node.js reverse proxy at end of express. to make post commands work must remove bodyparser and mothod override. use body parser as middleware of app.get command.

gistfile1.txt

// this is not a main file the main  file is opchart.js
var express = require('express')
//  , routes = require('./routes')
//  , user = require('./routes/user')
  , path = require('path');
  
sessionStore=false //defined on first time it could be catched from a request

app = express();//global  

// User validation
var auth = express.basicAuth(function(user, pass) {
 return (user=="test"&&pass=="test") ? true : false;
},'Secret Area');

var httpProxy = require('http-proxy');
var proxy = new httpProxy.RoutingProxy({
                 enable : {
                     xforward: true // enables X-Forwarded-For
                 }
               });

 // the idea behind user id , that it is like session id ... 
 // it is usualy if you like to interact between connected users you would share all the session ids of all users to all users in the room
 // when you expose session id someone can use it on other side which is a security risk
 // so it is another temporary id but without a security risk
  
  function session_adduserid(req,res,next){
     if(!req.session.userid)
     {
      req.session.userid=require('express/node_modules/connect/lib/utils').uid(24);// expose user's session it is unsecure lets have another id
      userid_to_sessionid[req.session.userid]=req.sessionID;
     }
     if(!sessionStore)sessionStore=req.sessions;
     req.session.lasttouch=new Date().getTime();
     next();
  }
  
  function session_userid_manager()
  {
   var ks=Object.keys(userid_to_sessionid),userid,sessionID,session;
   var expire_at=new Date();
   //   console.log(expire_at.getTime())
   expire_at.setMinutes(expire_at.getMinutes()-30);
   expire_at=expire_at.getTime();
   for(i =0;i<ks.length;i++)
   {
    userid=ks[i];
    sessionID=userid_to_sessionid[userid];
    session=sessionStore[sessionID];
    if(!session) delete userid_to_sessionid[userid];
    else if(session.lasttouch<expire_at)
    {
      //console.log('delete expired sessionID '+sessionID);
      delete sessionStore[sessionID];
      delete userid_to_sessionid[userid];
    }
   }
   //console.log('sessions ',sessionStore);
  }
  
userid_to_sessionid={};//global 


//var sesame=require('sesame');
  
//app.configure(function(){
  app.disable('x-powered-by');
  app.set('port', process.env.PORT || 80);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.favicon());
  //app.use(express.logger('dev'));
  app.use(express.cookieParser());
  //var sessionStore=new express.session.MemoryStore();//http://nodetoolbox.com/packages/mysql-session-store
  app.use(require('sesame')({ /*store: sessionStore ,*/ secret: 'secret' , key: 'express.sid',  /*maxAge :24*3600000 //1 Hour * 24*/  }));
  
  app.use(session_adduserid);
  
  setInterval(session_userid_manager,1*60*1000);// once a minute clear old userids
  
/*
  app.all('/', function (req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "X-Requested-With, Content-Type, Origin, X-File-Name, Content-Type, Cache-Control");
    res.header('Access-Control-Allow-Methods', 'PUT, GET, POST, DELETE, OPTIONS');
    next();
  });
*/
  bodyParser=express.bodyParser()
  //app.use(bodyParser);
  //app.use(require('connect-restreamer')());
  //app.use(express.methodOverride());
  app.use(app.router);

  app.use(express.static(path.join(__dirname, 'public')));
//});

app.use(function(req, res) {  // reverse proxyhere
    proxy.proxyRequest(req, res, {
        host: '127.0.0.1',
        port: 8000
    });
 });
//app.configure('development', function(){
  app.use(express.errorHandler());
//});

var gif_1x1_buffer = new Buffer("R0lGODlhAQABAIAAAAAAAAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==", encoding='base64');// Store imageData buffer 1x1 pixel transparent gif file
app.get('/keepsession.gif', function(req,res){  

  res.writeHead(200,
  {
   'Cache-Control': 'no-cache, private, no-store, must-revalidate, max-stale=0, post-check=0, pre-check=0',
   'Pragma': 'no-cache',
   'Expires':"Tue, 01 Jan 2000 12:12:12 GMT",
   'Content-Type': 'image/gif'
  });

	res.write(gif_1x1_buffer.toString('binary'), 'binary');
	res.end();
  if(!req.session)console.log("session is undefined")
  else  req.session.lasttouch=new Date().getTime()    
});


// view session (for development)
app.get('/s', function(req,res){
  //console.log(req);
  res.writeHead(200, 
  {
   'Cache-Control': 'no-cache',
   'Pragma': 'no-cache',
   'Content-Type': 'text/html',
   'Expires':"Tue, 01 Jan 2000 12:12:12 GMT"
  });
  res.end("sessionid="+req.sessionID+' session='+JSON.stringify(req.session));
});

//app.get('/', routes.index);
//app.get('/users', user.list);

//module.exports=app;

So what you did is remove bodyParser? that's not a good solution.