app.rb

require 'rubygems'
require 'sinatra'
require 'tumblr_client'
require 'omniauth'
require 'omniauth-tumblr'

class SinatraApp < Sinatra::Base

  configure do
    set :sessions, true
    set :inline_templates, true
  end

  use OmniAuth::Builder do
    provider :tumblr, ENV['TUMBLR_CONSUMER_KEY'], ENV['TUMBLR_CONSUMER_SECRET']
  end

  get '/' do
    if session[:authenticated]
      erb :index
    else
      erb :signin
    end
  end
	  
  get '/auth/:provider/callback' do
    session[:authenticated] = true  
    auth = request.env["omniauth.auth"]
    session[:user_id] = auth["uid"]
    session[:access_token] = auth['credentials']['token']
    session[:access_token_secret] = auth['credentials']['secret']
	  
    Tumblr.configure do |config|
      config.consumer_key = ENV['TUMBLR_CONSUMER_KEY']
      config.consumer_secret = ENV['TUMBLR_CONSUMER_SECRET']
      config.oauth_token = session[:access_token]
      config.oauth_token_secret = session[:access_token_secret]
    end
    
    @@client = Tumblr::Client.new 
    
    redirect '/'
  end

  post '/' do
    title = params[:title]
    body = params[:body]
    name = @@client.info['user']['name']
    @@client.text("#{name}.tumblr.com",{:title => title, :body => body})
    redirect '/'
  end

end

SinatraApp.run! if __FILE__ == $0