Question

我是node.js的新手。如何使用socket.io从node.js服务器向特定用户发送通知。

我计划创建应用，用户可以将其他用户添加为他/她的朋友，以便他们成为朋友后可以互相聊天。

因此，一旦用户A向用户B发送了请求，用户B将获得有关该请求的实时通知。现在我有用户管理系统，包括登录和注册。在数据库中，我有两个表：包含所有用户注册详细信息的用户和包含用户朋友关系数据的朋友（friend_id_one，friend_id_two是引用users.user_id的FOREIGN KEY），状态和时间戳。所以，我插入声明添加这样的朋友：

INSERT INTO friends
(friend_id_one,friend_id_two) 
VALUES 
(user_id_one,friend_id_two);

我尝试向用户发送通知。

客户端：

<html>
  <head>
    <title>Socket.IO chat</title>
    <style>
      * { margin: 0; padding: 0; box-sizing: border-box; }
      form input { border: 0; padding: 10px; width: 10%; margin-right: .5%; }
      form button { width: 9%; background: rgb(130, 224, 255); border: none; padding: 10px; }
    </style>
  </head>
    <ul id="messages"></ul>
    <form action="">
      <input id="m" autocomplete="off" /><button onclick="notifyMe()">Send</button>
    </form>
    <script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>
    <script src="https://code.jquery.com/jquery-1.11.1.js"></script>
    <script>
      $(function () {
        var socket = io();
        $('form').submit(function(){
          socket.emit('send notification', $('#m').val());
          $('#m').val('');
          return false;
        });
        socket.on('send notification', function(msg){
          notifyMe(msg);
        });
      });
      function notifyMe(msg) {
          // Let's check if the browser supports notifications
          if (!("Notification" in window)) {
            alert("This browser does not support desktop notification");
          }
          // Let's check if the user is okay to get some notification
          else if (Notification.permission === "granted") {
            // If it's okay let's create a notification
          var options = {
                body: msg,
                dir : "ltr"
            };
          var notification = new Notification(msg,options);
          }
          // Otherwise, we need to ask the user for permission
          // Note, Chrome does not implement the permission static property
          // So we have to check for NOT 'denied' instead of 'default'
          else if (Notification.permission !== 'denied') {
            Notification.requestPermission(function (permission) {
              // Whatever the user answers, we make sure we store the information
              if (!('permission' in Notification)) {
                Notification.permission = permission;
              }
              // If the user is okay, let's create a notification
              if (permission === "granted") {
                var options = {
                        body: msg,
                        dir : "ltr"
                };
                var notification = new Notification(msg,options);
              }
            });
          }
          // At last, if the user already denied any notification, and you
          // want to be respectful there is no need to bother them any more.
    }
    </script>
  </body>
</html>

服务器：

let usersMap = new Map;
io.on('connection', function(socket){
  console.info(`Client connected socketId = ${socket.id}`);
  console.log("session_id: " + socket.request.session.session_id);
  usersMap.set(socket.request.session.session_id, socket.id);
    socket.on('send notification',  data => {
      if(usersMap.has(parseInt(data))) {
        io.sockets.connected[usersMap.get(parseInt(data))].emit('send notification', "Friend want add you to friends");
        let today = helper.getDateNow();
        let sql = "INSERT INTO `friends` (`friends_one`, `friends_two`, `created`) VALUES ('" + socket.request.session.session_id+"', '"+parseInt(data)+"', '"+ today+"') ";
      connection.query(sql, (error, result ) => {
          if(error){
            console.log(error);
          }
          console.log("successfull");
      });
      } else {
        console.log(`User is not found`);
      }
 });
    socket.on('disconnect', function(){
       usersMap.delete(socket.request.session.session_id);
       console.log('user disconnected');  
    });
  });

但是通知会获得所有用户。请帮我修复这个错误。

向特定用户发送通知（node.js，express，mysql，socket.io）

0 个答案: