Re: [Technical Errata Reported] RFC7540 (5249)

> On Feb 2, 2018, at 1:43 AM, Loïc Hoguin <essen@ninenines.eu> wrote:
> On 02/01/2018 07:32 AM, Willy Tarreau wrote:
>> On Thu, Feb 01, 2018 at 12:43:53PM +1100, Martin Thomson wrote:
>>> The observation is correct.  However, I'm not sure that this is the
>>> solution I would choose.  I'm not sure, but I think that an empty
>>> header field would cause problems.
>> Some intermediaries risk to drop it, considering that empty is equivalent
>> to absent.
> 
> I'm curious about this as I don't recall reading this in the RFCs. [...]

FTR, an empty HTTP/1 field value is definitely not equivalent to absent.  In some cases
it is an error; in other cases it has a distinct meaning (like in Accept). An intermediary
that absent-mindedly removed empty fields is just broken, but that doesn't apply to
CGI (which is not HTTP) nor HTTP2-Settings (which should be listed in Connection to
prevent it from being forwarded).

Cheers,

....Roy

Received on Friday, 2 February 2018 17:10:10 UTC