使用express-fileupload后req.files未定义

Question

I'm trying to upload code on my React website. The problem is I see my file being uploaded, but the server can't find it in the request. By the way, the google scholar api works and is unrelated to my problem, but I kept it in server.js just in case it's the problem.

I've tried adding a form tag around my inputs. I've tried using multer instead. I've tried adding a content-type to headers in fetch. I have redirected output of my code into a log file and grepped for file.

PrivateCode.js

import React, {Component} from 'react'
import './PrivateCode.css'

class PrivateCode extends Component {
  state = {
    file: null,
    isLoading: false
  }

  changeHandler = (e) => {
    this.setState({file: e.target.files[0]})
  }

  onClickHandler = (e) => {
    fetch('/upload', {
      method: 'POST',
      body: this.state.file
    }).then(
      response => response.json()
    ).catch(
      err => console.log(err)
    )
  }

  render() {
    return(
      <div>
        Private Code
        <p className="description">
          Description: Search for files previously uploaded based on snippets of code.
        </p>
        <input
          type="file"
          name="code"
          id="fileinput"
          onChange={this.changeHandler}
        />
        <button 
          type="button" 
          onClick={this.onClickHandler}
          className="submitButton"
        >Upload</button>
      </div>
    )
  }
}

export default PrivateCode

server.js

var express = require('express')
var cors = require('cors')
var app = express()
var scholar = require('google-scholar')
var fileUpload = require('express-fileupload')
const port = 5000

app.use(cors())
app.use(fileUpload())
app.listen(port, () => {
  console.log("Server up!")
})

app.post('/upload', function(req, res) {
  console.log(req)
  if (!req.file) {
    console.log("Not found")
    res.send("File not found")
    return
  }
  var file = req.file
  console.log(file)
  res.send("File uploaded!")
})

app.get('/googlescholar_backend/:query', (req, res) => {
  var query = req.params.query
  scholar.search(
    query
  ).then(
    data => res.send(data)
  ).catch(
    err => console.log(err)
  )
})

You will find that after uploading a file, a "Not found" message will appear with respect to server.js.

