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javascript - 处理multer中的错误？

问题描述

对于错误处理 multer 建议

const multer = require('multer')
const upload = multer().single('avatar')

app.post('/profile', function (req, res) {
  upload(req, res, function (err) {
    if (err instanceof multer.MulterError) {
      // A Multer error occurred when uploading.
    } else if (err) {
      // An unknown error occurred when uploading.
    }

    // Everything went fine.
  })
})

我编写了一个自定义中间件来上传不同类型的文件。

const { check } = require("express-validator")
const multer  = require('multer')
const mime = require('mime-types')

const storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, 'uploads/')
    },
    filename: function (req, file, cb) {
        const filename = Date.now()+"-"+file.originalname
        cb(null, filename)
    }
})
const upload = multer({ storage: storage })

const uploadFile = (fieldname,filetypes,fileSize)=>{
    return (req,res,next)=>{
        let file = upload.single(fieldname)
        file(req,res,function(err){
            if (err instanceof multer.MulterError) {
                req.fileError = {
                    param: "image",
                    msg: "Unable to process request"
                }
                return next()
            } else if (filetypes.includes(mime.extension(req.file.mimetype)) === false) {
                req.fileError = {
                    param: "image",
                    msg: `Only ${filetypes.toString()} allowed`
                }                
                return next()
            } else if (req.file.size > fileSize) {
                req.fileError = {
                    param: "image",
                    msg: `File size should not exceed ${formatBytes(req.file.size)}`
                }                
                return next()
            }
        })
    }
}

course_validator = [
    check("name")
    .trim()
    .isLength({min:3,max:100})
    .withMessage("Course name should be between 3 to 100 characters")
]
app.get("/create/post",uploadFile("image",["jpeg","jpg"],122880),(req,res)=>{

    const errors = validationResult(req)
    if(!errors.isEmpty()){
        return res.json({
            status: false,
            error: req.fileError ? [...errors.array(),req.fileError] : errors.array()
        })
    }
})

如果没有错误，那么我只需要将文件上传到文件uploads夹。当我上传除 jpeg 或 jpg 以外的其他文件时，我收到错误消息，即仅允许 jpeg,jpg。这就是我需要的。但问题是文件也被上传到uploads文件夹。

标签： javascriptnode.jsexpressmulter

解决方案

对于自定义错误消息，您可以在此处通过此控制器我在上传图像时检查文件类型，并且在控制器中，如果当时没有选择文件，我将发送一条自定义消息，其中包含简单的 if 条件通过后如果图像和产品都将保存在数据库中

exports.postProduct = (req, res, next) => {
  const title = req.body.title;
  const image = req.file;
  const price = req.body.price;
  const description = req.body.description;

 if (!image) {
        return res.status(422).render("admin/add-product", {
          pageTitle: "Add Product",
          path: "/adminproducts",
          hasError: true,
          product: {
            title: title,
            price: price,
            description: description,
          },
          errorMessage: "Atteched file is not an image!!!",
          validationErrors: [],
        });
      }
  const imageUrl = image.path;

  const product = new Product({
    title: title,
    imageUrl: imageUrl,
    price: price,
    description: description,
    userId: req.user,
  });
  product
    .save()
    .then((results) => {
      console.log("Product Created Successfully");
      res.redirect("/admin/products");
    })
    .catch((err) => {
      console.log(err);
    });
};

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