How can I make a php script to run forever with Cron Job?

Question

<?php
 while(true){
 //code goes here.....
 }
  ?>

I want to make a PHP web server, so how can I make this script run forever with Curl?

Answer 1

Don't forget to set maximum execution time to infinite(0).

Better make sure you don't run more than one instance, if that's your intention:

ignore_user_abort(true);//if caller closes the connection (if initiating with cURL from another PHP, this allows you to end the calling PHP script without ending this one)
set_time_limit(0);

$hLock=fopen(__FILE__.".lock", "w+");
if(!flock($hLock, LOCK_EX | LOCK_NB))
    die("Already running. Exiting...");

while(true)
{

    //avoid CPU exhaustion, adjust as necessary
    usleep(2000);//0.002 seconds
}

flock($hLock, LOCK_UN);
fclose($hLock);
unlink(__FILE__.".lock");

If in CLI mode, just run the file.

If in another PHP on a webserver, you could start the one which must run infinetely like this (instead of using cURL, this eliminating a dependency):

$cx=stream_context_create(
    array(
        "http"=>array(
            "timeout" => 1, //at least PHP 5.2.1
            "ignore_errors" => true
        )
    )
);
@file_get_contents("http://localhost/infinite_loop.php", false, $cx);

Or you could start from linux cron using wget like this:

`* * * * * wget -O - http://localhost/infinite_loop.php`

Or you could start from Windows Scheduler using bitsadmin running a .bat file which contains this:

bitsadmin /create infiniteloop
bitsadmin /addfile infiniteloop http://localhost/infinite_loop.php
bitsadmin /resume infiniteloop

Answer 2

For a php code to run forever, it should have the ff.:

• set_time_limit(0); // so php won't terminate as normal, if you will be doing stuff that will take a very long processing time
• handler for keeping the page active [usually by setting up a client-side script to call the same page in intervals] See setInterval(), setTimeout()

EDIT: But since you will be setting up a cron job then you can keep away from the client-side handling.

EDIT: My suggestion, is not to use infinite loops unless you have a code that tells it to exit the loop after some time. Remember, you will be calling the same page using a cron job, so there is no point in keeping the loop infinite. [edit] Otherwise, you will be needing a locking system as suggested by @Tiberiu-Ionuț Stan so only 1 instance may run each time the cron job is called.

Answer 3

By default, no because PHP has an execution time limit. See: http://www.php.net/manual/en/info.configuration.php#ini.max-execution-time

You can make it run forever by either setting the value or call set_time_limit in your script (http://php.net/manual/en/function.set-time-limit.php).

But I don't recommend this because PHP (called by HTTP request) is not designed to have an infinite loop. Use a local script instead if you can, or request the page in intervals to do the task frequently.

If your website is browsed by others frequently you can do this in every page instead.

(And imagine if someone requests the script more than once, you will have multiple instance of it running)

Answer 4

You can make it happen only if you set set_time_limit(0) in your script, else it will stop execution after max_execution_time set in configuration.

And you are using while(true) condition, that will make your script to run always.