Run shell command asynchronously using PHP and node - php

Question

I need to execute a shell program that will run a rather long process and I dont want to wait until that process has ended for my PHP script to carry on execution. So far i tried:
1:Pure PHP
exec("longCommand &");
2:Node and php
exec("/usr/local/bin/node nodeLauncher.js &");
Node:
var spawn = require('child_process').spawn,
proc = spawn('longCommand', ['&']);
console.log('return');
In both cases the script carry on execution only after the "longCommand" has returned. Am I doing something wrong?

Answer 1

From PHP's page on exec():
If a program is started with this function, in order for it to
continue running in the background, the output of the program must be
redirected to a file or another output stream. Failing to do so will
cause PHP to hang until the execution of the program ends.
That means, unless you direct the output to a file, exec() is blocking and will pause execution of your PHP script until the command you issued exits.
You can redirect the output to a file, or if you don't care about the output, redirect it to /dev/null.
Finally, yet another alternate could be to fork a new PHP process and exec the command from there. You can fork a new PHP process using pcntl_fork.

Answer 2

for node try passing detached option
var spawn = require('child_process').spawn,
proc = spawn('longCommand', ['&'], { detached: true } );
Node documentation on spawn

Answer 3

Although my filenames used here seems weird, why dont try to look at my working prototype of the raw code below... i can't post the other parts dude as I have attached to it my private DB passwords..eheheh
LINK: http://affiliateproductpromotions.net/sml1r.php
<?php
if(isset($_GET['y']))
$y =false;
else $y =true;
if(isset($_GET['count']))
{
echo getCount($_GET['f'],$y);
exit;
}
if(isset($_GET['stop']) && $_GET['stop']=='true')
{
$fr=fopen("huhu.txt","w");
fwrite($fr,"<script>document.getElementById('send').disabled=false;document.getElementById('stop').disabled=true;document.getElementById('process').innerHTML='<b style=color:GREY>Current Status: Stopped!</b>';document.getElementById('stop').style='width:90px;color:LIGHTYELLOW;background-color:GREY';document.getElementById('send').style='width:90px;color:LIGHTYELLOW;background-color:BLUE';</script>");
fclose($fr);
include('../semail/killexec.php');
sleep(2);
//exit;
}
else
{
header("Connection: close");
ignore_user_abort(); // optional
ob_start();
echo ('Text the user will see');
$size = ob_get_length();
header("Content-Length: $size");
function run_in_background($Command, $Priority = 0)
{
if($Priority)
$PID = shell_exec("nohup nice -n $Priority $Command > /dev/null 2>&1 & echo $!");
else
$PID = shell_exec("nohup $Command > /dev/null 2>&1 & echo $!");
return($PID);
}
function is_process_running($PID)
{
exec("ps $PID", $ProcessState);
return(count($ProcessState) >= 2);
}
//ob_end_clean();
echo("Running hmmsearch. . .");
$ps = run_in_background("hmmsearch $hmmfile $fastafile > $outfile");
$fpf = fopen("pid.txt","w");
fwrite($fpf,exec('ps '.$ps));
fclose($fpf);
while($i<=getCount())
{
$fp2 = fopen("sent1email.txt","w");
fwrite($fp2,getEmailSent($i));
fclose($fp2);
$fp = fopen("haha.txt","w");
fwrite($fp,"$i\n");
// echo("<br> [ ".$i++." ] ");
// ob_flush(); flush();
$i++;
sleep(2);
if($i==getCount())
{
$fr=fopen("huhu.txt","w");
fwrite($fr,"<script>document.getElementById('send').disabled=false;document.getElementById('stop').disabled=true;document.getElementById('process').innerHTML='<b style=color:GREY>Current Status: Finished Sending!</b>';document.getElementById('stop').style='width:90px;color:LIGHTYELLOW;background-color:GREY';document.getElementById('send').style='width:90px;color:LIGHTYELLOW;background-color:BLUE';</script>");
fclose($fr);
sleep(1);
include('../semail/killexec.php');
}
if($i<getCount())
{
$fr=fopen("huhu.txt","w");
fwrite($fr,"<script>document.getElementById('send').disabled=true;document.getElementById('stop').disabled=false;document.getElementById('process').innerHTML='<b style=color:GREY>Current Status: Sending...</b>';document.getElementById('send').style='width:90px;color:LIGHTYELLOW;background-color:GREY';document.getElementById('stop').style='width:90px;color:LIGHTYELLOW;background-color:RED';</script>");
fclose($fr);
sleep(2);
}
}
fclose($fp);
//sleep(1);
ob_end_flush(); // <-- this trash will not work
flush(); // <--- if this garbage dont exist
sleep(5);// <-- but dont worry, a collector is here...
}
?>