Invalid argument supplied for foreach() in - php

Question

i keep getting the error for this code even though it works as it should when i run it in browser, but when called by include_once it doesnt work due to the error
foreach(($hostlist->uploaded) as $uploaded) {
if (strcmp($uploaded->url,"http://someurl.com/")==0) {
$host = simplexml_load_file($config['hostlist']);
unset($host->uploaded->url);
unset($host->uploaded->pass);
$host->uploaded->addChild('url',"http://anotherurl.com/");
$host->uploaded->addChild('pass',"anotherpass");
$host->uploaded->asXML($config['hostlist']);
$host->asXML($config['hostlist']);`
echo "URL Changed to http://anotherurl.com/";
}
}
knowing that the variables are as follows:
$config['hostlist'] = 'xml/host.xml';
$hostlist = simplexml_load_file($config['hostlist']);
and this is a sample of the xml file:
<host>
<uploaded>
<work>yes</work>
<url>http://someurl.com/</url>
<pass>pass</pass>
</uploaded>
</host>

Answer 1

As I had early mentioned via comments, your issue maybe that the file is using a relative path and being accessed via include_once by a script on a different folder, which causes the file path of your XML to be invalid.
Here is a simple example of what may be happening to you.
I have the following folder structure:
root
- include_folder/
- include_folder/read_host.php
- include_folder/xml
- include_folder/xml/host.xml
- test_xml.php
When accessing include_folder/read_host.php it reads the file just fine.
This is my read_host.php:
<?php
$config['hostlist'] = 'xml/host.xml';
$hostlist = simplexml_load_file($config['hostlist']);
foreach($hostlist->uploaded as $uploaded)
{
echo $uploaded->work, "\n";
echo $uploaded->url, "\n";
echo $uploaded->pass, "\n";
}
The output:
yes
http://someurl.com/
pass
However if I access from test_xml.php which have the following content:
<?php
include_once('include_folder/read_host.php');
echo "what happens";
It fails with error:
PHP Warning: simplexml_load_file(): I/O warning : failed to load external entity "xml/host.xml" in /home/admin/include_folder/read_host.php on line 4
PHP Notice: Trying to get property of non-object in /home/admin/include_folder/read_host.php on line 5
PHP Warning: Invalid argument supplied for foreach() in /home/admin/include_folder/read_host.php on line 5
what happens
However if I change $config['hostlist'] = 'xml/host.xml'; to the absolute path to the XML file it works just fine and output:
yes
http://someurl.com/
pass
what happens
So in my case the absolute folder was:
$config['hostlist'] = '/home/admin/include_folder/xml/host.xml';