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JavaScript

// 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;
});