • {...} is an Attribute Value Template (AVT) that is used when you want to evaluate an expression to generate some or all of an attribute value.

    The output from the XSLT stage would include the literal string resulting from evaluating the expression, and the XSL Formatter will use the actual URL to locate the image correctly.