如何将 RSVP 延迟与 WebSocket 一起使用？答案

【问题标题】：How do I use RSVP deferreds with WebSocket?如何将 RSVP 延迟与 WebSocket 一起使用？
【发布时间】：2015-08-14 22:35:57
【问题描述】：

我需要同时打开多个WebSocket 连接，然后在打开所有连接后执行操作。

我正在使用 RSVP.js 的 defer()、all() 和 then() 方法。但是，then() 和 catch() 都没有被触发，我无法弄清楚我哪里出错了。

这是我的代码：

var numberOfThreads = 6,
    openSockets = function () {
        var // the deferred object
            d,
            // array of promises
            socketsOpened = [],
            // websocket object and index
            ws, i;

        // open a new WebSocket connection for each iteration
        for (i = 0; i < numberOfThreads; i += 1) {
            // create deferred object
            d = RSVP.defer();

            // push promise into array
            socketsOpened.push(d.promise);

            // create websocket connection to valid, working socket server
            ws = new WebSocket(url);

            // websocket events
            ws.onopen = function () {
                // when socket is open, resolve deferred
                d.resolve();
            };
        }

        // when all connections are open, do stuff
        RSVP
        .all(socketsOpened)
        .then(function () {
            console.log('All sockets are opened!');
        }).catch(function () {
            console.log('Oops! Something has gone wrong!');
        });
    };

openSockets();

我做错了什么？

【问题讨论】：

标签： javascript websocket deferred rsvp.js

【解决方案1】：

我应该创建一个数组（d = []），而不是将deferred 分配给d，将每个deferred 分配给数组的i 位置（d[i] = RSVP.defer()），然后推送@987654327 @ 进入socketsOpened 数组。

这是新代码：

var numberOfThreads = 6,
    openSockets = function () {
        var // an array for deferred objects
            d = [],
            // array of promises
            socketsOpened = [],
            // websocket object and index
            ws, i;

        // open a new WebSocket connection for each iteration
        for (i = 0; i < numberOfThreads; i += 1) {
            // protect i with closure
            (function (i) {
                // create deferred object
                d[i] = RSVP.defer();

                // push promise into array
                socketsOpened.push(d[i].promise);

                // create websocket connection to valid, working socket server
                ws = new WebSocket(url);

                // websocket events
                ws.onopen = function () {
                    // when socket is open, resolve deferred
                    d[i].resolve();
                };
            }(i));
        }

        // when all connections are open, do stuff
        RSVP
        .all(socketsOpened)
        .then(function () {
            console.log('All sockets are opened!');
        }).catch(function () {
            console.log('Oops! Something has gone wrong!');
        });
    };

openSockets();

抱歉浪费了大家的时间！

【讨论】：