Why does php download stop on large files? - php

Question

I have a php script that allows users to download large files. The script works well except for files of over around 500mb. Everytime I try to download a file that is 664mb the download stops at about 460mb ( around 15-17 mins). There is no error. What can I do? I
suspect the script is timing out but I can't see why. I've spent days trying to get it to work and just can't make any progress. Any thoughts or suggestions would be great. I'm using a hosted server so cannot try modx_sendfile sadly. I'm using php 7.0.25
$db = new mysqli($dbHost, $dbUsername, $dbPassword, $dbName);
ob_start() or die('Cannot start output buffering');
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
$strDownloadFolder = "files/";
//- turn off compression on the server
//#apache_setenv('no-gzip', 1);
#ini_set('zlib.output_compression', 'Off');
//Download a file more than once
$boolAllowMultipleDownload = 2;
if(!empty($_GET['key'])){
//check the DB for the key
$sql = "SELECT * FROM downloads WHERE downloadkey = '".mysqli_real_escape_string($db,$_GET['key'])."' LIMIT 1";
$resCheck=mysqli_query($db, $sql);
$arrCheck = mysqli_fetch_array($resCheck); //Create array from first result
if(!empty($arrCheck['file'])){
//check that the download time hasnt expired
if($arrCheck['expires']>=time()){
if(!$arrCheck['downloads'] OR $boolAllowMultipleDownload){
//everything is ok -let the user download it
$strDownload = $strDownloadFolder.$arrCheck['file'];
if(file_exists($strDownload)){
$file_path = $arrCheck['file'];
$path_parts = pathinfo($file_path);
$file_name = $path_parts['basename'];
$file_ext = $path_parts['extension'];
$file_path = 'files/' . $file_name;
// allow a file to be streamed instead of sent as an attachment
$is_attachment = isset($_REQUEST['stream']) ? false : true;
// make sure the file exists
if (is_file($file_path))
{
$file_size = filesize($file_path);
$file = #fopen($file_path,"rb");
if ($file)
{
// set the headers, prevent caching
header("Pragma: public");
header("Expires: -1");
header("Cache-Control: public, must-revalidate, post-check=0, pre-check=0");
header("Content-Disposition: attachment; filename=\"$file_name\"");
// set appropriate headers for attachment or streamed file
if ($is_attachment) {
header("Content-Disposition: attachment; filename=\"$file_name\"");
}
else {
header('Content-Disposition: inline;');
header('Content-Transfer-Encoding: binary');
}
// set the mime type based on extension, add yours if needed.
$ctype_default = "application/octet-stream";
$content_types = array(
"exe" => "application/octet-stream",
"zip" => "application/zip",
"mp3" => "audio/mpeg",
"mpg" => "video/mpeg",
"avi" => "video/x-msvideo",
);
$ctype = isset($content_types[$file_ext]) ? $content_types[$file_ext] : $ctype_default;
header("Content-Type: " . $ctype);
//check if http_range is sent by browser (or download manager)
if(isset($_SERVER['HTTP_RANGE']))
{
list($size_unit, $range_orig) = explode('=', $_SERVER['HTTP_RANGE'], 2);
if ($size_unit == 'bytes')
{
list($range, $extra_ranges) = explode(',', $range_orig, 2);
}
else
{
$range = '';
header('HTTP/1.1 416 Requested Range Not Satisfiable');
exit;
}
}
else
{
$range = '';
}
//figure out download piece from range (if set)
list($seek_start, $seek_end) = explode('-', $range, 2);
//set start and end based on range (if set), else set defaults
//also check for invalid ranges.
$seek_end = (empty($seek_end)) ? ($file_size - 1) : min(abs(intval($seek_end)),($file_size - 1));
$seek_start = (empty($seek_start) || $seek_end < abs(intval($seek_start))) ? 0 : max(abs(intval($seek_start)),0);
//Only send partial content header if downloading a piece of the file (IE workaround)
if ($seek_start > 0 || $seek_end < ($file_size - 1))
{
header('HTTP/1.1 206 Partial Content');
header('Content-Range: bytes '.$seek_start.'-'.$seek_end.'/'.$file_size);
header('Content-Length: '.($seek_end - $seek_start + 1));
}
else
header("Content-Length: $file_size");
header('Accept-Ranges: bytes');
set_time_limit(0);
fseek($file, $seek_start);
while(!feof($file))
{
print(#fread($file, 1024*8));
ob_flush();
flush();
if (connection_status()!=0)
{
#fclose($file);
exit;
}
}
// file save was a success
#fclose($file);
exit;
}
else
{
// file couldn't be opened
header("HTTP/1.0 500 Internal Server Error");
exit;
}
}
else
{
// file does not exist
header("HTTP/1.0 404 Not Found");
exit;
}
}else{
echo "We couldn't find the file to download.";
}
}else{
//this file has already been downloaded and multiple downloads are not allowed
echo "This file has already been downloaded.";
}
}else{
//this download has passed its expiry date
echo "This download has expired.";
}
}else{
//the download key given didnt match anything in the DB
echo "No file was found to download.";
}
}else{
//No download key wa provided to this script
echo "No download key was provided. Please return to the previous page and try again.";
}
A much simpler piece of code that still throws up the same problem (but works with smaller files) mkaes me think it is a hosting / php.ini issue although I don't know why.
<?php
$local_file = 'my_big_file.zip';
$download_file = 'my_big_file.zip';
// set the download rate limit (=> 20,5 kb/s)
if(file_exists($local_file) && is_file($local_file))
{
header('Cache-control: private');
header('Content-Type: application/octet-stream');
header('Content-Length: '.filesize($local_file));
header('Content-Disposition: filename='.$download_file);
flush();
$file = fopen($local_file, "r");
while(!feof($file))
{
// send the current file part to the browser
print fread($file, round(1024 * 1024));
// flush the content to the browser
flush();
// sleep one second
sleep(1);
}
fclose($file);}
else {
die('Error: The file '.$local_file.' does not exist!');
}
?>
This script stops downloading after about 17 minutes.