perform_task()   B
last analyzed

Complexity

Conditions 9
Paths 12

Size

Total Lines 30
Code Lines 15

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 9
eloc 15
c 0
b 0
f 0
nop 1
dl 0
loc 30
rs 8.0555
nc 12
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<?php
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/**
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 * This is a slightly strange file. It is not designed to ever be run directly from within SMF's
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 * conventional running, but called externally to facilitate background tasks. It can be called
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 * either directly or via cron, and in either case will completely ignore anything supplied
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 * via command line, or $_GET, $_POST, $_COOKIE etc. because those things should never affect the
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 * running of this script.
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 *
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 * Because of the way this runs, etc. we do need some of SMF but not everything to try to keep this
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 * running a little bit faster.
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 *
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 * Simple Machines Forum (SMF)
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 *
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 * @package SMF
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 * @author Simple Machines https://www.simplemachines.org
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 * @copyright 2022 Simple Machines and individual contributors
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 * @license https://www.simplemachines.org/about/smf/license.php BSD
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 *
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 * @version 2.1.2
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 */
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define('SMF', 'BACKGROUND');
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define('SMF_VERSION', '2.1.2');
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define('SMF_FULL_VERSION', 'SMF ' . SMF_VERSION);
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define('SMF_SOFTWARE_YEAR', '2022');
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define('FROM_CLI', empty($_SERVER['REQUEST_METHOD']));
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define('JQUERY_VERSION', '3.6.0');
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define('POSTGRE_TITLE', 'PostgreSQL');
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define('MYSQL_TITLE', 'MySQL');
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define('SMF_USER_AGENT', 'Mozilla/5.0 (' . php_uname('s') . ' ' . php_uname('m') . ') AppleWebKit/605.1.15 (KHTML, like Gecko)  SMF/' . strtr(SMF_VERSION, ' ', '.'));
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// This one setting is worth bearing in mind. If you are running this from proper cron, make sure you
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// don't run this file any more frequently than indicated here. It might turn ugly if you do.
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// But on proper cron you can always increase this value provided you don't go beyond max_limit.
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define('MAX_CRON_TIME', 10);
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// If a task fails for whatever reason it will still be marked as claimed. This is the threshold
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// by which if a task has not completed in this time, the task should become available again.
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define('MAX_CLAIM_THRESHOLD', 300);
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// We're going to want a few globals... these are all set later.
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global $maintenance, $msubject, $mmessage, $mbname, $language;
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global $boardurl, $boarddir, $sourcedir, $webmaster_email;
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global $db_server, $db_name, $db_user, $db_prefix, $db_persist, $db_error_send, $db_last_error;
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global $db_connection, $modSettings, $context, $sc, $user_info, $txt;
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global $smcFunc, $ssi_db_user, $scripturl, $db_passwd, $cachedir;
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if (!defined('TIME_START'))
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	define('TIME_START', microtime(true));
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// Just being safe...
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foreach (array('db_character_set', 'cachedir') as $variable)
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	if (isset($GLOBALS[$variable]))
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		unset($GLOBALS[$variable]);
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// Get the forum's settings for database and file paths.
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require_once(dirname(__FILE__) . '/Settings.php');
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// Make absolutely sure the cache directory is defined and writable.
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if (empty($cachedir) || !is_dir($cachedir) || !is_writable($cachedir))
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{
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	if (is_dir($boarddir . '/cache') && is_writable($boarddir . '/cache'))
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		$cachedir = $boarddir . '/cache';
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	else
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	{
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		$cachedir = sys_get_temp_dir() . '/smf_cache_' . md5($boarddir);
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		@mkdir($cachedir, 0750);
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	}
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}
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// Don't do john didley if the forum's been shut down completely.
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if ($maintenance == 2)
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	die($mmessage);
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// Fix for using the current directory as a path.
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if (substr($sourcedir, 0, 1) == '.' && substr($sourcedir, 1, 1) != '.')
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	$sourcedir = dirname(__FILE__) . substr($sourcedir, 1);
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// Have we already turned this off? If so, exist gracefully.
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if (file_exists($cachedir . '/cron.lock'))
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	obExit_cron();
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// Before we go any further, if this is not a CLI request, we need to do some checking.
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if (!FROM_CLI)
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{
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	// When using sub-domains with SSI and ssi_themes set, browsers will receive a "Access-Control-Allow-Origin" error.
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	// * is not ideal but the best method to preventing this from occurring.
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	header('Access-Control-Allow-Origin: *');
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	// We will clean up $_GET shortly. But we want to this ASAP.
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	$ts = isset($_GET['ts']) ? (int) $_GET['ts'] : 0;
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	if ($ts <= 0 || $ts % 15 != 0 || time() - $ts < 0 || time() - $ts > 20)
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		obExit_cron();
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}
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else
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	$_SERVER['SERVER_PROTOCOL'] = 'HTTP/1.0';
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// Load the most important includes. In general, a background should be loading its own dependencies.
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require_once($sourcedir . '/Errors.php');
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require_once($sourcedir . '/Load.php');
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require_once($sourcedir . '/Security.php');
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require_once($sourcedir . '/Subs.php');
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// Ensure we don't trip over disabled internal functions
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if (version_compare(PHP_VERSION, '8.0.0', '>='))
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	require_once($sourcedir . '/Subs-Compat.php');
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// Create a variable to store some SMF specific functions in.
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$smcFunc = array();
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// This is our general bootstrap, a la SSI.php but with a few differences.
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unset ($db_show_debug);
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loadDatabase();
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reloadSettings();
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// Just in case there's a problem...
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set_error_handler('smf_error_handler_cron');
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$sc = '';
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$_SERVER['QUERY_STRING'] = '';
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$_SERVER['REQUEST_URL'] = FROM_CLI ? 'CLI cron.php' : $boardurl . '/cron.php';
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// Now 'clean the request' (or more accurately, ignore everything we're not going to use)
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cleanRequest_cron();
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// At this point we could reseed the RNG but I don't think we need to risk it being seeded *even more*.
