title: Building a REST API: API Keys with PUT, PATCH and DELETE
body: <p>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.</p>
  
  <p>With the old API, you would POST to the URL and one of the POST parameters would be your API key.</p>
  
  <p>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?</p>