W3C home > Mailing lists > Public > ietf-http-wg@w3.org > January to March 2003

expect header, clarification of status

From: Stefan Eissing <stefan.eissing@greenbytes.de>
Date: Tue, 28 Jan 2003 14:09:16 +0100
To: ietf-http-wg@w3.org
Message-Id: <B464EBB3-32C1-11D7-A23E-00039384827E@greenbytes.de>

Dear Experts,

I'd like to get a clarification of the HTTP/1.1 Expect header (RFC  
2616, 14.20).
This feature is very useful to authoring clients, however it currently  
causes
interoperability problems far outweighting the potential benefits.

There has been discussion on the http-wg mailing list ([1]) with the  
statement
by Roy that 2616 has broken compatibility to 2068.

There is however no clarification in the errata[2].

The conclusion I draw from the mentioned discussion is that
a) clients, talking to HTTP/1.1 servers, cannot rely on correct
     Expect header support, since they may be talking to 2068
     compliant servers.
b) Requests which have a body will cause the client to hang
    on a 2068 server. Unfortunately, using Expect together with
    PUT is one of the more attractive use cases.

Assuming these conclusions are correct, do you have any opinion
which direction WebDAV should take in this matter? It is highly
desirable to offer something like Execpt: 100-continue to a client,
before it tries PUTting its 100MB file onto a server.

As far as I can see, announcing support for Expect in a OPTIONS
response seems to be one way to move forward. Are there other
ideas how to make Except usable to clients?

//Stefan

1)  
http://lists.w3.org/Archives/Public/ietf-http-wg-old/1998MayAug/ 
0192.html
2) http://purl.org/NET/http-errata
Received on Tuesday, 28 January 2003 08:09:46 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 27 April 2012 06:49:22 GMT