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// Meanwhile, time we got on with the real business here.
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while ($task_details = fetch_task())
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{
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	$result = perform_task($task_details);
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	if ($result)
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	{
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		$smcFunc['db_query']('', '
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			DELETE FROM {db_prefix}background_tasks
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			WHERE id_task = {int:task}',
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			array(
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				'task' => $task_details['id_task'],
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			)
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		);
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	}
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}
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obExit_cron();
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exit;
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/**
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 * The heart of this cron handler...
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 *
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 * @return bool|array False if there's nothing to do or an array of info about the task
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 */
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function fetch_task()
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{
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	global $smcFunc;
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	// Check we haven't run over our time limit.
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	if (microtime(true) - TIME_START > MAX_CRON_TIME)
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		return false;
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	// Try to find a task. Specifically, try to find one that hasn't been claimed previously, or failing that,
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	// a task that was claimed but failed for whatever reason and failed long enough ago. We should not care
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	// what task it is, merely that it is one in the queue, the order is irrelevant.
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	$request = $smcFunc['db_query']('', '
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		SELECT id_task, task_file, task_class, task_data, claimed_time
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		FROM {db_prefix}background_tasks
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		WHERE claimed_time < {int:claim_limit}
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		LIMIT 1',
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		array(
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			'claim_limit' => time() - MAX_CLAIM_THRESHOLD,
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		)
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	);
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	if ($row = $smcFunc['db_fetch_assoc']($request))
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	{
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		// We found one. Let's try and claim it immediately.
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		$smcFunc['db_free_result']($request);
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		$smcFunc['db_query']('', '
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			UPDATE {db_prefix}background_tasks
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			SET claimed_time = {int:new_claimed}
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			WHERE id_task = {int:task}
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				AND claimed_time = {int:old_claimed}',
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			array(
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				'new_claimed' => time(),
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				'task' => $row['id_task'],
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				'old_claimed' => $row['claimed_time'],
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			)
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		);
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		// Could we claim it? If so, return it back.
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		if ($smcFunc['db_affected_rows']() != 0)
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		{
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			// Update the time and go back.
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			$row['claimed_time'] = time();
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			return $row;
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		}
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		else
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		{
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			// Uh oh, we just missed it. Try to claim another one, and let it fall through if there aren't any.
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			return fetch_task();
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		}
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	}
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	else
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	{
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		// No dice. Clean up and go home.
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		$smcFunc['db_free_result']($request);
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		return false;
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	}
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}
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/**
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 * This actually handles the task
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 *
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 * @param array $task_details An array of info about the task
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 * @return bool|void True if the task is invalid; otherwise calls the function to execute the task
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 */
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function perform_task($task_details)
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{
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	global $smcFunc, $sourcedir, $boarddir;
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	// This indicates the file to load.
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	if (!empty($task_details['task_file']))
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	{
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		$include = strtr(trim($task_details['task_file']), array('$boarddir' => $boarddir, '$sourcedir' => $sourcedir));
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		if (file_exists($include))
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			require_once($include);
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	}
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	if (empty($task_details['task_class']))
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	{
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		// This would be nice to translate but the language files aren't loaded for any specific language.
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		log_error('Invalid background task specified (no class, ' . (empty($task_details['task_file']) ? ' no file' : ' to load ' . $task_details['task_file']) . ')');
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		return true; // So we clear it from the queue.
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	}
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	// All background tasks need to be classes.
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	elseif (class_exists($task_details['task_class']) && is_subclass_of($task_details['task_class'], 'SMF_BackgroundTask'))
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	{
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		$details = empty($task_details['task_data']) ? array() : $smcFunc['json_decode']($task_details['task_data'], true);
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		$bgtask = new $task_details['task_class']($details);
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		return $bgtask->execute();
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	}
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	else
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	{
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		log_error('Invalid background task specified: (class: ' . $task_details['task_class'] . ', ' . (empty($task_details['task_file']) ? ' no file' : ' to load ' . $task_details['task_file']) . ')');
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		return true; // So we clear it from the queue.
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	}
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}
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// These are all our helper functions that resemble their big brother counterparts. These are not so important.
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/**
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 * Cleans up the request variables
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 *
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 * @return void
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 */
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function cleanRequest_cron()
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{
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	global $scripturl, $boardurl;
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	$scripturl = $boardurl . '/index.php';
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	// These keys shouldn't be set...ever.
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	if (isset($_REQUEST['GLOBALS']) || isset($_COOKIE['GLOBALS']))
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		die('Invalid request variable.');
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In general, usage of exit should be done with care and only when running in a scripting context like a CLI script.

