如何使用 multer expressjs 验证多个文件上传

Question

我遇到 express.js 和 multer 的问题，当我尝试上传 2 个有效图像和 1 个示例 pdf 以验证是否所有图像时，它会将那两个图像上传到一个文件夹中，并且然后它会抛出格式无效的 pdf 错误，我可以先以某种方式验证所有图像然后上传到文件夹还是抛出错误这是我的代码

const fileStorageEngine = multer.diskStorage({
    destination: (req, file, cb) => {
        cb(null, './images');
    },
    filename: (req, file, cb) => {
        cb(null, Date.now()+ '--' +file.originalname);
    }
});
    
const fileFilter = (req, file, cb) => {
    // Reject a file
    if (file.mimetype === 'image/jpeg' || file.mimetype === 'image/jpg' || file.mimetype === 'image/png') {
        cb(null, true);
    } else {
        req.fileValidationError = 'File type not supported';
        cb(null, false);
    }
};
    
const upload = multer({
    storage: fileStorageEngine,
    limits: {
        fileSize: 1024 * 1024 * 5 // Accept files to 5mb only
    }, 
    fileFilter: fileFilter
});

app.post('/multiple', upload.array('images', 3), async(req, res, next) => {
    try {
        console.log("POST Multiple Files: ", req.files);

        if (await req.fileValidationError) {
            throw new Error(req.fileValidationError);
        } else {
            for (let i = 0; i < req.files.length; i++) {
                let storeImage = await StoreImages.create({
                    images: req.files[i].path
                });
        
                if (!storeImage) {
                    throw new Error('Sorry, something went wrong while trying to upload the image!');
                }
            }
            res.status = 200;
            res.render("index", {
                success: true,
                message: "Your images successfully stored!"
            });
        }
    } catch(err) {
        console.log("POST Multiple Error: ", err);

        res.status = 406;
        return res.render('index', {
            error: true,
            message: err.message
        })
    }
});

我想在插入到文件夹、服务器等之前验证所有上传的文件...

Answer 1

我通过在 fileFilter 函数中抛出 cb 函数中的错误找到了解决方案

const fileFilter = (req, file, cb) => {
    // Reject a file
    if(file.mimetype === 'image/jpeg' || file.mimetype === 'image/jpg' || file.mimetype === 'image/png'){
        cb(null, true);
    }else{
        cb(new Error('File type not supported'));
    }
};

如何使用 multer expressjs 验证多个文件上传

How to validate multiple file uploads with multer expressjs

javascript

node.js

express

multer