ActionControllerAPI

ActionControllerAPI is a component of the Ruby on Rails web application framework. It is specifically designed for building JSON APIs. When creating an API with Rails, developers often inherit from ActionControllerAPI instead of the standard ActionController::Base. This inheritance provides a streamlined set of features and configurations optimized for API development, where HTML rendering is typically not required.

One of the key differences is that ActionControllerAPI disables certain features that are standard in ActionController::Base but are unnecessary for an API. For instance, it omits features like layout rendering, which is primarily used for presenting HTML views. This results in a lighter and more focused controller class.

When using ActionControllerAPI, controllers are often configured to render JSON directly. This is commonly achieved using the render json: method. The framework automatically handles the serialization of Ruby objects into JSON format. Additionally, CSRF (Cross-Site Request Forgery) protection, which is crucial for web applications that handle user sessions and forms, is also disabled by default in ActionControllerAPI, as stateless APIs typically do not rely on session-based authentication.

In summary, ActionControllerAPI serves as a specialized base class in Rails for crafting APIs, offering a more efficient and tailored environment for handling requests and responses in JSON format by stripping away non-essential web-centric features.