I need to execute a directory copy upon a user action, but the directories are quite large, so I would like to be able to perform such an action without the user being aware of the time it takes for the copy to complete.
Any suggestions would be much appreciated.
Assuming this is running on a Linux machine, I've always handled it like this:
exec(sprintf("%s > %s 2>&1 & echo $! >> %s", $cmd, $outputfile, $pidfile));
This launches the command $cmd, redirects the command output to $outputfile, and writes the process id to $pidfile.
That lets you easily monitor what the process is doing and if it's still running.
function isRunning($pid){
try{
$result = shell_exec(sprintf("ps %d", $pid));
if( count(preg_split("/\n/", $result)) > 2){
return true;
}
}catch(Exception $e){}
return false;
}
Write the process as a server-side script in whatever language (php/bash/perl/etc) is handy and then call it from the process control functions in your php script.
The function probably detects if standard io is used as the output stream and if it is then that will set the return value..if not then it ends
proc_close( proc_open( "./command --foo=1 &", array(), $foo ) );
I tested this quickly from the command line using "sleep 25s" as the command and it worked like a charm.
I'd just like to add a very simple example for testing this functionality on Windows:
Create the following two files and save them to a web directory:
foreground.php:
<?php
ini_set("display_errors",1);
error_reporting(E_ALL);
echo "<pre>loading page</pre>";
function run_background_process()
{
file_put_contents("testprocesses.php","foreground start time = " . time() . "\n");
echo "<pre> foreground start time = " . time() . "</pre>";
// output from the command must be redirected to a file or another output stream
// http://ca.php.net/manual/en/function.exec.php
exec("php background.php > testoutput.php 2>&1 & echo $!", $output);
echo "<pre> foreground end time = " . time() . "</pre>";
file_put_contents("testprocesses.php","foreground end time = " . time() . "\n", FILE_APPEND);
return $output;
}
echo "<pre>calling run_background_process</pre>";
$output = run_background_process();
echo "<pre>output = "; print_r($output); echo "</pre>";
echo "<pre>end of page</pre>";
?>
background.php:
<?
file_put_contents("testprocesses.php","background start time = " . time() . "\n", FILE_APPEND);
sleep(10);
file_put_contents("testprocesses.php","background end time = " . time() . "\n", FILE_APPEND);
?>
Give IUSR permission to write to the directory in which you created the above files
Give IUSR permission to READ and EXECUTE C:\Windows\System32\cmd.exe
Hit foreground.php from a web browser
The following should be rendered to the browser w/the current timestamps and local resource # in the output array:
loading page
calling run_background_process
foreground start time = 1266003600
foreground end time = 1266003600
output = Array
(
[0] => 15010
)
end of page
You should see testoutput.php in the same directory as the above files were saved, and it should be empty
You should see testprocesses.php in the same directory as the above files were saved, and it should contain the following text w/the current timestamps:
foreground start time = 1266003600
foreground end time = 1266003600
background start time = 1266003600
background end time = 1266003610
If you need to just do something in background without the PHP page waiting for it to complete, you could use another (background) PHP script that is "invoked" with wget command. This background PHP script will be executed with privileges, of course, as any other PHP script on your system.
Here is an example on Windows using wget from gnuwin32 packages.
The background code (file test-proc-bg.php) as an exmple ...
sleep(5); // some delay
file_put_contents('test.txt', date('Y-m-d/H:i:s.u')); // writes time in a file
The foreground script, the one invoking ...
$proc_command = "wget.exe http://localhost/test-proc-bg.php -q -O - -b";
$proc = popen($proc_command, "r");
pclose($proc);
You must use the popen/pclose for this to work properly.
The wget options:
-q keeps wget quiet.
-O - outputs to stdout.
-b works on background
Can you arrange to fork off a separate process, and then run your copy in the background? It's been a while since I did any PHP, but the function pcntl-fork looks promising.
A working solution for both Windows and Linux. Find more on My github page.
function run_process($cmd,$outputFile = '/dev/null', $append = false){
$pid=0;
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {//'This is a server using Windows!';
$cmd = 'wmic process call create "'.$cmd.'" | find "ProcessId"';
$handle = popen("start /B ". $cmd, "r");
$read = fread($handle, 200); //Read the output
$pid=substr($read,strpos($read,'=')+1);
$pid=substr($pid,0,strpos($pid,';') );
$pid = (int)$pid;
pclose($handle); //Close
}else{
$pid = (int)shell_exec(sprintf('%s %s %s 2>&1 & echo $!', $cmd, ($append) ? '>>' : '>', $outputFile));
}
return $pid;
}
function is_process_running($pid){
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {//'This is a server using Windows!';
//tasklist /FI "PID eq 6480"
$result = shell_exec('tasklist /FI "PID eq '.$pid.'"' );
if (count(preg_split("/\n/", $result)) > 0 && !preg_match('/No tasks/', $result)) {
return true;
}
}else{
$result = shell_exec(sprintf('ps %d 2>&1', $pid));
if (count(preg_split("/\n/", $result)) > 2 && !preg_match('/ERROR: Process ID out of range/', $result)) {
return true;
}
}
return false;
}
function stop_process($pid){
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {//'This is a server using Windows!';
$result = shell_exec('taskkill /PID '.$pid );
if (count(preg_split("/\n/", $result)) > 0 && !preg_match('/No tasks/', $result)) {
return true;
}
}else{
$result = shell_exec(sprintf('kill %d 2>&1', $pid));
if (!preg_match('/No such process/', $result)) {
return true;
}
}
}
Thanks to this answer: A perfect tool to run a background process would be Symfony Process Component, which is based on proc_* functions, but it's much easier to use. See its documentation for more information.
If you are looking to execute a background process via PHP, pipe the command's output to /dev/null and add & to the end of the command.
exec("bg_process > /dev/null &");
Note that you can not utilize the $output parameter of exec() or else PHP will hang (probably until the process completes).
New answer to an old question. Using this library, the following code would spawn an asynchronous/parallel PHPThread to do background work.
EZ code sample:
function threadproc($thread, $param) {
echo "\tI'm a PHPThread. In this example, I was given only one parameter: \"". print_r($param, true) ."\" to work with, but I can accept as many as you'd like!\n";
for ($i = 0; $i < 10; $i++) {
usleep(1000000);
echo "\tPHPThread working, very busy...\n";
}
return "I'm a return value!";
}
$thread_id = phpthread_create($thread, array(), "threadproc", null, array("123456"));
echo "I'm the main thread doing very important work!\n";
for ($n = 0; $n < 5; $n++) {
usleep(1000000);
echo "Main thread...working!\n";
}
echo "\nMain thread done working. Waiting on our PHPThread...\n";
phpthread_join($thread_id, $retval);
echo "\n\nOur PHPThread returned: " . print_r($retval, true) . "!\n";
<?php
function execInBackground($cmd) {
if (substr(php_uname(), 0, 7) == "Windows"){
pclose(popen("start /B ". $cmd, "r"));
}
else {
exec($cmd . " > /dev/null &");
}
}
?>