Another example Rack application to demonstrate authenticating with the Campaign Monitor API using OAuth. This example only uses the sinatra and createsend gems.

config.ru

# 1. Set CREATESEND_CLIENT_ID, CREATESEND_CLIENT_SECRET, 
#    and CREATESEND_REDIRECT_URI environment variables for
#    your registered OAuth application.
# 2. `bundle install`
# 3. `rackup`

require 'bundler/setup'
require 'sinatra/base'
require 'createsend'

class App < Sinatra::Base
  get '/' do
    redirect CreateSend::CreateSend.authorize_url(
      ENV['CREATESEND_CLIENT_ID'], ENV['CREATESEND_REDIRECT_URI'],
      'ViewReports,CreateCampaigns,SendCampaigns')
  end

  get '/exchange_token' do
    code = params['code']
    access_token, expires_in, refresh_token =
      CreateSend::CreateSend.exchange_token ENV['CREATESEND_CLIENT_ID'],
      ENV['CREATESEND_CLIENT_SECRET'], ENV['CREATESEND_REDIRECT_URI'], code

    response = "<pre>"
    response << "Your user is successfully authenticated. Here are the details you need:<br/><br/>"
    response << "access token: #{access_token}<br/>"
    response << "refresh token: #{refresh_token}<br/>"
    response << "expires in: #{expires_in}<br/>"
    response << "<br/><br/>"

    auth = {
      :access_token => access_token,
      :refresh_token => refresh_token
    }
    cs = CreateSend::CreateSend.new auth
    clients = cs.clients

    response << "We've made an API call too. Here are your clients:<br/><br/>"
    response << MultiJson.encode(clients)
    response << "</pre>"
    response
  end
end

run App.new

Gemfile

source :rubygems
 
gem 'sinatra'
gem 'createsend'

Procfile

web: bundle exec rackup config.ru -p $PORT