how to check if simpleXML is null - php

Question

So, I build a script which contains multi curl to verify the XML and extrac $xml->loc from more urls but my script crash(stop) when he found anything else which is not a xml file
...multi curl code...
if($httpcode>=200 && $httpcode<=300) {
$xml = new SimpleXMLElement($data);
if($xml !== NULL) {
foreach ($xml->url as $url_list) {
$url = $url_list->loc;
$newurls[] = $url;
}
}
}
If i put 5 valid xml urls it works but if I put 100 link and one of them is not a XML file the script stops.
ERROR:
[root#test ~]# php a z2
PHP Fatal error: Uncaught exception 'Exception' with message 'String could not be parsed as XML' in /root/a:160
Stack trace:
#0 /root/a(160): SimpleXMLElement->__construct('\r\n<!DOCTYPE htm...')
#1 /root/a(65): mycurl_done('http://southpas...', '\r\n<!DOCTYPE htm...', Resource id #36)
#2 /root/a(175): ThreadsLoop()
#3 {main}
thrown in /root/a on line 160
[root#test ~]#
Seems like my script try to extract information from a html file because if the file don't exist it will redirect me to homepage(I guess)...
What options do I have to make to continue if the SimpleHTMLElement can't parse my $data variable which is the entire source code from a XML file?

Answer 1

You can use a try catch block to handle the exception.
try {
$xml = new SimpleXMLElement($data);
//XML is valid
...
} catch(Exception $e) {
//XML is invalid
}