使用Promise封装Websocket

await 后面若是跟的Promise,则接受Promise resolve的值。Promise reject的值需要try...catch住，或者await 后面的表达式跟着.catch()

//私有变量
const options = Symbol("options");
const intUniqueId = Symbol("intUniqueId");//
const arrQueueRequest = Symbol("arrQueueRequest");
const arrQueueNotice = Symbol("arrQueueNotice");


export default class SocketConn {
    /**
     * 构造函数，初始化数据
     * @param {*} objOption 
     */
    constructor(objOption) {
        this[options] = {
            connWbSK: null, //Websocket实例
            secure: objOption.secure || "wss",
            hostName: objOption.hostName || "127.0.0.1",
            portNo: objOption.portNo || "80",
            user: objOption.user,
            password: objOption.password
        };
        this[intUniqueId] = 0; //请求的id，也是请求的key值（在请求序列里根据id找对应的包）
        this[arrQueueRequest] = {};//请求序列
        this[arrQueueNotice] = {};//server的通知序列
    };

    /***************私有函数start*********** */
    /**
     * 处理请求对应的响应
     */
    _onRequestMessage = (objResp) => {      
        let {id} = objResp;//从响应里获取id
        this[arrQueueRequest][id].resolve(objResp);//只返回resolve函数，不reject，可以在外面捕获
        delete this[arrQueueRequest][id];//删除序列id对应数据包
    };

    _onNoticeMessage = (objResp) => {
        //处理通知
    }

    /***************私有函数end*********** */


    /***************公开函数start*********** */
    //公开函数
    open = (onSocketClose) => {
        //await只能接收resolve的值，reject的值需要在外面catch
        return new Promise((resolve, reject) => {
            let _private = this[options],
                url = "" + _private.secure + "://" + _private.hostName;
            if (_private.portNo) {
                url += ":" + _private.portNo;
            }
            url += "?";
            url += "user=" + _private.user;
            url += "&password=" + _private.password;
            _private.connWbSK = new WebSocket(url);
            
            _private.connWbSK.onopen = (event) => {//成功连接上
                console.log("onopen")
                resolve(true);
            }

            _private.connWbSK.onmessage = (event) => {//收到server发来的消息
                let objResp = JSON.parse(event.data);
                //如果是我们发送的请求
                if(objResp.packet_type === "response"){
                    this._onRequestMessage(objResp);
                }else{//如果是server的通知
                    this._onNoticeMessage(objResp);
                }
            }

            _private.connWbSK.onerror = (event) => {
                // reject(false);
            };

            //传入onclose事件，以便于server主动断开时触发
            _private.connWbSK.onclose = (event) => {
                onSocketClose(event); 
            };
        });
    };

    /**
     * 外部调用的发送方法
     */
    send = (serviceName, methodName, objData, dataFormat, timeout) => {
        return new Promise((resolve, reject) => {
            let objPkg, objPkgSendReq;
            this[intUniqueId] += 1;
            
            //构建发送包
            objData = JSON.stringify(objData);//先序列化
            objData = Base64.encode(objData);//加密
            objPkg = {
                id: this[intUniqueId],
                packet_type: "request",
                service: serviceName,
                method: methodName,
                data: objData
            };

            objPkgSendReq = JSON.stringify(objPkg);
            this[arrQueueRequest][objPkg.id] = {
                id: objPkg.id,
                strReq: objPkgSendReq,
                reject: reject,
                resolve: resolve,
                dataFormat: dataFormat,
                timeoutId: null
            }
            this[options].connWbSK.send(this[arrQueueRequest][objPkg.id].strReq);
        })
    };

    //主动关闭连接，并且重置数据
    closeSocketAndResetVar = () => {
        if(this[options].connWbSK){
            this[options].connWbSK.close();
            this[options].connWbSK = null;
        }
    };

    /***************公开函数end*********** */
}

使用

    connectServer = async(options, onSocketClose) => {
        let socketConn = new SocketConn({
            hostName: options.hostName,
            portNo: options.portNo,
            secure: options.isSSL ? "wss" : "ws",
            user: options.user,
            password: options.password,
            resource
        }, onSocketClose);
        await socketConn.open(onSocketClose).catch(e){
            console.log(e)//捕获reject错误
        };
        let data = {
        }
        await socketConn.send("", "", data , "",).catch(e){
            console.log(e)//捕获reject错误
        };
    }