Multithread image download with cURL, PHP - php

Question

I'm trying to use cURL to download images from an URL with multiple connections to speed up the process.
Here's my code:
function multiRequest($data, $options = array()) {
// array of curl handles
$curly = array();
// data to be returned
$result = array();
// multi handle
$mh = curl_multi_init();
// loop through $data and create curl handles
// then add them to the multi-handle
foreach ($data as $id => $d) {
$path = 'image_'.$id.'.png';
if(file_exists($path)) { unlink($path); }
$fp = fopen($path, 'x');
$url = $d;
$curly[$id] = curl_init($url);
curl_setopt($curly[$id], CURLOPT_HEADER, 0);
curl_setopt($curly[$id], CURLOPT_FILE, $fp);
fclose($fp);
curl_multi_add_handle($mh, $curly[$id]);
}
// execute the handles
$running = null;
do {
curl_multi_exec($mh, $running);
} while($running > 0);
// get content and remove handles
foreach($curly as $id => $c) {
curl_multi_remove_handle($mh, $c);
}
// all done
curl_multi_close($mh);
}
And executing:
$data = array(
'http://example.com/img1.png',
'http://example.com/img2.png',
'http://example.com/img3.png'
);
$r = multiRequest($data);
So it's not really working. It creates the 3 files, but with zero bytes (empty), and giving me the following error (3 times) and it's printing some kind of content of the original .PNGs:
Warning: curl_multi_exec(): CURLOPT_FILE resource has gone away, resetting to default in /Applications/MAMP/htdocs/test.php on line 34
So please, could you let me know how to work it out?
Thanks in advance for your help!

Answer 1

What you are doing is creating a file handle then closing it before the end of the loop. This is going to result in curl not having any file to write to. Try something like this:
//$fp = fopen($path, 'x'); Remove
$url = $d;
$curly[$id] = curl_init($url);
curl_setopt($curly[$id], CURLOPT_HEADER, 0);
curl_setopt($curly[$id], CURLOPT_FILE, fopen($path, 'x'));
//fclose($fp); Remove