Node.js：在express.js路径中使用Socket.io将消息发送到特定客户端

Question

我做了一个非常随意的评论系统，现在我想添加回复。所以，当有人发表回复他人的评论时，该用户必须通知有人回复了他们的评论。为了做到这一点，当回答者点击答复按钮时，向服务器发出AJAX发布请求，然后服务器需要获得第一个评论者的ID并使用socket.io向他们发送响应文本（socket.io是如果有另一种方式将回复文本发送到另一个模块或表达自己，则不需要使用它们）。这是到目前为止我的代码：

app.post('/reply', function(req, res){ 
    var commenterId = req.body.userId; // this is the id of the original commenter, not the replier 
    User.findOne({'_id':commenterId}, function(err, user){ 
    user.send({'replied': req.user._id}); // this is what I need to do, and 
    //I don't know if this specific code works and that's why I'm asking if there is a way to do it with socket.io, 
    // io.to(socketId).emit('reply', 'some reply text here...'); // but if I do this I don't know how to get the socketId! 
    //Is there even a way to do this? Maybe with another module, 
    //or some express function I don't know about? And if it is done with express how would 
    //the client side code, look like? Thank you! 
    }); 
    res.end(); 
}); 

Answer 1

//app.js file 
var express = require('express'); 
var app = express(); 
var server = require('http').createServer(app); 
var io = require('socket.io').listen(server); 
var routes = require('./routes/routes')(io); 
app.use('/', routes); 

//router file 
var express = require('express'); 
var router = express.Router(); 
var _socket = null; 

//list of socket users.once they logout delete the socket by 
//delete users[_socket.userid]; 
var users = {}; 

var returnRouter = function(io) { 

    io.sockets.on('connection', function (socket) { 
     //now _Socket is available inside routes 
     _socket = socket; 
    }); 

    router.post('/login', function(req, res) { 
     //authentication logic 
     User.findOne({'email': req.body.email}, function (err, user) { 

      //userid must be unique 
      _socket.userId= user.userId 
      //set session variable to store id of the user 
      req.session.userId = user.userId; 
      //now every user has a socket associated with their id 
      users[_socket.userId] = _socket; 
     }); 
    }); 

    router.post('/reply', function (req, res) { 
     var commenterId = req.body.userId; 
     User.findOne({'_id': commenterId}, function (err, user) { 

     // you can get the id of the logged in user that is the creator 
     //of the original post from req.session.userId 
     //if you have implemented session store 

     //the commenter user object is obtained from findOne method 
     users[req.session.userId].emit('notification', { 
     notification: user.username+' commented on your post' 
     }}); 
     }); 
     res.end(); 
    }); 

    return router; 
}; 
module.exports = returnRouter;