React-Native-Reconnecting-WebSocket

React native auto reconnect websocket extends WebSocketModule. API design referenced reconnecting-websocket.

🇨🇳中文文档

It is API compatible, so when you have:

var ws = new WebSocket('ws://....');

you can replace with:

import ReconnectingWebSocket from 'react-native-reconnecting-websocket'

var ws = new ReconnectingWebSocket('ws://....');

Less code, more exponential.

Install

npm i react-native-reconnecting-websocket

How reconnections occur

With the standard WebSocket API, the events you receive from the WebSocket instance are typically:

onopen
onmessage
onmessage
onmessage
onclose // At this point the WebSocket instance is dead.

With a ReconnectingWebSocket, after an onclose event is called it will automatically attempt to reconnect. In addition, a connection is attempted repeatedly (with a small pause) until it succeeds. So the events you receive may look something more like:

onopen
onmessage
onmessage
onmessage
onclose
// ReconnectingWebSocket attempts to reconnect
onopen
onmessage
onmessage
onmessage
onclose
// ReconnectingWebSocket attempts to reconnect
onopen
onmessage
onmessage
onmessage
onclose

This is all handled automatically for you by the library.

Parameters

var socket = new ReconnectingWebSocket(url, protocols, options);

url

• The URL you are connecting to.
• https://html.spec.whatwg.org/multipage/comms.html#network

protocols

• Optional string or array of protocols per the WebSocket spec.
• https://tools.ietf.org/html/rfc6455

options

• Options (see below)

Options

Options can either be passed as the 3rd parameter upon instantiation or set directly on the object after instantiation:

var socket = new ReconnectingWebSocket(url, null, {reconnectInterval: 3000});

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

maxReconnectAttempts

• The maximum number of reconnection attempts that will be made before giving up. If null, reconnection attempts will be continue to be made forever.
• Accepts integer or null.
• Default: null

origin

• Preserve deprecated backwards compatibility for the origin option

headers

• Specifying origin as a WebSocket connection option is deprecated. Include it under headers instead
• Accepts origin and Cookie
• Example:

  WebSocket(url, '', { headers: { Cookie: 'key=value', origin: "https://secret-host.com" } });

---

Methods

ws.close(code?: number, reason?: string)

• Closes the WebSocket connection or connection attempt, if any. If the connection is already CLOSED, this method does nothing.
• code is optional the closing code (default value 1000). https://tools.ietf.org/html/rfc6455#section-7.4.1
• reason is the optional reason that the socket is being closed. https://tools.ietf.org/html/rfc6455#section-7.1.6

ws.send(data: string | ArrayBuffer | ArrayBufferView | Blob)

• Transmits data to the server over the WebSocket connection.
• Accepts @param data a text string, ArrayBuffer, ArrayBufferView or Blob

ws.ping()

• Sending websocket ping/pong frame.
• Some servers do not support it and need to be implemented manually, like How to add heartbeat?

ws.reconnect()

• 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.

See the more detail in [react-native/WebSocket.js@3982a2c6]

For example: How to add heartbeat?

1. usual

import ReconnectingWebSocket from 'react-native-reconnecting-websocket'

const ws = new ReconnectingWebSocket("ws://...");

// ws listeners
ws.onopen = (e) => {
    console.log("onopen",e)
};
ws.onmessage = (evt) => {
    console.log("onmessage",JSON.parse(evt.data))
};
ws.onclose = (e) => {
    console.log("onclose",e)
};
ws.onerror = (e) => {
    console.log("onerror",e)
};

/*
 * listen reconnecting event (Powered by ReconnectingWebSocket)
 * @params reconnectAttempts 尝试重连的次数
 */
ws.onconnecting = (reconnectAttempts) => {
    console.log("onconnecting", reconnectAttempts)
}

2. add heartbeat

ws.onopen = (e) => {
    // execute immediately!
    ws.send("heartbeat string");
    
    heartCheck.reset().start()
};

ws.onmessage = (evt) => {
    heartCheck.reset().start()
};

ws.onclose = () => {
    if(logout){//如果前端主动关闭(如退出登陆)，不做处理

    }else {//如果服务器主动关闭，前端也需要重连时使用
        heartCheck.reset().start() 
    }
};

var heartCheck = {
    timeout: 10000,//default 10s
    timeoutObj: null,
    serverTimeoutObj: null,
    reset:function(){
        clearTimeout(this.timeoutObj);
        clearTimeout(this.serverTimeoutObj);
        return this;
    },
    start:function(){
        let self = this;
        this.timeoutObj = setTimeout(function(){
            if(ws.readyState === ws.OPEN){
              ws.send("heartbeat string");
            }
            self.serverTimeoutObj = setTimeout(function(){
                ws.reconnect();//本库提供
            }, self.timeout)
        }, this.timeout)
    }
}