CORS for Sinatra

app.rb

before do
  headers['Access-Control-Allow-Methods'] = 'GET, POST, PUT, DELETE, OPTIONS'
  headers['Access-Control-Allow-Origin'] = '*'
  headers['Access-Control-Allow-Headers'] = 'accept, authorization, origin'
end

options '*' do
  response.headers['Allow'] = 'HEAD,GET,PUT,DELETE,OPTIONS,POST'
  response.headers['Access-Control-Allow-Headers'] = 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Cache-Control, Accept'
end