How to forbid auto-redirections in open-uri?

Ruby
1

Hi

Is there a way to forbid the redirections in open-uri?

When I use open-uri to open

"http://www.youtube.com/get_video?video_id=tRTk0RPXtW4&t=OEgsToPDskKxoaqtuZPaCfByGHs4LL6K
", I just wish to obtain the film real url
address-“http://sjc-v98.sjc.youtube.com/get_video?video_id=tRTk0RPXtW4”,
rather than automatically download the film. How should I do? Thanks!