API: Register a webhook, pass attributes through a GET request to the URL

Online store platform WordPress, plugin WooCommerce. In the users cart you need to add a custom button with a redirect to the external system.

Process:
1. The user redirects from the external system to his personal account on the website of the online store - A GET request is sent
2. The user selects the products he needs and clicks the checkout button in the cart - A GET response is generated in the form of a URL to which the redirect will occur
3. The online store returns the user back to the external system by HOOK_URL with information about the selected products (attributes) - Return to the external system occurs through a redirect using the link.

Detailed description in the TK file.