Create Login in Ruby on Rails

Want a simple login for your rails app? I'll cover that in this tutorial.

We will require the user to login in order to gain access to certain pages. Take note that this is a simple login, user roles and authentication won't be covered in this post.

First, we will create simple pages to demonstrate the website requiring the user to log in.

Create Pages

I'll create two pages, admin and home.

Create the views, admin.html.erb and home.html.erb at app/views/pages/.

    // app/views/pages/admin.html.erb

   <h1>Admin Home</h1>
   <p>app/views/pages/admin.html.erb</p>

    // app/views/pages/home.html.erb

   <h1>Home</h1>
   <p>app/views/pages/home.html.erb</p>

Now create the controller for these pages at app/controllers/.

  # app/controllers/pages_controller.rb

  class PagesController < ApplicationController
    def home
    end

    def admin
    end
  end

Finally, create routes for these pages.

  # config/routes.rb

  get "/admin" => "pages#admin", as: "admin"

  root "pages#home"

The pages should work by checking your localhost. The page for localhost:3000 should be app/views/pages/home.html.erb and localhost:3000/admin is app/views/pages/admin.html.erb.

Create Login

Now the pages were done, we will start implementing a login system. I'll be using devise gem. It has all of the things we need for a simple login.

1. Install devise gem by adding this to your Gemfile:
   

   gem 'devise'
   

   Then run bundle install.

2. Generate necessary files for devise running this in your terminal:
   

   $ rails generate devise:install
   

   If you're using rails 7 you may encounter an error. You may need to paste this code in your config/initializers/devise.rb:
   
   
   config.navigational_formats = ['*/*', :html, :turbo_stream]
   
   
   source

3. Create the migration files we would be using.
   

   $ rails generate devise MODEL
   

   Replace MODEL with the class name used for the application’s users (I mostly use User but could also be Admin).

   Then run rails db:migrate.

4. Require the user to log in when visiting the admin page.

   You could do this by updating app/controllers/pages.
   

   class PagesController < ApplicationController
    before_action :authenticate_user!, only: :admin
   
    def home
    end
   
    def admin
    end
   end
   

   The before_action :authenticate_user! will check if the user is logged in. Depending on the model you might need to change to authenticate_MODEL!, example, if you chose to name your devise model Admin then it should be authenticate_admin!.

   By adding only: :admin the action is only performed at admin action(app/views/pages/admin.html.erb).

That should do it! Restart your server and check it out!

Add links (Optional)

In here, I'll add a sign in and sign out links for the website.

1. Create file _user_detail.html.erb atapp/views/shared/.
   

   // app/views/shared/_user_detail.html.erb
   <% if user_signed_in? %>
    <%= button_to("Log Out", destroy_user_session_path, method: :delete) %>
   <% else %>
    <%= link_to 'Log in', new_user_session_path %>
   <% end %>
   

   If you're using rails 7 logout button may not work properly you need to use this:
   <%= button_to("Log Out", LOGOUT_PATH, method: :delete) %>
   source

   The paths here are the login in and sign out. You could check yours by running rails routes.

   The user_signed_in? is a helper in devise. It returns true or false depending on if the user is logged in. This might changed depending on the chosen name for the devise model. If you chose Admin then it should be admin_signed_in?.

2. Add links to app/views/pages/home.html.erb and app/views/pages/admin.html.erb.
   

   <%= render "shared/user_detail"%>
   

References:

• https://stackoverflow.com/questions/36646226/undefined-method-user-url-for-devise-sessionscontrollercreate
• https://dev.to/spaquet/rails-7-devise-log-out-d1n
• https://github.com/heartcombo/devise

You could check out my repository here.

Please do not repost