node.js - Socket.io 实时聊天——管理用户好友

Question

我正在用 React/Redux、Node (Express)、Socket.io 和 MySql 开发一个实时聊天应用程序。我想做的是没有“公共(public)”房间的实时聊天。它适用于用户之间的友谊/关系(与另一个用户是 friend 的用户可以一对一聊天)并且还处理组创建(用户可以创建一个与他想要的许多其他用户的组)。
一切正常，唯一的问题是我不确定获取每个用户的 friend /群组列表(也显示在线/离线状态)的最佳方法。
我目前的做法如下:

每个连接的用户都存储在后端的一个对象中(带有他们的套接字 ID)。每个键是连接的用户 ID，值是它的套接字 ID。它看起来像这样:

let connectedUsers = {
    1: 'socketIdUser1'
    2: 'socketIdUser2',
    5: 'socketIdUser5',
    // ... And so on for every user that is connected
}

如果我们以上面的对象为例，我们知道 ID 为 1、2 和 5 的用户是连接的。

然后，对于每个单独的连接用户，我将他们与其他人的友谊关系存储在另一个对象中，如下所示(我只存储 ID):

let userFriendsObject = {
    1: {
        2: 2,
        4: 4,
        5: 5,
    },
    2: {
        1: 1,
        5: 5,
        9: 9,
        12: 12,
    }
}

这个对象向我们展示了 ID 为 1 的用户与 ID 为 2、4 和 5 的用户有 friend 关系(因此可以与他们聊天)。而 ID = 2 的用户与 ID 为 1 的用户是 friend ， 5、9 和 12。
我会像这样跟踪每一个友谊，以便能够为每个用户发送正确的 friend 列表。我发现这种方法目前最方便，因为在更新的情况下(假设用户添加了 friend 或有人登录并且我必须向用户发送他正确更新的 friend 列表)，发送会很痛苦正确的 friend 列表给正确的用户。或者也许我错过了什么？
当用户连接并将他的 friend 列表从后端发送到前端时的代码如下所示:

前端:

useEffect(() => {

    /* When a user connects, this event is emited to the backend, which 
    will then emit back the below "set user friends list" event */

    socket.emit('new connected user', { id: currentUser.id, pseudo: currentUser.pseudo });


    // Listening emited event from the backend, holding the user's friend list

    socket.on('set user friends list', friendStack => {
        if (friendStack) {
            // dispatch hook to set the friend list in Redux global state
            dispatch(setFriendList(friendStack)); 
        }   
    });

    
    // Listening emited event from the backend, updates online status for newly connected user's friends

    socket.on('set friend status', ({ friendId, isActive }) => {
        dispatch(setOnline({ id: friendId, changes: { isActive } }));
    });

}, []);

后台:

// "Global" object containing every connected user (key = user ID, value = socket ID)

let connectedUsers = {};

// "Global" object containing every user ID, themselves containing every friends IDs (= holding every friendships)

let userFriendsObject = {};

socket.on('new connected user', ({ userId, pseudo => {
    session.user = {
        id: userId,
        pseudo: pseudo,
        isActive: true,
    };
            

    connectedUsers[userId] = socket.id; // Used to know which users are connected
            
    session.save();


    /* I use EventEmitter() from the 'events' library to emit events 
    from the backend to the backend for everything DB related,
    to better split the code */ 
    
    eventEmitter.emit('get friends list', { userId });
            

    /* Function triggered below (after all the "sockets.on()",
    in eventEmitter.on('get friends list'), to process the 
    friend list received from the DB just above) */

    setFriendList = function(friends) {
        

         /* I emit to the newly connected user's socket his friend list */

         ioChat.to(socket.id).emit('set user friends list', friends[userId]);
                

        /* To update the online status ("isActive") of the friends side of the newly connected 
        user, I loop through connectedUser object keys (= connected users IDs) ... */

        for (let i in connectedUsers) {


            /* ... to compare it with the userFriendsObject key of the user to check
            (= his friend list), to know which of his friends are connected... */

            if (userFriendsObject[userId] && userFriendsObject[userId][i] === parseInt(i, 10) && parseInt(i, 10) !== userId) {

         
                /* ... and then send to his connected friends an event which will say 
                to them to update the status of the newly connected user */

                ioChat.to(connectedUsers[i]).emit('set friend status', { friendId: userId, isActive: true });
            }
        }
    };
});

// ...

eventEmitter.on('get friends list', async ({ userId }) => {
    try {
        // Setting the online status of the user in DB (1 = online, 0 = offline)

        await User.setUserStatus(userId, 1);


