Question

When building XML in PHP, is it quicker to build a string, then echo out the string or to use the XML functions that php gives you? Currently I’m doing the following:

UPDATED to better code snippet:

$searchParam = mysql_real_escape_string($_POST['s']);
$search = new Search($searchParam);

if($search->retResult()>0){
    $xmlRes = $search->buildXML();
}
else {
    $xmlRes = '<status>no results</status>';
}

$xml = "<?xml version=\"1.0\"?>";
$xml.="<results>";
$xml.=$xmlRes;
$xml.="</results>"

header ("content-type: text/xml");
header ("content-length: ".strlen($xml));
echo($xml);


class Search {
private $num;
private $q;

function __construct($s){
    $this->q = mysql_query('select * from foo_table where name = "'.$s.'"');
    $this->num = mysql_num_rows($this->q);
}

function retResult(){
    return $this->num;
}

function buildXML(){
    $xml ='<status>success</status>';
    $xml.='<items>';
    while($row = mysql_fetch_object($this->q)){
        $xml.='<item>';
        $desTag = '<info><![CDATA[';
        foreach ($row as $key => $current){
            if($key=='fob'){
                //do something with current
                $b = mysql_query('select blah from dddd where id ='.$current);
                $a = mysql_fetch_array($b);
                $xml.='<'.$key.'>'.$a['blah'].'</'.$key.'>';
            }
            else if($key =='this' || $key=='that'){
                $desTag = ' '.$current;
            }
            else {
                $xml.='<'.$key.'>'.$current.'</'.$key.'>';
            }   
        }
        $desTag.= ']]></info>';
        $xml.=$desTag;
        $xml.='</item>';
    }
    $xml.='</items>';
    return $xml;
}

}

Is there a faster way of building the xml? I get to about 2000 items and it starts to slow down..

Thanks in advance!

Answer 1

I don’t see that you’re making no attempt to escape the text before concatenating it. Which means that sooner or later you’re going to generate something that is almost-but-not-quite XML, and which will be rejected by any conforming parser.

Use a library (XMLWriter is probably more performant than others, but I haven’t done XML with PHP).