Alert dovecot imap users about them exceeding quotum using IMAP ALERT (compatible with outlook 2007-2013)

postlogin.sh

#!/bin/bash
# 
# Author: Stijn Van Campenhout <stijn.vancampenhout@gmail.com>
# 
# Calculate the percentage of the maildir quota using a mysql calculation.
# Compatible with dovecot & postfixadmin, using the quota2 format.
# 
# Add this to the dovecot (2.x) configuration:
## /etc/dovecot/conf.d/10-master.conf
#service imap-postlogin {
#  # all post-login scripts are executed via script-login binary
#  executable = script-login /location/of/postlogin.sh
#  # the script process runs as the user specified here (v2.0.14+):
#  user = $default_internal_user
#  # this UNIX socket listener must use the same name as given to imap executable
#  unix_listener imap-postlogin {
#  }
#}
# 
# Save this file to /location/of/postlogin.sh
# Configure:

#DB stuff
DB="my_postfixadmin_mail_db"
DB_USER="mail_db_user"
DB_PASS="mail_db_secret"
SQL="select round((quota2.bytes/mailbox.quota * 100),0) as percent FROM mailbox,quota2 WHERE mailbox.username = quota2.username AND mailbox.username='${USER}';"

#Settings

# 90% seems reasonable.
MAX_PERCENTAGE=90
#Only display once an hour. Don't let them get to mad.
GRACE_PERIOD=3600

RESULT=$(echo "${SQL}" | mysql -u ${DB_USER} -p${DB_PASS} -D${DB} -ss);
TIME_FILE=/var/spool/quota-warnings/${USER}.time;
LAST_WARN_FILE=/var/log/quota-warnings/${USER}.warn;
TIME=$(date +"%s");

if [ $RESULT -gt $MAX_PERCENTAGE ];then
        #Read the last time of warning
        if [ -f $TIME_FILE ];then
                LAST_WARNING=$(cat ${TIME_FILE});
        else
        #Write the current time
                echo $TIME > $TIME_FILE;
        fi
        DIFF=$(expr $TIME - $LAST_WARNING);
        #If the time is larger than the grace period
        if [ $DIFF -gt $GRACE_PERIOD ];then
                # write to time file
                echo $TIME > $TIME_FILE;
                # and display warning
                echo -n -e "* OK [ALERT] Account ${USER} is using $RESULT% of mailbox space!\r\n" > ${LAST_WARN_FILE}
                echo -n -e "* OK [ALERT] Account ${USER} is using $RESULT% of mailbox space!\r\n"
        fi
else
        echo "" > ${LAST_WARN_FILE}
fi
exec "$@"