For example some question was asked about youtube in the past if it's
cachable or not.
Once we see the request and the response we can say it is cachable.
for example this request:
Host: r8---sn-nhpax-ua8e.googlevideo.com
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:28.0) Gecko/20100101
Firefox/28.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-gb,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://s.ytimg.com/yts/swfbin/player-vflXH_6x-/watch_as3.swf
Connection: keep-alive
##end
should be cachable but forces or accepts gzip.
and indeed it's being cached.
The issue is that the player is using vbr which changes the requests and
responses size and shape each time as far as I understand.
A store log can show that the object is being stored but the next
request is not the same as the previous one that seems pretty similar.
So in a case you do try to cache youtube for example it will be very
hard to cache an application which changes it's way of fetching the same
object in different sizes and shapes.
Eliezer
