WebSocket断线自动重连javascript库(含心跳包)

大家好，又见面了，我是你们的朋友全栈君。

ReconnectingWebSocket 是一个小型的 JavaScript 库，封装了 WebSocket API
提供了在连接断开时自动重连的机制。

// 只需要简单的将：
var ws = new WebSocket('ws://....');
// 替换成：
var ws = new ReconnectingWebSocket('ws://....');

原ReconnectingWebSocket的GITHUB下载地址
下面是我从ReconnectingWebSocket源代码里根据我自身的业务需求修改的重连库

(function (global, factory) { 

if (typeof define === 'function' && define.amd) { 

define([], factory);
} else if (typeof module !== 'undefined' && module.exports){ 

module.exports = factory();
} else { 

global.SlWebSocket = factory();
}
})(this, function () { 

if (!('WebSocket' in window)) { 

return;
}
function SlWebSocket(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',
/** 心跳包定时器-by slong .*/
heartbeat_time: null,
/** 心跳持续时间-by slong .*/
heartbeat_duration: 30,
/** 心跳包数据-by slong .*/
heartbeat_content: ''
}
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) { 

let that = this;
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 || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', 'attempt-connect', self.url);
}
var localWs = ws;
var timeout = setTimeout(function() { 

if (self.debug || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', 'connection-timeout', self.url);
}
timedOut = true;
localWs.close();
timedOut = false;
}, self.timeoutInterval);
ws.onopen = function(event) { 

// that.send();// 触发心跳包,一般接入成功就会进行token等鉴权判断，所以该行可忽略
clearTimeout(timeout);
if (self.debug || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', '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 || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', '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 || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', 'onmessage', self.url, event.data);
}
var e = generateEvent('message');
e.data = event.data;
eventTarget.dispatchEvent(e);
};
ws.onerror = function(event) { 

if (self.debug || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', 'onerror', self.url, event);
}
eventTarget.dispatchEvent(generateEvent('error'));
};
}
// Whether or not to create a websocket upon instantiation
if (this.automaticOpen == true) { 

this.open(false);
}
/** * 改造后的send方法 * * @param data a text string, ArrayBuffer or Blob to send to the server. */
this.send = function(type,param) { 

if (ws) { 

if (self.debug || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', 'send', self.url, data);
}
clearTimeout(this.heartbeat_time);// 清除上次未执行的心跳
this.heartbeat_time = setTimeout(this.send.bind(this),this.heartbeat_duration * 1000,'__HEARTBEAT__');
if(type === '__HEARTBEAT__'){ 

ws.send(this.heartbeat_content);
}
else if(typeof type === 'object'){ 

ws.send(JSON.stringify(type));
}
else if(type && param){ 

ws.send(JSON.stringify({ 
type,param}));
}
} else { 

throw 'INVALID_STATE_ERR : Pausing to reconnect websocket';
}
};
/** * Transmits data to the server over the WebSocket connection. * * @param data a text string, ArrayBuffer or Blob to send to the server. */
this.sendRaw = function(data) { 

if (ws) { 

if (self.debug || SlWebSocket.debugAll) { 

console.debug('SlWebSocket', '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. */
SlWebSocket.prototype.onopen = function(event) { 
};
/** An event listener to be called when the WebSocket connection's readyState changes to CLOSED. */
SlWebSocket.prototype.onclose = function(event) { 
};
/** An event listener to be called when a connection begins being attempted. */
SlWebSocket.prototype.onconnecting = function(event) { 
};
/** An event listener to be called when a message is received from the server. */
SlWebSocket.prototype.onmessage = function(event) { 
};
/** An event listener to be called when an error occurs. */
SlWebSocket.prototype.onerror = function(event) { 
};
/** * Whether all instances of SlWebSocket should log debug messages. * Setting this to true is the equivalent of setting all instances of SlWebSocket.debug to true. */
SlWebSocket.debugAll = false;
SlWebSocket.CONNECTING = WebSocket.CONNECTING;
SlWebSocket.OPEN = WebSocket.OPEN;
SlWebSocket.CLOSING = WebSocket.CLOSING;
SlWebSocket.CLOSED = WebSocket.CLOSED;
return SlWebSocket;
});