Question

我在node.js中使用multer，在c9上使用express，尝试创建元数据读取器。我搜索了很长时间，找不到任何遇到此错误的人。错误是：

TypeError: fields.forEach is not a function
at Multer.setup (/home/ubuntu/workspace/node_modules/multer/index.js:29:12)
at multerMiddleware (/home/ubuntu/workspace/node_modules/multer/lib/make-middleware.js:20:19)
at Layer.handle [as handle_request] (/home/ubuntu/workspace/node_modules/express/lib/router/layer.js:95:5)
at next (/home/ubuntu/workspace/node_modules/express/lib/router/route.js:131:13)
at Route.dispatch (/home/ubuntu/workspace/node_modules/express/lib/router/route.js:112:3)
at Layer.handle [as handle_request] (/home/ubuntu/workspace/node_modules/express/lib/router/layer.js:95:5)
at /home/ubuntu/workspace/node_modules/express/lib/router/index.js:277:22
at Function.process_params (/home/ubuntu/workspace/node_modules/express/lib/router/index.js:330:12)
at next (/home/ubuntu/workspace/node_modules/express/lib/router/index.js:271:10)
at serveStatic (/home/ubuntu/workspace/node_modules/express/node_modules/serve-static/index.js:74:16)

我尝试提交上传文件后得到它。我认为这意味着它没有正确安装，但我尝试过以某种方式重新安装。它看起来是最新的：

{  "name": "workspace",


"version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "dependencies": {
    "body-parser": "^1.15.2",
    "cookie-parser": "~1.4.3",
    "debug": "~2.2.0",
    "express": "~4.13.4",
    "jade": "~1.11.0",
    "morgan": "~1.7.0",
    "multer": "^1.2.0",
    "serve-favicon": "~2.3.0"
  }
}

这是我的代码：

app.js

var express = require('express');
var app = express();
var path = require('path');
var multer  = require('multer');
var upload = multer({ dest: __dirname + '/public/uploads/'});
var bodyParser = require('body-parser');

app.use(bodyParser.json());

app.use(express.static(path.join(__dirname, 'public')));

app.get('/', function (req, res) {
  res.sendFile(path.join(__dirname, 'index.html'));
});

app.post('/file-upload', upload.fields('files'), function (req, res, next) {
  console.log(req.files);
  console.log(req.body);
});

app.listen(process.env.PORT, function () {
  console.log('app listening on port ' + process.env.PORT );
});

和前端：

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<html>
  <body>
    <div align='center'>
      <form method="post" enctype="multipart/form-data" action="/file-upload" name="upload">
      <h1>Upload a file</h1>
      <input type="file" id="fileUpload"></input>
      <h2>View its Metadata</h2>
      <button type="submit" value="submit" id="submit">submit</button>
      </form>
    </div>

  </body>
</html>

从中删除'文件' upload.fields（）给出错误

TypeError: Cannot read property 'forEach' of undefined

我只是尝试上传单个文件，但如果我使用

app.post('/file-upload', upload.single('file'), function (req, res, next) {
  console.log(req.file);
  console.log(req.body);
});

// or upload.single()

我的控制台输出

undefined
{}

我希望我遗漏一些简单的东西。我已经引用了所有这些主题，还没有找到适合我的解决方案：

hot multer issues

req files undefined

nodejs-multer-is-not-working

express-multer-cannot-read-property-profileimage-of-undefined

multer-callbacks-not-working

multer-node-eacces-error-on-c9-io

multer-configuration-with-app-use-returns-typeerror

Github multer issues thread

Answer 1

非常简单。发布后五分钟发现。如果有人犯了同样的错误，我会把它留在这里。

问题出在我的前端：

<input type="file" id="fileUpload"></input>

需要

<input type="file" id="file"></input>

Multer TypeError：fields.forEach不是函数

1 个答案: