文件过大错误处理Nodejs Express Multer

Question

我在ExpressJS中使用multer。我想将文件上传限制在0.5 MB以内。

var limits = { fileSize: 0.5 * 1024 * 1024 };
var upload = multer({ dest: './public/uploads/', limits: limits
 }).single('upl')
 app.post('/',upload, function (req, res) {
  upload(req, res, function (err) {
    if (err) {
            console.log("cs " + err);
      return
    }
           res.end('You new avatar is uploaded')
    // Everything went fine
  })
})

当文件低于0.5 MB时，我可以看到"你的新头像上传了"，但当它结束时，我得到了

Error: File too large
   at makeError (C:UsersOwnerDesktopnodejs projectsdummynode_modulesmulterlibmake-error.js:12:13)
   at abortWithCode (C:UsersOwnerDesktopnodejs projectsdummynode_modulesmulterlibmake-middleware.js:77:22)
   at FileStream.<anonymous> (C:UsersOwnerDesktopnodejs projectsdummynode_modulesmulterlibmake-middleware.js:139:11)
   at emitNone (events.js:80:13)
   at FileStream.emit (events.js:179:7)
   at PartStream.onData (C:UsersOwnerDesktopnodejs projectsdummynode_modulesbusboylibtypesmultipart.js:220:18)
   at emitOne (events.js:90:13)
   at PartStream.emit (events.js:182:7)
   at readableAddChunk (_stream_readable.js:153:18)
   at PartStream.Readable.push (_stream_readable.js:111:10)

显然，我永远不希望最终用户看到这个。我该如何正确处理？

Answer 1

试着这样重写（先删除"上传"）：

app.post('/', function (req, res) {
  upload(req, res, function (err) {
    if (err) {
        console.log("cs " + err);
      return
    }
    res.end('You new avatar is uploaded')
    // Everything went fine
  })

Answer 2

我在server.js文件的末尾创建了一个Express处理程序。

1. 将处理程序函数放在所有app.use()之后，检查multer是否出现此错误并发送所需的数据。我的代码发送LIMIT_FILE_SIZE字符串

app.use(() => (err: Error, req: Request, res: Response, next: NextFunction) => {
    if (err instanceof multer.MulterError) {
        return res.status(418).send(err.code);
    }
});

文档：http://expressjs.com/en/guide/error-handling.html#error-处理