Devise is now compatible with Rails 4 out of the box as of the time of this answer.
Our end goal is to have users be able to register, log in and log out of the website. We'll also create a small partial view letting us know if we're logged in or out.
Install the Devise gem.
Open up your Gemfile and install the Devise gem.
gem 'devise'
Then in your terminal run the bundle install command to install the gem.
$ bundle install
Run some Devise generators to set up the initial configurations.
Run this command from your terminal:
rails generate devise:install
This generator installs the initializer that configures all of Devise's available settings.
Generate your User model.
Next we need to generate our User model. I'm going to name it User but you can name it whatever you like, just replace User with Whatever.
rails generate devise User
rake db:migrate
Configure your default URL option for Development.rb
Inside of config/environments/development.rb, set the Action Mailer's default URL to localhost:
config.action_mailer.default_url_options = { :host => 'localhost:3000' }
Make sure you have a root route declared in Routes.rb
You need to make sure that routes.rb has a default root route - if you don't have one, set it!
root to: 'home#index'
Create a partial view to see if we're logged in or not.
Inside of your views/layouts folder create a file named _user_widget.html.erb and copy this code in:
<% if user_signed_in? %>
<p>Welcome <%= current_user.email %></p>
<%= link_to 'Logged In [click to logout]', destroy_user_session_path, :method => :delete %>
<% else %>
<p>You are not signed in.</p>
<%= link_to 'Login', new_user_session_path %>
<% end %>
And invoke it within your layout (views/layouts/application.html.erb):
<!DOCTYPE html>
<html>
<head>
<title>FacebookAuthTest</title>
<%= stylesheet_link_tag "application", media: "all" %>
<%= javascript_include_tag "application" %>
<%= csrf_meta_tags %>
</head>
<body>
<p class="notice"><%= notice %></p>
<p class="alert"><%= alert %></p>
<%= yield %>
<%= render 'layouts/user_widget' %>
</body>
</html>
Make sure you stop and restart the server otherwise you will find all sorts of nasty bugs! It's always best to restart your local
server when you update your gemfile or change anything in the
environment configuration file.
With all this in place, you should be able to sign up, log in and log out from your very own Rails website.
If you have any questions feel free to leave a comment below and I'll try to help.