HTTP version number for 1.1 -> 1.0 responses

On Sat, 28 Dec 1996, Ben Laurie wrote:

> John Franks wrote:
> > 
> > I am still waiting for consensus on the response header from an 
> > HTTP/1.1 server to an HTTP/1.0 request.  Did I miss it?
> > 
> > The options were:
> > 
> > 1) Send HTTP/1.0 because that is the protocol the server is actually
> > using.
> > 
> > 2) Send HTTP/1.1 to advertise the servers capability to use 1.1 even
> > though what it is using is the 1.0 protocol.
> > 
> > 3) This is an implementation issue and up to the server.  The browser/proxy
> > must be able to accomodate either.
> 
> Option 3 is clearly foolish. You either MUST or you MUSTN'T. The problem is
> that the spec doesn't say you MUST, and the HTTP/1.0 spec is entirely unclear
> on the point.
> 
> > 
> > The bottom line is that 2) is consistent with the spec and may even
> > have been the intention of some spec authors.  But it is sufficiently
> > counter-intuitive that it will continue to cause problems unless the
> > spec spells out explicitly that this is what is required.  The fact
> > that the WG can't agree on what the current spec says about this is
> > prima facie evidence that ambiguity needs to be removed.
> 
> I couldn't agree more. And since 1.1 responses don't appear to break all that
> many clients, I'm in favour of 2).
> 

All of the arguments in favor of 2) which I have seen presented here
are of the form: It doesn't break anything or doesn't break much or it
only impacts broken clients.  I am willing to stipulate any of these.
What I don't understand is what is the function of 2)?  The only
situation where 1) and 2) differ is a 1.1 server talking to a 1.0
client or proxy.  In this situation if the server sends a 1.1 version
number that information is never usable by the client or proxy.
Am I missing the point of 2)?  If so what is it?

Also several people have pointed out the spec's distinction between
major and minor version numbers, but it seems to me the same issue
will arise with both.  If at some future time I create an HTTP/2.3
server it is likely that I will want that same server to be able to
communicate with 1.0 clients.  Would the advocates of option 2)
recommend that a HTTP/2.3 server put HTTP/2.3 in the response header
sent to a 1.0 client?


John Franks 	Dept of Math. Northwestern University
		john@math.nwu.edu

Received on Friday, 3 January 1997 16:54:04 UTC