server.log

Server up!
IncomingMessage {
  _readableState: 
   ReadableState {
     objectMode: false,
     highWaterMark: 16384,
     buffer: BufferList { head: null, tail: null, length: 0 },
     length: 0,
     pipes: null,
     pipesCount: 0,
     flowing: null,
     ended: false,
     endEmitted: false,
     reading: false,
     sync: true,
     needReadable: false,
     emittedReadable: false,
     readableListening: false,
     resumeScheduled: false,
     destroyed: false,
     defaultEncoding: 'utf8',
     awaitDrain: 0,
     readingMore: true,
     decoder: null,
     encoding: null },
  readable: true,
  domain: null,
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  socket: 
   Socket {
     connecting: false,
     _hadError: false,
     _handle: 
      TCP {
        reading: true,
        owner: [Circular],
        onread: [Function: onread],
        onconnection: null,
        writeQueueSize: 0,
        _consumed: true },
     _parent: null,
     _host: null,
     _readableState: 
      ReadableState {
        objectMode: false,
        highWaterMark: 16384,
        buffer: [Object],
        length: 0,
        pipes: null,
        pipesCount: 0,
        flowing: true,
        ended: false,
        endEmitted: false,
        reading: true,
        sync: false,
        needReadable: true,
        emittedReadable: false,
        readableListening: false,
        resumeScheduled: false,
        destroyed: false,
        defaultEncoding: 'utf8',
        awaitDrain: 0,
        readingMore: false,
        decoder: null,
        encoding: null },
     readable: true,
     domain: null,
     _events: 
      { end: [Array],
        finish: [Function: onSocketFinish],
        _socketEnd: [Function: onSocketEnd],
        drain: [Array],
        timeout: [Function: socketOnTimeout],
        data: [Function: bound socketOnData],
        error: [Function: socketOnError],
        close: [Array],
        resume: [Function: onSocketResume],
        pause: [Function: onSocketPause] },
     _eventsCount: 10,
     _maxListeners: undefined,
     _writableState: 
      WritableState {
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        highWaterMark: 16384,
        finalCalled: false,
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        ending: false,
        ended: false,
        finished: false,
        destroyed: false,
        decodeStrings: false,
        defaultEncoding: 'utf8',
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        writing: false,
        corked: 0,
        sync: true,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
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        bufferedRequest: null,
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        pendingcb: 0,
        prefinished: false,
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        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: true,
     allowHalfOpen: true,
     _bytesDispatched: 0,
     _sockname: null,
     _pendingData: null,
     _pendingEncoding: '',
     server: 
      Server {
        domain: null,
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        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _server: 
      Server {
        domain: null,
        _events: [Object],
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        _maxListeners: undefined,
        _connections: 1,
        _handle: [Object],
        _usingSlaves: false,
        _slaves: [],
        _unref: false,
        allowHalfOpen: true,
        pauseOnConnect: false,
        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _idleTimeout: 120000,
     _idleNext: 
      TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idlePrev: 
      TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idleStart: 5015,
     _destroyed: false,
     parser: 
      HTTPParser {
        '0': [Function: parserOnHeaders],
        '1': [Function: parserOnHeadersComplete],
        '2': [Function: parserOnBody],
        '3': [Function: parserOnMessageComplete],
        '4': [Function: bound onParserExecute],
        _headers: [],
        _url: '',
        _consumed: true,
        socket: [Circular],
        incoming: [Circular],
        outgoing: null,
        maxHeaderPairs: 2000,
        onIncoming: [Function: bound parserOnIncoming] },
     on: [Function: socketOnWrap],
     _paused: false,
     read: [Function],
     _consuming: true,
     _httpMessage: 
      ServerResponse {
        domain: null,
        _events: [Object],
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        _maxListeners: undefined,
        output: [],
        outputEncodings: [],
        outputCallbacks: [],
        outputSize: 0,
        writable: true,
        _last: false,
        upgrading: false,
        chunkedEncoding: false,
        shouldKeepAlive: false,
        useChunkedEncodingByDefault: true,
        sendDate: true,
        _removedConnection: false,
        _removedContLen: false,
        _removedTE: false,
        _contentLength: null,
        _hasBody: true,
        _trailer: '',
        finished: false,
        _headerSent: false,
        socket: [Circular],
        connection: [Circular],
        _header: null,
        _onPendingData: [Function: bound updateOutgoingData],
        _sent100: false,
        _expect_continue: false,
        req: [Circular],
        locals: {},
        [Symbol(outHeadersKey)]: [Object] },
     [Symbol(asyncId)]: 25,
     [Symbol(bytesRead)]: 0,
     [Symbol(asyncId)]: 26,
     [Symbol(triggerAsyncId)]: 25 },
  connection: 
   Socket {
     connecting: false,
     _hadError: false,
     _handle: 
      TCP {
        reading: true,
        owner: [Circular],
        onread: [Function: onread],
        onconnection: null,
        writeQueueSize: 0,
        _consumed: true },
     _parent: null,
     _host: null,
     _readableState: 
      ReadableState {
        objectMode: false,
        highWaterMark: 16384,
        buffer: [Object],
        length: 0,
        pipes: null,
        pipesCount: 0,
        flowing: true,
        ended: false,
        endEmitted: false,
        reading: true,
        sync: false,
        needReadable: true,
        emittedReadable: false,
        readableListening: false,
        resumeScheduled: false,
        destroyed: false,
        defaultEncoding: 'utf8',
        awaitDrain: 0,
        readingMore: false,
        decoder: null,
        encoding: null },
     readable: true,
     domain: null,
     _events: 
      { end: [Array],
        finish: [Function: onSocketFinish],
        _socketEnd: [Function: onSocketEnd],
        drain: [Array],
        timeout: [Function: socketOnTimeout],
        data: [Function: bound socketOnData],
        error: [Function: socketOnError],
        close: [Array],
        resume: [Function: onSocketResume],
        pause: [Function: onSocketPause] },
     _eventsCount: 10,
     _maxListeners: undefined,
     _writableState: 
      WritableState {
