node-storm/lib/prepare.js

Node.js multilang protocol implementation for Storm

var through = require('event-stream').through

// Ensures the handshake is at the beginning of the stream
module.exports = function() {
	var _queue = []
	var _handshakeReceived = false

	function dequeue() {
		var len = _queue.length
		while(len--) {
			var queued = _queue.shift()
			this.queue(queued)
		}
	}

	return through(function(data) {
		if (data.conf) {
			this.emit('prepare', data)

			_handshakeReceived = true

			dequeue.call(this)
		} else if (_handshakeReceived) {
			this.queue(data)
		} else {
			_queue.push(data)
		}
	}, function() {
		dequeue.call(this)
		this.queue(null)
	})
}