Warden integration with Sinatra and DataMapper - http://ruby-ua.blogspot.com/2011/10/warden-sinatra-datamapper.html

sinatra-warden.rb

# -*- encoding: utf-8 -*-

require 'sinatra'
require 'slim'
require 'warden'

require 'dm-core'
require 'dm-migrations'

DataMapper::Logger.new(STDOUT, :debug)
DataMapper.setup(:default, "sqlite:///#{Dir.pwd}/project.db")

# Model and database table to hold administrator's usernames and passwords
#
class User
  include DataMapper::Resource

  property :id,       Serial
  property :username, String, :unique => true
  property :password, String

  # Public class method than returns a user oblect if the caller supplies the correct name and password
  #
  def self.authenticate(username, password)
    user = first(:username => username)
    if user
      if user.password != password
        user = nil
      end
    end
    user
  end

end

# finalize them after declaring all of the models
DataMapper.finalize

# wipes out existing data
DataMapper.auto_upgrade!

# create test user
#User.create(:username => 'user', :password => 'qwerty')

### Rack Setup
#
use Rack::Session::Cookie, :secret => "bla-bla-bla"

use Warden::Manager do |manager|
  manager.default_strategies :password
  manager.failure_app = FailureApp.new
end
###

### Session Setup
# Tell Warden how to serialize the user in and out of the session.
#
Warden::Manager.serialize_into_session do |user|
  puts '[INFO] serialize into session'
  user.id
end

Warden::Manager.serialize_from_session do |id|
  puts '[INFO] serialize from session'
  User.get(id)
end
###

### Declare Some Strategies
#
Warden::Strategies.add(:password) do
  def valid?
    puts '[INFO] password strategy valid?'
    
    params['username'] || params['password']
  end
  
  def authenticate!
    puts '[INFO] password strategy authenticate'

    u = User.authenticate(params['username'], params['password'])
    u.nil? ? fail!('Could not login in') : success!(u)
  end
end
###

class FailureApp
  def call(env)
    uri = env['REQUEST_URI']
    puts "failure #{env['REQUEST_METHOD']} #{uri}"
  end
end

get '/' do
  redirect '/login' unless env['warden'].user
  slim :index
end

get '/login/?' do
  slim :login
end

post '/login/?' do
  if env['warden'].authenticate
    redirect '/'
  else
    redirect '/login'
  end
end

get '/logout/?' do
  env['warden'].logout
  redirect '/'
end

__END__
@@index
p Welcome, #{env['warden'].user.username}
a href='/logout' Log out

@@login
form action='/login' method='post'
  ul
    li#username
      label Username:
      br
      input name='username' type='text'
    li#password
      label Password:
      br
      input name='password' type='text'

  input type='submit' value='Log in'