Zetta Toolkit: JSON RPC over TLS

This library offers clear-text JSON RPC over TLS with optional second layer encryption.

Security Features:

• Uses TLS (SSL) for data transport
• HMAC based authentication against user-supplied secret
• Optional message signing against MITM attacks
• Optional second layer message encryption (aes-256-cbc by default, if enabled)

Authentication is based on user supplied secret keys, so this is as secure as your host.

This library is currently under development & testing. Until this message is removed, use at your own risk!

Usage

npm install zetta-rpc

Messaging

Zetta RPC library allows sending of JSON objects between client and server. If these JSON objects contain an opcode (op field), they will be emitted to the registered event listeners as well as on the RPC objects themselves (Client, Server and Multiplexer). If op field is missing, rpc.digest(function(msg) { ... }) must be used to capture transmission of incoming JSON objects.

Client

var zrpc = require('zetta-rpc');

var rpc = new zrpc.Client({		// or zrpc.Client() for connection to a single server
    address: "host:port",				// or multiple servers specified as ["host:port",...]  (Multiplexer only)
    auth: "user-supplied-secret-key",
    certificates: ...,					// standard node certificates containing 'key', 'cert', 'ca' data
    node: "...",  						// id of this node instance (typically host mac address)
    designation: 'user-application-id',	// name of the application (used to differentiate connections coming from the same host)
    ping: true,							// optional: enable automatic server ping (see Client::setPingDataObject())
    pingFreq : 3 * 1000,				// optional: ping frequency (default 3 seconds)
    pingDataObject : ...,				// this object will be transmitted during ping
    cipher: true,						// optional: 'true' or name of cipher algorithm for 2nd layer encryption 
    									// (default 'aes-256-cbc' if true)
    signatures: true					// optional: enable message signing
});


// receive messages
rpc.on('user-message', function(msg, rpc) { ... })	

// receive messages with external event emitter
rpc.registerListener(eventEmitter);		// register event emitter that will receive messages
eventEmitter.on('user-message', function(msg, rpc) { ... })	

// send messages or JSON objects
rpc.dispatch({ op : 'user-message ', ... })	

// receive JSON
rpc.digest(function(msg, rpc) { ... })

zrpc.Multiplexer() and zrpc.Client() provide same initialization interface. Multiplexer, however, supports an array of addresses allowing client to connect to multiple servers simultaneously.

Server

var zrpc = require('zetta-rpc');

var rpc = new zrpc.Server({
	port : 12345, 						// listening port
	auth : "user-supplied-secret-key",
    certificates: ...,					// standard node certificates containing 'key', 'cert', 'ca' data
}, function(err) {
	console.log('zetta-rpc server is listening for new connections');
});

// client connection event: cid is a unique remote end-point identifier (built from designation+node)
rpc.on('connect', function(address, cid, stream) { ... })

// client disconnection event
rpc.on('disconnect', function(cid, stream) { ... })

// receive messages
rpc.on('user-message', function(msg, cid, stream) { ... })

// send messages
rpc.dispatch(cid, { op : 'user-message' })

// receive JSON objects (without 'op' field)
rpc.digest(function(msg, cid, stream) { ... })

Router

If the number of sockets on the system running as a Server is limited, Router can be used to create multiple fron-ends that will accept incoming connections and exchange message between these connection and the server. For example: if a server is limited to 10 connections, having 10 routers would allow to scale socket limit to 100 (this refers to ulimit settings that can) impact systems when there are a lot of external connections.

Router allows creation of multiple front-ends for the Server is the number of socket

var router = zrpc.Router({
	port : 6699,
	auth : "f72d7c54d7354f7a8f9d111c6033b6281e7096acc4dcb198763a4555f264259d",
	certificates : self.certificates,
	client : {
		address : "127.0.0.1:4488",
		node : mac
	}
})

License

This library is a part of Zetta Toolkit, released under MIT license.
Copyright (c) 2014 ASPECTRON Inc.
All Rights Reserved.