Push a file download after registration. - hides url of file to prevent unauthorized sharing - uses custom field in ACF to store download file - uses gravity forms for form management

force-file-download

add_action("gform_after_submission_1", "push_pdf", 10, 2);

function push_pdf($entry, $form) {
    

    $host = $_SERVER['HTTP_HOST'];
    preg_match("/[^\.\/]+\.[^\.\/]+$/", $host, $matches);

    global $post;
    $postID = $post->ID;
    $filePath = get_field('file_download',  $postID);

    $file = $filePath;
    $protocol = ((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off') || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
    $domainName = $_SERVER['HTTP_HOST'];

    $urlFileToDl = str_replace($protocol.$domainName.'/',"", $file);

    if(is_file($urlFileToDl)) {
        
        $type = "application/pdf";
        ob_start();
        header('Content-Description: File Transfer');
        header("Content-disposition: attachment; filename=".basename($urlFileToDl));
        header("Content-Type: $type");
        header("Content-Transfer-Encoding: $type\n" );
        header("Content-Length: ".filesize($urlFileToDl)); 
        ob_clean();
        flush();
        readfile( $urlFileToDl);
        exit(); 
    }

}