From Rails devise auth to backbone & api? - ruby-on-rails-3

Question

i want to rebuild an app which is a typical rails 3.2 mvc app into a API + Frontend (Backbone) only. As I have no experience in building APIs in rails including authenticatin:
What's the best way to authenticate with devise using backbone? Using auth_tokens?
How should I make he API? Just printing out JSON or use a gem like Grape?
thanks in advance!

Answer 1

I can explain you the way i do this :
First, i install a standard rails application with devise. After that, i create my own session controller :
class SessionsController < ApplicationController
def authenticate
# this method logs you in and returns you a single_access_token token for authentication.
#user = User.find_for_authentication(:email => params[:user][:email])
if #user && #user.valid_password?(params[:user][:password])
render :json => {:user => {:email => #user.email, :id => #user.id, :firsname => #user.firstname, :lastname => #user.lastname, :team_id => #user.team_id, :singleAccessToken => #user.generate_access_token}}
else
render :json => {:errors => ["Nom d'utilisateur ou mot de passe invalide"]}, :status => 401
end
end
end
As you can see, i send a request to this url with the json looking like :
{
user => {
email => "myemail#toto.com",
password => "monpass"
}
}
And my controller return me the json with user data if every thing is fine, or an error. On json with user, i return an access_token used on next requests to check that the user is allowed to request. I made this filters in my application controller :
class ApplicationController < ActionController::Base
protect_from_forgery
protected
def user_access_token
request.headers["HTTP_X_USER_ACCESS_TOKEN"] || request.headers["HTTP_USER_ACCESS_TOKEN"]
end
def current_user
if token = user_access_token
#user ||= User.find_by_access_token(token)
end
end
def require_user
unless current_user
render :json => {:error => "Invalid Access Token"}, :status => 401
end
end
def require_owner
unless current_user && current_user == object.user
render :json => {:error => "Unauthorized"}
end
end
end
As you can see, on each next request, i will add the access_token in html header on key : HTTP_USER_ACCESS_TOKEN
So, i can check if the user is allowed to make the request.
To make an API, you can use the Rails API gem as see here :
http://railscasts.com/episodes/348-the-rails-api-gem
Good luck.