WiFi Presence for ISY994 - Let ISY know when you're in the house

wifipresence.sh

#!/bin/bash
#
# WiFi Presence for ISY994
#
# Keeps track of your presence by the virtue of the WiFi in your
# cellphone. This script assumes that the server that runs it
# is also your Firewall/Router so it will see the device in
# question.
#
# You CANNOT run this on a machine which doesn't see all traffic
# to/from the cellphone. It doesn't work, period.
#
# Most linux machines keep the ARP table entries for 1-5 minutes,
# meaning that the device will be marked as gone after that time
# if it's nolonger using wifi.
#
# Check /proc/sys/net/ipv4/neigh/default/gc_stale_time for the
# exact time to live for ARP entries without traffic.
#
# I run this script from crontab on a 5min interval, which is more
# than enough to catch the changes in a timely manner.
#
# NOTE!
# Currently, you need to find the ID of the variable you want
# to toggle. Also, this script assumes you want to use state
# variables.
#
# Get the list of state variables and their ids using the following
#
#  http://<isy994 address>/rest/vars/definitions/2
#
# wifipresence is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# wifipresence is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with wifipresence.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

# List of devices, space separated. Can be DNS names or MAC addresses
# Android: "Settings > About phone > Status" for WiFi MAC
#     iOS: ???
#
DEVICES="phone-husband phone-wife"

# Matching variable IDs, use parenthesis and space separate them.
#
VARID=(7 8)

# Login information and ISY994 location (with leading http:// )
# (make SURE only root is allow to read this file)
#
USER=someuser
PASS=somepassword
ADDRESS=http://insteon.my.local.network.com

# Do not edit anything below this point
##############################################################################
#
I=0
for DEV in $DEVICES; do
  # Look up the status of our device
  STATE=0
  arp -a | grep -v incomp | grep ${DEV} >/dev/null 2>/dev/null
  if [ $? -eq 0 ]; then
    # It's on the network
    STATE=1
  fi

  # Get the current value
  CURRENT=$(curl -s -u "${USER}:${PASS}" ${ADDRESS}/rest/vars/get/2/${VARID[$I]} | egrep -o 'val>([01])</val' | egrep -o '[01]' )
  if [ $? -ne 0 ]; then
    echo "ERROR: Unable to read variable state, did you configure it correctly?"
    exit 1
  fi

  # Only update the server if the value is changed, this way, last-modified date is useful
  if [ "${CURRENT}" != "${STATE}" ]; then
    curl -s -u "${USER}:${PASS}" ${ADDRESS}/rest/vars/set/2/${VARID[$I]}/${STATE} | grep '>200<' >/dev/null 2>/dev/null
    if [ $? -ne 0 ]; then
      echo "ERROR: Unable to change variable state, did you configure it correctly?"
      exit 1
    fi
  fi

  # Next!
  I=$(( $I + 1 ))
done