foreword
Recently, I have done a large data screen project, using websocket to realize the real-time data update requirement, and simply record and share it.
What are websockets?
1. The WebSocket protocol is a new network protocol based on TCP, which allows the server to actively push data to the client to achieve full-duplex communication.
2. In the WebSocket API, the browser and the server only need to complete a handshake, and a persistent connection can be created directly between the two, and two-way data transmission can be performed.
1. Encapsulate websocket code
The websocket request address starts with 'ws://' or 'wss://'.
// websocket实例
let wsObj = null;
// ws连接地址
let wsUrl = null;
// let userId = null;
// 是否执行重连 true/不执行 ； false/执行
let lockReconnect = false;
// 重连定时器
let wsCreateHandler = null;
// 连接成功，执行回调函数
let messageCallback = null;
// 连接失败，执行回调函数
let errorCallback = null;
// 发送给后台的数据
let sendDatas = {
};
/**
* 发起websocket请求函数
* @param {string} url ws连接地址
* @param {Object} agentData 传给后台的参数
* @param {function} successCallback 接收到ws数据，对数据进行处理的回调函数
* @param {function} errCallback ws连接错误的回调函数
*/
export const connectWebsocket = (
url,
agentData,
successCallback,
errCallback
) => {
wsUrl = url;
createWebSoket();
messageCallback = successCallback;
errorCallback = errCallback;
sendDatas = agentData;
console.log(sendDatas);
};
// 手动关闭websocket （这里手动关闭会执行onclose事件）
export const closeWebsocket = () => {
if (wsObj) {
writeToScreen("手动关闭websocket");
wsObj.close(); // 关闭websocket
// wsObj.onclose() // 关闭websocket(如果上面的关闭不生效就加上这一条)
// 关闭重连
lockReconnect = true;
wsCreateHandler && clearTimeout(wsCreateHandler);
// 关闭心跳检查
heartCheck.stop();
}
};
// 创建ws函数
const createWebSoket = () => {
if (typeof WebSocket === "undefined") {
writeToScreen("您的浏览器不支持WebSocket，无法获取数据");
return false;
}
// wsUrl = "ws://" + host + "/websoket" + userId;
// your_params：你要传给后端的参数
try {
wsObj = new WebSocket(wsUrl, your_params);
initWsEventHandle();
} catch (e) {
writeToScreen("连接异常，开始重连");
reconnect();
}
};
const initWsEventHandle = () => {
try {
// 连接成功
wsObj.onopen = (event) => {
console.log("连接成功");
onWsOpen(event);
heartCheck.start();
};
// 监听服务器端返回的信息
wsObj.onmessage = (event) => {
console.log("监听服务器端返回的信息");
onWsMessage(event);
heartCheck.start();
};
wsObj.onclose = (event) => {
writeToScreen("onclose执行关闭事件");
onWsClose(event);
};
wsObj.onerror = (event) => {
writeToScreen("onerror执行error事件，开始重连");
onWsError(event);
reconnect();
};
} catch (err) {
writeToScreen("绑定事件没有成功，开始重连");
reconnect();
}
};
const onWsOpen = (event) => {
writeToScreen("CONNECT");
// // 客户端与服务器端通信
// wsObj.send('我发送消息给服务端');
// 添加状态判断，当为OPEN时，发送消息
if (wsObj.readyState === wsObj.OPEN) {
// wsObj.OPEN = 1
// 发给后端的数据需要字符串化
wsObj.send(JSON.stringify(sendDatas));
}
if (wsObj.readyState === wsObj.CLOSED) {
// wsObj.CLOSED = 3
writeToScreen("wsObj.readyState=3, ws连接异常，开始重连");
reconnect();
errorCallback();
}
};
const onWsMessage = (event) => {
const jsonStr = event.data;
writeToScreen("onWsMessage接收到服务器的数据: ", jsonStr);
messageCallback(jsonStr);
};
const onWsClose = (event) => {
writeToScreen("DISCONNECT");
// e.code === 1000 表示正常关闭。 无论为何目的而创建, 该链接都已成功完成任务。
// e.code !== 1000 表示非正常关闭。
console.log("onclose event: ", event);
if (event && event.code !== 1000) {
writeToScreen("非正常关闭");
errorCallback();
// 如果不是手动关闭，这里的重连会执行；如果调用了手动关闭函数，这里重连不会执行
reconnect();
}
};
const onWsError = (event) => {
writeToScreen("onWsError: ", event.data);
errorCallback();
};
const writeToScreen = (massage) => {
console.log(massage);
};
// 重连函数
const reconnect = () => {
if (lockReconnect) {
return;
}
writeToScreen("3秒后重连");
lockReconnect = true;
// 没连接上会一直重连，设置延迟避免请求过多
wsCreateHandler && clearTimeout(wsCreateHandler);
wsCreateHandler = setTimeout(() => {
writeToScreen("重连..." + wsUrl);
createWebSoket();
lockReconnect = false;
writeToScreen("重连完成");
}, 3000);
};
// 从浏览器地址中获取对应参数
const GetQueryString = (name) => {
let reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
// 获取url中 ? 符后的字符串并正则匹配
let r = window.location.search.substr(1).match(reg);
let context = "";
r && (context = r[2]);
reg = null;
r = null;
return context;
};
// 心跳检查（看看websocket是否还在正常连接中）
let heartCheck = {
timeout: 15000,
timeoutObj: null,
serverTimeoutObj: null,
// 重启
reset() {
clearTimeout(this.timeoutObj);
clearTimeout(this.serverTimeoutObj);
this.start();
},
// 停止
stop() {
clearTimeout(this.timeoutObj);
clearTimeout(this.serverTimeoutObj);
},
// 开启定时器
start() {
this.timeoutObj && clearTimeout(this.timeoutObj);
this.serverTimeoutObj && clearTimeout(this.serverTimeoutObj);
// 15s之内如果没有收到后台的消息，则认为是连接断开了，需要重连
this.timeoutObj = setTimeout(() => {
writeToScreen("心跳检查，发送ping到后台");
try {
const sendData = {
active: "heart" };
wsObj.send(JSON.stringify(sendData));
} catch (err) {
writeToScreen("发送ping异常");
}
console.log("内嵌定时器this.serverTimeoutObj: ", this.serverTimeoutObj);
// 内嵌定时器
this.serverTimeoutObj = setTimeout(() => {
writeToScreen("没有收到后台的数据，重新连接");
reconnect();
}, this.timeout);
}, this.timeout);
},
};
2. Page usage:
First import:
import {
connectWebsocket, closeWebsocket } from "@/utils/websocket.js";
This is a large data screen project because there is only one page, so I put the method of establishing a link in the mounted on the homepage, and you can put it in main.js.
mounted() {
connectWebsocket(
// 地址
"ws://后端提供的地址",
// 传递给后台的数据
{
},
// 成功拿到后台返回的数据的回调函数
(res) => {
let datas = JSON.parse(res);
let result = datas.data.data;
console.log(result,'返回结果，拿到之后该干啥干啥吧！')
},
// websocket连接失败的回调函数
() => {
console.log("失败的回调函数");
}
);
},
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