Processessing multiple XML files with XSLT in PHP

I often use a message class for a lot of things with PHP. This allows me to build messages to display to the user for errors, successes and general feedback.

Classes for each of these three things are created in CSS to display the information, and then I use a simple PHP class for appending messages to a arrays.

I wanted to include this in some XML data I was processing with XSLT, but I found it difficult to combine multiple XML files with PHP’s XSLT processor. However, in PHP4, you can do it like this:

    // this is a code fragment
    //
    $XML = implode('', file($XML_File));
    $XSL = implode('', file($XSL_File));
    $XML_Messages = $Messages->xml_all_messages();

    define(XSLT_SABOPT_PARSE_PUBLIC_ENTITIES, 0);
    $Entities = array_flip(get_html_translation_table(HTML_ENTITIES));

    $Processor = xslt_create();
    xslt_set_encoding($Processor, 'UTF-8');

    $Args = array('/_xml' ==> $XML,
                  '/_xml_messages' ==> $XML_Messages,
                  '/_xsl' ==> $XSL);

    $HTML = xslt_process($Processor, 'arg:/_xml', 'arg:/_xsl', NULL, $Args);
    xslt_free($Processor);

Notice I’ve got the extra XML file ‘_xml_messages’ in the argument list. This is the extra file I wanted processed by the xslt processor. Next, I added the following to my XST file:

<xsl:variable name="Messages_Info" select="document('_xml_messages')/Messages/Info"/>
<xsl:variable name="Messages_Error" select="document('_xml_messages')/Messages/Error"/>
<xsl:variable name="Messages_Success" select="document('_xml_messages')/Messages/Success"/>
This reads the XML data into the variables you can access elsewhere (in scope) in your XSL file:

<xsl:for-each select="$Messages_Info">
    <div class="Info"><xsl:copy-of select="." /></div>
</xsl:for-each>
<xsl:for-each select="$Messages_Error">
    <div class="Error"><xsl:copy-of select="." /></div>
</xsl:for-each>
<xsl:for-each select="$Messages_Success">
    <div class="Success"><xsl:copy-of select="." /></div>
</xsl:for-each>

You can see how I’m referencing the CSS classes here.

For completeness, here is the PHP error class I was using:

    class Message_Class
    {
        var $_Errors = array();
        var $_Successes = array();
        var $_Info = array();

        function &Messages_Class()
        {
        }

        function add_error($Message)
        {
            array_push($this->_Errors, $Message);
        }

        function add_success($Message)
        {
            array_push($this->_Successes, $Message);
        }

        function add_info($Message)
        {
            array_push($this->_Info, $Message);
        }

        function xml_all_messages()
        {
            $XML =<<<EOD
<?xml version="1.0" encoding="UTF-8"?>
<Messages>

EOD;
            foreach ($this->_Errors as $Error)
            {
                $XML .=<<<EOD
    <Error>$Error</Error>

EOD;
            }

            foreach ($this->_Successes as $Success)
            {
                $XML .=<<<EOD
    <Success>$Success</Success>

EOD;
            }
            foreach ($this->_Info as $Info)
            {
                $XML .=<<<EOD
    <Info>$Info</Info>

EOD;
            }

            $XML .=<<<EOD
</Messages>

EOD;

            return $XML;
        }
    }