I'm working on a web application that needs to send a lot of HTTP requests and update the table, this will block the PHP from executing. So I though I might have to write a separate PHP script and run it via my main application. I tried Exec but still the program waits until the script is executed.
exec('php do_job.php');
I even tried redirecting the output to a file as PHP.Net suggests:
Note: 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.
$result = exec('php do_job.php > output.txt &',$output);
But still no success ... Further down the same page I came accross this:
$command = 'php do_job.php';
$shell = new COM("WScript.Shell");
$shell->run($command, 0, false);
Still no sucess ... Lastly I tried:
pclose(popen("start /B ". $command, "r"));
What am I doing wrong here?
I'm developing my app on localhost (XAMPP - Windows), later I'll be releasing it on a Linux host. My last resort would be to run the script via CRON jobs. Is this the only way?
By just adding & at the end of command you can run any command in background. Here I'm redirecting o/p to /dev/null to avoid hang(For Linux).
exec('php do_job.php > /dev/null &');
If you want see the o/p of the command you can redirect it to a file.
exec('php do_job.php > full_path_to_file &');
Related
I have a process intensive task that I would like to run in the background.
The user clicks on a page, the PHP script runs, and finally, based on some conditions, if required, then it has to run a shell script, E.G.:
shell_exec('php measurePerformance.php 47 844 email#yahoo.com');
Currently I use shell_exec, but this requires the script to wait for an output. Is there any way to execute the command I want without waiting for it to complete?
How about adding.
"> /dev/null 2>/dev/null &"
shell_exec('php measurePerformance.php 47 844 email#yahoo.com > /dev/null 2>/dev/null &');
Note this also gets rid of the stdio and stderr.
This will execute a command and disconnect from the running process. Of course, it can be any command you want. But for a test, you can create a php file with a sleep(20) command it.
exec("nohup /usr/bin/php -f sleep.php > /dev/null 2>&1 &");
You can also give your output back to the client instantly and continue processing your PHP code afterwards.
This is the method I am using for long-waiting Ajax calls which would not have any effect on client side:
ob_end_clean();
ignore_user_abort();
ob_start();
header("Connection: close");
echo json_encode($out);
header("Content-Length: " . ob_get_length());
ob_end_flush();
flush();
// execute your command here. client will not wait for response, it already has one above.
You can find the detailed explanation here: http://oytun.co/response-now-process-later
On Windows 2003, to call another script without waiting, I used this:
$commandString = "start /b c:\\php\\php.EXE C:\\Inetpub\\wwwroot\\mysite.com\\phpforktest.php --passmsg=$testmsg";
pclose(popen($commandString, 'r'));
This only works AFTER giving changing permissions on cmd.exe - add Read and Execute for IUSR_YOURMACHINE (I also set write to Deny).
Use PHP's popen command, e.g.:
pclose(popen("start c:\wamp\bin\php.exe c:\wamp\www\script.php","r"));
This will create a child process and the script will excute in the background without waiting for output.
Sure, for windows you can use:
$WshShell = new COM("WScript.Shell");
$oExec = $WshShell->Run("C:/path/to/php-win.exe -f C:/path/to/script.php", 0, false);
Note:
If you get a COM error, add the extension to your php.ini and restart apache:
[COM_DOT_NET]
extension=php_com_dotnet.dll
If it's off of a web page, I recommend generating a signal of some kind (dropping a file in a directory, perhaps) and having a cron job pick up the work that needs to be done. Otherwise, we're likely to get into the territory of using pcntl_fork() and exec() from inside an Apache process, and that's just bad mojo.
That will work but you will have to be careful not to overload your server because it will create a new process every time you call this function which will run in background. If only one concurrent call at the same time then this workaround will do the job.
If not then I would advice to run a message queue like for instance beanstalkd/gearman/amazon sqs.
I run a background PHP program with exec() like this :
exec('/usr/bin/php bgScript.php "arg1" "arg2" > /dev/null 2>&1 &');
It works and the program does run in background.
Problem
I have Output Buffering Enabled and would like to keep it that way.
My whole script is this :
exec('/usr/bin/php bgScript.php "arg1" "arg2" > /dev/null 2>&1 &');
echo json_encode(array(
"status" => "started"
));
When an AJAX request is made to the file above, the process is started and is in background. I assume this because, further requests to the server returns data and doesn't wait for the previous AJAX script to finish.
But, the problem is that the JSON data is not outputted until the background process is completed.
Since the program is made to run in the background, shouldn't the JSON Data be outputted without waiting for the exec() to end ? I don't know how to say this techinically (Forgive me) : Why does the Output Buffer continue until exec() ends ?
How can I make the script output the JSON Data right after the program is started in the background and close the connection between the AJAX script and browser ?
The command does not run in the background if it's stdio is not redirected. From the official documentation
Note:
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.
There are several methods to alter this behavior in Unix like systems you can run the command with command >/dev/null & on windows you can use start command.
I would like to run a php script in the background as it takes much time and I don't want to wait for it.
This question relates to:
php execute a background process
I tried to make this work on my linux centos machine, but unfortunately it seems not to be working.
This is my code:
$cmd = 'php '.realpath($_SERVER["DOCUMENT_ROOT"]).'/test/sample.php';
exec(sprintf("%s > %s 2>&1 & echo $! >> %s", $cmd, $outputfile, $pidfile));
exec(sprintf("$s > $s 2>&1 & echo $1", $cmd, $outputfile),$pidArr);
sleep(2);
print_r($outputfile);
print_r($pidfile);
I included the sleep(2) to make sure the sample.php script is finished. The sample.php only contains echo 'Hello world'; I tried both exec options, but none of them worked. The above script doesn't show any output.
