MaxListenersExceededWarning: Possible EventEmitter memory leak detected

[daviscai]

(node:20128) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 field listeners added. Use emitter.setMaxListeners() to increase limit
(node:20128) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 file listeners added. Use emitter.setMaxListeners() to increase limit
(node:20128) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit
(node:20128) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 end listeners added. Use emitter.setMaxListeners() to increase limit

my code :

'use strict'

const fs = require('mz/fs')
const formidable = require('formidable')

module.exports = uploadFile

function uploadFile(opts) {
  opts = opts || {}

  const form = new formidable.IncomingForm(opts);
  form.uploadDir = opts.uploadDir ||  (os.tmpdir && os.tmpdir()) || os.tmpDir();
  fs.mkdir(form.uploadDir).then(function() {}).catch((err) => {});

  return async (ctx, next)=> {

    if(!ctx.req.get('Content-Type').includes('multipart/form-data')) return next();

    if (undefined !== ctx.req.body) return next()

    await form.parse(ctx.req.raw, function(err, fields, files) {
      if (err) throw err
      let filesObj = {};
      if(files){
          for(let f in files){
              let file = {};
              for(let k in files[f]){
                  if(['domain','size','path','name','type','hash','lastModifiedDate'].includes(k)){
                      file[k] = files[f][k];
                  }
              }
              filesObj[f] = file;
          }
      }
      ctx.req.body = fields
      ctx.req.files = filesObj
    })

    return next();
  }
}

Does anyone know why? and how to fix it ?

[ratwix]

I have the same issue until I wait up to " form.on('end' "

[nchanged]

Same issue here, is it possible to fix it?

app.post("/route", expressFormidable(), (req, res) => {

}_

[xarguments]

Hi, thanks for reporting. @daviscai, @nchanged (and others who encounter this) could you please give more info? When does it happen?

(node:20128) MaxListenersExceededWarning: ... 11 field listeners added. Use emitter.setMaxListeners() to increase limit

There is number "11" in the error. Perhaps it happens when sending 11 upload requests at once?

[pbdm]

got the same issue. perhaps it's because const form = new formidable.IncomingForm(opts) is in a closure and only call once. I think we need to init a new IncomingForm for each request.

[tunnckoCore]

Closing, more info and examples are always welcome.

[cunha-ambisis]

That is still an issue. When I do POST requests, (doesn't matter if it has files or not), that warning displays. I'm not really sure if that impacts perfomance in any way, but I have not noticed any performance impact on my API. _

WARNING MESSAGE: MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 field listeners added to [IncomingForm]. Use emitter.setMaxListeners() to increase limit (Use node --trace-warnings ... to show where the warning was created)

_

I am including formidable middleware on my express.js application like this:

const form = formidable({ multiples: true, uploadDir: path.join(_dirname, 'uploads'), }); app.use((req, , next) => { form.parse(req, (_, fields, files) => { req.fields = fields; req.files = files; next(); }); });

The only middleware I include before fomidable is CORS index.js file atached. Any ideas on why that is happening? I don't like the idea to supress this warning changing the limit. issue.txt :

[GrosSacASac]

@cunha-ambisis you should create a new form on each request (inside app.use) See examples

[cunha-ambisis]

That solved my problem, thanks. My app.use is like this now:

app.use((req, _, next) => { formidable({ multiples: true, uploadDir: path.join(_dirname, 'uploads'), }).parse(req, (, fields, files) => { req.fields = fields; req.files = files; next(); }); });

[bmarianome]

Creating a new instance on each request worked for me. Thanks const formidable = new Formidable({ multiples: true, keepExtensions: true }) formidable.parse(req, (error, fields, files) => { console.log(fields) })

Before i defined the instance in the constructor of a class, and it throw that error.