Even though REST APIs do not have an official standard, most developers agree on the same foundation. It helps that HTTP, which is the protocol that this technology uses to communicate, does have a standard. In this section, we will try to describe how REST APIs should work.
We've already introduced the idea of HTTP methods in Chapter 2, Web Applications with PHP. We explained that an HTTP method is just the verb of the request, which defines what kind of action it is trying to perform. We've already defined this method when working with HTML forms: the form tag can get an optional attribute, method, which will make the form submit with that specific HTTP method.
You will not use forms when working with REST APIs, but you can still specify the method of the request. In fact, two requests can go to the same endpoint with the same parameters, headers, and so on, and yet have completely different behaviors due to their methods, which makes them...