本文介绍了MaxListenersExceededWarning：检测可能的事件Emitter内存泄漏的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我已经阅读过有关此错误的内容，知道它是什么，也知道如何通过将MaxListeners设置为0来禁用它。但是我想知道是什么导致了这个错误，这样我就可以正确地处理它。
这里基本上是一个机器人，用来检查和查看我的帐户是否有新消息。我需要一次检查很多账户，所以我写了这个机器人来做这件事。我在此代码中有4个函数：
1 - load_proxy -> reads list of proxies from a file and puts them into an array
2 - load_accounts -> reads list of accounts from a file and puts them into an array
3 - init-> opens a browser , in a while loop fetching accounts and calling the next function
4 - open_tab-> opens a tab in the browser and checks the account and calles the next function to log the result
5 - wite_to_file-> writing the result into a text file
const puppeteer = require('puppeteer');
const fs = require('fs');
const PROXYSTACK = [] ;
const PROXYDB = [] ;
const ACCOUNTSTACK = [] ;
const ACCOUNTDB = [] ;
var inprogress = false ;
setInterval(()=>load_proxy() , 5000 );
setInterval(()=>load_accounts() , 5000 );
setInterval(function(){
if( !inprogress)
{
init();
}
} , 2000 );
function load_proxy(){
var lines = fs.readFileSync('./proxy.txt', 'utf-8')
.split('
');
for(var i = 0 ; i< lines.length ; i++ )
{
let line = lines[i];
if(line == '' || typeof line == 'undefined')
{
continue ;
}
line = line.replace('
' , '');
if(PROXYDB.includes(line))
continue ;
PROXYSTACK.push(line);
PROXYDB.push(line);
}
}
function load_accounts(){
var lines = fs.readFileSync('./accounts.txt', 'utf-8')
.split('
');
for(var i = 0 ; i< lines.length ; i++ )
{
let line = lines[i];
if(line == '' || typeof line == 'undefined')
{
continue ;
}
line = line.replace('
' , '');
if(ACCOUNTDB.includes(line))
continue ;
ACCOUNTDB.push(line);
ACCOUNTSTACK.push(line);
}
}
async function init(){
inprogress = true ;
if(PROXYSTACK.length <= 0 )
{
console.log('========================================= > OUT OF PROXY !!!!');
inprogress = false ;
return ;
}
if(ACCOUNTSTACK.length <= 0 )
{
console.log('========================================= > OUT OF ACCOUNT !!!!');
inprogress = false ;
return ;
}
var ipport = PROXYSTACK.pop().replace('
' , '');
console.log(` ----> current ${ipport} `);
var browser = await puppeteer.launch({headless: true , args: ['--proxy-server=' + ipport , '--no-sandbox', '--disable-setuid-sandbox' , ]});
browser._process.once('close', () => {
console.log(' ------------------------ closed !');
inprogress = false;
});
browser.on('disconnected', () => {
console.log(' ------------------------ disconnecte !');
inprogress = false;
});
var mainpage = await browser.newPage();
await mainpage.setViewport({width: 1200, height: 1000});
while( inprogress )
{
var line_number = ACCOUNTSTACK.length ;
if(line_number == 0 )
{
inprogress = false ;
break ;
}
var account = ACCOUNTSTACK.pop();
console.log(account);
var check = await open_tab(account , line_number , mainpage);
if(check === 'fatalerror')
{
console.log('========================================= > FATAL ERROR CHANGING IP ');
try {
await browser.close();
}
catch (e) {
}
inprogress = false ;
}
}
}
async function open_tab(account , line_num , mainpage ) {
console.log(` ---- > checking ${account} `);
let link = `https://example.com`;
try {
let user_password = account.split(':');
if(!await mainpage.$('#username'))
{
console.log('...loading login page');
await mainpage.goto(link , {timeout: 0});
console.log('...done');
if(await mainpage.$('.fatalerror'))
{
ACCOUNTSTACK.push(account);
await mainpage.screenshot({path: './fatalerror-a-'+line_num+'.jpg' });
return 'fatalerror';
}
console.log('...waitnign for login filds');
await Promise.race([
mainpage.waitForSelector('#username'),
mainpage.waitForSelector('.fatalerror'),
]).catch(function (error) {
throw new Error(error);
});
if(await mainpage.$('.fatalerror'))
{
ACCOUNTSTACK.push(account);
await mainpage.screenshot({path: './fatalerror-b-'+line_num+'.jpg' });
return 'fatalerror';
}
console.log('...done');
}
console.log('...typing user password');
