Re: Distinguishing 0-byte request body in HTTP/2

["Roy T. Fielding" <[e-mail]>]

> On Sep 15, 2016, at 3:06 PM, Willy Tarreau <[e-mail]> wrote:
> 
> Hi Roy,
> 
> On Thu, Sep 15, 2016 at 01:13:01PM -0700, Roy T. Fielding wrote:
>>> I'd be tempted to simplify this as "if you're sending a body even an empty
>>> one, announce its size in content-length". Methods like POST and PUT expect
>>> a message body so that should always be done.
>> 
>> No.  It is never a good idea to send extra information just in case you
>> might encounter a broken server.  It is better to send less information and
>> let people fix their own broken code.  Otherwise, the Internet becomes a
>> cesspool of poorly imagined cases that are far less likely to exist than
>> the keel-over-waiting-for-the-extra-TCP-packets cases that always exist.
> 
> But if c-l:0 is supposed to be exactly equivalent to no c-l, then what's
> the purpose of status code 411 ? My understanding no c-l means there is
> no body while c-l: 0 means the body is empty, both of which are totally
> equivalent from a framing perspective, but not necessarily from a
> semantics perspective.
> 
> Regards,
> Willy

CL is present only for message framing and can be removed at any hop.
CL:0 versus no CL has no semantic distinction whatsoever, so any recipient
that chooses to interpret it as a distinction is inherently broken.

....Roy