Setting Cookie for Custom URL Parameter - wordpress/woocommerce

Question

I've created a shortcode that always me to use a URL parameter to dynamically swap the featured product on the home page which works well:

// Shortcode to display specific product page via URL - ?myppid=46
// =============================================================================
function ppid_from_query( $atts ) {
    $atts = shortcode_atts( array(
        'default' => 46
    ), $atts, 'myppid' );
    $pp_id = $atts['default']; 
    if ( isset( $_REQUEST['ppid'] ) && $_REQUEST['ppid'] != '' ) {
        $pp_id = intval( $_REQUEST['ppid'] );
    }
    return do_shortcode( "[product_page id='".$pp_id."']" );
    
}
add_shortcode( 'myppid', 'ppid_from_query' );

The challenge I'm having, is that if the user goes to any other page on my site and returns, the URL parameter is gone, and the default product shows up.

I've tried several methods for passing the parameter, but have not succeeded... Even if I had, it would have worked for that session only. In other words, if user leaves site and comes back to primary domain without ?ppid=X, then they won't see that product. So to that end, I've tried setting a cookie per this thread I found (granted it's a bit dated): https://wordpress.stackexchange.com/questions/188749/i-am-looking-to-append-url-parameter-to-all-urls

So in my header, I have:

<script>
if(!isset($_SESSION['ppid']) and $_GET['ppid']){
$cookie_expire = time()+60*60*24*30;
$_SESSION['ppid'] = $_GET['ppid'];
setcookie('ppid', $_SESSION['ppid'], $cookie_expire, '/', '.'.$_SERVER['HTTP_HOST']);
</script>

and in functions:

function wprdcv_param_redirect(){
    if(isset($_COOKIE['ppid']) and !$_GET['ppid']){
        $location = esc_url(add_query_arg('ppid', $_COOKIE['ppid']));
        wp_redirect($location);
    }
}
add_action('template_redirect', 'wprdcv_param_redirect');

Still no luck. What am I doing wrong?

Answer 1

The PHP code is processed by the web server and not by the browser. You don't have to set the cookie between the <script> tags. Instead, run it via the Wordpress init hook.

Based on @MattMelton's comment I added the checkout page exclusion in the wprdcv_param_redirect function.

You can optimize your functions like this:

add_shortcode( 'myppid', 'ppid_from_query' );
function ppid_from_query( $atts ) {
    $atts = shortcode_atts( array(
        'default' => 46
    ), $atts, 'myppid' );
    $pp_id = $atts['default']; 
    if ( isset( $_REQUEST['ppid'] ) && $_REQUEST['ppid'] != '' ) {
        $pp_id = intval( $_REQUEST['ppid'] );
    }
    return do_shortcode( "[product_page id='".$pp_id."']" );
    
}

// set the cookie based on the url parameter "ppid"
add_action( 'init', 'set_cookie_based_on_url_parameter_ppid' );
function set_cookie_based_on_url_parameter_ppid() {
    if ( ! isset($_SESSION['ppid'] ) && $_GET['ppid'] ) {
        $cookie_expire = time()+60*60*24*30;
        $_SESSION['ppid'] = $_GET['ppid'];
        setcookie('ppid', $_SESSION['ppid'], $cookie_expire, '/', '.'.$_SERVER['HTTP_HOST']);
    }    
}

add_action('template_redirect', 'wprdcv_param_redirect');
function wprdcv_param_redirect(){

    // if it's the checkout page, don't redirect
    if ( is_checkout() ) {
        return;
    }

    /*
    // if it is the order confirmation page in checkout, please do not redirect
    if ( is_checkout() && is_wc_endpoint_url( 'order-received' ) ) {
        return;
    }
    */

    if ( isset($_COOKIE['ppid']) && ! $_GET['ppid'] ) {
        $location = esc_url( add_query_arg('ppid', $_COOKIE['ppid']) );
        wp_redirect($location);
    }
}

The code has been tested and works for me. Add it to your active theme's functions.php.