Re: make standard If-Modified-Since headers

[Jason Rumney]

Ted Zlatanov wrote:
> The specific function change I am proposing, so we have a specific
> reference point:
>
> (defun url-get-normalized-date (&optional specified-time)
>   "Return a 'real' date string that most HTTP servers can understand."
>   (let ((system-time-locale "C"))
>     (format-time-string "%a, %d %b %Y %T %Z" 
>                         (or specified-time (current-time)))))
>
> Will this work on all systems?  It avoids the hardcoded week and month
> abbreviations through the locale specification, but I can only test that
> on Linux.
>   

IIRC, only a small subset of timezone names are allowed in HTTP headers, 
so %z would be better than %Z, or alternatively hardcode GMT:
...
(format-time-string "%a, %d %b %Y %T GMT"
        (or specified-time (current-time)) t)
...


%Z seems to give an empty string here (Windows XP), but that is probably 
a bug.