jsonrpc.client.js

function JSONRPC(options) {
	if (!(this instanceof JSONRPC)) return new JSONRPC(options);

	this.socket = options.socket || null;
	this.fallback = options.fallback || null;

	this.callbacks = {};
}

// FIXME: check for unloved callbacks at a user-defined interval
//        call them with Error objects
//        we already store original call time because keys ARE the time :-)
//        are intervals/timeouts GCed if this object is deleted/unset?

// params: <method>, params**, [callback]
// return: sent jsonrpc object, handy if you haven't set a socket
JSONRPC.prototype.send = function(method) {
	if ( typeof method !== 'string' ) throw new Error({
		code: -32600,
		message: "Invalid JSON-RPC: <method> must be a string."
	});

	var params = Array.prototype.slice.call(arguments, 1),
		callback = arguments[arguments.length - 1],
		rpc = {jsonrpc: '2.0', method: method};

	// if we have a callback, generate an id for it so we catch the result
	if ( typeof callback === 'function' ) {
		rpc.id = Date.now();
		this.callbacks[rpc.id] = callback;
		// dump the nulled callback from the args to params conversion
		params.pop();
	}

	// FIXME: making assumptions here that won't work with named params
	if ( params.length > 0 ) rpc.params = params;

	if ( this.socket.send ) this.socket.send(rpc);

	return rpc;
};

// params: message = jsonrpc 2.0 result object
JSONRPC.prototype.receive = function(message) {
	if ( message && message.jsonrpc && message.jsonrpc === '2.0' ) {
		var result = message.result || message || null;

		// hit up our callback (and then delete it)
		if ( message.id && typeof this.callbacks[message.id] === 'function' ) {
			this.callbacks[message.id](result);
			delete this.callbacks[message.id];

		// or hit up our fallback
		} else if ( typeof this.fallback === 'function' ) {
			this.fallback(result);

		// or log it and see what happens, FIXME: smarter please
		} else {
			if (console) console.log(message);
		}
	}
};