How to configure emacs/gnus to use per newsgroup time zone in posted messages?
I would like to use CET time zone in pl.* newsgroups and UCT in general newsgroups.
I would use message-header-setup-hook or message-send-hook with this function:
(defvar date-rewrite-rules
'(("pl" . return-time-string-in-CET)
("." . return-time-string-in-UTC)))
(defun rewrite-date-based-on-newsgroup ()
(save-excursion
(save-restriction
(widen)
(goto-char 0)
(narrow-to-region 0 (search-forward mail-header-separator))
(goto-char 0)
(search-forward-regexp "^Newsgroup: ")
(let ((date-f nil)
(tail date-rewrite-rules))
(while (and (null date-f)
tail)
(let ((rule (pop tail)))
(when (looking-at (car rule))
(setq date-f (cdr rule)))))
(when date-f
(goto-char 0)
(search-forward-regexp "^Date: ")
(delete-region (point) (line-end-position))
(insert (funcall date-f)))))))
NB: the code is untested, this is merely a starting point from which you should develop your solution.