How do I handle Warning: SimpleXMLElement::__construct()? - php

Question

I'm getting this error when I run in local host, if internet is disconnected (if internet is connect its ok) I want to handle this error, "error can show " but want to handle not fatal error break on PHP page.
Warning: SimpleXMLElement::__construct() [simplexmlelement.--construct]:
php_network_getaddresses: getaddrinfo failed: No such host is known.
in F:\xampp\htdocs\shoptpoint\sections\docType_head_index.php on line 30
but I'm trying to handle using try-catch. Below is my code
$apiurl="http://publisher.usb.api.shopping.com/publisher/3.0/rest/GeneralSearch?apiKey=78b0db8a-0ee1-4939-a2f9-d3cd95ec0fcc&trackingId=7000610&categoryId='5855855'";
try{
new SimpleXMLElement($apiurl,null, true);
}catch(Exception $e){
echo $e->getMessage();
}
How do I handle the error and my page can execute end of the project?

Answer 1

Using set_error_handler, you can do the following to convert any notices/warnings raised by SimpleXMLElement into a catchable Exception.
Take the following:-
<?php
function getData() {
return new SimpleXMLElement('http://10.0.1.1', null, true);
}
$xml = getData();
/*
PHP Warning: SimpleXMLElement::__construct(http://10.0.1.1): failed to open stream: Operation timed out
PHP Warning: SimpleXMLElement::__construct(): I/O warning : failed to load external entity "http://10.0.1.1"
PHP Fatal error: Uncaught exception 'Exception' with message 'String could not be parsed as XML'
*/
See how we get 2 Warnings before the the Exception from SimpleXMLElement is thrown? Well, we can convert those to an Exception like this:-
<?php
function getData() {
set_error_handler(function($errno, $errstr, $errfile, $errline) {
throw new Exception($errstr, $errno);
});
try {
$xml = new SimpleXMLElement('http://10.0.1.1', null, true);
}catch(Exception $e) {
restore_error_handler();
throw $e;
}
return $xml;
}
$xml = getData();
/*
PHP Fatal error: Uncaught exception 'Exception' with message 'SimpleXMLElement::__construct(http://10.0.1.1): failed to open stream: Operation timed out'
*/
Good luck,
Anthony.

Answer 2

If for any reason you don't want to set up the error handler you can also use some libxml functions to suppress E_WARNING from raising:
// remembers the old setting and enables usage of libxml internal error handler
$previousSetting = libxml_use_internal_errors(true);
// still need to try/catch because invalid XML raises an Exception
try {
// XML is missing root node
new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?>',null, true);
} catch(Exception $e) {
echo $e->getMessage(); // this won't help much: String could not be parsed as XML
$xmlError = libxml_get_last_error(); // returns object of class LibXMLError or FALSE
if ($xmlError) {
echo $xmlError->message; // this is more helpful: Start tag expected, '<' not found
}
}
// sets libxml usage of internal error handler to previous setting
libxml_use_internal_errors($previousSetting);
Alternatively you can use libxml_get_errors() instead of libxml_get_last_error() to get all errors. With it you can get all errors regarding parsing the XML as an array of LibXMLError objects.
Some helpful links:
https://www.php.net/manual/en/function.libxml-use-internal-errors.php
https://www.php.net/manual/en/function.libxml-get-last-error.php