W3C home > Mailing lists > Public > ietf-http-wg-old@w3.org > January to April 1996

Re: 505 HTTP Version Not Supported

From: Daniel DuBois <ddubois@spyglass.com>
Date: Wed, 03 Apr 1996 10:04:55 -0600
Message-Id: <2.2.32.19960403160455.0099ee64@rafiki>
To: Chuck Shotton <cshotton@biap.com>, "Roy T. Fielding" <fielding@avron.ICS.UCI.EDU>, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
At 07:17 AM 4/3/96 -0600, Chuck Shotton wrote:
>At 6:36 PM 4/2/96, Roy T. Fielding wrote:
>>Please note that, among other things, this allows future applications
>>to cease support for older protocols and yet do so in a way that is
>>meaningful to older clients.
>
>I think "meaningful" is a relative term. It isn't going to be very useful
>for a 0.9 client to receive a 505 message, for example. It isn't going to

But a 0.9 client won't ever see the error status code, so what's the point.
(Haven't people pretty much given up on 0.9 doing anything useful in the
future?  There's too many features you can't have when you don't have headers.)

>be much more useful for a 1.0 client to receive a 505 error if it simply
>treats it as an unknown failure.  There are other, existing error codes that
>are interpreted as meaning a particular requested service or method is
>unavailable. If the intent is to let a client know WHY the service or

Neither 501 nor 503 are appropriate.  501 indicates the method is bad, 503
indicates the server is overloaded.  Neither one of those codes should be
overloaded to indicate a protocol version rejection.

>method is unavailable (i.e., because of a protocol version mismatch), why
>don't we just add an entity to the existing error code(s) that clients
>already support?
>This would allow new clients to provide more info to the user and/or switch
>protocol versions to accomodate the server.

If they don't understand 1.1, how would they be able to switch protocol
versions?  There's no 1.05 they could be theoretically upgrading to from 1.0.

>Existing older clients would
>continue to process the error code(s) that existed when they were written
>and respond accordingly.

The appropriate response to a 505 for a 1.0 client is the same as for a 500:
total failure, report the entity body to the user.  Following the logic of
your line of arguement, we should just get rid of all 5xx codes and have one
500 code.

-----
the Programmer formerly known as Dan          
                                     http://www.spyglass.com/~ddubois/
                                     New direct dial phone: 708-245-6577
Received on Wednesday, 3 April 1996 08:10:53 EST

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