等待双方玩家选择答案的 Socket.io 事件

Question

我正忙于学习 socket.io 并试图弄清楚如何让一些 JS 只有在两个用户都点击了他们的答案后才会触发。

我要启动的有问题的代码是：

// Random number function    
function randomIntFromInterval(min,max){
    return Math.floor(Math.random()*(max-min+1)+min);
}

// Check if correct + send to server
function correctAnswer() {
    var correct = true;
    socket.emit('playerCorrect', {answer: correct});
    console.log(correct);
    buttonRemover();

}
// Check if wrong + send to server
function incorrectAnswer () {
    var wrong   = false;
    socket.emit('playerWrong', {answer: wrong});
    buttonRemover();
}

socket.on ('updatePlayer', function (data) {
    if (data.answer === true) {
        console.log ('Player got it right! ' + data.answer);
    }else if (data.answer === false) {
        console.log ('Player got it wrong! ' + data.answer);
    }

});

这些函数向服务器发送数据以让服务器知道答案是否正确。

socket.on('playerCorrect', function (data) {
    io.sockets.emit('updatePlayer', data);
    dataRequest();
});    

socket.on('playerWrong', function (data) {
    io.sockets.emit('updatePlayer', data);
    dataRequest();
});

但是，我只希望在两个客户都单击一个选项时发生这种情况。有没有办法跟踪这个？

Answer 1

对于一组用户，这样做就足够了：

// Global variables for maintaining game states
// TODO: Clear this when a new game is started
var nrecieved = 0;
var responses = {}; // Socket id to response


function finish(/* todo: maybe also pass in a game_id or one of the user ids to know which game is being played */){
   // Loop through users in game and send them their responses
   for(var id in responses){
        if(responses.hasOwnProperty(id)){
             // Send the response
             io.to(id).emit('updatePlayer', responses[id]);
        }
   }
}

socket.on('playerCorrect', function (data) {
    responses[socket.id] = data;
    nrecieved++;

    if(nrecieved == 2){
        finish();
        dataRequest();
    }
});    

socket.on('playerWrong', function (data) {
    responses[socket.id] = data;
    nrecieved++;

    // Only respond if both responses received
    if(nrecieved == 2){
       finish();
       dataRequest();
    }
});

socket.id 是分配给每个套接字的唯一标识符，它可能很有用。对于多游戏性能，您可能需要更多逻辑来维护哪些套接字/播放器属于哪些游戏的列表，然后使用该列表将消息定向到正确的用户对。