I recently set up a VPS on DigitalOcean to run a few different Node.js scripts under the same domain.

You can’t have two Node.js apps listening on the same port, so you need a reverse proxy. Nginx is commonly used for that.

I set up each Node app to run on its own subfolder, so I had to edit the Nginx configuration:

sudo nano /etc/nginx/sites-available/default

which was this:

server {
        listen 80 default_server;
        listen [::]:80 default_server;
        root /var/www/html;
        index index.html index.htm index.nginx-debian.html;
        server_name hellonode;

        location ^~ /assets/ {
                gzip_static on;
                expires 12h;
                add_header Cache-Control public;
        }

        location / {
                proxy_http_version 1.1;
                proxy_cache_bypass $http_upgrade;

                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection 'upgrade';
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header X-Forwarded-Proto $scheme;

                proxy_pass http://localhost:3000;
        }
}

This configuration allows one Node.js app, running on port 3000, to be the main app served on /.

I wanted an app running under /myservice, so I created a Node app listening on port 3001 and added this configuration:

location /myservice {
        rewrite ^/myservice/(.*)$ /$1 break;

        proxy_http_version 1.1;
        proxy_cache_bypass $http_upgrade;

        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        proxy_pass http://localhost:3001;
}

I verified the configuration with:

sudo nginx -t

Then I restarted Nginx:

sudo systemctl restart nginx

Lessons in this unit:

0:	Introduction
1:	What is a reverse proxy?
2:	How to configure Nginx for HTTPS
3:	▶︎ A simple nginx reverse proxy for serving multiple Node.js apps from subfolders