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        highWaterMark: 16384,
        finalCalled: false,
        needDrain: false,
        ending: false,
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        finished: false,
        destroyed: false,
        decodeStrings: false,
        defaultEncoding: 'utf8',
        length: 0,
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        sync: true,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
        writecb: null,
        writelen: 0,
        bufferedRequest: null,
        lastBufferedRequest: null,
        pendingcb: 0,
        prefinished: false,
        errorEmitted: false,
        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: true,
     allowHalfOpen: true,
     _bytesDispatched: 0,
     _sockname: null,
     _pendingData: null,
     _pendingEncoding: '',
     server: 
      Server {
        domain: null,
        _events: [Object],
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        _maxListeners: undefined,
        _connections: 1,
        _handle: [Object],
        _usingSlaves: false,
        _slaves: [],
        _unref: false,
        allowHalfOpen: true,
        pauseOnConnect: false,
        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _server: 
      Server {
        domain: null,
        _events: [Object],
        _eventsCount: 2,
        _maxListeners: undefined,
        _connections: 1,
        _handle: [Object],
        _usingSlaves: false,
        _slaves: [],
        _unref: false,
        allowHalfOpen: true,
        pauseOnConnect: false,
        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _idleTimeout: 120000,
     _idleNext: 
      TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idlePrev: 
      TimersList {
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        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idleStart: 5015,
     _destroyed: false,
     parser: 
      HTTPParser {
        '0': [Function: parserOnHeaders],
        '1': [Function: parserOnHeadersComplete],
        '2': [Function: parserOnBody],
        '3': [Function: parserOnMessageComplete],
        '4': [Function: bound onParserExecute],
        _headers: [],
        _url: '',
        _consumed: true,
        socket: [Circular],
        incoming: [Circular],
        outgoing: null,
        maxHeaderPairs: 2000,
        onIncoming: [Function: bound parserOnIncoming] },
     on: [Function: socketOnWrap],
     _paused: false,
     read: [Function],
     _consuming: true,
     _httpMessage: 
      ServerResponse {
        domain: null,
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        _maxListeners: undefined,
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        outputCallbacks: [],
        outputSize: 0,
        writable: true,
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        upgrading: false,
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        shouldKeepAlive: false,
        useChunkedEncodingByDefault: true,
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        _removedTE: false,
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        _hasBody: true,
        _trailer: '',
        finished: false,
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        socket: [Circular],
        connection: [Circular],
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        _onPendingData: [Function: bound updateOutgoingData],
        _sent100: false,
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        req: [Circular],
        locals: {},
        [Symbol(outHeadersKey)]: [Object] },
     [Symbol(asyncId)]: 25,
     [Symbol(bytesRead)]: 0,
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     [Symbol(triggerAsyncId)]: 25 },
  httpVersionMajor: 1,
  httpVersionMinor: 1,
  httpVersion: '1.1',
  complete: false,
  headers: 
   { 'x-forwarded-host': 'localhost:3000',
     'x-forwarded-proto': 'http',
     'x-forwarded-port': '3000',
     'x-forwarded-for': '127.0.0.1',
     cookie: 'csrftoken=wKCVCYMHIlDtLeJLXzxOeZerTrQ3oR4LnhL9EUlK0j59TZ1SQ8MZ6LxlSaOKSl7g',
     connection: 'close',
     dnt: '1',
     'content-length': '985',
     origin: 'http://localhost:5000/',
     'content-type': 'text/plain',
     referer: 'http://localhost:3000/privatecode/?code=',
     'accept-encoding': 'gzip, deflate',
     'accept-language': 'en-US,en;q=0.5',
     accept: '*/*',
     'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0',
     host: 'localhost:5000' },
  rawHeaders: 
   [ 'x-forwarded-host',
     'localhost:3000',
     'x-forwarded-proto',
     'http',
     'x-forwarded-port',
     '3000',
     'x-forwarded-for',
     '127.0.0.1',
     'cookie',
     'csrftoken=wKCVCYMHIlDtLeJLXzxOeZerTrQ3oR4LnhL9EUlK0j59TZ1SQ8MZ6LxlSaOKSl7g',
     'connection',
     'close',
     'dnt',
     '1',
     'content-length',
     '985',
     'origin',
     'http://localhost:5000/',
     'content-type',
     'text/plain',
     'referer',
     'http://localhost:3000/privatecode/?code=',
     'accept-encoding',
     'gzip, deflate',
     'accept-language',
     'en-US,en;q=0.5',
     'accept',
     '*/*',
     'user-agent',
     'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0',
     'host',
     'localhost:5000' ],
  trailers: {},
  rawTrailers: [],
  upgrade: false,
  url: '/upload',
  method: 'POST',
  statusCode: null,
  statusMessage: null,
  client: 
   Socket {
     connecting: false,
     _hadError: false,
     _handle: 
      TCP {
        reading: true,
        owner: [Circular],
        onread: [Function: onread],
        onconnection: null,
        writeQueueSize: 0,
        _consumed: true },
     _parent: null,
     _host: null,
     _readableState: 
      ReadableState {
        objectMode: false,
        highWaterMark: 16384,
        buffer: [Object],
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        pipes: null,
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        flowing: true,
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        readableListening: false,
        resumeScheduled: false,
        destroyed: false,
        defaultEncoding: 'utf8',
        awaitDrain: 0,
        readingMore: false,
        decoder: null,
        encoding: null },
     readable: true,
     domain: null,
     _events: 
      { end: [Array],
        finish: [Function: onSocketFinish],
        _socketEnd: [Function: onSocketEnd],
        drain: [Array],
        timeout: [Function: socketOnTimeout],
        data: [Function: bound socketOnData],
        error: [Function: socketOnError],
        close: [Array],
        resume: [Function: onSocketResume],
        pause: [Function: onSocketPause] },
     _eventsCount: 10,
     _maxListeners: undefined,
     _writableState: 
      WritableState {
        objectMode: false,
        highWaterMark: 16384,
        finalCalled: false,
        needDrain: false,
        ending: false,
        ended: false,
        finished: false,
        destroyed: false,
        decodeStrings: false,
