- From: Julian Reschke <julian.reschke@gmx.de>
- Date: Sun, 25 Jun 2017 12:50:30 +0200
- To: Willy Tarreau <w@1wt.eu>
- Cc: ietf@ietf.org, httpbis-chairs@ietf.org, Mark Nottingham <mnot@mnot.net>, draft-ietf-httpbis-early-hints@ietf.org, ietf-http-wg@w3.org, alexey.melnikov@isode.com
On 2017-06-25 12:46, Willy Tarreau wrote: > Hi Julian, > > On Sun, Jun 25, 2017 at 12:11:29PM +0200, Julian Reschke wrote: >> An intermediary MAY drop the informational response. (...) >> >> That seems to contradict a MUST-level requirement in RFC 7231 >> (https://www.greenbytes.de/tech/webdav/rfc7231.html#rfc.section.6.2.p.3) > > Not completely. An intermediary not aware of 103 may map it to 100. If It may do so, but it's not allowed to (IMHO). > the intermediary inserted an "Expect: 100 continue" header field, we > can reasonably imagine that such an intermediary might also drop the > returning 103. This wording in 7231 may even encourage some implementations > to do so : "A proxy MUST forward 1xx responses unless the proxy itself > requested the generation of the 1xx response". Speaking about 1xx here > may be read as "I asked for 100, I'm receiving 1xx so that matches". But that sounds like a bug in the proxy to me. A 103 is not a 100. >> Server response: >> >> HTTP/1.1 103 Early Hints >> Link: </style.css>; rel=preload; as=style >> Link: </script.js>; rel=preload; as=script >> >> HTTP/1.1 200 OK >> Date: Fri, 26 May 2017 10:02:11 GMT >> Content-Length: 1234 >> Content-Type: text/html; charset=utf-8 >> Link: </style.css>; rel=preload; as=style >> Link: </script.js>; rel=preload; as=script >> >> <!doctype html> >> [... rest of the response body is ommitted from the example ...] >> >> The example suggests that early hints are repeated in the final response. Do >> they have to, actually? > > If we imagine that clients ignore 103 or that intermediaries occasionally > drop it, I think it's desirable to send them. Said differently, the 103 > response prepends a copy of the Link header fields that the final response > is supposed to present to help the client fetch them earlier. > ... Understood. But is this a requirement or just a suggestion? Does a client need to forget the information from the 103 when it's not repeated in the final response? Best regards, Julian
Received on Sunday, 25 June 2017 10:51:33 UTC