Generate a random order number but prevent regeneration in WooCommerce

Question

I am trying to add a random string when the order number is created as the default sequential number can be very easily guessed.

I tried this snippet:

function generate_random_string( $length = 16 ) {
    return substr( str_shuffle( str_repeat( $x = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil( $length / strlen( $x ) ) ) ), 1, $length );
}
    
add_filter( 'woocommerce_order_number', 'ct_change_woocommerce_order_number', 1, 2);

function ct_change_woocommerce_order_number( $order_id, $order ) {
     $random_string1 = generate_random_string(5);
    return $random_string1 . $order->get_id();
}

The problem is that this change the order number every time the order number is requested somewhere.

This would work if I will use a constant prefix and suffix, but in the actual way a different order number is shown each time for the same order. Any advice?

Answer 1

To prevent this you can save the result as meta data, once this exists return the meta data instead of the result of the function

So you get:

function generate_random_string( $length = 16 ) {
    return substr( str_shuffle( str_repeat( $x = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil( $length / strlen( $x ) ) ) ), 1, $length );
}

function filter_woocommerce_order_number( $order_number, $order ) {
    // Get meta
    $random_meta_string = $order->get_meta( '_random_meta_string' );

    // When meta empty
    if ( empty ( $random_meta_string ) ) {
        // Call function
        $generate_random_string = generate_random_string( 5 );

        // Append
        $random_string = $generate_random_string . $order->get_id();

        // Add the meta data
        $order->update_meta_data( '_random_meta_string', $random_string );

        // Return random string
        $order_number = $random_string;
    } else {
        // Return meta
        $order_number = $random_meta_string;
    }
    
    return $order_number;
}
add_filter( 'woocommerce_order_number', 'filter_woocommerce_order_number', 10, 2 );