PHP pass through proxy - php

Question

I want to create a proxy like application from which I send the header to the server and the response goes right to the client and doesn't use all of the server bandwidth.
The only way I can think of is using PHP cURL for this, but that doesn't work since it downloads the file and the sends it to client. I want to know is there a way to remove or minimize the used bandwidth.
What I want to do:
Clients opens the page, presses the download button, then MY server requests to the file server for the file (using a header) and sends its directly to the client or MY server redirects to client.

Answer 1

Clients opens the page presses the download button
MY server requests to the file server the file and sends to the client 8k at time (in the following example).
This using CURLOPT_BUFFERSIZE, CURLOPT_HEADERFUNCTION and CURLOPT_WRITEFUNCTION.
<?php
/*
* curl-pass-through-proxy.php
*
* propose: php curl pass through proxy handle: big file, https, autentication
* example: curl-pass-through-proxy.php?url=precise/ubuntu-12.04.4-desktop-i386.iso
* limitation: don't work on binary if is enabled in php.ini the ;output_handler = ob_gzhandler
* licence: BSD
*
* Copyright 2014 Gabriel Rota <gabriel.rota#gmail.com>
*
*/
$url = "http://releases.ubuntu.com/" . $_GET["url"]; // NOTE: this example don't use https
$credentials = "user:pwd";
$headers = array(
"GET ".$url." HTTP/1.1",
"Content-type: text/xml",
"Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
"Cache-Control: no-cache",
"Pragma: no-cache",
"Authorization: Basic " . base64_encode($credentials)
);
global $filename; // used in fn_CURLOPT_HEADERFUNCTION setting download filename
$filename = substr($url, strrpos($url, "/")+1); // find last /
function fn_CURLOPT_WRITEFUNCTION($ch, $str){
$len = strlen($str);
echo( $str );
return $len;
}
function fn_CURLOPT_HEADERFUNCTION($ch, $str){
global $filename;
$len = strlen($str);
header( $str );
//~ error_log("curl-pass-through-proxy:fn_CURLOPT_HEADERFUNCTION:str:".$str.PHP_EOL, 3, "/tmp/curl-pass-through-proxy.log");
if ( strpos($str, "application/x-iso9660-image") !== false ) {
header( "Content-Disposition: attachment; filename=\"$filename\"" ); // set download filename
}
return $len;
}
$ch = curl_init(); // init curl resource
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, false); // a true curl_exec return content
curl_setopt($ch, CURLOPT_TIMEOUT, 600); // 60 second
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers); // login $url
curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); // don't check certificate
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // don't check certificate
curl_setopt($ch, CURLOPT_HEADER, false); // true Return the HTTP headers in string, no good with CURLOPT_HEADERFUNCTION
curl_setopt($ch, CURLOPT_BUFFERSIZE, 8192); // 8192 8k
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_HEADERFUNCTION, "fn_CURLOPT_HEADERFUNCTION"); // handle received headers
curl_setopt($ch, CURLOPT_WRITEFUNCTION, 'fn_CURLOPT_WRITEFUNCTION'); // callad every CURLOPT_BUFFERSIZE
if ( ! curl_exec($ch) ) {
error_log( "curl-pass-through-proxy:Error:".curl_error($ch).PHP_EOL, 3, "/tmp/curl-pass-through-proxy.log" );
}
curl_close($ch); // close curl resource
?>