class WebConsole::Injector

def initialize(body, headers)
  @body = "".dup
  body.each { |part| @body << part }
  body.close if body.respond_to?(:close)
  @headers = headers
end

def inject(content)
  # Set Content-Length header to the size of the current body
  # + the extra content. Otherwise the response will be truncated.
  if @headers["Content-Length"]
    @headers["Content-Length"] = (@body.bytesize + content.bytesize).to_s
  end
  [
    if position = @body.rindex("</body>")
      [ @body.insert(position, content) ]
    else
      [ @body << content ]
    end,
    @headers
  ]
end