class Rackup::Handler::WEBrick

def service(req, res)
  res.rack = true
  env = req.meta_vars
  env.delete_if { |k, v| v.nil? }
  rack_input = StringIO.new(req.body.to_s)
  rack_input.set_encoding(Encoding::BINARY)
  env.update(
    RACK_INPUT        => rack_input,
    RACK_ERRORS       => $stderr,
    RACK_URL_SCHEME   => ["yes", "on", "1"].include?(env[HTTPS]) ? "https" : "http",
    RACK_IS_HIJACK    => true,
  )
  env[QUERY_STRING] ||= ""
  unless env[PATH_INFO] == ""
    path, n = req.request_uri.path, env[SCRIPT_NAME].length
    env[PATH_INFO] = path[n, path.length - n]
  end
  env[REQUEST_PATH] ||= [env[SCRIPT_NAME], env[PATH_INFO]].join
  status, headers, body = @app.call(env)
  begin
    res.status = status
    if value = headers[RACK_HIJACK]
      io_lambda = value
    elsif !body.respond_to?(:to_path) && !body.respond_to?(:each)
      io_lambda = body
    end
    if value = headers.delete('set-cookie')
      res.cookies.concat(Array(value))
    end
    headers.each { |key, value|
      # Skip keys starting with rack., per Rack SPEC
      next if key.start_with?('rack.')
      # Since WEBrick won't accept repeated headers,
      # merge the values per RFC 1945 section 4.2.
      value = value.join(", ") if Array === value
      res[key] = value
    }
    if io_lambda
      rd, wr = IO.pipe
      res.body = rd
      res.chunked = true
      io_lambda.call wr
    elsif body.respond_to?(:to_path)
      res.body = ::File.open(body.to_path, 'rb')
    else
      body.each { |part|
        res.body << part
      }
    end
  ensure
    body.close if body.respond_to? :close
  end
end