Download multiple images from remote server with PHP (a LOT of images) - php

Question

I am trying to download lots of files from an external server (approx. 3700 images). These images go from 30KB to 200KB each.
When I use the copy() function on 1 image, it works. When I use it in a loop, all I get are 30B images (empty images files).
I tried using copy, cURL, wget, and file_get_contents. Every time, I either get a lot of empty files, or nothing at all.
Here are the codes I tried:
wget:
exec('wget http://mediaserver.centris.ca/media.ashx?id=ADD4B9DD110633DDDB2C5A2D10&t=pi&f=I -O SIA/8605283.jpg');
copy:
if(copy($donnees['PhotoURL'], $filetocheck)) {
echo 'Photo '.$filetocheck.' updated<br/>';
}
cURL:
$ch = curl_init();
$source = $data[PhotoURL];
curl_setopt($ch, CURLOPT_URL, $source);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$data = curl_exec ($ch);
curl_close ($ch);
$destination = $newfile;
$file = fopen($destination, "w+");
fputs($file, $data);
fclose($file);
Nothing seems to be working properly. Unfortunately, I don't have much choice to download all these files at once, and I need a way to make it work as soon as possible.
Thanks a lot, Antoine

Answer 1

Getting them one by one might be quite slow. Consider splitting them into packs of 20-50 images and grabbing them with multiple threads. Here's the code to get you started:
$chs = array();
$cmh = curl_multi_init();
for ($t = 0; $t < $tc; $t++)
{
$chs[$t] = curl_init();
curl_setopt($chs[$t], CURLOPT_URL, $targets[$t]);
curl_setopt($chs[$t], CURLOPT_RETURNTRANSFER, 1);
curl_multi_add_handle($cmh, $chs[$t]);
}
$running=null;
do {
curl_multi_exec($cmh, $running);
} while ($running > 0);
for ($t = 0; $t < $tc; $t++)
{
$path_to_file = 'your logic for file path';
file_put_contents($path_to_file, curl_multi_getcontent($chs[$t]));
curl_multi_remove_handle($cmh, $chs[$t]);
curl_close($chs[$t]);
}
curl_multi_close($cmh);
I used that approach to grab a few millions of images recently, since one by one would take up to a month.
The amount of images you grab at once should depend on their expected size and your memory limits.

Answer 2

I used this function for that and worked pretty well.
function saveImage($urlImage, $title){
$fullpath = '../destination/'.$title;
$ch = curl_init ($urlImage);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_BINARYTRANSFER,1);
$rawdata=curl_exec($ch);
curl_close ($ch);
if(file_exists($fullpath)){
unlink($fullpath);
}
$fp = fopen($fullpath,'x');
$r = fwrite($fp, $rawdata);
setMemoryLimit($fullpath);
fclose($fp);
return $r;
}
Combined with this other one to prevent memory overflow:
function setMemoryLimit($filename){
set_time_limit(50);
$maxMemoryUsage = 258;
$width = 0;
$height = 0;
$size = ini_get('memory_limit');
list($width, $height) = getimagesize($filename);
$size = $size + floor(($width * $height * 4 * 1.5 + 1048576) / 1048576);
if ($size > $maxMemoryUsage) $size = $maxMemoryUsage;
ini_set('memory_limit',$size.'M');
}