Is it possible to upload to S3 directly from URL using POST?

Question

I know there is a way to upload to S3 directly from the web browser using POST without the files going to your backend server. But is there a way to do it from URL instead o

Answer 1

I thought I should share my code to achieve something similar. I was working on the backend but possibly could do something similar in frontend though be mindful about AWS credentials likely to be exposed.

For my purposes, I wanted to download a file from the external URL and then ultimately get back the URL form S3 of the uploaded file instead.

I also used axios in order to get the uploadable format and file-type to get the proper type of the file but that is not the requirement.

Below is the snippet of my code:

async function uploadAttachmentToS3(type, buffer) {
  var params = {
   //file name you can get from URL or in any other way, you could then pass it as parameter to the function for example if necessary
    Key : 'yourfolder/directory/filename', 
    Body : buffer,
    Bucket : BUCKET_NAME,
    ContentType : type,
    ACL: 'public-read' //becomes a public URL
  }
  //notice use of the upload function, not the putObject function
  return s3.upload(params).promise().then((response) => {
    return response.Location
  }, (err) => {
    return {type: 'error', err: err}
  })
}

async function downloadAttachment(url) {
  return axios.get(url, {
    responseType: 'arraybuffer'
  })
  .then(response => {
    const buffer = Buffer.from(response.data, 'base64');
    return (async () => {
      let type = (await FileType.fromBuffer(buffer)).mime
      return uploadAttachmentToS3(type, buffer)
    })();
  })
  .catch(err => {
    return {type: 'error', err: err}
  });  
}

let myS3Url = await downloadAttachment(url)

I hope it helps people who still struggle with similar issues. Good luck!