Node.js + Nginx - What now?

I've set up Node.js and Nginx on my server. Now I want to use it, but, before I start there are 2 questions:

1. How should they work together? How should I handle the requests?

2. There are 2 concepts for a Node.js server, which one is better:

   a. Create a separate HTTP server for each website that needs it. Then load all JavaScript code at the start of the program, so the code is interpreted once.

   b. Create one single Node.js server which handles all Node.js requests. This reads the requested files and evals their contents. So the files are interpreted on each request, but the server logic is much simpler.

It's not clear for me how to use Node.js correctly.

Nginx works as a front end server, which in this case proxies the requests to a node.js server. Therefore you need to set up an Nginx config file for node.

This is what I have done in my Ubuntu box:

Create the file yourdomain.example at /etc/nginx/sites-available/:

vim /etc/nginx/sites-available/yourdomain.example

In it you should have something like:

# the IP(s) on which your node server is running. I chose port 3000.
upstream app_yourdomain {
    server 127.0.0.1:3000;
    keepalive 8;
}

# the nginx server instance
server {
    listen 80;
    listen [::]:80;
    server_name yourdomain.example www.yourdomain.example;
    access_log /var/log/nginx/yourdomain.example.log;

    # pass the request to the node.js server with the correct headers
    # and much more can be added, see nginx config options
    location / {
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_set_header X-NginX-Proxy true;

      proxy_pass http://app_yourdomain/;
      proxy_redirect off;
    }
 }

If you want Nginx (>= 1.3.13) to handle websocket requests as well, add the following lines in the location / section:

proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";

Once you have this setup you must enable the site defined in the config file above:

cd /etc/nginx/sites-enabled/
ln -s /etc/nginx/sites-available/yourdomain.example yourdomain.example

Create your node server app at /var/www/yourdomain/app.js and run it at localhost:3000

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n');
}).listen(3000, "127.0.0.1");
console.log('Server running at http://127.0.0.1:3000/');

Test for syntax mistakes:

nginx -t

Restart Nginx:

sudo /etc/init.d/nginx restart

Lastly start the node server:

cd /var/www/yourdomain/ && node app.js

Now you should see "Hello World" at yourdomain.example

One last note with to starting the node server: you should use some kind of monitoring system for the node daemon. There is an awesome tutorial on node with upstart and monit.