How can PHP scripts be used to securely transfer files to a user's local disk?

To securely transfer files to a user's local disk using PHP, you can utilize the `readfile()` function along with proper authentication and authorization checks. This function reads a file and sends it to the output buffer, allowing the user to download it securely. Make sure to validate user input and restrict access to authorized users only to prevent unauthorized file downloads. 

<?php
// Check if the user is authenticated and authorized to download the file
if($authenticated && $authorized) {
    $file = '/path/to/file.txt';

    // Set appropriate headers for file download
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename=' . basename($file));
    header('Content-Length: ' . filesize($file));
    header('Pragma: public');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Expires: 0');

    // Read and output the file contents
    readfile($file);
    exit;
} else {
    // Handle unauthorized access
    echo 'You are not authorized to download this file.';
}
?>

Keywords

PHP file transfer local disk security functions

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