await mainpage.$eval('#username', (el ) => el.value = '' );
await mainpage.$eval('#password', (el ) => el.value = '' );
await mainpage.type('#username', user_password[0], {delay: 10})
await mainpage.type('#password', user_password[1], {delay: 10})
console.log('...done');
console.log('...clicking login button');
await mainpage.click('button.primary-button')
await Promise.race([
mainpage.waitForSelector('.theme-noticeerror-font'), // timeout
mainpage.waitForSelector('.empty-inbox'),
mainpage.waitForSelector('.new-message'),
mainpage.waitForNavigation(),
]).catch(function (error) {
throw new Error(error);
});
console.log('...done');
if (await mainpage.$('.theme-noticeerror-font'))
{
console.log(account + '-- '+ line_num +' --> TIMEOUT')
ACCOUNTSTACK.push(account);
await mainpage.screenshot({path: './timeout'+line_num+'.jpg' });
return 'fatalerror';
}
else if (await mainpage.$('.empty-inbox'))
{
console.log(account + '-- '+ line_num +' --> empty');
wite_to_file('empty.txt' , account );
}
else if (await mainpage.$('.new-message'))
{
console.log(account + '-- '+ line_num +' --> new message')
wite_to_file('newmsg.txt' , account );
}
}
catch(e)
{
console.log(`--------ERRRO----${account}-${line_num}---------------------`);
await mainpage.screenshot({path: './images/error'+line_num+'.jpg' });
ACCOUNTSTACK.push(account);
const html = await mainpage.content();
fs.writeFileSync('./images/error'+line_num+'.html', html);
}
}
function wite_to_file( file , acc){
fs.appendFile('./' + file , `${acc}
` , function (err) {})
}
我不时在我的控制台之间收到此错误。日志：
(node:17535) MaxListenersExceededWarning: Possible EventEmitter memory leak dete cted. 11 lifecycleevent listeners added to [FrameManager]. Use emitter.setMaxLis teners() to increase limit
(node:17535) MaxListenersExceededWarning: Possible EventEmitter memory leak dete cted. 11 framenavigatedwithindocument listeners added to [FrameManager]. Use emi tter.setMaxListeners() to increase limit
我不确定是什么原因造成的，或者它是否严重？
使用--trace-warnings
(node:992) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 framedetached listeners added to [FrameManager]. Use emitter.setMaxListeners() to increase limit
at _addListener (events.js:261:17)
at FrameManager.addListener (events.js:277:10)
at Function.addEventListener (/home/robot/node_modules/puppeteer/lib/helper.js:188:13)
at new NavigatorWatcher (/home/robot/node_modules/puppeteer/lib/NavigatorWatcher.js:50:14)
at Page.waitForNavigation (/home/robot/node_modules/puppeteer/lib/Page.js:618:21)
at open_tab (/home/robot/psn.js:212:22)
at processTicksAndRejections (internal/process/task_queues.js:85:5)
at async init (/home/robot/psn.js:115:21)
(node:992) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 response listeners added to [NetworkManager]. Use emitter.setMaxListeners() to increase limit
at _addListener (events.js:261:17)
at NetworkManager.addListener (events.js:277:10)
at Function.addEventListener (/home/robot/node_modules/puppeteer/lib/helper.js:188:13)
at Page.waitForNavigation (/home/robot/node_modules/puppeteer/lib/Page.js:621:29)
at open_tab (/home/robot/psn.js:212:22)
at processTicksAndRejections (internal/process/task_queues.js:85:5)
at async init (/home/robot/psn.js:115:21)
推荐答案
当调用了太多未完成的同步函数时，通常会出现这种情况。如果所有异步函数都有最小超时(0ms)，它们总是被推到堆栈的末尾，并且它们都不会在调用许多函数的循环之前完成。
无论如何，如果您试图让大量异步事件并行发生，
通过将MaxListeners设置为0来禁用它
process.setMaxListeners(0);
或者，您可以使用for循环(而不是forEach)，将其封装在带有等待的异步函数中，以使您的代码完全同步。如果运行时不是对象，这可以使日志记录更好。
// example of de-parallelizing
(async () => {
const userIds = await myDb.getAllUserIds();
const usersWithoutFirstnames = [];
for (userId of userIds) {
console.log("Getting first name of user:", userId);
const firstName = await myDb.getFirstName(userId);
if (firstName) {
console.log("SUCCESS: ", firstName);
} else {
console.log("First name not found");
usersWithoutFirstnames.push(userId);
}
}
})(); // closures are back
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