zipファイルのダウンロード（更新確認付）

download.php

<?php
	define('DOWMNLOAD_PATH', '/home/download/');      // download file path

	$time = time();

	$filename = isset($_REQUEST['name']) ? $_REQUEST['name'] : null;

	if ($filename == null) {
		header("HTTP/1.0 404 Not Found");
		exit;
	}

	$hash = isset($_REQUEST['hash']) ? $_REQUEST['hash'] : '';

	if (!file_exists(DOWMNLOAD_PATH.$filename)) {
		header("HTTP/1.0 404 Not Found");
		exit;
	}

	$file = File::file_info($download_file_path.$filename);

	$redis = new Redis();
    	$files = $redis->get('download-files');

	if ($files && isset($files[$filename]))
		$file_info = $files[$filename];
	else
		$file_info = false;

    	if ($files && $file_info && ($file['time_modified'] == $file_info['time'] && $hash && ($hash == $file_info['hash']))) {
		header("HTTP/1.0 304 Not Modified");
		exit;
    	}

	$hash = hash_file("md5", $download_file_path.$filename, false);

	$file_info = array('time' => $file['time_modified'], 'hash' => $hash);

	$files[$filename] = $file_info;
		
    	$redis->set('download-files', $files);

	header("X-Download-Hash: " . $hash);
	header("Content-Type: application/zip");
 	header('Content-Disposition: attachment; filename="'.$filename.'"'); 
	header('Content-Length: '.filesize($download_file_path.$filename));

	readfile($download_file_path.$filename);

	$handle = fopen($path, "rb");
	while(!feof($handle))
	{
		print fread($handle, 4096);
		ob_flush();
		flush();
 	}
 	fclose();