Send File to the User

When a user interacts with a PHP script, you may encounter scenarios where you need to transmit a file, such as a PDF, to the client's browser. To achieve this, the appropriate approach depends on the storage location of the file.

Server-Side File

Assuming the file resides on the server, the preferred method is to utilize the readfile() function. However, merely executing readfile($file) is insufficient. The script must include appropriate headers to enable the client to receive the file successfully.

Refer to the following example from the official PHP manual:

<?php
$file = 'monkey.gif';

if (file_exists($file)) {
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename='.basename($file));
    header('Content-Transfer-Encoding: binary');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Pragma: public');
    header('Content-Length: ' . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exit;
}
?>