Initial commit

.gitignore

+# See https://help.github.com/articles/ignoring-files for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile '~/.gitignore_global'
+
+# Ignore bundler config.
+/.bundle
+
+# Ignore all logfiles and tempfiles.
+/tmp/*
+!/tmp/.keep
+
+# Ignore config file
+/config.yml

.ruby-gemset

+twitter-profile-pic-uploader

.ruby-version

+ruby-2.3.1

Gemfile

+source 'https://rubygems.org'
+
+gem 'sinatra'
+gem 'sinatra-contrib'
+gem 'haml'
+gem 'twitter'
+gem 'omniauth-twitter'

Gemfile.lock

+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.4.0)
+    backports (3.6.8)
+    buftok (0.2.0)
+    domain_name (0.5.20161021)
+      unf (>= 0.0.5, < 1.0.0)
+    equalizer (0.0.10)
+    faraday (0.9.2)
+      multipart-post (>= 1.2, < 3)
+    haml (4.0.7)
+      tilt
+    hashie (3.4.6)
+    http (1.0.4)
+      addressable (~> 2.3)
+      http-cookie (~> 1.0)
+      http-form_data (~> 1.0.1)
+      http_parser.rb (~> 0.6.0)
+    http-cookie (1.0.3)
+      domain_name (~> 0.5)
+    http-form_data (1.0.1)
+    http_parser.rb (0.6.0)
+    json (1.8.3)
+    memoizable (0.4.2)
+      thread_safe (~> 0.3, >= 0.3.1)
+    multi_json (1.12.1)
+    multipart-post (2.0.0)
+    naught (1.1.0)
+    oauth (0.5.1)
+    omniauth (1.3.1)
+      hashie (>= 1.2, < 4)
+      rack (>= 1.0, < 3)
+    omniauth-oauth (1.1.0)
+      oauth
+      omniauth (~> 1.0)
+    omniauth-twitter (1.2.1)
+      json (~> 1.3)
+      omniauth-oauth (~> 1.1)
+    rack (1.6.4)
+    rack-protection (1.5.3)
+      rack
+    rack-test (0.6.3)
+      rack (>= 1.0)
+    simple_oauth (0.3.1)
+    sinatra (1.4.7)
+      rack (~> 1.5)
+      rack-protection (~> 1.4)
+      tilt (>= 1.3, < 3)
+    sinatra-contrib (1.4.7)
+      backports (>= 2.0)
+      multi_json
+      rack-protection
+      rack-test
+      sinatra (~> 1.4.0)
+      tilt (>= 1.3, < 3)
+    thread_safe (0.3.5)
+    tilt (2.0.5)
+    twitter (5.16.0)
+      addressable (~> 2.3)
+      buftok (~> 0.2.0)
+      equalizer (= 0.0.10)
+      faraday (~> 0.9.0)
+      http (~> 1.0)
+      http_parser.rb (~> 0.6.0)
+      json (~> 1.8)
+      memoizable (~> 0.4.0)
+      naught (~> 1.0)
+      simple_oauth (~> 0.3.0)
+    unf (0.1.4)
+      unf_ext
+    unf_ext (0.0.7.2)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  haml
+  omniauth-twitter
+  sinatra
+  sinatra-contrib
+  twitter
+
+BUNDLED WITH
+   1.13.6

app.rb

+# frozen_string_literal: true
+require 'sinatra'
+require 'sinatra/namespace'
+require 'omniauth-twitter'
+require 'haml'
+require 'yaml'
+
+APP_CONFIG = YAML.load_file(File.expand_path('../config.yml', __FILE__))
+
+configure do
+  enable :sessions
+
+  use OmniAuth::Builder do
+    provider :twitter,
+             APP_CONFIG['twitter']['consumer_key'],
+             APP_CONFIG['twitter']['consumer_secret']
+  end
+end
+
+helpers do
+  def current_user
+    !session[:uid].nil?
+  end
+end
+
+before do
+  pass if request.path_info =~ %r{\A/auth/}
+  #redirect to('/auth/twitter') unless current_user
+end
+
+namespace '/auth' do
+  get '/:provider/callback' do
+    halt 403 unless params[:provider] == 'twitter'
+    session[:uid] = env['omniauth.auth']['uid']
+    # TODO: also store tokens
+    redirect to('/')
+  end
+
+  get '/failure' do
+    'FEHLER ' * 25
+  end
+end
+
+get '/' do
+  if current_user
+    'You are signed in!'
+  else
+    'Hey there, you might want to <a href="/auth/twitter">sign in</a>'
+  end
+end

config.yml.example

+---
+twitter:
+  consumer_key: ''
+  consumer_secret: ''