example oauth2

example_app.rb

# encoding: utf-8

require 'rubygems'
require 'bundler/setup'

require 'oauth2'
require 'sinatra'
require 'faraday'

OAuth2::Response.register_parser(:text, 'text/plain') do |body|
  key, value = body.split('=')
  {key => value}
end

class ExampleApp < Sinatra::Base
  SITE = 'https://graph.facebook.com'
  TOKEN_URI = '/oauth/access_token'
  KEY = ENV['FACEBOOK_KEY']
  SECRET = ENV['FACEBOOK_SECRET']

  set :port, 3000

  configure do
  	use Rack::Session::Cookie
  end

  get '/' do
    callback_url='http://example.com:3000/oauth/callback'

    client = OAuth2::Client.new(KEY, SECRET, site: SITE, token_url: TOKEN_URI)
    url = client.auth_code.authorize_url(redirect_uri: callback_url)
    redirect url
  end

  get '/oauth/callback' do
    client = OAuth2::Client.new(KEY, SECRET, site: SITE, token_url: TOKEN_URI)
    access_token = client.auth_code.get_token(params[:code], {redirect_uri: request.url})

    session[:access_token] = access_token.token

    redirect '/me'
  end

  get '/me' do
    conn = Faraday::Connection.new(:url => 'https://graph.facebook.com') do |builder|
      builder.use Faraday::Request::UrlEncoded  # リクエストパラメータを URL エンコードする
      builder.use Faraday::Response::Logger     # リクエストを標準出力に出力する
      builder.use Faraday::Adapter::NetHttp     # Net/HTTP をアダプターに使う
    end

    response = conn.get "/me?access_token=#{session[:access_token]}"
    response.body
  end
end

ExampleApp.run! if __FILE__ == $0