S3 上传 Excel 文件并通过 SignedURL 下载

Question

I'm trying to upload an excel file into S3 and download it via a signedURL. What I've noticed is that the object comes back in a different file-type instead of the expected xlsx type, and thus is unreadable locally.

I have two lambdas, one for uploading the object and another for retrieving the signedURL.

Upload:

async function () => {
  const s3 = new aws.S3({ signatureVersion: 'v4' })
  const params = {
    Bucket: bucket,
    Key: key
  }

  try {
    const signedURL = await s3.getSignedUrl('getObject', params)
    return response(200, signedURL)
  } catch (err) {
    console.log(JSON.stringify(err))
    return response(400, err)
  }
}

GetSignedURL:

async function () => {
  const s3 = new aws.S3({ signatureVersion: 'v4' })
  const params = {
     Bucket: bucket,
     Key: key
  }

  try {
     const signedURL = await s3.getSignedUrl('putObject', params)
     return response(200, { signedURL, key })
  } catch (err) {
    return response(400, err)
  }
}

I'm guessing that the file doesn't actually get saved with its original file-type and S3 actually just converts it to text-file. Maybe I need an additional parameter or package to explicitly save it as an Excel file. Please let me know your thoughts!

Answer 1

You are missing the ContentType in params. Im not sure if this one is the right one for excel but providing the correct content type should address the issue. I had a similar issue when uploading images. I forgot to set the ContentType to image/jpeg

const params = {
    Bucket: bucket,
    Key: key,
    ContentType: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
  }

 Other possible options "xls" => "application/vnd.ms-excel", "xlsx" => "vnd.ms-excel",