        defaultEncoding: 'utf8',
        length: 0,
        writing: false,
        corked: 0,
        sync: true,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
        writecb: null,
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        lastBufferedRequest: null,
        pendingcb: 0,
        prefinished: false,
        errorEmitted: false,
        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: true,
     allowHalfOpen: true,
     _bytesDispatched: 0,
     _sockname: null,
     _pendingData: null,
     _pendingEncoding: '',
     server: 
      Server {
        domain: null,
        _events: [Object],
        _eventsCount: 2,
        _maxListeners: undefined,
        _connections: 1,
        _handle: [Object],
        _usingSlaves: false,
        _slaves: [],
        _unref: false,
        allowHalfOpen: true,
        pauseOnConnect: false,
        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _server: 
      Server {
        domain: null,
        _events: [Object],
        _eventsCount: 2,
        _maxListeners: undefined,
        _connections: 1,
        _handle: [Object],
        _usingSlaves: false,
        _slaves: [],
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        allowHalfOpen: true,
        pauseOnConnect: false,
        httpAllowHalfOpen: false,
        timeout: 120000,
        keepAliveTimeout: 5000,
        _pendingResponseData: 0,
        maxHeadersCount: null,
        _connectionKey: '6::::5000',
        [Symbol(asyncId)]: 5 },
     _idleTimeout: 120000,
     _idleNext: 
      TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idlePrev: 
      TimersList {
        _idleNext: [Circular],
        _idlePrev: [Circular],
        _timer: [Object],
        _unrefed: true,
        msecs: 120000,
        nextTick: false },
     _idleStart: 5015,
     _destroyed: false,
     parser: 
      HTTPParser {
        '0': [Function: parserOnHeaders],
        '1': [Function: parserOnHeadersComplete],
        '2': [Function: parserOnBody],
        '3': [Function: parserOnMessageComplete],
        '4': [Function: bound onParserExecute],
        _headers: [],
        _url: '',
        _consumed: true,
        socket: [Circular],
        incoming: [Circular],
        outgoing: null,
        maxHeaderPairs: 2000,
        onIncoming: [Function: bound parserOnIncoming] },
     on: [Function: socketOnWrap],
     _paused: false,
     read: [Function],
     _consuming: true,
     _httpMessage: 
      ServerResponse {
        domain: null,
        _events: [Object],
        _eventsCount: 1,
        _maxListeners: undefined,
        output: [],
        outputEncodings: [],
        outputCallbacks: [],
        outputSize: 0,
        writable: true,
        _last: false,
        upgrading: false,
        chunkedEncoding: false,
        shouldKeepAlive: false,
        useChunkedEncodingByDefault: true,
        sendDate: true,
        _removedConnection: false,
        _removedContLen: false,
        _removedTE: false,
        _contentLength: null,
        _hasBody: true,
        _trailer: '',
        finished: false,
        _headerSent: false,
        socket: [Circular],
        connection: [Circular],
        _header: null,
        _onPendingData: [Function: bound updateOutgoingData],
        _sent100: false,
        _expect_continue: false,
        req: [Circular],
        locals: {},
        [Symbol(outHeadersKey)]: [Object] },
     [Symbol(asyncId)]: 25,
     [Symbol(bytesRead)]: 0,
     [Symbol(asyncId)]: 26,
     [Symbol(triggerAsyncId)]: 25 },
  _consuming: false,
  _dumped: false,
  next: [Function: next],
  baseUrl: '',
  originalUrl: '/upload',
  _parsedUrl: 
   Url {
     protocol: null,
     slashes: null,
     auth: null,
     host: null,
     port: null,
     hostname: null,
     hash: null,
     search: null,
     query: null,
     pathname: '/upload',
     path: '/upload',
     href: '/upload',
     _raw: '/upload' },
  params: {},
  query: {},
  res: 
   ServerResponse {
     domain: null,
     _events: { finish: [Function: bound resOnFinish] },
     _eventsCount: 1,
     _maxListeners: undefined,
     output: [],
     outputEncodings: [],
     outputCallbacks: [],
     outputSize: 0,
     writable: true,
     _last: false,
     upgrading: false,
     chunkedEncoding: false,
     shouldKeepAlive: false,
     useChunkedEncodingByDefault: true,
     sendDate: true,
     _removedConnection: false,
     _removedContLen: false,
     _removedTE: false,
     _contentLength: null,
     _hasBody: true,
     _trailer: '',
     finished: false,
     _headerSent: false,
     socket: 
      Socket {
        connecting: false,
        _hadError: false,
        _handle: [Object],
        _parent: null,
        _host: null,
        _readableState: [Object],
        readable: true,
        domain: null,
        _events: [Object],
        _eventsCount: 10,
        _maxListeners: undefined,
        _writableState: [Object],
        writable: true,
        allowHalfOpen: true,
        _bytesDispatched: 0,
        _sockname: null,
        _pendingData: null,
        _pendingEncoding: '',
        server: [Object],
        _server: [Object],
        _idleTimeout: 120000,
        _idleNext: [Object],
        _idlePrev: [Object],
        _idleStart: 5015,
        _destroyed: false,
        parser: [Object],
        on: [Function: socketOnWrap],
        _paused: false,
        read: [Function],
        _consuming: true,
        _httpMessage: [Circular],
        [Symbol(asyncId)]: 25,
        [Symbol(bytesRead)]: 0,
        [Symbol(asyncId)]: 26,
        [Symbol(triggerAsyncId)]: 25 },
     connection: 
      Socket {
        connecting: false,
        _hadError: false,
        _handle: [Object],
        _parent: null,
        _host: null,
        _readableState: [Object],
        readable: true,
        domain: null,
        _events: [Object],
        _eventsCount: 10,
        _maxListeners: undefined,
        _writableState: [Object],
        writable: true,
        allowHalfOpen: true,
        _bytesDispatched: 0,
        _sockname: null,
        _pendingData: null,
        _pendingEncoding: '',
        server: [Object],
        _server: [Object],
        _idleTimeout: 120000,
        _idleNext: [Object],
        _idlePrev: [Object],
        _idleStart: 5015,
        _destroyed: false,
        parser: [Object],
        on: [Function: socketOnWrap],
        _paused: false,
        read: [Function],
        _consuming: true,
        _httpMessage: [Circular],
        [Symbol(asyncId)]: 25,
        [Symbol(bytesRead)]: 0,
        [Symbol(asyncId)]: 26,
        [Symbol(triggerAsyncId)]: 25 },
     _header: null,
     _onPendingData: [Function: bound updateOutgoingData],
     _sent100: false,
     _expect_continue: false,
     req: [Circular],
     locals: {},
     [Symbol(outHeadersKey)]: 
      { 'x-powered-by': [Array],
        'access-control-allow-origin': [Array] } },
  route: Route { path: '/upload', stack: [ [Object] ], methods: { post: true } } }
Not found

