Question

I have written a http server using node js

var sys = require("sys"),
    http = require("http"),
    url = require("url"),
    path = require("path"),
    fs = require("fs");



http.createServer(function(request, res) {

    var parsed_url = url.parse(request.url);
    var uri = parsed_url.pathname;
   if(uri === "/test"){

  res.writeHead(200, {'Content-Type': 'text/javascript'});

      request.addListener('data', function (chunk) {
          var data = eval("(" + chunk + ")");
          console.log(data[0].id);
      })
      request.addListener('end', function() {
          console.log('end triggered');
          res.write("Post data");
          res.end();
      }); 
   }
}).listen(8080);

and i am trying to send back response of ajax request but i am unable to receive any response. Here is the code for ajax request ,

    var myhttp = new XMLHttpRequest();
    var url = "http://localhost:8080/test";

    var data = [{"a":"1"},{"b":"2"},{"c":"3"}];

    var dataJson = JSON.stringify(data);
    myhttp.open('POST', url, true);
    myhttp.send(dataJson);
    myhttp.onreadystatechange = function() {        
        if ((myhttp.readyState == 4) && (myhttp.status == 200)){
            alert(myhttp.responseText);
        }
        else if ((myhttp.readyState == 4) && (myhttp.status != 200))
        {
            console.log("Error in Connection");
        }

Can anyone help me what i am doing wrong …

Thanks
Vinay

Answer 1

You have to read the data in a different way. Posted data arrives on a node server in chunks (the ‘data’ event), that have to be collected until the ‘end’ event fires. Inside this event, you are able to access your payload.

var body = '';

request.addListener('data', function (chunk) {
  body += chunk;
});

request.addListener('end', function() {
  console.log(body);
  res.write('post data: ' + body);
});

Additionaly, there seem to be some issues with your client-side code (especially concerning the status-code checks), but i can’t really help you with those as i always work with frameworks like jQuery to manage async requests.

If you want to build reliable node.js servers for web use, i highly recommend the high-performance HTTP-Framework Express. It takes away alot of the pain when developing a web-based server application in node and is maintained actively.