I tried to run the same $cmd in linux command line and it showed me the output from sample.php script.
I would like to make this run first, but in addition I would like to send variables to the sample.php script as well.
Your help is very appreciated.
You can use set_time_limit(0) to allow script to run indefinitely and ignore_user_abort() to keep running script in background, even if the browser of tab have been closed. This way if you redirect your browser to somewhere else, script will keep running in background.
This approach to running php scripts in the background seems a bit awkward. And depending on if you pass additional parameters based on user input, could also create a scenario where an attacker could inject additional commands.
For use cases like this, you could be using cron, if you don't need a response immediately, or a job manager like Gearman, where you can use a Gearman server to manage the communication between the we request and the background job.
I made some adjustments
$cmd = 'php '.realpath($_SERVER["DOCUMENT_ROOT"]).'/test/sample.php';
$outputfile = 'ouput.txt';
$pidfile = 'pid.txt';
exec(sprintf("%s > %s 2>&1 & echo $! >> %s", $cmd, $outputfile, $pidfile));
exec(sprintf("$s > $s 2>&1 & echo $1", $cmd, $outputfile),$pidArr);
sleep(2);
print_r(file_get_contents($outputfile));
print_r(file_get_contents($pidfile));
Not sure if you defined the variables before. I tested it on Windows and it works
I am trying to manage a queue of files waiting to be processed by ffmpeg. A page is run using CRON that runs through a database of files waiting to be processed. The page then builds the commands and sends them to the command line using exec().
However, when the PHP page is run from the command line or CRON, it runs the exec() OK, but does not return to the PHP page to continue updating the database and other functions.
Example:
<?php
$cmd = "ffmpeg inpupt.mpg output.m4v";
exec($cmd . ' 2>&1', $output, $return);
//Page continues...but not executed
$update = mysql_query("UPDATE.....");
?>
When this page is run from the command line, the command is run using exec() but then the rest of the page is not executed. I think the problem may be that I am running a command using exec() in a page run from the command line.
Is it possible to run a PHP page in full from the command line which includes exec()?
Or is there a better way of doing this?
Thank you.
I wrote an article about Running a Background Process from PHP on Linux some time ago:
<?php system( 'sh test.sh >/dev/null &' ); ?>
Notice the & operator at the end. This starts a process that returns control to the shell immediately AND CONTINUES TO RUN in the background.
More examples:
<!--
saving standard output to a file
very important when your process runs in background
as this is the only way the process can error/success
-->
<?php system( 'sh test.sh >test-out.txt &' ); ?>
<!--
saving standard output and standard error to files
same as above, most programs log errors to standard error hence its better to capture both
-->
<?php system( 'sh test.sh >test-out.txt 2>test-err.txt &' ); ?>
Have you tried using CURL instead?
Unsure but probably thats due to the shell constraints of cron processes if it works as a web page then use it as a web page, setup a cron job that calls wget wherever_your_page_is and it will be called via your web server and should mimic your tests.
I have a process intensive task that I would like to run in the background.
The user clicks on a page, the PHP script runs, and finally, based on some conditions, if required, then it has to run a shell script, E.G.:
shell_exec('php measurePerformance.php 47 844 email#yahoo.com');
Currently I use shell_exec, but this requires the script to wait for an output. Is there any way to execute the command I want without waiting for it to complete?
How about adding.
"> /dev/null 2>/dev/null &"
shell_exec('php measurePerformance.php 47 844 email#yahoo.com > /dev/null 2>/dev/null &');
Note this also gets rid of the stdio and stderr.
This will execute a command and disconnect from the running process. Of course, it can be any command you want. But for a test, you can create a php file with a sleep(20) command it.
exec("nohup /usr/bin/php -f sleep.php > /dev/null 2>&1 &");
You can also give your output back to the client instantly and continue processing your PHP code afterwards.
This is the method I am using for long-waiting Ajax calls which would not have any effect on client side:
ob_end_clean();
ignore_user_abort();
ob_start();
header("Connection: close");
echo json_encode($out);
header("Content-Length: " . ob_get_length());
ob_end_flush();
flush();
// execute your command here. client will not wait for response, it already has one above.
You can find the detailed explanation here: http://oytun.co/response-now-process-later
On Windows 2003, to call another script without waiting, I used this:
$commandString = "start /b c:\\php\\php.EXE C:\\Inetpub\\wwwroot\\mysite.com\\phpforktest.php --passmsg=$testmsg";
pclose(popen($commandString, 'r'));
This only works AFTER giving changing permissions on cmd.exe - add Read and Execute for IUSR_YOURMACHINE (I also set write to Deny).
Use PHP's popen command, e.g.:
pclose(popen("start c:\wamp\bin\php.exe c:\wamp\www\script.php","r"));
This will create a child process and the script will excute in the background without waiting for output.
Sure, for windows you can use:
$WshShell = new COM("WScript.Shell");
$oExec = $WshShell->Run("C:/path/to/php-win.exe -f C:/path/to/script.php", 0, false);
Note:
If you get a COM error, add the extension to your php.ini and restart apache:
[COM_DOT_NET]
extension=php_com_dotnet.dll
If it's off of a web page, I recommend generating a signal of some kind (dropping a file in a directory, perhaps) and having a cron job pick up the work that needs to be done. Otherwise, we're likely to get into the territory of using pcntl_fork() and exec() from inside an Apache process, and that's just bad mojo.
That will work but you will have to be careful not to overload your server because it will create a new process every time you call this function which will run in background. If only one concurrent call at the same time then this workaround will do the job.
If not then I would advice to run a message queue like for instance beanstalkd/gearman/amazon sqs.