gistfile1.js

var http = require('http');
var sys  = require('sys');

var startsWithSlash = /^\//;

var oldIM = http.IncomingMessage;

http.IncomingMessage = function(){
  this = Object.create(oldIM.prototype);
  oldIM.apply(this, arguments)

  var scriptName = "";

  this.__defineSetter__("scriptName", function(val){
    if(val.length > 0){
      if(!val.match(startsWithSlash))
        throw(new Error("Must start with \"/\""));
    }
    return scriptName = val;
  })

  this.__defineGetter__("scriptName", function(){
    return scriptName;
  })
}