Question

我的裸骨Node.js应用程序看起来像这样（基本上我经常调用一个Web服务，并将数据推送到客户端）大约一天后，即使添加了发射器，我也会得到以下运行错误.setMaxListeners（0）。我很确定我的代码没有任何内存泄漏。有什么建议吗？

/*
* Server setup
*/
var querystring = require('querystring');
var xml2js = require('xml2js');
var parser = new xml2js.Parser();
var eyes = require('eyes');
var http = require('http');
var app = http.createServer(handler);
var io  = require('socket.io').listen(app);
var emitter = new (require('events').EventEmitter);
emitter.setMaxListeners(0);
io.set('log level', 0);

app.listen(8080);


function handler(req, res){
    res.writeHead(200, {'Content-Type':'text/html'});
    res.end('Test');
}

/*
* Global data object
*/
var xmlData= '';
var cache = [];

/*
* web service info
*/
var postData = querystring.stringify({  
    'index' : '',
    'type' : '-1',
}); 


var options = {
    host: 'localhost',
    path: '/WebService.asmx',
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',  
        'Content-Length': postData.length 
    }
};



var getData = function(){

    // Web Service Request Obj
    var webServiceReq = http.request(options, function(res) {  

      res.setEncoding('utf8');  

      res.on('data', function (chunk) {  
        xmlData += chunk;
      }).on('end', function() {

        parser.parseString(xmlData, function(err, data){
                cache = JSON.parse(data['#']);
        });

        io.sockets.emit('message', { "data": cache});

      });// end res.on('end')

    });  


    webServiceReq.write(postData);
    webServiceReq.end();
}

// grab the info every 10 seconds
setInterval(getData, 5000);

// emit the latest data when client initially connects
io.sockets.on('connection', function (socket) {
    // emit the data
    socket.emit('message', {"data": cache});
});

错误：

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
    at Parser.EventEmitter.addListener (events.js:168:15)
    at Parser.exports.Parser.Parser.parseString (C:\WebApplications\WebApp\scripts\node_modules\xml2js\lib\xml2js.js:197:14)
    at Parser.__bind [as parseString] (C:\WebApplications\WebApp\scripts\node_modules\xml2js\lib\xml2js.js:6:61)
    at IncomingMessage.getData (C:\WebApplications\WebApp\scripts\nodeService.js:87:20)
    at IncomingMessage.EventEmitter.emit (events.js:115:20)
    at IncomingMessage._emitEnd (http.js:366:10)
    at HTTPParser.parserOnMessageComplete [as onMessageComplete] (http.js:149:23)
    at Socket.socketOnData [as ondata] (http.js:1356:20)
    at TCP.onread (net.js:410:27)

Answer 1

问题在于

Use emitter.setMaxListeners() to increase limit.

并不意味着'创建发射器对象并将emitter.setMaxListeners（0）添加到您的代码'。字'发射器'在这里指的是从EventEmitter继承的任何对象，例如服务器，进程，请求等。在您的情况下，您在显示的代码中有2个发射器：app和io。你应该写的是：

var http = require('http');
var app = http.createServer(handler);
var io  = require('socket.io').listen(app);
app.setMaxListeners(0);
io.setMaxListeners(0);
io.set('log level', 0);

app.listen(8080);

Answer 2

如果您想全局增加限额，请将该行放在应用的开头： require('events').EventEmitter.prototype._maxListeners = 100;

Node.js“检测到EventEmitter内存泄漏”

2 个答案: