how to use jQuery ajax calls with node.js
Question
This is similar to Stream data with Node.js , but I don't feel that question was answered sufficiently.
I'm trying to use a jQuery ajax call (get, load, getJSON) to transfer data between a page and a node.js server. I can hit the address from my browser and see 'Hello World!", but when I try this from my page, it fails and shows that I get no response back. I setup a simple test page and hello world example to test this:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>get test</title>
</head>
<body>
<h1>Get Test</h1>
<div id="test"></div>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.js"></script>
<script>
$(document).ready(function() {
//alert($('h1').length);
$('#test').load('http://192.168.1.103:8124/');
//$.get('http://192.168.1.103:8124/', function(data) {
// alert(data);
//});
});
</script>
</body>
</html>
and
var http = require('http');
http.createServer(function (req, res) {
console.log('request received');
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(8124);
4 answers
solution1
86 ACCPTED 2011-03-21 10:05:52
If your simple test page is located on other protocol/domain/port than your hello world node.js example you are doing cross-domain requests and violating same origin policy therefore your jQuery ajax calls (get and load) are failing silently. To get this working cross-domain you should use JSONP based format. For example node.js code:
var http = require('http');
http.createServer(function (req, res) {
console.log('request received');
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('_testcb(\'{"message": "Hello world!"}\')');
}).listen(8124);
and client side JavaScript/jQuery:
$(document).ready(function() {
$.ajax({
url: 'http://192.168.1.103:8124/',
dataType: "jsonp",
jsonpCallback: "_testcb",
cache: false,
timeout: 5000,
success: function(data) {
$("#test").append(data);
},
error: function(jqXHR, textStatus, errorThrown) {
alert('error ' + textStatus + " " + errorThrown);
}
});
});
There are also other ways how to get this working, for example by setting up reverse proxy or build your web application entirely with framework like express .
solution2
8 2011-03-30 12:28:46
Thanks to yojimbo for his answer. To add to his sample, I wanted to use the jquery method $.getJSON which puts a random callback in the query string so I also wanted to parse that out in the Node.js. I also wanted to pass an object back and use the stringify function.
This is my Client Side code.
$.getJSON("http://localhost:8124/dummy?action=dostuff&callback=?",
function(data){
alert(data);
},
function(jqXHR, textStatus, errorThrown) {
alert('error ' + textStatus + " " + errorThrown);
});
This is my Server side Node.js
var http = require('http');
var querystring = require('querystring');
var url = require('url');
http.createServer(function (req, res) {
//grab the callback from the query string
var pquery = querystring.parse(url.parse(req.url).query);
var callback = (pquery.callback ? pquery.callback : '');
//we probably want to send an object back in response to the request
var returnObject = {message: "Hello World!"};
var returnObjectString = JSON.stringify(returnObject);
//push back the response including the callback shenanigans
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end(callback + '(\'' + returnObjectString + '\')');
}).listen(8124);
solution3
3 2011-03-21 06:36:34
I suppose your html page is hosted on a different port. Same origin policy requires in most browsers that the loaded file be on the same port than the loading file.
solution4
1
Use something like the following on the server side:
http.createServer(function (request, response) {
if (request.headers['x-requested-with'] == 'XMLHttpRequest') {
// handle async request
var u = url.parse(request.url, true); //not needed
response.writeHead(200, {'content-type':'text/json'})
response.end(JSON.stringify(some_array.slice(1, 10))) //send elements 1 to 10
} else {
// handle sync request (by server index.html)
if (request.url == '/') {
response.writeHead(200, {'content-type': 'text/html'})
util.pump(fs.createReadStream('index.html'), response)
}
else
{
// 404 error
}
}
}).listen(31337)
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