cross-channel/src/channel/transports/nw.transport.js

Cross window messaging

'use strict'

var MessageEvent = require('../../types/message-event.js')
var Message = require('../../types/message.js')
var generateRandomKey = require('../../utils/generate-random-key.js')
var getAllWindows = require('../../utils/frames.js').getAll
var environment = require('../../utils/environment.js')

/*
Known issues:
1. From NW to child window - NO
2. From child window to NW - NO
3. From child frame to child window - NO
4. From child window to child frame - NO
5. <iframe nwfaketop> disables message bubbling to the parent frame
*/

var global = environment.global

function getGUI(window) {
	return window && window.nwDispatcher.requireNwGui()
}

function whenGuiReadyThen(callback) {
	var gui = getGUI(global.window)
	if (gui) {
		callback(gui)
		return
	}
	var timerId = setInterval(function () {
		gui = getGUI(global.window)
		if (gui) {
			clearInterval(timerId)
			callback(gui)
		}
	}, 4)
}

function getNWWindowThen(callback) {
	whenGuiReadyThen(function (gui) {
		var nwWindow = gui.Window.get()
		callback(nwWindow)
	})
}

function Transport(name) {
	var transport = this
	// this.port - computed value
	this.origin = '*' //location = window.location, location && (location.origin || (location.protocol + '//' + location.host)) || '*'
	this.listener = null
	this.name = name
	this.key = generateRandomKey()
	this.nwLoadedListener = function () {
		var listener = transport.listener
		var port = transport.port
		if (listener) {
			//port.removeEventListener(Transport.EVENT_TYPE, listener)
			port.addEventListener(Transport.EVENT_TYPE, listener)
		}
	}
	getNWWindowThen(function (nwWindow) {
		//listen when page is refreshed
		nwWindow.on('loaded', transport.nwLoadedListener)
	})
}

Transport.supported = Boolean(environment.is.node && environment.is.nodeWebkit)
Transport.EVENT_TYPE = 'message'

Transport.prototype = {
	constructor: Transport,

	send: function (data) {
		var transport = this
		var origin = this.origin
		var message = new Message(data, this)
		getNWWindowThen(function (nwWindow) {
			var browserWindow = transport.port
			var topBrowserWindow = browserWindow.top
			var browserFrames = getAllWindows(topBrowserWindow)
			// try {
			// 	if (global.__nwWindowsStore) {
			// 		browserFrames = Object.keys(global.__nwWindowsStore)
			// 			.map(function(id) {
			// 				return global.__nwWindowsStore[id];
			// 			})
			// 			.map(function(nwWindow) {
			// 				var browserWindow = nwWindow.window;
			// 				return getAllWindows(browserWindow.top)
			// 			})
			// 			.reduce(function(allBrowserWindows, browserWindows) {
			// 				return allBrowserWindows.concat(browserWindows)
			// 			}, [])
			// 	}
			// }
			// catch (err) {
			// 	setTimeout(console.error.bind(console, err), 4000)
			//
			// }
			var index = -1
			while (++index in browserFrames) {
				//.replace(/'/g, '\\\'')
				nwWindow.eval(browserFrames[index].frameElement || null, 'window.postMessage(' + JSON.stringify(message.asJSON()) + ', "' + origin + '")')
			}
		})
	},

	onMessageEvent: function (handler) {
		var transport = this
		function listener(e) {
			var window = this
			var nativeMessageEventWorks = window.MessageEvent && window.MessageEvent.length
			var event = nativeMessageEventWorks ? (new window.MessageEvent(Transport.EVENT_TYPE, e)) : e //fixes crashes in NWjs, when read `e.data`
			var messageEvent = new MessageEvent(event)

			if (
				('key' in messageEvent)
				&& ('sourceChannel' in messageEvent)
				&& transport.name === messageEvent.sourceChannel //events on the same channel
				&& transport.key !== messageEvent.key //skip returned back events
			) {
				handler(messageEvent)
			}
		}

		getNWWindowThen(function () {
			var port = transport.port
			port.removeEventListener(Transport.EVENT_TYPE, transport.listener)
			port.addEventListener(Transport.EVENT_TYPE, listener)
			transport.listener = listener
		})

	},

	close: function () {
		var transport = this
		getNWWindowThen(function (nwWindow) {
			transport.port.removeEventListener(Transport.EVENT_TYPE, transport.listener)
			transport.listener = null
			nwWindow.removeListener('loaded', transport.nwLoadedListener)
		})
	}
}

//computed `this.port`
Object.defineProperty(Transport.prototype, 'port', {
	get: function () {
		return global.window
	},
	set: function (value) { }
})


module.exports = Transport