refresh chromium browser by shell script with xdotool via PHP

Question

I want to refresh the browser, like pressing the F5 or Ctrl+F5 key on the keyboard with a shell script.

I ́m new in writing shell scripts so i aks you to help me with this:

when I type in this into the command line, the refresh works perfectly:

DISPLAY=:0 xdotool getactivewindow key F5

I wrote a script refresh.sh with this content:

export DISPLAY=:0.0
xdotool getactivewindow
xdotool key F5

But it reurns:

pi@babaloo ~ $ sudo sh /var/www/refresh.sh
No protocol specified
Error: Can't open display: (null)
Failed creating new xdo instance
No protocol specified
Error: Can't open display: (null)
Failed creating new xdo instance

can someone give me a hint?

Chromium Browser is in Kiosk mode, here is my

/etc/xdg/lxsession/LXDE/autostart

-

#@lxpanel --profile LXDE
#@pcmanfm --desktop --profile LXDE
#@xscreensaver -no-splash
@xset s off
@xset -dpms
@xset s noblank
@chromium --kiosk --incognito http://localhost/output/output.php?monitor=1

~~ EDIT:

I changed my script to

export DISPLAY=:"0.0"
XAUTHORITY=/home/pi/.Xauthority
xdotool getactivewindow
xdotool key F5

when i start it from console with

sh /var/www/refresh.sh

it works!

But now i want to execute this script by PHP with user www-data. Therefor i added to visudo:

www-data ALL=(ALL) NOPASSWD: ALL
www-data ALL=(ALL) NOPASSWD: /var/www/refresh.sh

and Created a PHP-File with this content:

<?php
exec("sudo sh /var/www/refresh.sh");
?>
<h1>Refreshing output</h1>

But nothing happend...

Is there a chance to get more informations about the returning errors? I found nothing in documentation for "exec"-command.

Also tried:

<?php
$output = array();
$output[] = exec("sudo sh /var/www/refresh.sh");
print_r($output)
?>

but the returning array is empty

• kursus: It might be because you run your script as root.
• s3bi: theres no difference when I run it without sudo
• Piotr Kula: Why do you run PHP exec to refresh a web page. That is so overkill! Just use Javascript to refresh the page window.location.reload(false); -You use a timer, or ajax to control when to refresh. Since you have PHP running to execute the page you are viewing I assume the page you want to refresh is your page...
• s3bi: I have a lot of JS stuff in the browser and I need a "real" browser refresh (without javascript). This should clear the DOM. Another posibility is to close the browser with killall chromium and restart the application after... but i thin it´s a more "overkill".
• Lawrence: meta refresh tag ?

Answer 1

I used a mix with PHP and jQuery Ajax now. I write a parameter into a Databas, if its "0", nothing will happen, if it is "1" the page relaods.

 var times = 0;
 var refreshId = window.setInterval(function(){
 // check refresh!
 $.ajax({
 type : "GET",
 url : "check.php",
 cache : false,
 success: function(data){
 var data = $.parseJSON(data);
 var refresh = data.refresh;
 if(refresh == 1){
 location.reload();
 }
...

• Piotr Kula: use location.reload(true) to force the cache to be dropped and load the freshest data. like CRTL+F5. You should mark your answer as solved.
• s3bi: thanks, I already solved the caching problem in the document header, but your solution is also good!

Answer 2

I achieve to do this by creating a dummy file on the folder, and making the php check if that file exists.

1.- My website has a time interval to check it ever

$(document).ready(function() {
 setInterval(checkRefresh, 10000); 
 });
function checkRefresh()
{
 $.ajax({
 url: "checkrefresh.php"
 }).done(function (response) {
 if (response == 1)
 {
 document.location.reload(true); 
 }
 });
}

2.- In an administrative website, I have a button to launch the php that creates the file:

(in admin.html..)

 $('#btn_refresh').click(function () { 
 $.ajax({
 url: "refresh.php"
 }).done(function (msg){
 alert(msg);
 }).fail(function () {
 alert('Error calling refresh script!');
 });
 });

(refresh.php contents...)

<?php 
 // I put the time inside the file, to help me know when something didn't work ok if the file gets stuck there
 $time = time();
 if(!touch('refreshcookie', $time)) {
 echo 'Something went wrong when trying to reload the webpage!';
 } else {
 echo 'Refresh order sent, this may take up to ten seconds';
 }
?>

3.- Finally, the checkrefresh.php checks if the file is there, and if is so responds and deletes it

<?php
 $imagefile = 'admin/refreshcookie';
 if (file_exists($imagefile))
 {
 unlink($imagefile);
 echo 1;
 }
 else
 {
 echo 0;
 }
?>

I would prefer to have an event instead of checking every x seconds, but it works...

Hope it helps!

Answer 3

Try this:

<?php
@exec("sudo sh /var/www/refresh.sh", $output, $resultCode);
echo "<br>output: ";
var_dump($output);
echo "<br>resultCode: ";
var_dump($resultCode);
// remove the echoes/dumps later
?>

Something similar is working on my pi (3B+ => stretch)