Re: How to change encoding temporarily?

[Zhang Wei <id.brep@gmail.com>]

Reiner Steib <reinersteib+gmane@imap.cc> writes:

> I'd suggest something like this (barely tested):
>
> --8<---------------cut here---------------start------------->8---
> (setq sssslang-message-change-charset-regexp "@hotmail\\.com\\>")
> (setq mm-coding-system-priorities '(iso-8859-1 utf-8)))))
> (add-hook 'message-send-mail-hook 'sssslang-message-change-charset)
> (defun sssslang-message-change-charset ()
>   (save-restriction
>     (message-narrow-to-headers)
>     (when (or (string-match sssslang-message-change-charset-regexp
> 			    (or (message-fetch-field "to") ""))
> 	      (string-match sssslang-message-change-charset-regexp
> 			    (or (message-fetch-field "cc") ""))
> 	      (string-match sssslang-message-change-charset-regexp
> 			    (or (message-fetch-field "bcc") "")))
>       (set (make-local-variable 'mm-coding-system-priorities)
> 	   '(iso-8859-1 gbk utf-8)))))
> --8<---------------cut here---------------end--------------->8---

Good argument, but there's two subtle details should be point out,

first, we couldn't do this:

(set (make-local-variable 'mm-coding-system-priorities)
     '(iso-8859-1 gbk utf-8))

It's a good idea to make a variable buffer local before change
it's value, but perhaps gnus makes a new buffer for the encoded
message, so if we don't change the global value of
`mm-coding-system-priorities', it won't take effect.

second, if we send mail through a SMTP server, be careful with
the message-send-mail-function, set it like this:

(setq message-send-mail-function 'message-smtpmail-send-it)

not,

(setq message-send-mail-function 'smtpmail-send-it)

otherwise the `message-send-mail-hook' won't run.

so something like this should cope with the problem:
 
--8<---------------cut here---------------start------------->8---
(setq sssslang-message-change-charset-regexp "@hotmail\\.com\\>")
(setq mm-coding-system-priorities '(iso-8859-1 utf-8))
(add-hook 'message-send-mail-hook 'sssslang-message-change-charset)
(defun sssslang-message-change-charset ()
  (save-restriction
    (message-narrow-to-headers)
    (if (or (string-match sssslang-message-change-charset-regexp
			    (or (message-fetch-field "to") ""))
	      (string-match sssslang-message-change-charset-regexp
			    (or (message-fetch-field "cc") ""))
	      (string-match sssslang-message-change-charset-regexp
			    (or (message-fetch-field "bcc") "")))
	(setq mm-coding-system-priorities
	      '(iso-8859-1 gbk utf-8))
      (setq mm-coding-system-priorities
	    '(iso-8859-1 utf-8)))))
--8<---------------cut here---------------end--------------->8---


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