multer-s3-transform文件上传不起作用

Question

我正在multer-s3-transform将文件上传到s3，但是在上传之前我想调整文件大小，并保存为两个不同的大小。以下是我的代码，没有错误发生，但是文件未上传。

let multer = require("multer-s3-transform");
const aws = require('aws-sdk');
const sharp = require('sharp');

aws.config.update({
  secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
  accessKeyId: process.env.AWS_ACCESS_KEY_ID
);

const s3 = new aws.S3();
var upload = multer({
  storage: multerS3({
    s3: s3,
    bucket: process.env.AWS_BUCKET_NAME,
    shouldTransform: function (req, file, cb) {
      console.log("hereeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee");
      let originalname = file.originalname;
      file.stream.once('data', async function (firstChunk) {
        let magic = firstChunk.toString('hex', 0, 4);
        let extName = path.extname(originalname).toLowerCase();
        // let filename = req.file.fieldname + '-' + Date.now() + path.extname(req.file.originalname);
        if (checkMagicNumbers(magic, extName, req)) {
          console.log("Valid File***************************");
          cb(null, true);
        }
      });
    },
    transforms: [{
      id: 'original',
      key: async function (req, file, cb) {
        let basePath = await getDynamicFilePath(req, false);
        console.log(basePath, "Path ^^^^^^^^^^^^^^^^^^^^^^^");
        let filePath = basePath;
        let filename;
        if (req.params.container === "resumes") {
          void function (req, file, callback) {
            filename = Date.now().toString() + '-' + file.originalname;
            filePath += "/cropped_" + filename;
          }()
        } else {
          filename = Date.now().toString();
          filePath += "/cropped_" + filename;
        }
        console.log(filePath, "path -------------------");
        cb(null, filePath);
      },
      transform: function (req, file, cb) {
        cb(null, sharp().resize(330, 512))
      }
    }
    {
      id: 'thumbnail',
      key: async function (req, file, cb) {
        let basePath = await getDynamicFilePath(req, false);
        console.log(basePath, "Path ^^^^^^^^^^^^^^^^^^^^^^^");
        let filePath = basePath;
        let filename;
        if (req.params.container === "resumes") {
          void function (req, file, callback) {
            filename = Date.now().toString() + '-' + file.originalname;
            filePath += "/normal" + filename;
          }()
        } else {
          filename = Date.now().toString();
          filePath += "/normal_" + filename;
        }
        console.log(filePath, "path -------------------");
        cb(null, filename);
      },
      transform: function (req, file, cb) {
        cb(null, sharp().resize(1200, 628));
      }
    }
    ]
  })
}).single("file");
upload(req, res, function (err, filePath) {
  console.log(err, "Error");
  console.log(filePath, "*************");
});

如果我使用from multer-s3，则一切正常，除了图像大小调整，但multer-s3-transform没有错误发生，并且文件未上传，并且从不进入以下行：

console.log(err, "Error"); console.log(filePath, "*************");

我在下面的代码块中发现了问题，它要检查文件的幻数。

file.stream.once('data', async function (firstChunk) {
    let magic = firstChunk.toString('hex', 0, 4);
    let extName = path.extname(originalname).toLowerCase();
    // let filename = req.file.fieldname + '-' + Date.now() + path.extname(req.file.originalname);
    if (checkMagicNumbers(magic, extName, req)) {
      console.log("Valid File***************************");
      cb(null, true);
    }
  });

如果我对此发表评论，那么一切都会正常。似乎在获取不可思议的文件数量时，文件更改为流，并且上传不起作用，将流更改回文件的方法可能有效。

Answer 1

对我来说更改为以下有效。

let uploadToCloud = (req, res) => {
let bufferUpload = multer({
  storage: multer.memoryStorage(),
  limits: {
    fileSize: 10485760
  }
}).single('file');
bufferUpload(req, res, async function (err) {
  try {
    let buffer = new Buffer(req.file.buffer);
    let magic = buffer.toString('hex', 0, 4);
    let extName = path.extname(req.file.originalname).toLowerCase();
    let filename;
    if (checkMagicNumbers(magic, extName, req)) {
       // Your codes
    }
  } catch (error) {
    res.status(400).json(error);
    res.end();
    return;
  }
 });
};