Le 25 juin 2012 à 13:34, Oscar Otero a écrit :
> For example, for an image 100% width in a div of 400px, the browser would
> send a header indicating it need a 400px width image. This solution is also
> valid for css images (backgrounds, for example) and even for video. The
> values to send could be the same of css values (width, min-width, max-width,
> height, min-height, max-height), for example:
>
> Content-Size: width:400px, min-height: 300px;
There has been a similar proposal for a long time but which has never really
been implemented. It was called "Transparent Content Negotiation" [1] because
it was explicitly listing the alternate available resources for a specific URI.
I was wondering about the possibility of negotiating that way too. [2].
Alternates: {"bigpussycat" {size 1Mo} {dpi 300}},
{"pussycat" {size 100ko} {dpi 72}},
{"tinypussycat" {size 10ko} {dpi 72}
or could be something else for keywords and relevant information. This solution
doesn't really work with the following constraints.
* The client (and owner of the client) knows best about its capabilities and
its context.
* The server knows about the available resources.
* Avoid HTTP Round Trips to discover what are the available resources (HTTP
HEAD, then GET)
You could imagine a system where the "parent" resource is the one containing
the information about all alternate children. But that would make quite a lot
of HTTP headers. No perfect solution.
[1]: http://tools.ietf.org/html/rfc2295
[2]:
http://my.opera.com/karlcow/blog/2011/12/08/responsive-images-and-transparent-content-negotiation-in-http
--
Karl Dubost - http://dev.opera.com/
Developer Relations, Opera Software
