Update 2: The PR was merged and documentation for redirection following is spray-can can now be found here
Update: I decided to have a crack at implementing this and have sent a PR. Hopefully it will get merged.
There is no way to currently tell spray-can client to follow 3xx
redirects. See this thread for more details.
There is an open ticket, so hopefully this will happen in the future. I'm sure a contribution would be welcomed.