HTTP Server in 5 Lines With Webrick

Usually when I am prototyping a web UI - either in Javascript or Flex, I would just write a static html, because that's the simplest thing that works. But, once in a while, it doesn't work because of the security restrictions that the browser imposes on local files. Maybe you want to use ajax calls(which is sometimes problematic on IE), trying to use the google maps api, or the FABridge, whatever the reason may be. Well, you can get around this problem easily using this ruby script:

require 'webrick'
server = WEBrick::HTTPServer.new :Port => 1234
server.mount "/", WEBrick::HTTPServlet::FileHandler, './'
trap('INT') { server.stop }
server.start

This runs a web server at http://localhost:1234/ which mounts the top level directory to your current directory.

Update: Oops, it's not exactly that easy after all. In order to prevent caching - which you will want to do if you are doing development - you will want to write an extra class. The modified script:

require 'webrick'
class NonCachingFileHandler < WEBrick::HTTPServlet::FileHandler
  def prevent_caching(res)
    res['ETag']          = nil
    res['Last-Modified'] = Time.now + 100**4
    res['Cache-Control'] = 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0'
    res['Pragma']        = 'no-cache'
    res['Expires']       = Time.now - 100**4
  end
  
  def do_GET(req, res)
    super
    prevent_caching(res)
  end

end

server = WEBrick::HTTPServer.new :Port => 1234
server.mount "/", NonCachingFileHandler , './'
trap('INT') { server.stop }
server.start

Not 5 lines anymore, bummer! The code for NonCachingFileHandler was stolen  from unittest_js.