在PHP中一次限制1次下载

$file = 'path/to/file.txt';
$filename = basename($file);

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.$filename);
header('Content-Length: '.filesize($file));

readfile($file);
exit();

$file = 'path/to/file.txt';
$filename = basename($file);

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.$filename);
header('Content-Length: '.filesize($file));

$handle = fopen($file, 'rb');
if ($handle === false) {
    exit('Error: could not open file');
}

while (!feof($handle)) {
    echo fread($handle, 1024);
    ob_flush();
    flush();
    sleep(1);
}

fclose($handle);
exit();

$file = 'path/to/file.txt';
$filename = basename($file);

// 获取已下载次数
$downloads = isset($_COOKIE['downloads']) ? $_COOKIE['downloads'] : 0;

// 限制下载次数为1
if ($downloads >= 1) {
    exit('Error: download limit reached');
}

// 设置下载次数
setcookie('downloads', $downloads + 1, time() + 86400);

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.$filename);
header('Content-Length: '.filesize($file));

readfile($file);
exit();

$file = 'path/to/file.txt';
$filename = basename($file);

// 获取下载开始时间
$start_time = isset($_COOKIE['start_time']) ? $_COOKIE['start_time'] : 0;

// 限制下载时间为1小时
if (time() - $start_time > 3600) {
    exit('Error: download time limit reached');
}

// 设置下载开始时间
setcookie('start_time', time(), time() + 86400);

header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.$filename);
header('Content-Length: '.filesize($file));

readfile($file);
exit();