Ajax reading response from server as it gets sent

Question

I'm trying to do some long polling and I'm having a hard time figuring out how I can read data from the server as it gets sent.

I have the following on the client:

var xhr = $.ajax('/getData');

setInterval(function(){
    console.log(xhr.responseText);
}, 1000); // reads response each 1s

The server

app.get('/getData', function(req, res){
  setInterval(function(){
    res.write('hi-' + Math.random()); // write random stuff each 1s
  }, 1000);
});

But xhr.responseText only gets populated when the request finishes.

Is this even possible to do? I have to make a new request for /getData every time I need something? I can't take advantages of the same request?

Answer 1

Please read about onreadystatechange

http://www.w3schools.com/ajax/ajax_xmlhttprequest_onreadystatechange.asp https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest

$.ajax({
// ...
beforeSend: function (request, settings) {
    $(request).bind("readystatechange", function (e) { alert("changed " + e.target.readyState); });
}});

Answer 2

You need to poll server multiple times or use a socket connection like socket.io . I reccomend reading this article .