Sinatra example for Twitter OAuth.

twitter_oauth.rb

require 'rubygems'
require 'sinatra'
require 'oauth'
require 'json'

SERVER_HOST = '0.0.0.0'
SERVER_PORT = '3000'
BASE_URL    = "http://0.0.0.0:3000"

TWITTER_KEY      = ''
TWITTER_SECRET   = ''
TWITTER_CALLBACK = "#{BASE_URL}/auth/twitter/callback"

GITHUB_KEY      = ''
GITHUB_SECRET   = ''
GITHUB_CALLBACK = "#{BASE_URL}/auth/github/callback" 


# Sinatra settings
enable :sessions

set :bind, SERVER_HOST
set :port, SERVER_PORT

set :static, false
set :run, true

get '/' do
  
  erb "<a href='/auth/twitter'>Loggin with Twitter</a><br/>
      <a href='/auth/github'>Loggin with Github</a>"
end

# Twitter

get '/auth/twitter' do
  oauth = OAuth::Consumer.new(
    TWITTER_KEY,
    TWITTER_SECRET,  
    :site => 'http://api.twitter.com',
    :scheme => :header,
    :http_method => :post,
    :request_token_path => "/oauth/request_token",
    :access_token_path => "/oauth/access_token",
    :authorize_path => "/oauth/authorize"
  )
  request_token            = oauth.get_request_token :oauth_callback => TWITTER_CALLBACK
  session[:twitter_token]  = request_token.token
  session[:twitter_secret] = request_token.secret
  redirect request_token.authorize_url
end

get '/auth/twitter/callback' do
  oauth = OAuth::Consumer.new(
    TWITTER_KEY,
    TWITTER_SECRET,  
    :site => 'http://api.twitter.com',
    :scheme => :header,
    :http_method => :post,
    :request_token_path => "/oauth/request_token",
    :access_token_path => "/oauth/access_token",
    :authorize_path => "/oauth/authorize"
  )

  request_token = OAuth::RequestToken.new(oauth, session[:twitter_token], session[:twitter_secret])

  access_token = oauth.get_access_token(request_token, :oauth_verifier => params[:oauth_verifier])

  oauth = OAuth::Consumer.new(TWITTER_KEY, TWITTER_SECRET, { :site => 'http://api.twitter.com'})
  response = oauth.request(:get, '/1.1/account/verify_credentials.json', access_token, { :scheme => :query_string })

  erb "#{JSON.parse(response.body)}"
end

# Github

get '/auth/github' do
  # ...
end

get '/auth/github/callback' do
  # ...
end