[RUBY] Make a login function with Rails anyway

Let's create a login function anyway

This article is only for creating a login function in a WEB application using Rails. Let's memorize this in the body and be able to make it at explosive speed!

Make an app template

If you don't make this, nothing will start! Execute the following command from the terminal.

% rails _5.2.3_new app name-d mysql

Once you have created the app template with the above command, move to the app directory.

%cd app name

install devise

Open the Gemfile in an editor and add devise. devise is a gem that makes it easy to create the functions required for user authentication. Also, this time I use haml instead of erb, so I also install a gem that converts erb files to haml.

gem 'devise'
gem "haml-rails"

Add devise to Gemfile and install it!

% bundle install

After the installation is complete, convert the erb file to haml.

% rails haml:erb2haml

After completing the above conversion work, create a devise configuration file.

% rails g devise:install

Then, the following configuration file is created. config/initializers/devise.rb config/locales/devise.en.yml

Settings around the database

Then execute the following command to create the user model.

% rails g devise user

The routing file will now also contain devise's routing.

Rails.application.routes.draw do
  devise_for :users
end

The database used by this app has not been created yet, so let's create it.

% rails db:create 

I think that the migration file was created when the model was created, so let's migrate xxxxxxxxxxxxxx_devise_create_users.rb

% rails db:migrate

This completes the settings around the database.

Display the top page

Next, create a view file for the top page. Let's make a lead to login, new registration, and logout here. This time, we will create index.html.haml in app / views / posts assuming that the app allows users to post some posts. After installing devise, you can use a helper method called user_signed_in, so let's separate the display when not logged in and when logged in.

%header
  - if user_signed_in?
    %div
      = link_to "Log out", destroy_user_session_path, method: :delete
  - else
    %div
      = link_to "Login", new_user_session_path
      = link_to "sign up", new_user_registration_path

When the top page is created, add the routing to routes.rb.

Rails.application.routes.draw do
  devise_for :users
  root to: 'posts#index'
end

At the moment, when I try to open the top page, I think that the following error will occur, so I will make a controller.

% rails g controller posts

Now you have a controller! You should be able to open the top page by adding the index action to the created controller.

class PostsController < ApplicationController
  def index
  end
end

It's a dull screen, but if all goes well, it should look like the one below.

Login and new registration

Next, log in and create a new registration screen. Execute the following command to create a view for new registration and login.

% rails g devise:views

.New registration screen app/views/devise/registrations/new.html.erb

·Login screen app/views/devise/sessions/new.html.erb

This time it will be created with haml, so let's execute the following command again to convert erb to haml.

% rails haml:erb2haml

If you can do so far, you should be able to newly register, log in, and log out, so I will try it immediately. ・ Click new registration

・ Enter your email address and password and click "sign up"

・ Go to the top page and log out will be displayed. Click log out.

・ I was able to log out, so click Login.

・ Enter your email address and password and click Login

-Transition to the top page and logout is displayed.

It looks awkward because the style isn't right, but for the time being, the server-side implementation is complete! Please refer to this article and aim for explosive implementation!