Using OAuth methods
Using the RESTful Web Services module, we can define specific supported authentication providers for an endpoint. Drupal core provides a cookie provider, which authenticates through a valid cookie, such as your regular login experience. Then, there is the HTTP Basic Authentication module to support HTTP authentication headers.
Some alternatives provide more robust authentication methods. With cookie-based authentication, you need to use CSRF tokens to prevent unrequested page loads by an unauthorized party. When you use HTTP authentication, you are sending a password for each request in the request header.
A popular, and open, authorization framework is OAuth. OAuth is a proper authentication method that uses tokens and not passwords. In this recipe, we will implement the Simple OAuth module to provide OAuth 2.0 authentication for GET and POST requests.
Getting ready
If you are not familiar with OAuth or OAuth 2.0, it is a standard for authorization...