ChunkedUploady to AWS S3 (Multipart Upload)

[peacockbah]

We have the desire to leverage chunked uploady to send multi-part uploads to S3 using signedURLs.

We assume it'll be fine to hit our backend to generate a presigned URL in the item start listener & keep track of...

How can we update the URL per chunk to work with these presigned URLs? (https://aws.amazon.com/blogs/compute/uploading-large-objects-to-amazon-s3-using-multipart-upload-and-transfer-acceleration/) AWS uses a presigned URL PER part on the update.

We're currently looking at something like this:

useChunkStartListener(({ item, chunk }) => {
    const partNumber = chunk.index + 1; // S3 part numbers start at 1
    const urls = presignedUrls[item.id];
    
    if (!urls || !urls[partNumber]) {
      console.error(`No pre-signed URL found for part ${partNumber}`);
      return;
    }
    
    // This is the key part - we're returning a custom URL and options
    // for this specific chunk
    return {
      url: urls[partNumber],
      sendOptions: {
        method: 'PUT', // S3 pre-signed URLs expect PUT
        headers: {
          'Content-Type': item.file.type,
        }
      }
    };
  });

Above is untested, trying to ask some questions before we go down this route :)
Thank you for your time!

[yoavniran]

hey @peacockbah
Exactly. The useChunkStartListener event hook is the way to go.