The nodejs version of stunnel

stunnel.js

var net=require("net");
var tls = require("tls");

/* listen address and port */
var listen_host = "0.0.0.0";
var listen_port = 8080;

/* the upstream https servers */
var servers = [
    {host: "a.example.com",port:18080},
    {host: "b.example.com",port:18088},
    {host: "c.example.com",port:18080},
    {host: "d.example.com",port:18088}
];

var index = 0;

var server = net.createServer(function(c){
    console.log("client connected from %s:%d", c.remoteAddress, c.remotePort);

    var p = tls.connect(servers[index % 4], function(){
        console.log("connect to %s:%d success", p.remoteAddress, p.remotePort);
        c.pipe(p);
        p.pipe(c);
    });

    index++;

    p.on("error", function(e){
        console.log(e);
        c.write("HTTP/1.1 503 service unaviable\r\n\r\n");
        c.end();
    });
});

server.listen(listen_port, listen_host, function(){
    addr = server.address();
    console.log("listening on %s:%d", addr.address, addr.port);
});