NodeJS - long polling/pushing/rejeverse ajax? What do i need to push live data isntantly to the web?

Question 1

Ok, here is a really simple example. A textarea synchronizes with login members.

Please install http, socket.io and express(ver3).

sudo npm install http, socket.io, express

And create a javascript file.

server.js

var app = require('express')(), 
  server = require('http').createServer(app), 
  io = require('socket.io').listen(server),
  member_sockets = {},
  key;

server.listen(80);

app.get('/', function (req, res) {
  res.sendfile(__dirname + '/index.html');
});

io.sockets.on('connection', function (socket) {
  var user_id = socket.id;

  member_sockets[user_id] = socket;
  console.log("[login]-->", user_id);

  socket.on('txt_change', function (data) {
    for (key in member_sockets) {
      if (key != user_id) {
        member_sockets[key].emit("txt_change", data);
      }
    };
  });


  socket.on('disconnect', function (socket) {
    console.log("[logout]-->", user_id);
    delete member_sockets[user_id];
  });
});

In the same directory, you also create an index.html file.

index.html

<!DOCTYPE html>
<html>
  <head>
    <script src="http://code.jquery.com/jquery-1.8.2.min.js"></script>
    <script src="/socket.io/socket.io.js"></script>
    <script>
      var socket = io.connect('http://localhost');
      socket.on('txt_change', function (data) {
        console.log(data);
        $("#txt").val(data.txt);
      });
      $(document).ready(function(){
        $("#txt").keyup(function(){
          socket.emit('txt_change', { "txt" : $(this).val() });
        });
      });
    </script>
  </head>
  <body>
    <textarea id="txt" style="width:200px;height:100px"></textarea>
  </body>
</html>

Then run the server with this command:

sudo node server.js

So the code should work like this picture: enter image description here

Question 2

Did you check socket.io? You can create the push server easily using socket.io module.

http://socket.io/