Force Download with PHP

// Force download of the file
header( 'Content-Description: File Transfer' );
header( 'Content-Type: application/octet-stream' );
header( 'Content-Disposition: attachment; filename=' . basename( $file_path ) );
header( 'Content-Transfer-Encoding: binary' );
header( 'Expires: 0' );
header( 'Cache-Control: must-revalidate' );
header( 'Pragma: public' );
header( 'Content-Length: ' . filesize( $file_path ) );
readfile( $file_path );