EDIT: I fixed this by surrounding a form tag around my input!

Answer 1

You need to use body-parser .

const bodyParser = require('body-parser');

// support parsing of application/json type post data
app.use(bodyParser.json());

//support parsing of application/x-www-form-urlencoded post data
app.use(bodyParser.urlencoded({ extended: true }));

And You also need to look connect-multiparty While dealing with req.files

const express = require('express');
const multipart = require('connect-multiparty');

const multipartMiddleware = multipart({ maxFieldsSize: (20 * 1024 * 1024) });

const router = express.Router();

// Convert 
router.use(multipartMiddleware);

Summary : The body-parser will helps you to convert your request from binary to req.body whereas connect-multiparty will help to access uploaded files on the req.files object.

Answer 2

It should be req.files.fileName instead of req.file , also fileName should be the same name you have provided in <input name="fileName" /> . So, in your case it should be

// ...same code
var multipart = require('connect-multiparty');    
var multipartMiddleware = multipart({ maxFieldsSize: (20 * 1024 * 1024) });
app.use(multipartMiddleware);
// ...rest code
app.post('/upload', function(req, res) {
    console.log(req)
    if (!req.files) {
        console.log("Not found")
        res.send("File not found")   
        return
    }
    let file = req.files.code
    console.log(file)
    res.send("File uploaded!")
})

Have a look at this, https://www.npmjs.com/package/express-fileupload