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Re: handling of unknown 1xx http codes

From: Jamie Lokier <>
Date: Fri, 27 Jun 2008 00:29:40 +0100

Dan Fandrich wrote:
> Does this occur in the wild? With which server and which conditions?
> This patch sound a bit dangerous. For example, the 101 response requires
> that the client switch to a different protocol, which if not done would
> result in a hung transfer or otherwise unsavoury results. The RFC reads
> a bit ambiguous to me. It talks about unexpected 1xx codes, but it doesn't
> differentiate between an unexpected 1xx code that has been defined in
> the RFC (or which there are two) or a 1xx code that has not been defined.

Whatever you do - don't treat a 1xx as the final response and continue
pipelining on that connection. It's part of the HTTP syntax that 1xx
isn't the final response. Treating unknown 1xx as an error and
aborting the connection would be ok.

There is occasionally talk of defining other 1xx codes in
ietf-http-wg, but none being standardised as far as I know. Possibly
through fear of implementations that will break when they see one :-)

-- Jamie
Received on 2008-06-27