try / retry (WP)

try_retry.php

<?php

namespace Globalis\WP\Retry;

// @todo:
// 1. POO style
// 2. if last try, and fail -> do_action
// 3. if last try : try / catch exception ? if $on_exception : throws exception ?

add_action('event_retry', __NAMESPACE . '\\_try', 10, 7);

function _try($callable, $args = [], $delay = 5, $retries = 1, $validator = 'validator_default', $use_cron = false, $on_exception = false)
{
	if(!is_array($args)) {
		$args = [$args];
	}

	if($retries < 1) {
		return call_user_func_array($callable, $args);
	} else {
		$retries--;
	}

	$must_retry = false;

	if($on_exception)
		try {
			$value = call_user_func_array($callable, $args);
		} catch (Exception $e) {
			$must_retry = true;
		}
	} else {
		$value = call_user_func_array($callable, $args);
	}

	if($must_retry || !valid_return($value, $validator)) {
		if($use_cron) {
			$time = time() + $delay;
			wp_schedule_single_event($time, 'event_retry', [$callable, $args, $delay, $retries, $validator, $cron, $on_exception]);
		} else {
			sleep($delay);
			return _try($callable, $args, $delay, $retries, $validator, $cron, $on_exception)
		}
	} else {
		return $value;
	}
}

function valid_return($value, $validator)
{
	call_user_func($validator, $value);
}

function validator_default($value)
{
	return false !== $value;
}