上传到 S3 的文件打不开

Question

我正在开发 nodejs api 以将文件上传到我的 AWS s3。我关注了一些在线文章并使用了下面的代码。文件 (images/word/pdf) 成功上传到 s3。但是他们不打开。或者在本地下载打开报错。这里注意到的一件事是，通过我的网络应用程序上传的文件具有元数据内容类型：“application/octet-stream”，而手动上传到 s3 的文件具有元数据内容类型：“image/jpeg”。我错过了什么吗？这是我的 nodejs api：

    app.post("/uploadfile", upload.single("file"), async (req, res) => {
      try {
        console.log(req.file);
        var file = req.file;
    
        const fileStream = fs.createReadStream(file.path);
    
        const params = {
          Bucket: bucketName,
          Key: file.originalname,
          Body: fileStream,
        };
        const result = await s3.upload(params).promise();
        return res.status(200).send({
          ok: true,
          message: "File upload successful",
          location: result.Location,
        });
      } catch (err) {
        res.status(500).send({
          ok: false,
          message: "Failed to upload file. Error: " + err.message,
        });
      }
    });

前端代码：

const [file, setFile] = useState();
  const onSubmit = async (data) => {
    console.log(data);
    const fileData = new FormData();
    fileData.append("upload", file);

    const uploadResult = await uploadFile(fileData);
    console.log(uploadResult);
}

const uploadFile = async (data) => {
  const requestOptions = {
    method: "POST",
    body: data,
  };
  const endPoint = DEV_API_URL + "uploadfile";
  const response = await fetch(endPoint, requestOptions);
  const responseJson = await response.json();
  return responseJson;
};

Answer 1

配置 Multer 以将文件存储在内存中：

const multer = require('multer');

const upload = multer({
  storage: multer.memoryStorage(),
});

现在，将文件缓冲区直接传递给 s3。另外，将 ContentType 添加到选项中：

app.post("/uploadfile", upload.single("file"), async (req, res) => {
  try {
    console.log(req.file);
    const file = req.file;

    const params = {
      Bucket: bucketName,
      Key: file.originalname,
      Body: file.buffer,
      ContentType: file.mimetype
    };
    const result = await s3.upload(params).promise();
    return res.status(200).send({
      ok: true,
      message: "File upload successful",
      location: result.Location,
    });
  } catch (err) {
    res.status(500).send({
      ok: false,
      message: "Failed to upload file. Error: " + err.message,
    });
  }
});