I'm trying to create a browser-started self-calling/repeating PHP script on Windows with PHP (currently 5.3.24 but soon will be latest). It will act as a daemon to monitor changes in a database (every few seconds, so cron/schedule is out) and then call other PHP scripts to perform work when changes are found. For the purposes of this question please ignore the fact that I'd be better off doing this in C# or some other language :)
To keep things simple I started out by trying to use popen to run a second PHP script in the background...
// BatchMonitor.php
SaveToMonitorTable(1); // save 1st test entry to see if the script reached this point
$Command = '"" "C:\Program Files (x86)\PHP\v5.3\php.exe" C:\inetpub\wwwroot\Test.php --Instance=' . $Data->Instance;
pclose(popen("start /B $Command", "r"));
SaveToMonitorTable(2); // save 2nd test entry to see if the script reached this point
exit();
// Test.php
SaveToTestTable(1);
Sleep(10);
SaveToTestTable(2);
exit();
If I run BatchMonitor.php in the browser it works fine. As expected it will save 1 to the monitor table, call Test.php which saves 1 to the test table, the original BatchMonitor.php will continue without waiting for a response and save 2 to the monitor table before exiting, then 10 seconds later the test page saves 2 to the test table before exiting. The second script starts fine, the first script does not wait for a reply and all parameters are correctly passed between scripts. With everything working as intended I then changed the system to work as a repeating loop by calling itself (with delay) instead of another script...
// BatchMonitor.php
SaveToMonitorTable(1); // save 1st test entry to see if the script reached this point
$Command = '"" "C:\Program Files (x86)\PHP\v5.3\php.exe" C:\inetpub\wwwroot\BatchMonitor.php --Instance=' . $Data->Instance;
pclose(popen("start /B $Command", "r"));
SaveToMonitorTable(2); // save 2nd test entry to see if the script reached this point
exit();
If I run BatchMonitor.php in the browser it runs once and that is it. It will save 1 to the database, wait 10 seconds and then save 2 to the database before exiting. The page returns successfully with no script or PHP errors but it doesn't repeat as it should.
Both BatchMonitor.php and Test.php use line-for-line identical functions to get the parameters and both files run correctly and identical on the first iteration. If I use exec instead of popen then the page loops correctly with all logic working as expected (with the one obvious flaw of creating a never-ending chain of scripts awaiting for response values that will never come).
Am I missing something obvious? Does popen have some sort of secret rule that prevents a page/process from opening duplicates of itself? Are there any alternatives to using popen or exec? I read about WScript.Shell but it might be a while before I can schedule that to get enabled so for now it's not an option and I'm hoping there is something more standard that I can use.
I dont feel like this should cbe your actual answer, But why do you disbandon scheduled tasks/cronjobs because you want something done every X seconds? Having the script minute.php calling 5seconds.php with ofcouse 5 second intervals in between would create a repeated taak evert 5 seconds right?
Strangely enough you are kinda using the same sort of mechanism from your browser already.
My only concern would be to take the processed time in account and create a safe script which ensures no more than 1 '5seconds.php' can run at any given time.
Related
I have a PHP Code that does some tasks.
Lets say someone executes the code by doing so https://localhost/code.php.
I have an employee that executes the script over curl from a separate server, what is the best way to prevent him from launching the script twice, before the (already running) script is actually completed/finished goes to the end.
TLDR: I would need a function, to wait until the task/code (that's running now) completes and the secondary task that is trying to be launched has given (sleep for few seconds or until the first tasks completes).
TLDR2: Looking for function [The title says it]
Any ideas? thanks.
While a session won't work with cURL, the idea is valid -- you need to set something persistent outside of your script. So, how about writing to a local file, or writing to a database?
if ( file_exists('lock.txt') ) die;
file_put_contents ('lock.txt', 'This file prevents script execution', LOCK_EX);
(... your script code here...)
unlink ('lock.txt');
If you know that there is only one user who will hit your server you can simply use session data.
