Automatically downloading images from any URL location

Question

I have a serious problem in the late stage of a project I'm working on:

I wrote a PHP function that makes it possible for a user to download an image automatically on a hard drive by clicking on its link. But that was easy because the image was uploaded to the website server and I knew it's full server address. For Example: "home/clients/websites/w_apo/public_html/wp-content/uploads/image.jpg"

But now the client wants the ability to paste the image URL from his own address http://www.something.com/image.jpg and still be able to automatically download that image by clicking on the link on the frontend.

I'm kind of new in this area of programming so I really need your help. Any links, advice, resources are most welcome.

Thanks!

This is my current function for downloading:

download_file($_GET['file']);

/******************************************************************/

function download_file( $fullPath ){

  // Must be fresh start
  if( headers_sent() )
    die('Headers Sent');

  // Required for some browsers
  if(ini_get('zlib.output_compression'))
    ini_set('zlib.output_compression', 'Off');

  // File Exists?
  if( file_exists($fullPath) ){

    // Parse Info / Get Extension
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);

    // Determine Content Type
    switch ($ext) {
      case "pdf": $ctype="application/pdf"; break;
      case "exe": $ctype="application/octet-stream"; break;
      case "zip": $ctype="application/zip"; break;
      case "doc": $ctype="application/msword"; break;
      case "xls": $ctype="application/vnd.ms-excel"; break;
      case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
      case "gif": $ctype="image/gif"; break;
      case "png": $ctype="image/png"; break;
      case "jpeg":
      case "jpg": $ctype="image/jpg"; break;
      default: $ctype="application/force-download";
    }

    header("Pragma: public"); // required
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false); // required for certain browsers
    header("Content-Type: $ctype");
    header("Content-Disposition: attachment; filename=\"".basename($fullPath)."\";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".$fsize);
    ob_clean();
    flush();
    readfile( $fullPath );

  } else
    die('File Not Found');

}

Answer 1

You have a couple of options. #1 use file_get_contents. It's not the greatest way, but it will work.

<?php
//Get the file
$content = file_get_contents("http://example.com/image.jpg");


//Store in the filesystem.
$fp = fopen("/location/to/save/image.jpg", "w");
fwrite($fp, $content);
fclose($fp);
?>

Option #2 use cURL:

See this example