I am learning how to build a REST API to implement on a system that has an old API. The old (and new) APIs require authentication, which comes in the form of an API key.
With the old API, you would POST to the URL and one of the POST parameters would be your API key.
With the REST API, I get that the API key could be passed as a GET or POST parameter for the GET and POST methods, but how do I pass it through for PUT, PATCH and DELETE and how do I extract the API key in PHP?