# Introduction to Controllers

Controllers are responsible for controlling the flow of the application execution. When you make a request, a controller is responsible for returning the response to that request. The controller can perform one or more actions.

# Creating a controller

A controller file can be created manually or automatically using xjs-cli make:controller command.

Xpresser has 3 types of controllers.

• A Class file controller
• An Object file controller
• An Object with custom services controller

Don't get overwhelmed, they all serve the same purpose with just a little preference difference, For a start we will be using a the class based controllers in our documentation.

# Class file controller

Filename: PostsController.js

const {ControllerClass} = require('xpresser');

class PostController extends ControllerClass {
    all() { /** take action here **/ }
    static create() { /** same as above but static **/}
}

module.exports = PostController;
 
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The above is an example of a class file controller.

The class file controller MUST extend xpresser's base controller (ControllerClass), this extension lets xpresser know that you are using a class and not an object. this is because javascript has no official way of checking if a variable is a class.

The PostController contains a static method and a non-static method, both works exactly the same way. Usage depends on your preference.

# Handling Requests.

In the method of your controller class is where you are likely to spend most of your time because it is where the action for a routed request is taken place.

You can route to a controller action like so:

$.router.get('/posts/all', 'PostsController@all');
 
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Now, when a request matches the specified route URI, the all method on the PostsController class will be executed.

We can send a basic response like so

const {ControllerClass} = require('xpresser');

class PostController extends ControllerClass {

    all(http) {
        http.send("List of all posts.");
        // Or like in express
        http.res.send("List of all posts.")
    }

}
 
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The http variable includes express req and res variables with more functions/helpers

# --- To be continued ---