Omit region from S3 pre-signed URL in aws-sdk-go-v2

Question

Recently I migrated a code base from aws-sdk-go v1 to v2. But I noticed a difference that it seems isn't described on the migration guide, the pre-signed URL generated between v1 and v2 has changed:

• v1: https://s3.amazonaws.com/<bucket>/<path>
• v2: https://s3.<region>.amazonaws.com/<bucket>/<path>

After some research, I found another Slack thread mentioning that v2 now uses sig4 which includes the region into the URL (here).

My problem is that I need to use the old hostname version without the region because of a legacy code that depends on s3.amazonaws.com hostname matching. So, I was hoping if there is any way to omit the region addition into the pre-signed URL in aws-sdk-go-v2.

Here is the code I am using to generate the S3 pre-signed URL:

input := &s3.GetObjectInput{
    Bucket: aws.String(bucket),
    Key:    aws.String(key),
}

psClient := s3.NewPresignClient(c.s3Client, s3.WithPresignExpires(expires))

res, _ := psClient.PresignGetObject(ctx, input)

res.URL