1. Introduction

In this tutorial, we will be focusing on the actions of a controller and how Rails renders views based on these actions. The goal is to make you understand how to work efficiently with actions and render views in Rails.

By the end of this tutorial, you will learn:
- What actions in a controller are
- How Rails renders views
- How to work with actions and render views

Prerequisites
- Basic understanding of Ruby on Rails
- A local development environment for Ruby on Rails

2. Step-by-Step Guide

Concepts

In Rails, a controller is a Ruby class which inherits from ApplicationController and has methods. These methods are referred to as actions. Each action corresponds to a specific route defined in your routes.rb file.

Rendering views in Rails means creating a full HTTP response to send back to the client. Rails does this by combining the controller action's output with the corresponding view template.

Best practices and tips

• Keep your controllers skinny. They should only be responsible for connecting models with views.
• Use meaningful names for your actions.
• Keep the logic in the controller to a minimum.

3. Code Examples

Here is an example of a controller with an action:

class WelcomeController < ApplicationController
  def index
    @message = "Hello, world!"
  end
end

• WelcomeController is a class that inherits from ApplicationController.
• index is an action. When called, it sets @message to "Hello, world!".

And here is the associated view, index.html.erb:

<h1><%= @message %></h1>

This view simply prints the content of @message.

When you visit the route associated with the index action, Rails will execute the index action and render index.html.erb, displaying "Hello, world!".

4. Summary

You've learned about controller actions and how Rails renders views. You've seen an example of a controller with an action and the associated view.

You can continue learning by exploring other controller actions and how to render different types of responses.

5. Practice Exercises

1. Create a new controller with a show action. Make it display a welcome message.
2. Modify the show action to accept a parameter and include it in the welcome message.
3. Create a new action that renders a different view.

Solutions

class WelcomeController < ApplicationController
  def show
    @message = "Welcome to our site!"
  end
end

In the associated show.html.erb view:

<h1><%= @message %></h1>

class WelcomeController < ApplicationController
  def show
    @name = params[:name]
    @message = "Welcome to our site, #{@name}!"
  end
end

In the associated show.html.erb view:

<h1><%= @message %></h1>

class WelcomeController < ApplicationController
  def another_action
    render :another_view
  end
end

You will need to create another_view.html.erb in the same directory as your other views.

Keep practicing with different actions and views to get a better understanding of how they work together.