javascript - Socket.io --- 一个对象用于多个用户

Question

我正在使用 socket.io 在 node.js 中构建一个应用程序，我希望人们能够对问题进行投票并包含一个计时器，这将为他们提供回答问题的时间限制。我遇到的问题(我将在下面突出显示)是每次有人连接到该页面时，它都会再次记录来自秒表对象的滴答声。即使在人们离开后，每次有人连接时它都会继续记录一次。到目前为止，这是我的项目代码。

秒表.js:

function Stopwatch() {
    if (false === (this instanceof Stopwatch)) {
        return new Stopwatch();
    }

    this.hour = 3600000;
    this.minute = 60000;
    this.second = 1000;
    this.time = this.hour;
    this.interval = undefined;

    events.EventEmitter.call(this);

    _.bindAll(this, 'start', 'stop', 'reset', 'onTick');
    };

    util.inherits(Stopwatch, events.EventEmitter);

    Stopwatch.prototype.start = function() {
        console.log("Starting the Timer!");
        this.interval = setInterval(this.onTick, this.second);
        this.emit('start');
    };

    Stopwatch.prototype.onTick = function() {
        var remainder = this.time,
        numhours,
        numMinutes,
        numSeconds,
        output = "";

        if (this.time === 0) {
            this.stop();
            return;
        }

        numHours = String(parseInt(remainder / this.hour, 10));
        remainder -= this.hour * numHours;

        numMinutes = String(parseInt(remainder / this.minute, 10));
        remainder -= this.minute * numMinutes;

        numSeconds = String(parseInt(remainder / this.second, 10));

        output = _.map([numHours, numMinutes, numSeconds], function(str) {
            if (str.length === 1) {
                 str = "0" + str;
            }
            return str;
        }).join(":");

        this.emit('tick', output);
        this.time -= this.second;
    }

    module.exports = Stopwatch;
}

套接字.js:

var Stopwatch = require('../models/stopwatch');
var people = {};
var stopwatch = Stopwatch();

module.exports = function (io) {

    io.on('connection', function (socket) {
        //console.log("Someone joined...");

        //socket.on('join', function () {
        if (Object.keys(people).length === 0) {
            console.log('host joined');
            people[socket.id] = {"name": "host", "image": "fake picture", "host": true};
        } else {
            console.log("Someone else joined");
            people[socket.id] = {"name": "person", "image": "other picture", "host": false};
        }
        console.log(people);
    //});

    socket.on('startTimer', function() {
        stopwatch.start();
    });
    socket.on('disconnect', function() {
        delete people[socket.id];
        console.log("someone left");
        console.log(people);
    });
    stopwatch.on('tick', function(time) {
            console.log(socket.id + '---stopwatch tick!' + time);
            socket.emit('timer', { countdown: time });
        });
    });
}; 

客户端的javascript:

var socket;

$(document).ready(function() {
    socket = io();

    socket.on('timer', function (data) {
        $('#timer').html(data.countdown);
    });

    $('#start-timer').click(function() {
        socket.emit('startTimer');
    });
});

提前致谢!我不明白为什么它仍然记录每个用户和时间，即使在他们与服务器断开连接之后也是如此。

Answer 1

发生的事情是，每次新客户端打开与服务器的连接时，您都会为 stopwatch 分配一个事件监听器并且永远不会删除它，这会导致您遇到的行为。如 node event emitter class 中所述，当套接字断开连接时，您必须删除 eventListener .

你应该得到这样的结果:

io.on('connection', function (socket) {
  //console.log("Someone joined...");

  //socket.on('join', function () {
  if (Object.keys(people).length === 0) {
    console.log('host joined');
    people[socket.id] = {"name": "host", "image": "fake picture", "host": true};
  } else {
    console.log("Someone else joined");
    people[socket.id] = {"name": "person", "image": "other picture", "host": false};
  }
  console.log(people);

  socket.on('startTimer', function() {
    stopwatch.start();
  });

  var _tickListener = function(time) {
    console.log(socket.id + '---stopwatch tick!' + time);
    socket.emit('timer', { countdown: time });
  };
  socket.on('disconnect', function() {
    delete people[socket.id];
    stopwatch.removeListener('tick', _tickListener);
    console.log("someone left");
    console.log(people);
  });
  stopwatch.on('tick', _tickListener);
});