how to post text from url in wordpress?

I have WordPress e commerce site with responsive comparison theme , Now I have setup crawler which scrapes the price from various pages . This crawler gives me an api (url) which i want to post instead of numeric values. Now how do I program it to get the data from url and if the data from url is not available then to use another variable which would contain a fallback price. I want to use this api because the crawler runs every 15 minutes and could help me in getting live data. I would be importing these urls through csv import tool.

I modified class_core.php file to this:
Price Display
================================================== ======================== */
function curl_download($Url){
// is cURL installed yet?
if (!function_exists('curl_init')){
die('Sorry cURL is not installed!');
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $Url);
curl_setopt($ch, CURLOPT_REFERER, "http://www.example.org/yay.htm");
curl_setopt($ch, CURLOPT_USERAGENT, "MozillaXYZ/1.0");
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
$output = curl_exec($ch);
curl_close($ch);
return $output;
}
$url_for_value = "https://www.xyz.com/dddddd/ddddd";
// remember to add http colon and two slashes in front of url...
// stackoverflow tools won't let me do that here...
$val = curl_download($url_for_value);

function PRICE($val){

if(!is_numeric($val) && defined('WLT_JOBS') ){
// if not numeric, e.g. $100 , strip off non-numeric characters.
preg_match_all('/([\d]+)/', $val, $match);
// Do we have a valid number now?
if (!is_numeric($match[0]){
// perform other tests on return info from the CURL function?
return $val;
}
$val = $match[0];
}

but this code doesnt work
it gives me 500 internal error
In short can anyone tell how to post text from url in price function