        // Calling the DB to get the user friends

        const friendList = await User.getUserFriendsData(userId);
        

        /* This variable will be "local" and hold all the user's friend list
        as a normalized object ready for Redux */
        
        let friends = {};

        
        // Loop through the friendList retrieved from the DB

        let i = 0, resultLength = friendList.length;
        for (i; i < resultLength; i++) {


            // Putting the "local" user's friend list in "friends" object   

            friends[userId] = {
                ...friends[userId],
                [friendList[i].userId]: {
                    id: friendList[i].userId,
                    pseudo: friendList[i].pseudo,
                    email: friendList[i].email,
                    createdOn: friendList[i].createdOn,
                    isActive: friendList[i].isActive !== 0,
                    roomId: friendList[i].roomId,
                }
            };


            /* Using userFriendsObject as a "global" object, holding every user's friend list
            (only the IDs though, as explained in the beginning of my post) */

            userFriendsObject[userId] = {
                ...userFriendsObject[userId],
                [friendList[i].userId]: friendList[i].userId,
            };
        }


            /* Here I call the setFriendList() function which is in 
            "socket.on('new connected user')" and is used 
            to process the friend list and emit events accordingly */

            setList(friends);
    }
    catch (error) { 
        console.error(`Error EE.on('get list') : ${error}`);
    }
});

如果这不是很清楚，我很抱歉，代码已经加载得很好了。我尽力解释正在发生的事情，但如果不清楚，请随时告诉我详细说明(另外，英语不是我的母语，使它变得更加困难)。
我对这段代码的担忧是:

是否可以将每个用户的每个友谊关系存储在“全局”对象 (userFriendsObject) 中？我很担心，因为如果我有 100 个连接的用户，每个用户有 20 个 friend ，那么对象会很大(最少 2000 个键/值，嵌套 2 层深)。更不用说它应该随着应用程序的使用而呈指数增长。

什么是不将所有这些友谊关系存储在一个对象中的替代方法，但仍然能够以有效且可扩展的替代方法让每个用户的 friend 列表“在手边”？

在代码的以下部分(setFriendList() 函数，在 socket.on('new connected user') 中:

// Looping through the connectedUsers object...
for (let i in connectedUsers) {


    /* ... to compare it with the userFriendsObject key of the user to check
    (= his friend list), to know which of his friends are connected... */

    if (userFriendsObject[userId] && userFriendsObject[userId][i] === parseInt(i, 10) && parseInt(i, 10) !== userId) {

         
        /* ... and then send to his connected friends an event which will say 
        to them to update the status of the newly connected user */

        ioChat.to(connectedUsers[i]).emit('set friend status', { friendId: userId, isActive: true });
    }
}

可以像我所做的那样在循环中向用户(可能是很多用户)发射吗？如果没有，我如何确保为给定用户发送正确的更新好友列表？ (我想答案与我的其他问题有关)。

我应该使用某种类型的存储，例如 indexedDB 吗？

我希望有人能帮助我。我的代码有效，但我很确定它远非最佳性能。非常感谢您的时间和帮助。

Answer 1

我终于成功了。
我通过使用 Redis 缓存存储来做到这一点。
我所做的是，当我为每个用户获取每个 friend 和组时，我会在 Redis 存储中创建一个位置来存储它。然后我可以得到任何具有用户 ID 的用户 friend 。

const redis = require('redis');
const redisStore = redis.createClient();

// I can then store a friend (friend being a JSON object) like so :
redisStore.hset(`${userId}:friends`, friend.id, JSON.stringify(friend));

// This way I store every friend as a key / value in ${userId}:friends
// I can retrieve a specific friend by its ID like so :
redisStore.hget(`${userId}:friends`, friendID, (err, result) => {
    // Here, the stringified friend object with ID = friendID is in result variable
});

// Or I can get all friends of user = userId like so :
redisStore.hgetall(`${userId}:friends`, (err, results) => {
     // Here, every friends (stringified) of user with id = userId are in results variable
}); 

我刚开始使用 Redis，我发现它非常强大，非常适合我使用的那种应用程序。
我不再需要使用“全局”对象，就像我之前存储用户的友谊关系(如“userFriendsObject”对象)。我可以在 Redis 中存储我想要的任何东西并快速取回。它也应该是非常快的表演。
我还可以根据情况使用任何其他存储数据类型或技术。
我找到了一个开始了解 Redis 的好地方:https://redis.io/topics/data-types-intro
你可以在这里找到每个 Redis 命令:https://redis.io/commands#