drw/public/wss.js

// MIT License:
//
// Copyright (c) 2010-2012, Joe Walnes
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

/**
 * This behaves like a WebSocket in every way, except if it fails to connect,
 * or it gets disconnected, it will repeatedly poll until it successfully connects
 * again.
 *
 * It is API compatible, so when you have:
 *   ws = new WebSocket('ws://....');
 * you can replace with:
 *   ws = new ReconnectingWebSocket('ws://....');
 *
 * The event stream will typically look like:
 *  onconnecting
 *  onopen
 *  onmessage
 *  onmessage
 *  onclose // lost connection
 *  onconnecting
 *  onopen  // sometime later...
 *  onmessage
 *  onmessage
 *  etc...
 *
 * It is API compatible with the standard WebSocket API, apart from the following members:
 *
 * - `bufferedAmount`
 * - `extensions`
 * - `binaryType`
 *
 * Latest version: https://github.com/joewalnes/reconnecting-websocket/
 * - Joe Walnes
 *
 * Syntax
 * ======
 * var socket = new ReconnectingWebSocket(url, protocols, options);
 *
 * Parameters
 * ==========
 * url - The url you are connecting to.
 * protocols - Optional string or array of protocols.
 * options - See below
 *
 * Options
 * =======
 * Options can either be passed upon instantiation or set after instantiation:
 *
 * var socket = new ReconnectingWebSocket(url, null, { debug: true, reconnectInterval: 4000 });
 *
 * or
 *
 * var socket = new ReconnectingWebSocket(url);
 * socket.debug = true;
 * socket.reconnectInterval = 4000;
 *
 * debug
 * - Whether this instance should log debug messages. Accepts true or false. Default: false.
 *
 * automaticOpen
 * - Whether or not the websocket should attempt to connect immediately upon instantiation. The socket can be manually opened or closed at any time using ws.open() and ws.close().
 *
 * reconnectInterval
 * - The number of milliseconds to delay before attempting to reconnect. Accepts integer. Default: 1000.
 *
 * maxReconnectInterval
 * - The maximum number of milliseconds to delay a reconnection attempt. Accepts integer. Default: 30000.
 *
 * reconnectDecay
 * - The rate of increase of the reconnect delay. Allows reconnect attempts to back off when problems persist. Accepts integer or float. Default: 1.5.
 *
 * timeoutInterval
 * - The maximum time in milliseconds to wait for a connection to succeed before closing and retrying. Accepts integer. Default: 2000.
 *
 */
(function (global, factory) {
	if (typeof define === "function" && define.amd) {
		define([], factory);
	} else if (typeof module !== "undefined" && module.exports) {
		module.exports = factory();
	} else {
		global.ReconnectingWebSocket = factory();
	}
})(this, function () {
	if (!("WebSocket" in window)) {
		return;
	}

	function ReconnectingWebSocket(url, protocols, options) {
		// Default settings
		var settings = {
			/** Whether this instance should log debug messages. */
			debug: false,

			/** Whether or not the websocket should attempt to connect immediately upon instantiation. */
			automaticOpen: true,

			/** The number of milliseconds to delay before attempting to reconnect. */
			reconnectInterval: 1000,
			/** The maximum number of milliseconds to delay a reconnection attempt. */
			maxReconnectInterval: 30000,
			/** The rate of increase of the reconnect delay. Allows reconnect attempts to back off when problems persist. */
			reconnectDecay: 1.5,

			/** The maximum time in milliseconds to wait for a connection to succeed before closing and retrying. */
			timeoutInterval: 2000,

			/** The maximum number of reconnection attempts to make. Unlimited if null. */
			maxReconnectAttempts: null,

			/** The binary type, possible values 'blob' or 'arraybuffer', default 'blob'. */
			binaryType: "blob",
		};
		if (!options) {
			options = {};
		}

		// Overwrite and define settings with options if they exist.
		for (var key in settings) {
			if (typeof options[key] !== "undefined") {
				this[key] = options[key];
			} else {
				this[key] = settings[key];
			}
		}

