class Rack::Recursive

def _call(env)
  @script_name = env[SCRIPT_NAME]
  @app.call(env.merge(RACK_RECURSIVE_INCLUDE => method(:include)))
rescue ForwardRequest => req
  call(env.merge(req.env))
end

def call(env)
  dup._call(env)
end

def include(env, path)
  unless path.index(@script_name) == 0 && (path[@script_name.size] == ?/ ||
                                           path[@script_name.size].nil?)
    raise ArgumentError, "can only include below #{@script_name}, not #{path}"
  end
  env = env.merge(PATH_INFO => path,
                  SCRIPT_NAME => @script_name,
                  REQUEST_METHOD => GET,
                  "CONTENT_LENGTH" => "0", "CONTENT_TYPE" => "",
                  RACK_INPUT => StringIO.new(""))
  @app.call(env)
end

def initialize(app)
  @app = app
end