Question

使用node.js，我正在尝试每秒向所有客户端发送当前server_time。因此，我想使用setInterval()向所有客户端发送事件并发送时间，但它不起作用。我是否在正确的位置定义了setInterval功能或者错过了其他功能？

var http = require("http");
var socketIO = require('socket.io');
var connect = require('connect');

//keep track of every connected client
var clients = {};

//create Server 
var httpServer = connect.createServer(
    connect.static(__dirname)
).listen(8888);


//socket
var io = socketIO.listen(httpServer);
io.sockets.on('connection', function (socket) {

    //add current client id to array
    clients[socket.id] = socket;
    socket.on('close', function() {
        delete clients[socket.fd]; // remove the client.
    });

    //send news on connection to client
    socket.emit('news', { hello: 'world' }); 

    //this one works fine!
    //send server time on connection to client
    socket.emit("server_time", { time: new Date().toString() });

});

//this doesn't work!
// Write the time to all clients every second.
setInterval(function() { 
    var i, sock;
    for (i in clients) {
        sock = clients[i];
        if (sock.writable) { // in case it closed while we are iterating.
            sock.emit("server_time", {
                console.log("server_time sended");
                time: new Date().toString()

            });
        }
    }
}, 1000);       //every second

Answer 1

我可以建议解决问题的解决方法/改进措施。将客户端添加到chat room。在某处：

io.sockets.on('connection', function (socket) {

添加

socket.join('timer');

然后setIntervall将是

setInterval(function() { 
    io.sockets.in('timer').emit("server_time", { time: new Date().toString() })
}, 1000);

希望这适合你！

Answer 2

问题是以下功能：

if (sock.writable) { // in case it closed while we are iterating.
  sock.emit("server_time", {
    // console.log("server_time sended"); // get rid of this line -> invalid code
    time: new Date().toString()
  });
}

sock.writable为undefined，因此永远不会发送emit事件。在连接时将属性设置为true，并在关闭时将其设置为false。

node.js setInterval不起作用

2 个答案: