Create a new account on site B with data from the purchase of site A

Question

Until recently we had a single members area that also integrated the store and the data was all recorded on a single DB.

Now, since the merchandising products are also coming out, we decided to create a separate store, to keep everything cleaner.

In this store we also sell access to the members area and we would like to do the following: The user who buys on site A (the store) is registered as a new user also on site B (the members area).

This is the code I've used so far, but I don't know how to continue:

//Code that links the DB of the site B
function connect_db_membership(){
global $db_membership;
$db_membership = new wpdb('USERNAME', 'PASSWORD', 'DATABASE_NAME', 'HOSTNAME');
}
add_action('init', 'connect_db_membership');

//Code that retrieves the first name, last name and email of the user who has just completed the purchase and passes it to the DB of site B.
add_action( 'woocommerce_order_status_completed', 'change_role_on_purchase' );
function change_role_on_purchase( $order_id ) {
    
    global $db_membership;
    
    $order = new WC_Order( $order_id );
    $items = $order->get_items();   
    
    $order = wc_get_order( $order_id );
    $order_data = $order->get_data();
    $order_billing_first_name = $order_data['billing']['first_name'];
    $order_billing_last_name = $order_data['billing']['last_name'];
    $order_billing_email = $order_data['billing']['email'];
    
}

Note: I would like the password to be set directly through the link that arrives by email.

Useful information:

• The two sites are both on WordPress;
• The two sites are all hosted on the same hosting.
• The sites are not on a multisite and I don't want to put them there since the only data they have to share is the user's data.

Answer 1

I managed to solve via CURL requests via PHP, the code is as follows.

functions.php of site A:

add_action( 'woocommerce_order_status_completed', 'change_role_on_purchase' );
function change_role_on_purchase( $order_id ) {
    
    $order = new WC_Order( $order_id );
    $items = $order->get_items();   
    
    foreach ( $items as $item_id => $item ) {
       $product_id = $item->get_variation_id() ? $item->get_variation_id() : $item->get_product_id();
       if ( $product_id === 3960 ) { // Check product
            $order_data = $order->get_data();
            $order_billing_first_name = $order_data['billing']['first_name'];
            $order_billing_last_name = $order_data['billing']['last_name'];
            $order_billing_email = $order_data['billing']['email'];

            // API url
            $url = 'https://example.com/register-user';

            // set post fields
            $data = array(
                'name' => $order_billing_first_name,
                'lastname' => $order_billing_last_name,
                'email'   => $order_billing_email,
            );

            $str = http_build_query($data);

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, $url);
            curl_setopt($ch, CURLOPT_POST, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $str);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

            // execute!
            $response = curl_exec($ch);

            // close the connection, release resources used
            curl_close($ch);
        }
    }
}

Code on page-register-user.php in the site B:

<?php
wp_head();
if(isset($_POST['name'])){
    $name = $_POST['name'];
    $lastname = $_POST['lastname'];
    $username = strtolower($name . $lastname);
    $email = $_POST['email'];
    //$user_id = username_exists( $username );
    if ( !email_exists( $email ) ) {
        $i = 1;
        while(username_exists($username)){
            $i++;
        }
        $username = $username . $i;
        $password = wp_hash_password(wp_generate_password());
        $user_id = wp_create_user( $username, $password, $email );
        $user = get_user_by( 'ID', $user_id );
        // Remove role
        $user->remove_role( 'subscriber' );
        // Add role
        $user->add_role( 'new_role' );
    } else {
        $user = get_user_by( 'email', $email );
        // Remove role
        $user->remove_role( 'subscriber' );
        // Add role
        $user->add_role( 'new_role' );
    }
}
wp_footer();
?>