I am trying to upload file using S3 multipart upload and pre-signed URLs using the Java SDK. I can successfully upload the file without multipart using pre-signed URL. I believe I can use multipart upload with pre-signed URL's provided I generate pre-signed URL's for every file part. However, I am not certain how to initiate the multipart upload as all examples that I have come across seem to mention the s3 credentials for initiating the multipart (and I need to avoid using AWS credentials for this request & was the reason behind using pre-signed URL's). Any insights on how to go about solving this would be quite welcome.
The intention is to avoid using any AWS credentials where the request is initiated from. If this is not possible using pre-signed URL's and multipart uploads, suggest an alternative whereby one can use temporary credentials on the upload requesting side without this upload requesting side having to rely on AWS credentials.
I realize I can initiate a multipart upload request (which takes in the bucket name and object key but it does not work without credentials). any thoughts?