		// These should be treated as read-only properties

		/** The URL as resolved by the constructor. This is always an absolute URL. Read only. */
		this.url = url;

		/** The number of attempted reconnects since starting, or the last successful connection. Read only. */
		this.reconnectAttempts = 0;

		/**
		 * The current state of the connection.
		 * Can be one of: WebSocket.CONNECTING, WebSocket.OPEN, WebSocket.CLOSING, WebSocket.CLOSED
		 * Read only.
		 */
		this.readyState = WebSocket.CONNECTING;

		/**
		 * A string indicating the name of the sub-protocol the server selected; this will be one of
		 * the strings specified in the protocols parameter when creating the WebSocket object.
		 * Read only.
		 */
		this.protocol = null;

		// Private state variables

		var self = this;
		var ws;
		var forcedClose = false;
		var timedOut = false;
		var eventTarget = document.createElement("div");

		// Wire up "on*" properties as event handlers

		eventTarget.addEventListener("open", function (event) {
			self.onopen(event);
		});
		eventTarget.addEventListener("close", function (event) {
			self.onclose(event);
		});
		eventTarget.addEventListener("connecting", function (event) {
			self.onconnecting(event);
		});
		eventTarget.addEventListener("message", function (event) {
			self.onmessage(event);
		});
		eventTarget.addEventListener("error", function (event) {
			self.onerror(event);
		});

		// Expose the API required by EventTarget

		this.addEventListener = eventTarget.addEventListener.bind(eventTarget);
		this.removeEventListener = eventTarget.removeEventListener.bind(eventTarget);
		this.dispatchEvent = eventTarget.dispatchEvent.bind(eventTarget);

		/**
		 * This function generates an event that is compatible with standard
		 * compliant browsers and IE9 - IE11
		 *
		 * This will prevent the error:
		 * Object doesn't support this action
		 *
		 * http://stackoverflow.com/questions/19345392/why-arent-my-parameters-getting-passed-through-to-a-dispatched-event/19345563#19345563
		 * @param s String The name that the event should use
		 * @param args Object an optional object that the event will use
		 */
		function generateEvent(s, args) {
			var evt = document.createEvent("CustomEvent");
			evt.initCustomEvent(s, false, false, args);
			return evt;
		}

		this.open = function (reconnectAttempt) {
			ws = new WebSocket(self.url, protocols || []);
			ws.binaryType = this.binaryType;

			if (reconnectAttempt) {
				if (
					this.maxReconnectAttempts &&
					this.reconnectAttempts > this.maxReconnectAttempts
				) {
					return;
				}
			} else {
				eventTarget.dispatchEvent(generateEvent("connecting"));
				this.reconnectAttempts = 0;
			}

			if (self.debug || ReconnectingWebSocket.debugAll) {
				console.debug("ReconnectingWebSocket", "attempt-connect", self.url);
			}

			var localWs = ws;
			var timeout = setTimeout(function () {
				if (self.debug || ReconnectingWebSocket.debugAll) {
					console.debug("ReconnectingWebSocket", "connection-timeout", self.url);
				}
				timedOut = true;
				localWs.close();
				timedOut = false;
			}, self.timeoutInterval);

			ws.onopen = function (event) {
				clearTimeout(timeout);
				if (self.debug || ReconnectingWebSocket.debugAll) {
					console.debug("ReconnectingWebSocket", "onopen", self.url);
				}
				self.protocol = ws.protocol;
				self.readyState = WebSocket.OPEN;
				self.reconnectAttempts = 0;
				var e = generateEvent("open");
				e.isReconnect = reconnectAttempt;
				reconnectAttempt = false;
				eventTarget.dispatchEvent(e);
			};

