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link to article: http://www.html5rocks.com/en/tutorials/eventsource/basics/
The node.js SSE server is not working in that example. I end up with an open connection to /events, but no response is received by the browser.
sse-server.js
var http = require('http');
var sys = require('sys');
var fs = require('fs');
http.createServer(function(req, res) {
//debugHeaders(req);
if (req.headers.accept && req.headers.accept == 'text/event-stream') {
if (req.url == '/events') {
sendSSE(req, res);
} else {
res.writeHead(404);
res.end();
}
} else {
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(fs.readFileSync(__dirname + '/sse-node.html'));
res.end();
}
}).listen(8000);
function sendSSE(req, res) {
res.writeHead(200, {
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache',
'Connection': 'keep-alive'
});
var id = (new Date()).toLocaleTimeString();
// Sends a SSE every 5 seconds on a single connection.
setInterval(function() {
constructSSE(res, id, (new Date()).toLocaleTimeString());
}, 5000);
constructSSE(res, id, (new Date()).toLocaleTimeString());
}
function constructSSE(res, id, data) {
res.write('id: ' + id + '\n');
res.write("data: " + data + '\n\n');
}
function debugHeaders(req) {
sys.puts('URL: ' + req.url);
for (var key in req.headers) {
sys.puts(key + ': ' + req.headers[key]);
}
sys.puts('\n\n');
}
sse-node.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<script>
var source = new EventSource('/events');
source.onmessage = function(e) {
document.body.innerHTML += e.data + '<br>';
};
</script>
</body>
</html>
560
A server-sent event is when a web page automatically gets updates from a server. This was also possible before, but the web page would have to ask if any updates were available. With server-sent events, the updates come automatically.
Long-Polling, Websockets, Server-Sent Events (SSE), and Comet are some of the ways for the client-side to connect with the server-side in real-time.
Differences. Obviously, the major difference between WebSockets and Server-Sent Events is that WebSockets are bidirectional (allowing communication between the client and the server) while SSEs are mono-directional (only allowing the client to receive data from the server).
The problem was with the server. In my case I was using node with IIS using the iisnode node package. To solve this, I needed to configure iisnode in the web.config like so:
<iisnode flushResponse="true" />
After this, everything worked fine. Others with a similar issue may start here, but apache and nginx may have similar configuration requirements.
179
Why did you comment out the res.end() at the end of the sendSSE function? That's the method that actually sends the response to the browser.
20
I already try that code and is working for me, as you are not using ngnix, or any other server as proxy for your node instances I would believe that the problem is with your machine, if you have firewall or anti virus running, stop it, and try again or any other software that could be intercepting yours req and res.
43
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