On Thu, 03 Mar 2011 22:15:58 +0100, Aaron Colwell acolw...@google.com
wrote:
Hi,
I was looking at the resource fetch
algorithmhttp://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#concept-media-load-resourcesection
and fetching
resources
http://www.whatwg.org/specs/web-apps/current-work/multipage/urls.html#fetch
sections of the HTML5 spec to determine what the proper behavior is for
handling
redirects. Both YouTube and Vimeo do 302 redirects to different hostnames
from
the URLs specified in the src attribute. It looks like the spec says that
playback should fail in these cases because they are from different
origins (Section 2.7 Fetching resources bullet 7). This leads me to a few
questions.
1. Is my interpretation of the spec correct? Sample YouTube Vimeo URLs
are
shown below.
YouTube : src : http://v22.lscache6.c.youtube.com/videoplayback?
...
redirect : http://tc.v22.cache6.c.youtube.com/videoplayback?
...
Vimeo : src : http://player.vimeo.com/play_redirect? ...
redirect : http://av.vimeo.com/05 ...
Yes, from what I can tell you're correct, but I think it's not
intentional. The behavior was changed by http://html5.org/r/5111 in
2010-06-25, and this is the first time I've noticed it. Opera (and I
assume most if not all other browsers) already supports HTTP redirects for
video and I don't think it makes much sense to disallow it. For security
purposes, the origin of the resource is considered to be the final
destination, not any of the origins in the redirect chain.
2. What about http: - https: redirects? Some content is required to be
delivered
only via https and this sort of redirect enforces that but isn't
really a
different origin.
Quoting
http://tools.ietf.org/html/draft-abarth-principles-of-origin-00#section-3:
two URLs are part of the same origin (i.e., represent the same principal)
if they have the same scheme, host, and port
Since both the scheme (http vs https) and port (80 vs 443) would be
different, it's considered a different origin.
3. If my interpretation of the spec is correct, are there proposals to
change this
or other specs that allow content providers to signal that these
different hostnames
actually represent the same origin.
I think the force same-origin flag introduced by http://html5.org/r/5111
should be removed from the resource fetch algorithm, but the http vs https
origin issue is not something that can really be changed.
--
Philip Jägenstedt
Core Developer
Opera Software
