Inconsistent behavior in production server with custom plugin

Thanks for your reply. I did read about that, I think regarding using wp transients, but frankly I couldn’t find a way to apply it to my situation. But the strange thing is that it really does run without issues whatsoever on my local server.

What I’m doing, in respect to managing the $_SESSION data, is fairly as described in this blog post:
https://wisdmlabs.com/blog/add-custom-data-woocommerce-order/

Thanks for the suggestion. I’ve changed from php sessions to WC based sessions, and the behavior is still the same: on my local server it works fine but on the production server it’s not.

Here’s some part of my code, the most pertaining to sessions at least. Again, this owrks fine on the local server:

if ( ! function_exists('my_ajax_custom_data_callback_inline')) {
                    function my_ajax_custom_data_callback_inline () {
                        global $woocommerce;
                        do_action( 'woocommerce_set_cart_cookies', true );
                        if ( !empty ( $_POST['my_post_data'] ) ) {
                            WC()->session->set( my_meta_data' , $_POST['my_post_data'] );
                        }
                        wp_die();
                    }
                }

                // AJAX hooks
add_action('wp_ajax_' . 'my_custom_data', 'my_ajax_custom_data_callback_inline', 1);
add_action('wp_ajax_nopriv_' . 'my_custom_data', 'my_ajax_custom_data_callback_inline', 1);

add_filter( 'woocommerce_add_cart_item_data', 'my_add_cart_item_data', 10, 2 );
function my_add_cart_item_data ( $cart_item_data, $product_id) {
    global $woocommerce;

    $new_value = array ();
    $my_data_from_session = WC()->session->get( 'my_meta_data' );

    if ( !empty ( $my_data_from_session ) ) {
        $new_value['my_meta_data_in_cart'] = $my_data_from_session;
        $merged_arrays = array_merge ( $cart_item_data, $new_value );
        return $merged_arrays;
    }
    return $cart_item_data;
}

add_filter( 'woocommerce_get_cart_item_from_session', 'my_get_cart_items_from_session', 10, 3 );
function my_get_cart_items_from_session ( $cart_item, $values, $key ) {
    if ( array_key_exists ( 'my_meta_data_in_cart' , $values ) ) {
        $cart_item['my_meta_data_in_cart'] = $values['my_meta_data_in_cart'];
    }
    return $cart_item;
}

I’m really lost with this :/

Thanks for those pointers. I ended up going back up a bit to see if I was doing something wrong that seemed to be working properly.

So, with all client sessions cleared, transients cleared and empty cart, I was able to identify one thing that is going wrong, can’t say if it happened before or not. Considering the code I wrote before, with these hooks:

add_action('wp_ajax_' . 'my_custom_data', 'my_ajax_custom_data_callback_inline', 1);
add_action('wp_ajax_nopriv_' . 'my_custom_data', 'my_ajax_custom_data_callback_inline', 1);

add_filter( 'woocommerce_add_cart_item_data', 'my_add_cart_item_data', 10, 2 );

What I’m seeing is that the AJAX php callback is getting called after the woocommerce_add_cart_item_data filter. As I have custom data being set with the ajax call that is supposed to be later used when actually adding the data to cart, what happens is that the custom data is being added only to the next cart item addition.

Is there any way to streamline this properly?
– AJAX sets data in session:

WC()->session->set( my_meta_data' , $_POST['my_post_data'] );

– Data is merged when adding to Cart:

$my_data_from_session = WC()->session->get( 'my_meta_data' );

Thanks