I come to you about a problem I meet for some days. I want to use the API to retrieve the categories of Magento website as well as the basket for a given client (+ add / modify / delete products from the shopping cart) and this separately. I tried to extend the Rest API to get a list of categories but when I query the API, I encounter this problem "error 403: Access denied" and I do not know how to solve it (this problem also comes when using POST or PUT).
So I turned to the Soap API which is slow compared to Rest. But I saw on the internet that we can use Talend ESB to call the magento Soap API (I do not know what it can do more and how). What is the best way to use the Magento API Soap (with or without Talend) and how?