In the case of 100-continue a 417 response means that 100
Continue interim response can not be expected to be seen and the client
needs to resend the request only using the delay heuristics when sending
request entities (PUT/POST etc..), and then obviously without the
"Expect: 100-continue".
What means "using the delay heuristics" ? Why it should be necessary to send
using delays ?
Heuristics ?!
Some client can crate request with both this header and http1.0 protocol ?!
----- Original Message -----
From: "Henrik Nordström" <henrik@xxxxxxxxxxxxxxxxxxx>
To: "Riccardo Castellani" <r.castellani@xxxxxxxxxxxxxxx>
Cc: "'Amos Jeffries'" <squid3@xxxxxxxxxxxxx>; <squid-users@xxxxxxxxxxxxxxx>
Sent: Friday, February 19, 2010 9:15 PM
Subject: Re: R: [squid-users] HTTP/1.0 417 Expectation failed
fre 2010-02-19 klockan 14:57 +0100 skrev Riccardo Castellani:
I ask if Squid previous versions ignored Expect header forwarding request
to
server.
But now why Squid code (2.7 version) detects this header and it handles
it
as error ? Why has this Squid behaviour been modified ?
Because more and more of HTTP/1.1 is getting implemented.
Part of getting HTTP/1.1 implemented is proper processing of Expect,
which includes responding with 417 if the Expect condition can not be
fulfilled.
Any software sending Expect also need to be prepared to receive a 417
response back as response to the expectation and deal with it
accordingly. In the case of 100-continue a 417 response means that 100
Continue interim response can not be expected to be seen and the client
needs to resend the request only using the delay heuristics when sending
request entities (PUT/POST etc..), and then obviously without the
"Expect: 100-continue".
Due to the amount of broken software out there not prepared to deal with
417 responses Squid-2.7 has a directive to disable 100-continue
expectation processing. ignore_expect_100
Regards
Henrik
