如何使用procmail以base 64编码过滤电子邮件

Question

I am trying to filter email with base 64 encoding, then decode the message body, then pass it for further filtering, but it won't find a match on the type of email from header, I tried Content-Transfer-Encoding and Content-Type, but no match are found from the header. Here is the procmailrc I configured:

DEFAULT=/var/mail/
LOGFILE=$HOME/procmail.log
SHELL=/bin/sh
msgID=""
errorMSG="Error."

:0
* (r|R)@domain.com

:0fw
* ^Content-Transfer-Encoding:.*base64 | mmencode -u -b

{
:0B
* ^()\/[a-z]+[0-9]+
{ msgID = "$MATCH" }

result=`mysql -uxxx -pxxx -e "select data from table1 where id='"$msgID"'`

....

Answer 1

The | mmencode -u -b | mmencode -u -b is in the wrong place. You have made it part of the regex you are trying to match -- of course it won't.

You probably mean

:0fw
* r@domain\.com
* ^Content-Transfer-Encoding:.*base64
| mmencode -u -b

or possibly

:0
* r@domain\.com
{
    :0fw
    * ^Content-Transfer-Encoding:.*base64
    | mmencode -u -b
#...
}

The general form of a Procmail recipe is

:0flags
* conditions
action

where you can omit the conditions to make a recipe unconditional; but the action is mandatory. You cannot leave it out.

If you change the content encoding, you should also update the corresponding MIME headers (unless you are ditching this message once you are done with it, of course).

Notice also how the (r|R) alternation is unnecessary, because Procmail matches case-insensitively by default.