Re: #409: is parsing OBS-FOLD mandatory?

[Amos Jeffries <[e-mail]>]

On 13.12.2012 07:18, Roy T. Fielding wrote:
> On Dec 11, 2012, at 7:48 PM, Mark Nottingham wrote:
>
>> <http://trac.tools.ietf.org/wg/httpbis/trac/ticket/409>
>>
>> """
>> p1 2.5 Conformance and Error Handling says "...recipient MUST be 
>> able to parse any value that would match the ABNF rules..." yet 3.2.2 
>> only make parsing obs-fold a SHOULD. Which is it?
>> """
>>
>> Roy made a proposed edit to remove the MUST NOT generate and change 
>> the SHOULD parse to a MUST parse.
>>  <http://trac.tools.ietf.org/wg/httpbis/trac/changeset/2039>
>
> No, the text still says "Senders MUST NOT generate ...".  I only 
> changed
> the SHOULD parse to a MUST parse, because that was not part of the 
> prior
> decision and is inconsistent with the ABNF requirement below.
>
>> However, this has the effect of un-deprecating line folding; IIRC we 
>> added those requirements because folding is not interoperable.
>
> No, it has the effect of requiring that line-folding be parsed, which
> is required for backwards compatibility with 2616 senders.  However,
> I do not personally know of any senders that send obs-fold.
>

Squid has a few bug reports with traces involving obs-fold in headers. 
Usually associated with complaints or problems handling >64KB long 
headers, and the fold is almost always occuring in custom X-* headers 
from some user generated data that should have been in the entity 
anyway.

Amos