
<?
    # Transformation of Weather XML into RDF/XML.

    # (c) 2003 Morten Frederiksen
    # License: http://www.gnu.org/licenses/gpl

    $path=$_SERVER['DOCUMENT_ROOT'].$_SERVER['REQUEST_URI'];
    $path=preg_replace('|\?.+|','',$path);
    $xsl=join('',@file('weather.xsl'));
    $metadata=join('',@file('weather.rdf'));
    $xhtml='';
    $weather='';

    # Create XSLT parser.
    $xslt=xslt_create();
    xslt_set_error_handler($xslt,'xsltError');
    $xslterror='';

    # Look for XML.
    $xml=@$_GET['xml'];
    if (preg_match('|^http://|',$xml))
    {
        # Try to retrieve weather XML.
        $weather=@file($xml);
        if ($weather)
        {
            # Try to convert to RDF/XML.
            if ($rdf=@xslt_process($xslt,'arg:/_xml','arg:/_xsl',NULL,
                    array('/_xsl'=>$xsl,'/_xml'=>@join('',$weather)),
                    array('url'=>$xml)))
            {
                header('Content-Type: application/rdf+xml; charset=utf-8');
                print($rdf);
                exit;
            };
            $xhtml='<h1>Error</h1><p>Unable to transform Weather XML (<a href="'.htmlspecialchars($xml).'">'.htmlspecialchars($xml).'</a>).</p><p>'.$xslterror.'</p>';
        }
        else
            # Flag non-retrievable RDF Schema.
            $xhtml='<h1>Error</h1><p>Unable to find or read Weather XML ('.htmlspecialchars($xml).').</p>';
    }
    elseif ($xml!='')
        $xhtml='<h1>Error</h1><p>Invalid request (<em>xml='.htmlspecialchars($xml).'</em>), only absolute HTTP URLs allowed.</p>';

    if ($xhtml=='')
    {
        # Create service form.
        if (!($xhtml=@xslt_process($xslt,'arg:/_xml','arg:/_xsl',NULL,
                array('/_xsl'=>join('',@file('services-xhtml.xsl',1)),'/_xml'=>$metadata),
                array('path'=>$path))))
            $xhtml='<p>Unable to parse metadata.</p><p>'.$xslterror.'</p>';
    };

    # Transform metadata into header and footer.
    if (!($metahead=@xslt_process($xslt,'arg:/_xml','arg:/_xsl',NULL,
            array('/_xsl'=>join('',@file('metahead.xsl',1)),'/_xml'=>$metadata))))
        $metahead='<title>Parse error: '.$xslterror.'</title>';
    elseif (!($metatop=@xslt_process($xslt,'arg:/_xml','arg:/_xsl',NULL,
            array('/_xsl'=>join('',@file('metatop.xsl',1)),'/_xml'=>$metadata),
            array('path'=>$path,'uri'=>$rdfs))))
        $metatop='<p>Unable to parse metadata.</p><p>'.$xslterror.'</p>';
    elseif (!($metafoot=@xslt_process($xslt,'arg:/_xml','arg:/_xsl',NULL,
            array('/_xsl'=>join('',@file('metafoot.xsl',1)),'/_xml'=>$metadata))))
        $metafoot='<p>Unable to parse metadata.</p><p>'.$xslterror.'</p>';

    # Display page.
    print('<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
'.$metahead.'
</head>
<body>
'.$metatop.'
  <div style="padding: 1em">
'.$xhtml.'
  </div>
'.$metafoot.'
</body>
<!--
'.str_replace('--','- -',$schema).'
-->
</html>');

    function xsltError($x,$e,$l,$f)
    {
        global $xslterror;
        $xslterror='Sablotron XSLT transformation error';
        reset($f);
        while(list($key,$val)=each($f))
        {
            if ($key=='line')
                $xslterror.=' on line '.$val;
            if ($key=='msg')
                $xslterror.=': <strong>'.$val.'</strong>';
        };
        $xslterror.='.';
    };

?>