Sethe23 Sethe23 - 1 year ago 297
Node.js Question

Node Multer unexpected field

I'm working on uploading a file to my app using the multer npm module.

The multer function I have defined is to allow a single file uploaded to the file system. Everything works during run time; the issue is after I upload the file I get an error below. Any advice appreciated on where to look.


Unexpected field

Error: Unexpected field
at makeError (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\lib\make-error.js:12:13)
at wrappedFileFilter (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\index.js:39:19)
at Busboy.<anonymous> (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\lib\make-middleware.js:97:7)
at Busboy.emit (events.js:118:17)
at Busboy.emit (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\node_modules\busboy\lib\main.js:31:35)
at PartStream.<anonymous> (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\node_modules\busboy\lib\types\multipart.js:205:13)
at PartStream.emit (events.js:107:17)
at HeaderParser.<anonymous> (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\node_modules\busboy\node_modules\dicer\lib\Dicer.js:51:16)
at HeaderParser.emit (events.js:107:17)
at HeaderParser._finish (c:\Users\Dev\WebstormProjects\Crunch\node_modules\multer\node_modules\busboy\node_modules\dicer\lib\HeaderParser.js:70:8)


var multer = require('multer');
var app = express();
var fs = require('fs');

//. . .

var upload = multer({ dest: 'upload/'});
var type = upload.single('file');'/upload', type, function (req,res) {
var tmp_path = req.files.recfile.path;
var target_path = 'uploads/' +;
fs.readFile(tmp_path, function(err, data)
fs.writeFile(target_path, data, function (err)


<form action="/upload" method="post" enctype="multipart/form-data">
<input type="file" name='recfile' placeholder="Select file"/>

"dependencies": {
"body-parser": "~1.13.2",
"cookie-parser": "~1.3.5",
"debug": "~2.2.0",
"easy-zip": "0.0.4",
"express": "~4.13.1",
"hbs": "~3.1.0",
"less-middleware": "1.0.x",
"morgan": "~1.6.1",
"multer": "~1.0.0",
"serve-favicon": "~2.3.0"

Answer Source
var multer  = require('multer');
var upload = multer({ dest: 'upload/'});
var fs = require('fs');

/** Permissible loading a single file, 
    the value of the attribute "name" in the form of "recfile". **/
var type = upload.single('recfile');'/upload', type, function (req,res) {

  /** When using the "single"
      data come in "req.file" regardless of the attribute "name". **/
  var tmp_path = req.file.path;

  /** The original name of the uploaded file
      stored in the variable "originalname". **/
  var target_path = 'uploads/' + req.file.originalname;

  /** A better way to copy the uploaded file. **/
  var src = fs.createReadStream(tmp_path);
  var dest = fs.createWriteStream(target_path);
  src.on('end', function() { res.render('complete'); });
  src.on('error', function(err) { res.render('error'); });

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