			ws.onclose = function (event) {
				clearTimeout(timeout);
				ws = null;
				if (forcedClose) {
					self.readyState = WebSocket.CLOSED;
					eventTarget.dispatchEvent(generateEvent("close"));
				} else {
					self.readyState = WebSocket.CONNECTING;
					var e = generateEvent("connecting");
					e.code = event.code;
					e.reason = event.reason;
					e.wasClean = event.wasClean;
					eventTarget.dispatchEvent(e);
					if (!reconnectAttempt && !timedOut) {
						if (self.debug || ReconnectingWebSocket.debugAll) {
							console.debug("ReconnectingWebSocket", "onclose", self.url);
						}
						eventTarget.dispatchEvent(generateEvent("close"));
					}

					var timeout =
						self.reconnectInterval *
						Math.pow(self.reconnectDecay, self.reconnectAttempts);
					setTimeout(
						function () {
							self.reconnectAttempts++;
							self.open(true);
						},
						timeout > self.maxReconnectInterval ? self.maxReconnectInterval : timeout
					);
				}
			};
			ws.onmessage = function (event) {
				if (self.debug || ReconnectingWebSocket.debugAll) {
					console.debug("ReconnectingWebSocket", "onmessage", self.url, event.data);
				}
				var e = generateEvent("message");
				e.data = event.data;
				eventTarget.dispatchEvent(e);
			};
			ws.onerror = function (event) {
				if (self.debug || ReconnectingWebSocket.debugAll) {
					console.debug("ReconnectingWebSocket", "onerror", self.url, event);
				}
				eventTarget.dispatchEvent(generateEvent("error"));
			};
		};

		// Whether or not to create a websocket upon instantiation
		if (this.automaticOpen == true) {
			this.open(false);
		}

		/**
		 * Transmits data to the server over the WebSocket connection.
		 *
		 * @param data a text string, ArrayBuffer or Blob to send to the server.
		 */
		this.send = function (data) {
			if (ws) {
				if (self.debug || ReconnectingWebSocket.debugAll) {
					console.debug("ReconnectingWebSocket", "send", self.url, data);
				}
				return ws.send(data);
			} else {
				throw "INVALID_STATE_ERR : Pausing to reconnect websocket";
			}
		};

		/**
		 * Closes the WebSocket connection or connection attempt, if any.
		 * If the connection is already CLOSED, this method does nothing.
		 */
		this.close = function (code, reason) {
			// Default CLOSE_NORMAL code
			if (typeof code == "undefined") {
				code = 1000;
			}
			forcedClose = true;
			if (ws) {
				ws.close(code, reason);
			}
		};

		/**
		 * Additional public API method to refresh the connection if still open (close, re-open).
		 * For example, if the app suspects bad data / missed heart beats, it can try to refresh.
		 */
		this.refresh = function () {
			if (ws) {
				ws.close();
			}
		};
	}

	/**
	 * An event listener to be called when the WebSocket connection's readyState changes to OPEN;
	 * this indicates that the connection is ready to send and receive data.
	 */
	ReconnectingWebSocket.prototype.onopen = function (event) {};
	/** An event listener to be called when the WebSocket connection's readyState changes to CLOSED. */
	ReconnectingWebSocket.prototype.onclose = function (event) {};
	/** An event listener to be called when a connection begins being attempted. */
	ReconnectingWebSocket.prototype.onconnecting = function (event) {};
	/** An event listener to be called when a message is received from the server. */
	ReconnectingWebSocket.prototype.onmessage = function (event) {};
	/** An event listener to be called when an error occurs. */
	ReconnectingWebSocket.prototype.onerror = function (event) {};

	/**
	 * Whether all instances of ReconnectingWebSocket should log debug messages.
	 * Setting this to true is the equivalent of setting all instances of ReconnectingWebSocket.debug to true.
	 */
	ReconnectingWebSocket.debugAll = false;

	ReconnectingWebSocket.CONNECTING = WebSocket.CONNECTING;
	ReconnectingWebSocket.OPEN = WebSocket.OPEN;
	ReconnectingWebSocket.CLOSING = WebSocket.CLOSING;
	ReconnectingWebSocket.CLOSED = WebSocket.CLOSED;

	return ReconnectingWebSocket;
});