Devise in rails

Devise is one of two popular rails user auth gems.

We will be implementing user auth with this library.

We will follow instuctions from the devise website: https://github.com/plataformatec/devise

Clone the base app

The base app is a one model rails app. You can insert and see each record. It has an index page.

https://github.com/wdi-sg/user-songs

git clone https://github.com/wdi-sg/user-songs.git
cd user-songs

Install the app and run it to see that it works. Create and view some songs.

bundle install
rails db:create
rails db:migrate
rails s

Install Devise

Add the gem devise to the Gemfile

gem 'devise'

Install it

bundle install

Run the gem's script files so it can generate the default files in the rails app

rails generate devise:install

Create the devise user model:

rails generate devise user

Link User to a new foreign key column in songs:

rails g migration AddUserToSongs user:references

( if you give a migration name of the form AddXXXToYYY it will create the change line in the migration file automatically for you )

rails db:migrate

Devise might ask you to copy the secret devise key into the initializer file: config/initializers/devise.rb

Set up authorization:

Add a before action filter to the controller:

before_action :authenticate_user!, :except => [ :show, :index ]

Restrict the new link in the songs index with the devise helper

<% if user_signed_in? %>
<%= link_to 'New Song', new_song_path %>
<% end %>

Other devise helpers:

current_user

Make a breakpoint (byebug) in the index song controller method.

Inside the console see the value of current_user

current_user.id

user_session

See the current value of user_session

user_session

Set something in the user session

user_session["song_cart"] = "Single Ladies"

Use c to continue out of the breakpoint.

Make another request.

See the value of user_session has been retained.

Adding user associations

Change both model files

app/models/song.rb

belongs_to :user

app/models/user.rb

has_many :song

Assign the logged in user as the song creator in app/controllers/songs_controller.rb

def create
  @song = Song.new(song_params)

  @song.user = current_user

  if @song.save
    redirect_to @song
  else
    render 'new'
  end
end

Logout Link

<%= link_to 'log out', destroy_user_session_url, method: :delete %>

Login Link

<%= link_to 'log in', new_user_session_url %>