Re: Changing the "Sender" for the summary buffer

[Reiner Steib <reinersteib+gmane@imap.cc>]

On Thu, Aug 30 2007, Bernhard Gschaider wrote:

> Hi!
>
> I have the following thing I want my Gnus to do, but before I set out
> to try it I want to know whether it can be done with juistifyable
> effort (my lisp is a bit rusty ....):
>
> I'm receiving mails from a message board software (and a filter sorts
> them into a separate folder). Obviously the sender address is that of
> the MessageBoard-software. Each mail starts with the message 
> "This was posted by Isidor Pepranek on Tuesday..."
> (the name variies obviously)
>
> Now what I would like to achive is that in the summary-buffer of the
> folder for the Sender-Name instead of the MessageBoard-name the name
> of the poster is displayed.
[...]
> Can somebody give me a hint how this could be done? Just something
> like "look at variable foo, implement hook bar for the buffer".
>
> One of the key questions for me is: Can it only be done by generating
> a new mail-header when filtering the mail (thus changing the messages
> on disk) or can it be done during the displaying of the summary
> buffer?

Using `nnmail-prepare-incoming-message-hook' should work, I think.

,----[ (info "(gnus)Washing Mail") ]
| `nnmail-prepare-incoming-message-hook'
|      This hook is called narrowed to each message.
`----

Untested (and a little ugly):

(defun rs-nnmail-fetch-sender-from-body ()
  "Fetch sender's name from body and isert it into the From: header."
  (save-excursion
    (let ((case-fold-search t)
	  endofheaders
	  name)
      (goto-char (point-min))
      (search-forward "\n\n" nil t)
      (setq endofheaders (1- (point)))
      (re-search-forward "^This was posted by \\(.*\\) on [MTWFS]" nil t)
      (setq name (match-string 1))
      (goto-char endofheaders)
      (beginning-of-line)
      (insert
       (format "From: %s <via-MessageBoard@YourCompany.invalid>\n" name))
      (goto-char (point-min))
      (re-search-forward "^From: ")
      (beginning-of-line)
      (insert "Old-"))))

(add-hook 'nnmail-prepare-incoming-message-hook
	  'rs-nnmail-fetch-sender-from-body)

You could also do it with procmail.  The following procmail recipe
extracts a line from the body and puts it in the Subject.  You need to
modify From instead.  The original header is renamed to "Old-Subject",
see procmailrc(5) or procmailex(5) for details.

,----[ Original ]
| Subject:      CNN Breaking News
| 
| -- Some relevant stuff
| ads, ads, ...
| more ads.
`----

,----[ Modified ]
| Subject: Some relevant stuff
| 
| -- Some relevant stuff
| ads, ads, ...
| more ads.
`----

--8<---------------cut here---------------start------------->8---
  :0
  * ^From: .*@(|.*\.)CNN.COM
  * < 5000
  {
    # Add a Subject to CNN Breaking News
    :0 BHf
    * ^From:.*BreakingNews
    * ^Subject:.*CNN Breaking News
    * ^-- \/.*
    | formail -i "Subject: $MATCH"
  }
  #
  :0
  * ^From: .*@(|.*\.)CNN.COM
  $NEWS_SPOOL_IN/local.newsletters.cnn.breakingnews
--8<---------------cut here---------------end--------------->8---

Bye, Reiner.
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/