How to download large files through PHP script

If you use fopen and fread instead of readfile, that should solve your problem.

There's a solution in the PHP's readfile documentation showing how to use fread to do what you want.

If you care about performance, there is xsendfile, available in apache, nginx and lighttpd as module. Check the readfile() doc's users comments.

There are also modules for these webservers which accept a url with an additional hash value which allows downloading the file for a short time period. This can be also used to solve authorization issues.

To download large files from server, I have changed the below settings in php.ini file:

Upload_max_filesize  - 1500 M
Max_input_time  - 1000
Memory_limit    - 640M
Max_execution_time -  1800
Post_max_size - 2000 M

Now, I am able to upload and download 175MB video on server. Since, I have the dedicated server. So, making these changes were easy.

Below is the PHP script to download the file. I have no made any changes in this code snippet for large file size.

// Begin writing headers

            ob_clean(); // Clear any previously written headers in the output buffer

            if($filetype=='application/zip')
            {
                if(ini_get('zlib.output_compression'))
                    ini_set('zlib.output_compression', 'Off');
                $fp = @fopen($filepath, 'rb'); 
                if (strstr($_SERVER['HTTP_USER_AGENT'], "MSIE"))
                {
                    header('Content-Type: "$content_type"');
                    header('Content-Disposition: attachment; filename="'.$filename.'"');
                    header('Expires: 0');
                    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
                    header("Content-Transfer-Encoding: binary");
                    header('Pragma: public');
                    header("Content-Length: ".filesize(trim($filepath)));
                }
                else
                {
                    header('Content-Type: "$content_type"');
                    header('Content-Disposition: attachment; filename="'.$filename.'"');
                    header("Content-Transfer-Encoding: binary");
                    header('Expires: 0');
                    header('Pragma: no-cache');
                    header("Content-Length: ".filesize(trim($filepath)));
                }

                fpassthru($fp);
                fclose($fp);
            }
            elseif($filetype=='audio'|| $filetype=='video')
            { 
                global $mosConfig_absolute_path,$my;
                ob_clean();
                header("Pragma: public");
                header('Expires: 0');
                header('Cache-Control: no-store, no-cache, must-revalidate');
                header('Cache-Control: pre-check=0, post-check=0, max-age=0');
                header("Cache-Control: public");    
                header("Content-Description: File Transfer");
                header("Content-Type: application/force-download"); 
                header("Content-Type: $content_type");
                header("Content-Length: ".filesize(trim($filepath)));
                header("Content-Disposition: attachment; filename=\"$filename\"");
                // Force the download           
                header("Content-Transfer-Encoding: binary");            
                @readfile($filepath);
            }
              else{ // for all other types of files except zip,audio/video
                ob_clean();
                header("Pragma: public");
                header('Expires: 0');
                header('Cache-Control: no-store, no-cache, must-revalidate');
                header('Cache-Control: pre-check=0, post-check=0, max-age=0');
                header("Cache-Control: public");    
                header("Content-Description: File Transfer");
                header("Content-Type: $content_type");
                header("Content-Length: ".filesize(trim($filepath)));
                header("Content-Disposition: attachment; filename=\"$filename\"");
                // Force the download           
                header("Content-Transfer-Encoding: binary");            
                @readfile($filepath);       
            }
            exit;