Re: Server response version number

At 12:05 PM 10/20/96 PDT, Larry Masinter wrote:
>> OK. A bunch of implementors are busy committing to the server
>> returning the version of the client.  I just changed my server to
>> return the client version.
>> I would really appreciate a definitive statement from the WG on this
>> matter as I need to release a new version of my server NOW (!) and I
>> would prefer not to pollute the world if at all possible.
>The WG would like a definitive statement from the implementors about
>which option makes the most sense.

As "one of the implementors" here is what I recommend as a practical solution:

1) A client always sends a request using the latest version it supports.
Only if the client already knows the version of the server and this version
is inferrior to the version of the client, then it should downgrade to a
version understood by the server.

2) A server always responds with the same version as the request. Only if
this version is not directly supported by the server, it should take the
version that comes closest. If the semantics of the response requires a
specific version and this is not the version of the client then it should
return "505 HTTP Version not supported".

This is basically the same as is stated in section 19.7:

It is beyond the scope of a protocol specification to mandate compliance
with previous versions. HTTP/1.1 was deliberately designed, however, to
make supporting previous versions easy. It is worth noting that at the time
of composing this specification, we would expect commercial HTTP/1.1
servers to:

 - recognize the format of the Request-Line for HTTP/0.9, 1.0, and 1.1
 - understand any valid request in the format of HTTP/0.9, 1.0, or 1.1;
 - respond appropriately with a message in the same major version used by
the client. 

>In general, IETF process works better when the implementors ARE the
>working group.

Yep - you said it!


Henrik Frystyk Nielsen, <>
World Wide Web Consortium, MIT/LCS NE43-356
545 Technology Square, Cambridge MA 02139, USA

Received on Sunday, 20 October 1996 15:26:50 UTC