Re: Concepts to improve Http2.0

On 29/07/2016 11:07 p.m., Mark Nottingham wrote:
> On 29 Jul 2016, at 9:50 AM, Amos Jeffries wrote:
>>
>> On 28/07/2016 6:30 p.m., Poul-Henning Kamp wrote:
>>> --------
>>> In message <em51dddd7f-de76-4e87-abcb-0f315b115499@bodybag>, "Adrien de Croy" w
>>> rites:
>>>
>>>> The problem with deferring headers in responses to after content, is=20
>>>> that proxies often make policy decisions based on response headers, and=20
>>>> therefore need these to be all up front.
>>>>
>>>> Trailers for this reason are also a problem
>>>
>>> We talked about this in the workshop, and yes, trailers *in general*
>>> is a problem, but the specific trailers people care about are not.
>>>
>>> The trailers people ask for, as far as I understood:
>>>
>>> 	Etag
>>>
>>> 	Set-cookie
>>>
>>> 	Cache-Control(/Expires/Age)
>>>
>>> They are *not* a problem.
>>>
>>
>> Technically true. But those last three are exceedingly annoying if
>> pushed into Trailers. Verging on being an outright attack. Since we
>> reserve cache space and do a lot of storage activity before finding out
>> whether its actually not cacheable after all. Usually something else
>> potentially useful got discarded to make room for it as well.
> 
> Trailer: ETag would probably be a good hint about that...
> 

By the last three I was meaning "Cache-Control(/Expires/Age)" in PHK's list.

Taking a second thought about it there are also some hidden security
considerations around potentially storing the reply to non-volatile
storage when a 'Cache-Control:no-store' is deferred to Trailers.

Amos

Received on Friday, 29 July 2016 11:41:06 UTC