Need help with setting up comet code
- by Saif Bechan
Does anyone know off a way or maybe think its possible to connect Node.js with Nginx http push module to maintain a persistent connection between client and browser.
I am new to comet so just don't understand the publishing etc maybe someone can help me with this.
What i have set up so far is the following. I downloaded the jQuery.comet plugin and set up the following basic code:
Client JavaScript
<script type="text/javascript">
function updateFeed(data) {
$('#time').text(data);
}
function catchAll(data, type) {
console.log(data);
console.log(type);
}
$.comet.connect('/broadcast/sub?channel=getIt');
$.comet.bind(updateFeed, 'feed');
$.comet.bind(catchAll);
$('#kill-button').click(function() {
$.comet.unbind(updateFeed, 'feed');
});
</script>
What I can understand from this is that the client will keep on listening to the url followed by /broadcast/sub=getIt. When there is a message it will fire updateFeed.
Pretty basic and understandable IMO.
Nginx http push module config
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
push_authorized_channels_only off;
server {
listen 80;
location /broadcast {
location = /broadcast/sub {
set $push_channel_id $arg_channel;
push_subscriber;
push_subscriber_concurrency broadcast;
push_channel_group broadcast;
}
location = /broadcast/pub {
set $push_channel_id $arg_channel;
push_publisher;
push_min_message_buffer_length 5;
push_max_message_buffer_length 20;
push_message_timeout 5s;
push_channel_group broadcast;
}
}
}
Ok now this tells nginx to listen at port 80 for any calls to /broadcast/sub and it will give back any responses sent to /broadcast/pub.
Pretty basic also. This part is not so hard to understand, and is well documented over the internet. Most of the time there is a ruby or a php file behind this that does the broadcasting.
My idea is to have node.js broadcasting /broadcast/pub. I think this will let me have persistent streaming data from the server to the client without breaking the connection. I tried the long-polling approach with looping the request but I think this will be more efficient.
Or is this not going to work.
Node.js file
Now to create the Node.js i'm lost. First off all I don't know how to have node.js to work in this way.
The setup I used for long polling is as follows:
var sys = require('sys'),
http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(new Date());
res.close();
seTimeout('',1000);
}).listen(8000);
This listens to port 8000 and just writes on the response variable.
For long polling my nginx.config looked something like this:
server {
listen 80;
server_name _;
location / {
proxy_pass http://mydomain.com:8080$request_uri;
include /etc/nginx/proxy.conf;
}
}
This just redirected the port 80 to 8000 and this worked fine.
Does anyone have an idea on how to have Node.js act in a way Comet understands it. Would be really nice and you will help me out a lot.
Recources
used
An example where this is done with ruby instead of Node.js
jQuery.comet
Nginx HTTP push module homepage
Faye: a Comet client and server for Node.js and Rack
To use faye I have to install the comet client, but I want to use the one supplied with Nginx. Thats why I don't just use faye. The one nginx uses is much more optimzed.
extra
Persistant connections
Going evented with Node.js
