Is there a set time out equivalent in php?

Question

Is there a PHP equivalent to setting timeouts in JavaScript?

In JavaScript you can execute code after certain time has elapsed using the set time out function.

Answer 1

PHP is single-threaded, and in general PHP is focused on the HTTP request cycle, so this would be tricky to allow a timeout to run code, potentially after the request is done.

I can suggest you look into Gearman as a solution to delegate work to other PHP processes.

Answer 2

Without knowing a use-case for your question it's hard to answer it:

• If you want to send additional data to the client a bit later you can do a JS timeout on the client side with a handler that will make a new HTTP request to PHP.
• If you want to schedule some task for a later time you can store that in a database and poll the DB in regular intervalls. It's not the best peforming solution but relatively easy to implement.

Answer 3

This is ugly, but basically works:

<?php
declare(ticks=1);

function setInterval($callback, $ms, $max = 0)
{
  $last = microtime(true);
  $seconds = $ms / 1000;

  register_tick_function(function() use (&$last, $callback, $seconds, $max)
  {
    static $busy = false;
    static $n = 0;

    if ($busy) return;

    $busy = true;

    $now = microtime(true);
    while ($now - $last > $seconds)
    {
      if ($max && $n == $max) break;
      ++$n;

      $last += $seconds;
      $callback();
    }

    $busy = false;
  });
}

function setTimeout($callback, $ms)
{
  setInterval($callback, $ms, 1);
}

// user code:

setInterval(function() {
  echo microtime(true), "\n";
}, 100); // every 10th of a second

while (true) usleep(1);

The interval callback function will only be called after a tickable PHP statement. So if you try to call a function 10 times per second, but you call sleep(10), you'll get 100 executions of your tick function in a batch after the sleep has finished.

Note that there is an additional parameter to setInterval that limits the number of times it is called. setTimeout just calls setInterval with a limit of one.

It would be better if unregister_tick_function was called after it expired, but I'm not sure if that would even be possible unless there was a master tick function that monitored and unregistered them.

I didn't attempt to implement anything like that because this is not how PHP is designed to be used. It's likely that there's a much better way to do whatever it is you want to do.

Answer 4

You can use the sleep() function:

int sleep ( int $seconds )

// Delays the program execution for the given number of seconds. 

Example:

public function sleep(){
   sleep(1);
   return 'slept for 1 second';
}