<?php
session_start();
if (true === $_SESSION["NOT_FINISHED"] ?? false) {
die("Previous job is not finished yet!");
} else {
$_SESSION["NOT_FINISHED"] = true;
// start whatever job need to be done here
...
// when job is done and finished lets release out busy flag
unset( $_SESSION["NOT_FINISHED"]);
}
I have a cron job on my hosting server that is supposed to execute a phpscript every 30 minutes. This php script is used to scrap a csv file and uptate that data into a database (i'm using MySQL for that). When executed manually that script works - it takes it about 45 seconds to finish the process.
Now when that cron job runs i'm getting this message:
Could not open input file.
At first i thought that this might be because it takes over 30 seconds to execute that script so i decided to set the max execution time at the begging of the php script:
ini_set('max_execution_time', 300);
But again the same message came up.
This is my cron job:
/usr/local/bin/php /home/emmaein/domain.com/folder/script.php?token=d8cn3j
P.S: that token get variable is sort of a password so it can't be executed by everybody so basically my php script looks like this:
if($_GET['token'] === 'd8cn3j'){
//open csv
//get data
//update db
} else{
exit('I see you >:)');
}
When PHP is not running inside a web server, you can't access $_GET variables (there's no such thing). Instead you should use command line arguments:
<?php
if ($argc > 1 && $argv[1] === 'd8cn3j') {
// Do stuff
}
And then your crontab becomes:
/usr/local/bin/php /home/emmaein/domain.com/folder/script.php d8cn3j
The concept of $argc (the number of arguments) and $argv (an array of the arguments) is fairly standard among CLI programs, and is documented on PHP's website.
The main reason is because I don't want to hold up the current PHP process. I want users to be able to navigate around during the script execution.
The script in question (importer.php) updates a txt file with a percentage as it completes, javascript intercepts this txt file and outputs the percentage using a timer every 5 seconds to keep the user updated (all in the form of a load bar).
I've been able to launch the script like so:
$cmd = '"C:\/path\/to\/v5.4\/php" importer.php';
pclose(popen($cmd, "r"));
exit;
This runs the script, but hangs the current process until importer.php completes. Is there a way to get out of the current process and launch this using another one instead?
I read that using & at the end of the cmd tells the script to not wait, but I believe this is a *nix command and since I'm running on a Windows box, I can't use it... unless perhaps there is an alternative for Windows?
According to the documentation at http://php.net/passthru you should be able to execute your command using that, as long as you redirect your output.
$cmd = '"C:\/path\/to\/v5.4\/php" importer.php';
// Use passthrough here, and redirect the output to a temp textfile.
passthru($cmd . '>%TEMP%\importerOutput.txt');
exit;
I was able to resolve this issue by using a WshShell Object; WScript.Shell
$WshShell = new COM("WScript.Shell");
$WshShell->Run('"C:\/path\/to\/v5.4\/php-win.exe" -f "C:\/path\/to\/code\/snippet\/importer.php" var1 var2 var3', 0, false);
Note: I have spaces in my file structure so I needed to add quotes around the paths to the files. I was also able to pass variables, var1, var2, and var3. I've also used \/ to escape my slashes.
I'll break the Run array down a bit for my case:
The first; is the command you want to run (path to php, path to script, and variables to pass).
The second; 0 - Hides the window and activates another window (link below for more options).
The third; false - Boolean value indicating whether the script should wait for the program to finish executing before continuing to the next statement in your script. If set to true, script execution halts until the program finishes.
For more information on WScript.Shell visit http://msdn.microsoft.com/en-us/library/d5fk67ky(v=vs.84).aspx for details.
Hope this helps someone else!
I've been completely unsuccessful finding an answer to this question. Hopefully someone here can help.
I have a PHP script (a WordPress template, to be specific) that automatically imports and processes images when a user hits it. The problem is that the image processing takes up a lot of memory, particularly if multiple users are accessing the template at the same time and initiating the image processing. My server crashed multiple times because of this.
My solution to this was to not execute the image-processing function if it was already running. Before the function started running, I would check a database entry named image_import_running to see if it was set to false. If it was, the function then ran. The very first thing the function did was set image_import_running to true. Then, after it was all finished, I set it back to false.
