Example of how to use Omniauth to access the Tumblr API in Sinatra.

sinatra_tumblr_omniauth_example.rb

gem 'sinatra',         '~> 1.4.7'
require 'sinatra'
gem 'omniauth-tumblr', '~> 1.2'
require 'omniauth-tumblr'
gem 'tumblr_client',   '~> 0.8.5'
require 'tumblr_client'
require 'yaml'


# omniauth-tumblr + tumblr_client + sinatra Example
# ------
# 
# 2016-09-30
# 
# This is an example of how to use Omniauth to access Tumblr API V2 via 
# Sinatra. Once you've gone through the process once in Sinatra, you can save 
# the OAuth token and token secret to use elsewhere.
# 
# A guide to doing this without Omniauth is here:
# 
#     https://gist.github.com/Snarp/4cb73066f8c5269199f092a444891a62



# - STEP 1: 
# 
# Register your app with Tumblr at:
# 
#     https://www.tumblr.com/oauth/register
# 
# For your the callback URL, enter:
# 
#     http://localhost:4567/oauth/callback
# 
# When you're done, you'll be given a consumer key and secret to use below.



# - STEP 2:
# 
# Fill in these two variables with your consumer key and secret:
# 
CONSUMER_KEY    = "YOUR CONSUMER KEY GOES HERE"
CONSUMER_SECRET = "YOUR CONSUMER SECRET GOES HERE"



# - STEP 3:
# 
# Fill in a random string of characters here:
# 
configure do
  enable :sessions
  set    :session_secret, "RANDOM STRING GOES HERE"
end

use OmniAuth::Strategies::Tumblr, CONSUMER_KEY, CONSUMER_SECRET



# - STEP 4:
# 
# Run this script.



# - STEP 5:
# 
# In your browser, while logged in to a Tumblr account, go to 
# 
#   http://localhost:4567/
# 
# and give Tumblr permission to connect to this app.
# 
get '/' do
  redirect to "/auth/tumblr"
end

get '/auth/tumblr/callback' do
  if !!env['omniauth.auth']
    session[:authenticated] = true
  else
    halt(401, 'Not Authorized')
  end

  auth                         = request.env['omniauth.auth']
  session[:user_id]            = auth['uid']
  session[:oauth_token]        = auth['credentials']['token']
  session[:oauth_token_secret] = auth['credentials']['secret']
  # ^ Saving credentials to a cookie.

  redirect to "/we_did_it"
end

get '/auth/failure' do
  "#{params[:message]}"
end



# - STEP 6:
# 
# Here, we use the credentials we saved to a cookie above to configure and
# a Tumblr::Client object, which is what we use to actually access the API.
# 
get "/we_did_it" do
  Tumblr.configure do |config|
    config.consumer_key       = CONSUMER_KEY
    config.consumer_secret    = CONSUMER_SECRET
    config.oauth_token        = session[:oauth_token]
    config.oauth_token_secret = session[:oauth_token_secret]
  end

  client = Tumblr::Client.new

  # Some output to be sure that it's working:
  # 
  "<p>A YAML serialization of your client object, including your OAuth info:</p>

  <p><pre>#{YAML::dump(client)}</pre></p>

  <p>If you're not working on a web-based app like this one, save a copy of the information above now - you'll need at least your token and token secret each time you initialize a new client object.</p>

  <p>To make sure the client's working, below is a YAML dump of a hash representing the first post on your dashboard. (You need to be following at least one blog for this to show anything.)</p>

  <p><pre>#{YAML::dump(client.dashboard(limit: 1))}</pre></p>"
end