/**
* retrieve date of last value update
*
* @param string the id of the value to be retrieved
* @return string modification date, or '0000-00-00'
*/
public static function get_stamp($id)
{
global $context;
// get one attribute of the record
if ($item = Values::get_record($id)) {
$item = $item['edit_date'];
} else {
$item = NULL_DATE;
}
return $item;
}
/**
* purge idle space
*
* This function OPTIMIZEs tables that may create overheads because of
* frequent deletions, including: cache, links, members, messages,
* notifications, values, versions, visits.
*
* Last purge is recorded as value 'sql.tick'.
*
* @param boolean optional TRUE to not report on any error
* @return a string to be displayed in resulting page, if any
*/
public static function purge($silent = FALSE)
{
global $context;
// useless if we don't have a valid database connection
if (!$context['connection']) {
return;
}
// remember start time
$stamp = get_micro_time();
// get date of last tick
include_once $context['path_to_root'] . 'shared/values.php';
$record = Values::get_record('sql.tick', NULL_DATE);
// wait at least 8 hours = 24*3600 seconds between ticks
if (isset($record['edit_date'])) {
$target = SQL::strtotime($record['edit_date']) + 8 * 3600;
} else {
$target = time();
}
// request to be delayed
if ($target > time()) {
return 'shared/sql.php: wait until ' . gmdate('r', $target) . ' GMT' . BR;
}
// recover unused bytes
$query = 'OPTIMIZE TABLE ' . SQL::table_name('cache') . ', ' . SQL::table_name('links') . ', ' . SQL::table_name('members') . ', ' . SQL::table_name('messages') . ', ' . SQL::table_name('notifications') . ', ' . SQL::table_name('values') . ', ' . SQL::table_name('versions') . ', ' . SQL::table_name('visits');
$result = SQL::query($query, $silent);
// remember tick date and resulting text
Values::set('sql.tick', 'purge');
// compute execution time
$time = round(get_micro_time() - $stamp, 2);
// report on work achieved
if ($result) {
return 'shared/sql.php: unused bytes have been recovered (' . $time . ' seconds)' . BR;
} else {
return 'shared/sql.php: nothing to recover (' . $time . ' seconds)' . BR;
}
}
// do the job and provide feed-back to user
$context['text'] = Hooks::include_scripts('hourly');
echo $context['text'];
// remember tick date and resulting text
Values::set('cron.hourly', $context['text']);
// log outcome of script execution in debug mode
if ($context['with_debug'] == 'Y') {
Logger::remember('cron.php: hourly processing', $context['text'], 'debug');
}
}
//
// daily jobs
//
echo 'Checking daily jobs...' . BR;
// get date of last run
$record = Values::get_record('cron.daily', NULL_DATE);
// wait at least 1 day = 86400 seconds between runs
if (isset($record['edit_date'])) {
$target = SQL::strtotime($record['edit_date']) + 86400;
} else {
$target = time();
}
// request to be delayed
if ($target > time()) {
echo 'Wait until ' . gmdate('r', $target) . ' GMT' . BR;
} else {
Values::set('cron.daily', 'running...');
// do the job and provide feed-back to user
$context['text'] = Hooks::include_scripts('daily');
echo $context['text'];
// remember tick date and resulting text
/**
* process deferred messages
*
* Most often, the server has to stay below a given rate of messages,
* for example 50 messages per hour.
*
* Of course, any lively community will feature bursts of activity and of
* messages, therefore the need for a shaping mechanism.
*
* YACS implements a leaking bucket algorithm to take care of messages sent
* previously:
*
* 1. Initially, the bucket is empty.
*
* 2. New messages are queued in the database, to be processed asynchronously.
*
* 3. On background ticks, the bucket is decremented. If the bucket becomes
* empty, and if some messages have been queued, a couple of them are sent, and
* the bucket is incremented accordingly.
*
* Bucket content is managed as value 'bucket.content' saved in the database.
*
* The bucket size is given by parameter $context['mail_hourly_maximum'], set
* in the configuration panel for system parameters.
*
* This parameter has a default value of 50, meaning YACS will not send more
* than 50 messages per hour.
*
* Background processing is either added to regular page generation or delegated
* to an external sub-system (e.g., cron). In case of a large site, we recommend
* to use the second solution, even if this adds additional setup steps. Your
* choice will be recorded in the configuration panel for system parameters.
*
* @see control/configure.php
*
* The number of messages sent on each tick can go up to the bucket size if
* background processing is external. Else it is one fourth of bucket size, to
* minimize impact on watching surfer.
*
* @see cron.php
*/
public static function tick_hook()
{
global $context;
// email services have to be activated
if (!isset($context['with_email']) || $context['with_email'] != 'Y') {
return;
}
// useless if we don't have a valid database connection
if (!$context['connection']) {
return;
}
// remember start time
$start = get_micro_time();
// get bucket size --force it if set to 0
if (!isset($context['mail_hourly_maximum']) || $context['mail_hourly_maximum'] < 5) {
$context['mail_hourly_maximum'] = 50;
}
// get record related to last tick
include_once $context['path_to_root'] . 'shared/values.php';
$bucket = Values::get_record('mailer.bucket.content', 0);
$bucket['value'] = intval($bucket['value']);
// some content to leak
if ($bucket['value'] > 0) {
// date of last stamp
if (isset($bucket['edit_date'])) {
$stamp = SQL::strtotime($bucket['edit_date']);
} else {
$stamp = time() - 3600;
}
// leak is maximum after one hour
$leak = intval($context['mail_hourly_maximum'] * (time() - $stamp) / 3600);
// preserve previous value until actual leak
if ($leak < 1) {
return;
}
// actual leak
$bucket['value'] = max(0, $bucket['value'] - $leak);
}
// process some messages only when bucket is empty
$count = 0;
if ($bucket['value'] < 1) {
// reduced speed if on-line processing
if (isset($_SERVER['REMOTE_ADDR'])) {
$slice = intval($context['mail_hourly_maximum'] / 4);
} else {
$slice = intval($context['mail_hourly_maximum']);
}
// get some messages, if any
$query = "SELECT * FROM " . SQL::table_name('messages') . " ORDER BY edit_date LIMIT 0, " . $slice;
if ($result = SQL::query($query)) {
// process every message
while ($item = SQL::fetch($result)) {
Mailer::process($item['recipient'], $item['subject'], $item['message'], $item['headers']);
// purge the queue
$query = 'DELETE FROM ' . SQL::table_name('messages') . ' WHERE id = ' . $item['id'];
SQL::query($query);
// fill the bucket
$bucket['value'] += 1;
$count++;
// take care of time
if (!($count % 50)) {
// ensure enough execution time
Safe::set_time_limit(30);
}
}
// close connection
Mailer::close();
}
}
// remember new state of the bucket
Values::set('mailer.bucket.content', $bucket['value']);
// compute execution time
$time = round(get_micro_time() - $start, 2);
// report on work achieved
if ($count > 1) {
return 'shared/mailer.php: ' . $count . ' messages have been processed (' . $time . ' seconds)' . BR;
} elseif ($count == 1) {
return 'shared/mailer.php: 1 message has been processed (' . $time . ' seconds)' . BR;
} elseif ($bucket['value']) {
return 'shared/mailer.php: delaying messages (' . $time . ' seconds)' . BR;
} else {
return 'shared/mailer.php: nothing to do (' . $time . ' seconds)' . BR;
}
}
