synchronode

A semi-decentralized file synchronization tool based on WebSockets.

High-level Design

Several instances of this app can run on separate servers. Each instance can act as a master and as a slave.

A slave communicates to the master via WebSocket the files available as well as a token.

A client can send the master HTTP / WebDAV requests to access the shared files.

Configuration

Configuration is defined as a Node.js module, by default in config.js in the application's root.

Options

port (number): The port to listen for incoming requests on. master (string): URL for the master of this instance. May be empty, if this is a Grandmaster. shareRoot (string): path to the folder relative to which the paths are shared

Example: master

{
	"port": 3000,
	"shareRoot": ".",
}

Example: slave

{
	"port": 80,
	"master": "example.org",
	"shareRoot": "/home/billg/Documents",
}

Reverse Proxy Configuration

Below examples can be used to configure the master. They assume that :

• you are running synchronode behind a reverse proxy, which takes care of the certificates for the HTTPS connection (Let's Encrypt's Certbot was used)
• the master is reachable on https://example.org
• the synchronode instance is listening on port 3000

Apache

Example: Apache reverse proxy configuration on master

Assuming Apache does the reverse proxying, these site configurations do the job. We are assuming that HTTP requests are redirected to use HTTPS

HTTP redirecting to HTTPS

<VirtualHost *:80>
	# Redirect traffic to HTTPS
	
	ServerName example.org
	ProxyRequests off

	<Proxy *>
		Order deny,allow
		Allow from all
	</Proxy>

	ProxyPass /ws/ ws://localhost:3000/ws/
	ProxyPassReverse /ws/ ws://localhost:3000/ws/

	ProxyPass /browserWs/ ws://localhost:3000/browserWs/
	ProxyPassReverse /browserWs/ ws://localhost:3000/browserWs/

	ProxyPass / http://localhost:3000/
	ProxyPassReverse / http://localhost:3000/

	ErrorLog ${APACHE_LOG_DIR}/error.log
	CustomLog ${APACHE_LOG_DIR}/access.log combined

	RewriteEngine on
	RewriteCond %{SERVER_NAME} =example.org
	RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

HTTPS traffic redirected to localhost:3000

<IfModule mod_ssl.c>
  <VirtualHost *:443>
    ServerName example.org
    ProxyRequests off

    <Proxy *>
      Order deny,allow
      Allow from all
    </Proxy>

    ProxyPass	/ws/ ws://localhost:3000/ws/
    ProxyPassReverse /ws/ ws://localhost:3000/ws/
		
		ProxyPass /browserWs/ ws://localhost:3000/browserWs/
		ProxyPassReverse /browserWs/ ws://localhost:3000/browserWs/

    ProxyPass	/ http://localhost:3000/
    ProxyPassReverse	/ http://localhost:3000/

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
    SSLCertificateFile /etc/letsencrypt/live/example.org/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/example.org/privkey.pem
    Include /etc/letsencrypt/options-ssl-apache.conf
  </VirtualHost>
</IfModule>

nginx

Reverse Proxy Configuration for nginx

server {        
	# redirect to HTTPS
	if ($host = example.org) {
		return 301 https://$host$request_uri;
	}
	listen 80 default_server;
	listen [::]:80 default_server;

	return 404;
}

server {
	listen example.org:443 ssl; 
	server_name example.org;
	ssl_certificate /etc/letsencrypt/live/example.org/fullchain.pem;
	ssl_certificate_key /etc/letsencrypt/live/example.org/privkey.pem;
	include /etc/letsencrypt/options-ssl-nginx.conf;
	ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
	# normal HTTP requests
	location / { 
		proxy_bind 127.0.0.1;
		proxy_pass http://127.0.0.1:3000;
	}
	# websocket requests coming from other synchronode instances
	location /ws {
		proxy_bind 127.0.0.1;
		proxy_pass http://127.0.0.1:3000;
		proxy_http_version 1.1;
		proxy_set_header Upgrade $http_upgrade; 
		proxy_set_header Connection "upgrade";
	}
	# websocket requests coming from the browser
	location /browserWs {
		proxy_bind 127.0.0.1;
		proxy_pass http://127.0.0.1:3000;
		proxy_http_version 1.1;
		proxy_set_header Upgrade $http_upgrade;
		proxy_set_header Connection "upgrade";
	}
}

Endpoints

The master exposes these endpoints:

GET /browse/hostId : browse files shared by hostId

GET /register : get a hostId for a new slave.