Three Methods to Implement File Download in PHP

The guide presents three ways to provide file downloads using PHP.

1. Directly add file link

HTML code creates a button containing an anchor tag that points to the file URL.

<button>
    <a href="http://localhost/demo.zip">下载文件</a>
</button>

Clicking the button initiates the download.

2. Pass parameters to locate and redirect to the download link

The button’s link includes a query parameter (e.g., f='down') that is processed by a PHP script.

<button>
    <a href="http://localhost?f='down'">下载文件</a>
</button>

The PHP script retrieves the parameter, builds the file name, checks its existence, and either redirects to the file or returns a 404 response.

<?php
$down = $_GET['f'];               // get file parameter
$filename = $down . '.zip';       // file name
$dir = "demo/";                  // download directory
$down_host = $_SERVER['HTTP_HOST'] . '/';
if (file_exists(__DIR__ . '/' . $dir . $filename)) {
    header('Location: http://' . $down_host . $dir . $filename);
} else {
    header('HTTP/1.1 404 Not Found');
}
?>

3. Use head() and fread() to output the file directly to the browser

This method streams the file with appropriate HTTP headers, hiding the real file path.

<?php
$file_name = "down.zip";
$file_dir = "./down/";
if (!file_exists($file_dir . $file_name)) {
    header('HTTP/1.1 404 NOT FOUND');
} else {
    $file = fopen($file_dir . $file_name, "rb");
    Header("Content-type: application/octet-stream");
    Header("Accept-Ranges: bytes");
    Header("Accept-Length: " . filesize($file_dir . $file_name));
    Header("Content-Disposition: attachment; filename=" . $file_name);
    echo fread($file, filesize($file_dir . $file_name));
    fclose($file);
    exit();
}
?>

Summary: The first two methods are simple but expose the real file address, reducing security, whereas the third method better hides the file path by streaming the content with proper headers.