It worked great -- in theory. The site hasn't crashed since, I can tell you that. But there are two major problems with it:
If the user closes the page while it's loading, the script never finishes processing the images and therefore never sets image_import_running back to false. The template will never process images again until it's manually set to false.
If the script times out while it's processing images -- and that's a strong possibility if there are many images in the queue -- you have essentially the same problem as No. 1: the script never gets to the point where it sets image_import_running back to false.
To handle No. 1 (the first one of the two problems I realized), I added ignore_user_abort(true) to the script. Did it work? I don't know, because No. 2 is still an issue. That's where I'm stumped.
If I could ask the server whether the script was running or not, I could do something like this:
if($import_running && $script_not_running) {
$import_running = false;
}
But how do I set that $script_not_running variable? Beats me.
I've shared this entire story with you just in case you have some other brilliant solution.
Try using
ignore_user_abort(true); it will continue to run even if the person leaves and closes the browser.
you might also want to put a number instead of true false in the db record and set a maximum number of processes that can run together
As others have suggested, it would be best to move the image processing out of the request itself.
As an interim "fix", store a timestamp alongside image_import_running when a processing job begins (e.g., image_import_commenced). This is a very crude mechanism, but if you know the maximum time that a job can run before timing out, the script can check whether that period of time has elapsed.
e.g., if image_import_running is still true but the current time is more than 10 minutes since image_import_commenced, run the processing anyway.
What about setting a transient with an expiry time that would throttle the operation?
if(!get_transient( 'import_running' )) {
set_transient( 'import_running', true, 30 ); // set a 30 second transient on the import.
run_the_import_function();
}
I would rather store the job into database flagging it pending and set a cron job to execute the processing one job at a time.
For Me i use just this simple idea with a text document. for example run.txt file
in the top script use :
if((file_get_contents('run.txt') != 'run'){ // here the script will work
$file = fopen('run.txt', 'w+');
fwrite($file, 'run');
fclose('run.txt');
}else{
exit(); // if it find 'run' in run.txt the script will stop
}
And add this in the end of your script file
$file = fopen('run.txt', 'w+');
fwrite($file, ''); //will delete run word for the next try ;)
fclose('run.txt');
That will check if script already work by checking runt.txt contents
if run word exist in run.txt it will not run
Running a cron would definitively be a better solution. Idea to store url in a table is a good one.
To answer to the original question, you may run a ps auxwww command with exec (Check this page: How to get list of running php scripts using PHP exec()? ) and move your function in a separated php file.
exec("ps auxwww|grep myfunction.php|grep -v grep", $output);
Just add following on the top of your script.
<?php
// Ensures single instance of script run at a time.
$fileName = basename(__FILE__);
$output = shell_exec("ps -ef | grep -v grep | grep $fileName | wc -l");
//echo $output;
if ($output > 2)
{
echo "Already running - $fileName\n";
exit;
}
// Your php script code.
?>
I'll show some code, first:
echo exec("compile\\save.exe Untitled.c tmpUntitled.c");
I have a program, named save.exe and i want to know if it already stopped?
If stopped, ok... Do something...
If not, may be an error, or a loop...
Now: I want to build same way to control the time that program use, and put a limit (time limit exceed, something like this...)
Any one has a sugestion ?
Edit[1]:save.exe is a program wrote on C language, and use two parameters: source and destiny.
popen just don't execute save.exe, i say this because it don't gerenate anymore the destiny (with execit happens);
exec() will suspend your script while the exec'd program is running. Control will be returned only when the external program terminates. If you want to see if the program's hung up or waiting for input or somesuch, you use popen(), which returns a filehandle from which you can read the program's output. At that point you can do a polling loop to see if there's been any output:
$app = popen("your shell command here");
while($output = fgets($app)) {
// handle output
sleep(5); // sleep 5 seconds
}
If you want to send something to the app as input, then you have to use proc_open(), which allows bi-directional communication between your script and the external program.