Re: Draft 01 of HTTP/1.0

Paul Burchard <burchard@math.utah.edu> writes:

> A couple of questions and comments on the new HTTP/1.0 spec...
> 
> (1)  In the definition of the Accept request header, there is no  
> mention of a "version" modifier, e.g.,
> 
> 	Accept: text/html; version=3.0
> 
> This would seem like the right way to determine HTML client  
> capabilities.  Going by the User-Agent field is a real quagmire.

The BNF for Accept (Section 5.5.8) includes *(";" parameter):

       Accept         = "Accept" ":" 1#(
                             ("*" | type) "/" ("*" | subtype)
                            *(";" parameter)
                             [ ";" "q" "=" ( "0" | "1" | float ) ]
                             [ ";" "mxb" "=" 1*DIGIT ] )

though I neglected to add an explanation of why it is there and
an example of how it would be used.  It's also a bit ambiguous,
but I can fix that.  "parameter" is defined under media types.

> (2)  The semantics of Expires should discourage clients from  
> _indiscriminately_ trying to refetch objects, just because they have  
> expired.  Dynamically-created pages can be ephemeral, without having  
> time-dependent content that needs to be updated.

I will try to clarify that.


......Roy Fielding   ICS Grad Student, University of California, Irvine  USA
                                     <fielding@ics.uci.edu>
                     <URL:http://www.ics.uci.edu/dir/grad/Software/fielding>