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I want to know if it is possible to stream data from the server to the client with Node.js. I want to post a single AJAX request to Node.js, then leave the connection open and continuously stream data to the client. The client will receive this stream and update the page continuously.
As an update to this answer - I cannot get this to work. The response.write is not sent before you call close. I have set up an example program that I use to achieve this:
Node.js:
var sys = require('sys'), http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/html'}); var currentTime = new Date(); setInterval(function(){ res.write( currentTime.getHours() + ':' + currentTime.getMinutes() + ':' + currentTime.getSeconds() ); },1000); }).listen(8000); HTML:
<html> <head> <title>Testnode</title> </head> <body> <!-- This fields needs to be updated --> Server time: <span id="time"> </span> <!-- import jQuery from google --> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> <!-- import jQuery --> <script type="text/javascript"> $(document).ready(function(){ // I call here node.localhost nginx ports this to port 8000 $('#time').load('http://node.localhost'); }); </script> </body> </html> Using this method I don't get anything back until I call close(). Is this possible or should I go with a long poll approach instead where I call the load function again as one comes in?
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Nodejs is very good to streaming audio and video, but nodejs is a new technology, so it's don't have a lot of softwares yet.
createWriteStream() Method. The createWriteStream() method is an inbuilt application programming interface of fs module which allows to quickly make a writable stream for the purpose of writing data to a file. This method may be a smarter option compared to methods like fs.
Streams are one of the fundamental concepts of Node. js. Streams are a type of data-handling methods and are used to read or write input into output sequentially. Streams are used to handle reading/writing files or exchanging information in an efficient way.
It is possible. Just use response.write() multiple times.
var body = ["hello world", "early morning", "richard stallman", "chunky bacon"]; // send headers response.writeHead(200, { "Content-Type": "text/plain" }); // send data in chunks for (piece in body) { response.write(body[piece], "ascii"); } // close connection response.end(); You may have to close and reopen connection every 30 seconds or so.
EDIT: this is the code I actually tested:
var sys = require('sys'), http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/html'}); var currentTime = new Date(); sys.puts('Starting sending time'); setInterval(function(){ res.write( currentTime.getHours() + ':' + currentTime.getMinutes() + ':' + currentTime.getSeconds() + "\n" ); setTimeout(function() { res.end(); }, 10000); },1000); }).listen(8090, '192.168.175.128'); I connected to it by Telnet and its indeed gives out chunked response. But to use it in AJAX browser has to support XHR.readyState = 3 (partial response). Not all browsers support this, as far as I know. So you better use long polling (or Websockets for Chrome/Firefox).
EDIT2: Also, if you use nginx as reverse proxy to Node, it sometimes wants to gather all chunks and send it to user at once. You need to tweak it.
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