Ciao io ti posto il mio codice

Ovviamente dato che sono un neofita è sicuramente possibile che il codice sia pieno zeppo di errori o peggio davvero poco chiaro, perciò approfitto con il ringraziare chi gli darà un'occhio e apportera le necessarie correzioni.

Codice PHP:
<?php
$name
=$_GET['nome_file'];
$link=$_GET['link'];




function 
output_file($file$name$mime_type='')
{
/*
This function takes a path to a file to output ($file),
the filename that the browser will see ($name) and
the MIME type of the file ($mime_type, optional).

If you want to do something on download abort/finish,
register_shutdown_function('function_name');
*/
if(!is_readable($file)) die('File not found or inaccessible!');

$size filesize($file);
$name rawurldecode($name);

/* Figure out the MIME type (if not specified) */
$known_mime_types=array(
    
"pdf" => "application/pdf",
    
"txt" => "text/plain",
    
"html" => "text/html",
    
"htm" => "text/html",
    
"exe" => "application/octet-stream",
    
"zip" => "application/zip",
    
"doc" => "application/msword",
    
"xls" => "application/vnd.ms-excel",
    
"ppt" => "application/vnd.ms-powerpoint",
    
"gif" => "image/gif",
    
"png" => "image/png",
    
"jpeg"=> "image/jpg",
    
"jpg" =>  "image/jpg",
    
"php" => "text/plain"
);

if(
$mime_type==''){
     
$file_extension strtolower(substr(strrchr($file,"."),1));
     if(
array_key_exists($file_extension$known_mime_types)){
        
$mime_type=$known_mime_types[$file_extension];
     } else {
        
$mime_type="application/force-download";
     };
};

@
ob_end_clean(); //turn off output buffering to decrease cpu usage

// required for IE, otherwise Content-Disposition may be ignored
if(ini_get('zlib.output_compression'))
  
ini_set('zlib.output_compression''Off');

header('Content-Type: ' $mime_type);
header('Content-Disposition: attachment; filename="'.$name.'"');
header("Content-Transfer-Encoding: binary");
header('Accept-Ranges: bytes');

/* The three lines below basically make the
    download non-cacheable */
header("Cache-control: private");
header('Pragma: private');
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

// multipart-download and download resuming support
if(isset($_SERVER['HTTP_RANGE']))
{
    list(
$a$range) = explode("=",$_SERVER['HTTP_RANGE'],2);
    list(
$range) = explode(",",$range,2);
    list(
$range$range_end) = explode("-"$range);
    
$range=intval($range);
    if(!
$range_end) {
        
$range_end=$size-1;
    } else {
        
$range_end=intval($range_end);
    }

    
$new_length $range_end-$range+1;
    
header("HTTP/1.1 206 Partial Content");
    
header("Content-Length: $new_length");
    
header("Content-Range: bytes $range-$range_end/$size");
} else {
    
$new_length=$size;
    
header("Content-Length: ".$size);
}

/* output the file itself */
$chunksize 1*(1024*1024); //you may want to change this
$bytes_send 0;
if (
$file fopen($file'r'))
{
    if(isset(
$_SERVER['HTTP_RANGE']))
    
fseek($file$range);

    while(!
feof($file) &&
        (!
connection_aborted()) &&
        (
$bytes_send<$new_length)
          )
    {
        
$buffer fread($file$chunksize);
        print(
$buffer); //echo($buffer); // is also possible
        
flush();
        
$bytes_send += strlen($buffer);
    }
fclose($file);
} else die(
'Error - can not open file.');

die();
}    

set_time_limit(0);
$link .= 'scheda.pdf';
$file_path=$link;
output_file($file_path$name'text/plain');
?>