Light up my hue if there is a traffic jam

traffic4hue.sh

#!/bin/bash

# Some environment variables ought to be set
: ${BINGMAP_API_KEY?"You need to set the BINGMAP_API_KEY"}
: ${HUE_BRIDGE?"You need to set the HUE_BRIDGE"}
: ${HUE_KEY?"You need to set the HUE_KEY"}

# preperation for storing the temp file
temp_dir=/tmp/$RANDOM-$$
install -d -m 700 "$temp_dir" || { echo "failed to create temp_dir" >&2; exit 1; }
temp_file=${temp_dir}/traffic4hue.txt

# Fetch traffic information
curl \
  --silent \
  --request GET \
  --output ${temp_file} \
  --header "Content-Type: application/json; charset=UTF-8" \
  "http://dev.virtualearth.net/REST/v1/Traffic/Incidents/52.96,5.92,53.21,6.57?key=${BINGMAP_API_KEY}&severity=3,4"

# Could fix this by giving the light bulb another colour
[ ! -f ${temp_file} ] &&  exit 1

# Parse the fetched information and determine the light bulb colour
let JAMS=$(perl -MJSON -MData::Dumper -e '
  my $hue=0;
  while (<>) {
    map {
      $hue++ if $_->{'description'} =~ /(A7|Julianaplein)/i;
    } @{${from_json($_)->{'resourceSets'}}[0]->{'resources'}};
  }
  print $hue;
' ${temp_file})

# Echo could be removed if output is not needed, while testing it is handy cron output
echo "Nr of traffic jams: ${JAMS}"

if [[ ${JAMS} -eq 0 ]]
then
  exit 0
fi

# We don't expect over 10 jams
if [[ ${JAMS} -gt 10 ]]
then
  JAMS=10
fi

let BRI=${JAMS}*25
let SAT=${JAMS}*25
let HUE=0 # red (http://www.developers.meethue.com/documentation/core-concepts)

# Build the JSON data
DATA=$(cat <<__EOT__
{ "on": true, "sat":${SAT}, "bri": ${BRI}, "hue": ${HUE} }
__EOT__
)

if [[ ${HUE} -gt 0 ]]
then
  # Traffic JAM, light up the hallway
  curl \
    --silent \
    --request PUT \
    --data "${DATA}" \
    --header "Content-Type: application/json; charset=UTF-8" \
    http://${HUE_BRIDGE}/api/${HUE_KEY}/lights/1/state
fi

# remove the temdir
[ -d ${temp_dir} ] && rm -f ${tempdir}

Check http://steviethecat.tumblr.com/post/122943696961/hue-light-up-my-hallway-if-there-is-a-traffic for a bit of description on how to use this script.