Javascript 无法发送到特定客户端：Socket IO会将其发送到每个客户端吗？

是的，我已经阅读了文档，文档写得很好：

问题是：当用户从Express应用程序的会话被破坏时，我想通知用户注销。现在发生了这样的事情：当我从会话中注销时，所有其他客户端（包括那些已登录或尚未登录的客户端）都会收到一条消息，说他们已注销。是的，我的express应用程序工作正常-他们没有被注销，但我相信SOCKET IO正在向他们发送消息。我运行了调试器，结果发现这两个客户端也是可以区分的

这是我的密码：

server.js：

var app = express();
var server = require('http').Server(app);
var io = require('socket.io')(server);
app.set('socketio', io);
io.on('connection', function (socket) {
  app.set('current_socket', socket);
  console.log('No of clients:', io.engine.clientsCount); 
});

userController.js：

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.sockets.in(sessionID).emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const userId = MAGIC_GET_USER_ID_FROM_SESSION_ID(sessionID) // who want to logout
    const io = req.app.get('socketio');
    const this_socket = req.app.get(userId); // get "user socket"

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

我甚至试过这样做：

io.emit('userAction', { action: 'logout' });

---

但事实证明，它仍然会向所有客户机发出信号。我很确定某个地方存在不匹配，只是不知道在哪里。

如果要向spesific用户发送emit，您需要为每个会话id创建空间

io.on('connection', function (socket) {
  app.set('current_socket', socket);
  var sessionId = socker.request.session.id
  //join room
  socket.join(sessionId);
});

userController.js：

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.sockets.in(sessionID).emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const userId = MAGIC_GET_USER_ID_FROM_SESSION_ID(sessionID) // who want to logout
    const io = req.app.get('socketio');
    const this_socket = req.app.get(userId); // get "user socket"

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

---

必须为每个用户定义唯一的套接字对象。我们有很多方法可以做到这一点

简单地说，我们使用用户id（unique）作为存储套接字对象的键（映射方式：key（userId）-vaule（socketObj））

跟着兔子走：

当用户登录时，客户端向服务器端发出一个事件（登录），该事件包括用户id

客户端：

// login success
socket.emit('userLoggedIn', {userId: THE_USER_ID})

服务器端：

io.on('connection', function (socket) {
  // app.set('current_socket', socket);
  console.log('No of clients:', io.engine.clientsCount);
  socket.on('userLoggedIn', function(data) => {
    app.set(data.userId, socket); // save socket object
  })
});

userController.js：

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const io = req.app.get('socketio');
    const this_socket = req.app.get('current_socket');

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.sockets.in(sessionID).emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

exports.userLogout = function(req, res, next) {
    const sessionID = req.session.id;
    const userId = MAGIC_GET_USER_ID_FROM_SESSION_ID(sessionID) // who want to logout
    const io = req.app.get('socketio');
    const this_socket = req.app.get(userId); // get "user socket"

    req.session.destroy(function (err){
        if(err) {
            console.error("userLogout failed with error:", err);
            return next(err);
        }
        else {
            console.log("this_socket:", this_socket);
            console.log("io:", io);
            this_socket.emit('userAction', { action: 'logout' });
            //other logic to remove old sessions from DB Session Store
            //and finally:
            res.status(200)
                .json({
                status: 'success',
                api_data: {'loggedIn':false},
                message: 'Logout successful.'
                });
        }
    }
}

---

socket.request.session.id未定义。嗯。@jfriend00你能给我一个详细的例子吗？你在给你的服务器编码，就像一次只有一个用户使用你的服务器一样。您不能将

当前\u套接字

存储在全球可用的位置。由于不同的用户在您的服务器上执行不同的操作，这些操作将发生冲突。相反，您需要将用户状态存储在用户会话中或直接存储在cookie中，然后当该特定用户发生请求时，您可以从该用户的会话或cookie中获取状态。嘿！非常感谢你的建议。我确实意识到我的设置对流量不友好，因此我需要帮助使其对大量用户稳定。我不熟悉节点和套接字。无论如何，我确实尝试过实现您的解决方案，但不知怎么的，“userLoggedIn”并没有被激发，尽管如此（这很奇怪），“userAction”正在被激发，我在所有客户端上都收到了一条注销消息。pm2/节点是否存在捕获问题？