gistfile1.rb

require 'rack/utils'

class FlashSessionCookieMiddleware
  def initialize(app, session_key = '_session_id')
    @app = app
    @session_key = session_key
  end

  def call(env)
    if env['HTTP_USER_AGENT'] =~ /^(Adobe|Shockwave) Flash/
      params = ::Rack::Utils.parse_query(env['QUERY_STRING'])

      unless params[@session_key].nil?
        env['HTTP_COOKIE'] = "#{@session_key}=#{params[@session_key]}".freeze
      end

      # Here's the goods
      unless params['_http_accept'].nil?
        env['HTTP_ACCEPT'] = "#{params['_http_accept']}".freeze
      end
    end

    @app.call(env)
  end
end