How refresh browser after lose Internet connection?

Question

I am using a Raspberry Pi 2 to show a webpage, using Midori, that shows the information given after invoking a webservice each 12 seconds. For some reason, when Raspbian lose Internet connection the webpage keeps showing the last information given. With Epiphany and Chromiun shows an error page as expected. Anyway, I included a script that checks the Internet connection very 2 minutes and if the connection is down then the webpage is refreshed. So the error page is shown.

How can I detect that the Internet connection is back again and refresh the webpage?

I am using UMTSkeeper to keep internet connection alive.

This is my script to refresh the webpage when connection is down.

ping -c4 192.168.1.1 > /dev/null

if [ $? != 0 ] 
then
  export DISPLAY=:0
  XAUTHORITY=/home/pi/.Xauthority
  xdotool search --onlyvisible --class midori windowsactivate
  xdotool key F5
fi

Answer 1

You should keep not only the status ($?) of the current ping command, but also the status of the previous one. Store it in a persistent place (e.g. in a file) or make a script which never exits, so you can use a variable.

Based on two values (let's call these old_ping and new_ping) you'll be able to decide when to refresh:

• old_ping=0 and new_ping=0: the connection is stable
• old_ping=0 and new_ping!=0: the connection has just been lost
• old_ping!=0 and new_ping!=0: the connection has been lost for some time
• old_ping!=0 and new_ping=0: the connection has just been restored, refresh!

Here's a code sample:

export DISPLAY=:0
export XAUTHORITY=/home/pi/.Xauthority
new_ping=0
while true
do
  old_ping=$new_ping
  ping -c4 192.168.1.1 > /dev/null
  new_ping=$?

  if [ $old_ping != 0 -a $new_ping = 0 ] 
  then
    xdotool search --onlyvisible --class midori windowsactivate
    xdotool key F5
  fi
  sleep 10
done