Run node file.js from php and kill it on unload - Windows - php

Question

my goal is to run a node file from my php page at the start of my script and then kill that process when the page is closed. I have been reading several questions and answers without luck. I can run by example
exec("node myapp.js arg1 arg2 2>&1", $retArr);
In my node file i added:
console.log(process.pid);
So now i receive the PID of the process on the output array but have to be ended, with this i could kill it later with exec('taskkill /PID '.$array[x].' /f'), how i can get that process pid from php to kill only that one?.
Any lights will be REALLY appreciated. Thanks in advance.

Answer 1

Windows Users:
Ok I found a workaround for this situation in case someone face the same issue.
In PHP
The node app need to listen in a defined port, so you can pass that port to the node app as argument and I needed to start that node app in the background at the beginning of my PHP, from all the possible solutions this one was the one that worked best for me:
$rshell = new COM("WScript.Shell");
$rexec = $rshell->Run("node C:\PATH\TO\NODE\APP\myapp.js ".$appPort." ", 0, false);
this will run the app in the background and you have the listening port in a variable.
In Node.js
Node apps can receive arguments and you can retrieve them using:
process.argv.forEach((val, index) => {
console.log(`${index}: ${val}`);
});
var appPort = process.argv[2];
...
app.listen(appPort);
Back to the PHP
Fine, so far you can start up the node app from php in the background and you have the listening port, so now we create a new php file to handle the closing process, lets say closeNode.php that will receive our listening variable via AJAX onunload :
$( window ).unload(function() {
<!-- your ajax call sending the appPort variable-->
});
closingNode.php
$appPort = $_POST('appPort')
exec('netstat -a -n -o | find "LISTENING" | find "'.$appPort.'"', $result);
if (!empty($result)) {
$pidArray = array();
foreach ($result as $value) {
// our pid is at the end of the string, then we trim the last 10 characters that is enough for the pid process number
$pidArray[] = substr($value, -10);
}
$pidTrimmed = array_map('trim', $pidArray);
$pid = $pidTrimmed[0];
exec('taskkill /f /PID '.$pid.'', $resultKill);
Maybe is not the more elegant solution, but it works.