Train Snow Leopard Spamassassin using shared IMAP folders

By default, Apple only supports training the Spamassassin bayesian spam filter for spam/ham by using two special useraccounts "junkmail" and "notjunkmail".

This might work for you.

But I for example use a shared imap account as a public folder for people in the company to share common emails.

The other day, I thought of a possibility to add two folders to this shared account (for SPAM/HAM emails) to learn spamassassin from these folders.

It works.

The only thing you need is:

• Folders in a shared IMAP account for spam and ham emails (e.g. "SPAM_not_detected" and "SPAM_false_positive")
• A script which learns from these emails and deletes them afterwards.
• A launcher script and a plist file for it to start regularly.

Here it comes.

Save the following file to /usr/local/bin/train-spamassassin:

#!/bin/sh

# Script to Train Spamassassin SPAM/HAM emails in certain folders

# USE AT YOUR OWN RISK!

################################################################################

# SETUP

# Set to mail user which hold the spam/ham folders

MAIL_USER=exampleuser

# Folder for not detected Spams (relative)

SPAM_MAILDIR="SPAM_not_detected"

# Folder for not false positive copies (relative)

FALSE_POSITIVE_MAILDIR="SPAM_false_positive"

# Email address to send status email to. You need to enable mail sending below.

EMAILADDR=you@anything.xxxx

################################################################################

SA_LEARN_PATH=/usr/bin/sa-learn

DB_PATH=/var/amavis/.spamassassin

SA_LEARN_CMD="$SA_LEARN_PATH --dbpath $DB_PATH --no-sync"

# Remove remark from next line and the last line in script to enable email sending of status

#(

echo "################################################################"

echo "Spam Assassin Training Script $0"

echo "################################################################"

# determine users GUID

USER_GUID=`/usr/bin/cvt_mail_data -i "$MAIL_USER"`

if [ `expr "$USER_GUID" : '[0-9A-F]*-[0-9A-F]*-[0-9A-F]*-[0-9A-F]*-[0-9A-F]*'` -eq 0 ]

then

echo "Error: Can't find GUID of mail user $MAIL_USER"

echo $USER_GUID

exit 1

fi

# determine the mail store path

PART_MAP_PATH=/etc/dovecot/partition_map.conf

MAIL_STORE_PATH=`grep "^default:" $PART_MAP_PATH | sed s,default:,,`

case "$MAIL_STORE_PATH" in

/*) # OK

;;

*) echo "Can't determine mail store path from $PART_MAP_PATH"

exit 1

;;

esac

USER_MAIL_PATH="$MAIL_STORE_PATH/$USER_GUID"

SPAM_MAIL_PATH=$USER_MAIL_PATH/.$SPAM_MAILDIR

FALSE_POSITIVE_MAIL_PATH=$USER_MAIL_PATH/.$FALSE_POSITIVE_MAILDIR

if [ ! -d $SPAM_MAIL_PATH ]; then

echo "Error: Spam mail dir $SPAM_MAIL_PATH does not exist"

exit 1

fi

if [ ! -d $FALSE_POSITIVE_MAIL_PATH ]; then

echo "Error: False postives mail dir $FALSE_POSITIVE_MAIL_PATH does not exist"

exit 1

fi

echo " "

echo "################################################################"

echo "Learning SPAM Entries in $SPAM_MAIL_PATH"

echo "################################################################"

$SA_LEARN_CMD --spam $SPAM_MAIL_PATH/cur/

$SA_LEARN_CMD --spam $SPAM_MAIL_PATH/new/

count=`ls $SPAM_MAIL_PATH/cur/ | wc -l`

echo "There are $count mails in the folder"

if [ $count != 0 ]; then

echo "Deleting spam mails.."

find $SPAM_MAIL_PATH/cur/ -type f -print0 | xargs -0 rm

else

echo "No Mails to delete."

fi

################################################################################

# FALSE Positives

################################################################################

echo " "

echo "##########################################################"

echo "Learning False Positive Entries in $FALSE_POSITIVE_MAIL_PATH"

echo "###########################################################"

$SA_LEARN_CMD --ham $FALSE_POSITIVE_MAIL_PATH/cur/

$SA_LEARN_CMD --ham $FALSE_POSITIVE_MAIL_PATH/tmp/

count=`ls $FALSE_POSITIVE_MAIL_PATH/cur/ | wc -l`

if [ $count != 0 ]; then

echo "Deleting false positives.."

find $FALSE_POSITIVE_MAIL_PATH/cur/ -type f -print0 | xargs -0 rm

else

echo "No mails to delete."

fi

echo "syncing database.."

sudo $SA_LEARN_PATH --dbpath $DB_PATH --sync

echo "end of script."

##) | /usr/bin/mail -s "$HOSTNAME Spamassassin Training status" $EMAILADDR

Save this script as /usr/local/bin/train-spamassassin-runner:

#!/bin/sh

# run train-spamassassin. Needed for launchd

/usr/local/bin/train-spamassassin

stat=$?

if [ $stat = 0 ]; then

# everything is ok

syslog -s -l NOTICE "$0: train-spamassassin signaled success"

exit 0

else

syslog -s -l NOTICE "$0: train-spamassassin signaled error $stat"

exit $stat

fi

And of course a launchd plist file to start the script regularly.

Save this content to /Library/LaunchDaemons/org.roosbertl.spamassassinlearn.plist:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0">

<!-- Start spamassassin sa-learn script every day at 6:33

24/03/10 Atomic.

-->

<dict>

<key>Label</key>

<string>org.roosbertl.spamassassinlearn</string>

<key>UserName</key>

<string>root</string>

<key>ProgramArguments</key>

<array>

<string>/usr/local/bin/train-spamassassin-runner</string>

</array>

<key>RunAtLoad</key>

<true/>

<key>StartCalendarInterval</key>

<array>

<dict>

<key>Hour</key>

<integer>6</integer>

<key>Minute</key>

<integer>0</integer>

</dict>

<dict>

<key>Hour</key>

<integer>12</integer>

<key>Minute</key>

<integer>0</integer>

</dict>

<dict>

<key>Hour</key>

<integer>18</integer>

<key>Minute</key>

<integer>0</integer>

</dict>

</array>

</dict>

</plist>

Then activate the start of the script:

sudo launchctl load /Library/LaunchDaemons/org.roosbertl.spamassassinlearn.plist

Now your users just have to move spam/ham email to the corresponding shared imap folders.