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	// Save some memory.. (since we don't use these anyway.)
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	unset($GLOBALS['HTTP_POST_VARS'], $GLOBALS['HTTP_POST_VARS']);
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	unset($GLOBALS['HTTP_POST_FILES'], $GLOBALS['HTTP_POST_FILES']);
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	unset($GLOBALS['_GET'], $GLOBALS['_POST'], $GLOBALS['_REQUEST'], $GLOBALS['_COOKIE'], $GLOBALS['_FILES']);
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}
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/**
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 * The error handling function
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 *
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 * @param int $error_level One of the PHP error level constants (see )
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 * @param string $error_string The error message
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 * @param string $file The file where the error occurred
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 * @param int $line What line of the specified file the error occurred on
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 * @return void
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 */
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function smf_error_handler_cron($error_level, $error_string, $file, $line)
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{
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	global $modSettings;
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	// Ignore errors that should not be logged.
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	if (error_reporting() == 0)
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		return;
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	$error_type = 'cron';
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	log_error($error_level . ': ' . $error_string, $error_type, $file, $line);
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	// If this is an E_ERROR or E_USER_ERROR.... die.  Violently so.
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	if ($error_level % 255 == E_ERROR)
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		die('No direct access...');
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Using exit here is not recommended.

In general, usage of exit should be done with care and only when running in a scripting context like a CLI script.

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}
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/**
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 * The exit function
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 */
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function obExit_cron()
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{
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	if (FROM_CLI)
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		die(0);
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show
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Using exit here is not recommended.

In general, usage of exit should be done with care and only when running in a scripting context like a CLI script.

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	else
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	{
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		header('content-type: image/gif');
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		die("\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x21\xF9\x04\x01\x00\x00\x00\x00\x2C\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00\x3B");
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	}
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}
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// We would like this to be defined, but we don't want to have to load more stuff than necessary.
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// Thus we declare it here, and any legitimate background task must implement this.
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/**
311
 * Class SMF_BackgroundTask
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 */
313
abstract class SMF_BackgroundTask
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{
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	/**
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	 * Constants for notification types.
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	*/
318
	const RECEIVE_NOTIFY_EMAIL = 0x02;
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	const RECEIVE_NOTIFY_ALERT = 0x01;
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	/**
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	 * @var array Holds the details for the task
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	 */
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	protected $_details;
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	/**
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	 * @var array Temp property to hold the current user info while tasks make use of $user_info
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	 */
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	private $current_user_info = array();
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	/**
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	 * The constructor.
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	 *
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	 * @param array $details The details for the task
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	 */
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	public function __construct($details)
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	{
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		global $user_info;
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		$this->_details = $details;
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		$this->current_user_info = $user_info;
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	}
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	/**
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	 * The function to actually execute a task
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	 *
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	 * @return mixed
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	 */
350
	abstract public function execute();
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	/**
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	 * Loads minimal info for the previously loaded user ids
354
	 *
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	 * @param array $user_ids
356
	 * @return array
357
	 * @throws Exception
358
	 */
359
	public function getMinUserInfo($user_ids = array())
360
	{
361
		return loadMinUserInfo($user_ids);
362
	}
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	public function __destruct()
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	{
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		global $user_info;
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		$user_info = $this->current_user_info;
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	}
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}
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?>