goliath async upload validation CORS

gistfile1.rb

module Goliath
  class Request
    old_post_process = instance_method(:post_process)

    define_method(:post_process) do |results|
      status, headers, body = *results
      # Include any data here
      # All requests will pass here
      if env['size-error']

        headers['Access-Control-Allow-Origin'] = '*'

        if env[Goliath::Request::REQUEST_METHOD] == 'OPTIONS'
          options_cors_headers = {
            'Access-Control-Allow-Origin' => '*',
            'Access-Control-Expose-Headers' => 'X-Error-Message,X-Error-Detail,X-RateLimit-Requests,X-RateLimit-MaxRequests',
            'Access-Control-Max-Age' => '172800',
            'Access-Control-Allow-Methods' => 'POST, GET, OPTIONS',
            'Access-Control-Allow-Headers' => 'X-Requested-With,Content-Type'
          }

          results = [200, headers.merge(options_cors_headers), '']
        end

      end
      old_post_process.bind(self).call(results)
    end
  end
end

class Upload < Goliath::API
  include Goliath::Validation
  
  def on_headers(env, headers)
    env.logger.info 'received headers: ' + headers.inspect
    env['async-headers'] = headers
  end
  
  def on_body(env, data)
    (env['async-body'] ||= '') << data
    size = env['async-body'].size
    
    if size >= 100000
      env['size-error'] = true
      raise Goliath::Validation::Error.new(422,
          "Please send smaller file. Received size is #{size.inspect}")
    end
    
  end
  
  def response(env)
    [200, {},{}]  
  end
  
end