Socket.io 聊天应用程序显示检测到 EventEmitter 内存泄漏。增加了 11 位听众。使用发射器.setMaxListeners()

Question

我正在使用socket.io 和node.js 加上mysql 作为私人聊天应用程序，当我使用socket.on('example', function(data){...}); 时，它会在这里抛出这样的错误代码。

 node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
    at PoolConnection.EventEmitter.addListener (events.js:175:15)
    at io.on.eventConnection (/Applications/MAMP/htdocs/mysite/node/server.js:72:15)
    at Ping.onOperationComplete [as _callback] (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/Pool.js:99:5)
    at Ping.Sequence.end (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/protocol/sequences/Sequence.js:96:24)
    at Ping.Sequence.OkPacket (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/protocol/sequences/Sequence.js:105:8)
    at Protocol._parsePacket (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/protocol/Protocol.js:280:23)
    at Parser.write (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/protocol/Parser.js:73:12)
    at Protocol.write (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/protocol/Protocol.js:39:16)
    at Socket.Connection.connect (/Applications/MAMP/htdocs/mysite/node/node_modules/mysql/lib/Connection.js:96:28)
    at Socket.EventEmitter.emit (events.js:96:17)

我的代码在 服务器端：-

function fetchMessages(data){
        var sql = "SELECT `msg_descr`,`msg_to` FROM `message` WHERE (msg_to="+data[0].iChatUserId+" AND msg_from="+data[1]+") OR (msg_to="+data[1]+" AND msg_from="+data[0].iChatUserId+") ORDER BY msg_created_date DESC LIMIT 20";
        eventConnection(sql, function(callback, rows){
            if(callback){
                users[data[1]].emit('Release Msg', {messages:rows, selfId:data[0].iChatUserId});
            }
        });
    }

    //when a user is actibe
    socket.on('load Message', function(data, callback){
        var repsondMsg = fetchMessages(data);
    });

在客户端：-

 chatList.click(function(){
        var __this  =   $(this);
            targetData  =   [];
            __userData  =   fetchUserData(__this);
            myId    =   myImage.data('myid');
            targetData.push(__userData, myId);
            socket.emit('load Message', targetData);
            checkExistance(targetData);
    });

    socket.on('Release Msg', function(data){
            $.each(data.messages, function(){
                $.each(this, function(k,v){
                    $('*[data-ichatid="'+data.selfId+'"]').children('.body_cht_box_ind').children('#chats').append($('<li>').text(v));
                })
            });
        });

Answer 1

以下链接有解释。 https://nodejs.org/docs/latest/api/events.html#events_emitter_setmaxlisteners_n

默认情况下，如果为特定事件添加了超过 10 个侦听器，EventEmitters 将打印警告。这是一个有用的默认值，有助于发现内存泄漏。显然，并非所有事件都应仅限于 10 个侦听器。 emitter.setMaxListeners() 方法允许为这个特定的 EventEmitter 实例修改限制。该值可以设置为 Infinity（或 0）以指示无限数量的侦听器。"

你可以使用这样的东西。

require('events').EventEmitter.defaultMaxListeners = Infinity;