Watch an IQeye camera HTTP stream for motion events and echo to the console

camwatch.sh

#!/bin/bash

## @author  Jay Goldberg
## @email  jaymgoldberg@gmail.com
## @license  Apache 2.0
## @description  Watch an IQeye camera HTTP stream for motion events and echo to the console
## @usage  camwatch.sh <list of IQeye camera URLS>
#=======================================================================

# http://stackoverflow.com/questions/10862970/inter-process-communication-without-fifos

urlfile='cams.txt'
fifo='eventstream.txt'

# open bidrectional TCP to a bidirectional file descriptor
open_tcp() {
  fd=$1
  hostport=$2
  
  exec ${fd}<> /dev/tcp/${hostport[0]}/${hostport[1]}
}

# generate data, output to STDOUT
camera_worker() {
  # TODO local vars
  fd_tcp=$1

  grep "Pragma:" <&${fd_tcp}
}

# read data from an fd, output to STDOUT
reader_worker() {
  # TODO local vars
  fd=$1
  hostport=$2
  fifo=$3

  while read status
  do
    if [[ $status == "motion" ]]
    then
      action $hostport $fifo
    fi
  done <&${fd}
}

start_stream() {
  # TODO local vars
  fd_tcp=$1

  printf "GET /now.jpg?snap=spush0.1&pragma=motion&noimage HTTP/1.0\r\nConnection: Keep-Alive\r\n\r\n" >&${fd_tcp}
}

action() {
  # perform an action when motion detectedi
  hostport=$1

  echo "action occurred on http://${hostport[0]}:${hostport[2]}/serverpush.html"
}

main() {

  mkfifo "$fifo"
 
  # start with a sane fd
  fd=5

  while read url; do
    # parse the URL
    strip_http=${url#*http\:\/\/}
    strip_path=${strip_http%\/**}

    if [[ $(echo $strip_path| grep ':') ]]; then
      port=${strip_path#*:}
      host=${strip_http%:*}
    else
      port=80
      host=$strip_path
    fi

    hostport=( "$host" "$port" )
    echo ${hostport[*]}

    echo $fd

    # start the tcp worker on the specfied bidirectional fd
    open_tcp $fd $hostport
    fd_out=$(( fd + 1 ))
    # feed motion status for this camera into a new fd
    exec $fd_out< <(camera_worker $fd)
    start_stream $fd
    reader_worker $fd_out $hostport $fifo

    fd=$((fd + 2 ))

  done < "$1"

  rm $fifo
}

input="${1:-'cams.txt'}"

main "$input"