[webkit-dev] Accept- & Content-Resolution headers proposal

Windy Road tom at windyroad.org
Mon Jun 11 22:40:18 PDT 2007


Are there any plans for Apache to support "Feature negotiation" as
specified in RFC 2295
(see http://www.ietf.org/rfc/rfc2295 )?

FYI the back story to this request is from a discussion on the
webkit-dev mailing list regarding having images served to a client
dependant on its resolution and/or viewport width. Normal browsers may
get an the image as 600px across, small screen devices may get an
image that is 150px across and browser requesting the image for
printing purposes may get an image that is 1200px across.

The idea would be to able to create a type-map file for the images
like or similar to the following:

URI: image

URI: image-1200x1000.jpg
Content-feature: width=1200; qs=0.9
Content-feature: height=1000; qs=0.9

URI: image-600x500.jpg
Content-feature: width=600; qs=1.0
Content-feature: height=500; qs=1.0

URI: image-300x250.jpg
Content-feature: width=300; qs=0.6
Content-feature: height=250; qs=0.6

URI: image-150x125.jpg
Content-feature: width=150; qs=0.3
Content-feature: height=125; qs=0.3

And have Apache perform server side selection to pick the variant
dependant of the "Accept-Features" portion of the request.  e.g. a
browser on a small display would send "Accept-Features:
width=[100-250], height=[100,200], *" and image-150x125.jpg would be
selected by Apache.

BTW if you are wondering why the image-1200x1000.jpg has a lower qs
than image-600x500.jpg, this is so that in the default scenario (no
Accept-Features sent) the smaller image is sent and the larger
bandwidth consuming image is only sent when specifically requested
(e.g. for printing).


Tom Howard

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