Question

我有一个应用程序，并且在该应用程序中，我想使用某种文件上传机制。

我的要求是：

文件上传后，其名称将更改为唯一的名称，例如uuid4（）。稍后，我将这个名称存储在数据库中。

我写了类似的东西，但是我有几个问题：

const multer = require('multer');
const upload = multer();
router.post('/', middleware.checkToken, upload.single('file'), (req,res,next)=>{

    // key:
    // file : "Insert File Here"

    console.log("req:");
    console.log(req.file);
    const str = req.file.originalname
    var filename = str.substring(0,str.lastIndexOf('.'));
    // I will use filename and uuid for storing it in the database
    // I will generate unique uuid for the document and store the document
    // with that name
    var extension = str.substring(str.lastIndexOf('.') + 1, str.length);

    // HERE!

    res.status(200).json();

})

我已经看到了将其存储在diskStorage中的示例：

var storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, '/tmp/my-uploads')
    },
    filename: function (req, file, cb) {
        cb(null, file.fieldname + '-' + Date.now())
  }
})

var upload = multer({ storage: storage })

但是，据我了解，这是API调用之外的配置。这意味着每次调用此API都无法修改它。我想为文件分配不同的名称，并且需要该名称（uuid）将该名称保存在数据库中。

如何保留此类功能？

Answer 1

不需要。因为您使用的是时间戳。

如果保存到数据库时出错，则可以使用此代码删除上载的文件，以避免将来发生冲突。试试这个：

const multer = require('multer');
const fs = require('fs'); // add this line
var storage = multer.diskStorage({
    destination: function (req, file, cb) {
        // the file is saved to here
        cb(null, '/PATH/TO/FILE')
    },
    filename: function (req, file, cb) {
        // the filename field is added or altered here once the file is uploaded
        cb(null, uuidv4() + '.xlsx')
    }
})
var upload = multer({ storage: storage })


router.post('/', middleware.checkToken, upload.single('file'), (req,res,next)=>{
    // the file is taken from multi-form and the key of the form must be "file"

    // visible name of the file, which is the original, uploaded name of the file
    const name = req.file.originalname;

    // name of the file to be stored, which contains unique uuidv4
    const fileName = req.file.filename;
    // get rid of the extension of the file ".xlsx"
    const file_id = fileName.substring(0, fileName.lastIndexOf('.'));

    // TODO
    // Right now, only xlsx is supported
    const type = "xlsx";

    const myObject = new DatabaseObject({
        _id : new mongoose.Types.ObjectId(),
        file_id: file_id,
        name : name,
        type: "xlsx"
    })

    myObject .save()
    .then(savedObject=>{
        // return some meaningful response
    }).catch(err=>{
        // add this
        // Assuming that 'path/file.txt' is a regular file.
        fs.unlink('path/file.txt', (err) => {
           if (err) throw err;
           console.log('path/file.txt was deleted');
        });
    })
})

另请参阅NodeJS File System Doc

Node.js保存上传的文件

1 个答案: