What is a very simple authentication scheme for Sinatra/Rack

Question

I am busy porting a very small web app from ASP.NET MVC 2 to Ruby/Sinatra.

In the MVC app, FormsAuthentication.SetAuthCookie was being used to set a persistent cookie when the users login was validated correctly against the database.

I was wondering what the equivalent of Forms Authentication would be in Sinatra? All the authentication frameworks seem very bulky and not really what I'm looking for.

Answer 1

Here is a very simple authentication scheme for Sinatra.

I’ll explain how it works below.

class App < Sinatra::Base   set :sessions => true    register do     def auth (type)       condition do         redirect "/login" unless send("is_#{type}?")       end     end   end    helpers do     def is_user?       @user != nil     end   end    before do     @user = User.get(session[:user_id])   end    get "/" do     "Hello, anonymous."   end    get "/protected", :auth => :user do     "Hello, #{@user.name}."   end    post "/login" do     session[:user_id] = User.authenticate(params).id   end    get "/logout" do     session[:user_id] = nil   end end 

For any route you want to protect, add the :auth => :user condition to it, as in the /protected example above. That will call the auth method, which adds a condition to the route via condition.

The condition calls the is_user? method, which has been defined as a helper. The method should return true or false depending on whether the session contains a valid account id. (Calling helpers dynamically like this makes it simple to add other types of users with different privileges.)

Finally, the before handler sets up a @user instance variable for every request for things like displaying the user’s name at the top of each page. You can also use the is_user? helper in your views to determine if the user is logged in.

Answer 2

Todd's answer does not work for me, and I found an even simpler solution for one-off dead simple authentication in Sinatra's FAQ:

require 'rubygems' require 'sinatra'  use Rack::Auth::Basic, "Restricted Area" do |username, password|     [username, password] == ['admin', 'admin']   end  get '/' do     "You're welcome" end 

I thought I would share it just in case anyone wandered this question and needed a non-persistent solution.