/**
* Check that a prepared edit is in cache and still up-to-date
*
* This method blocks if the prepared edit is already being rendered,
* waiting until rendering finishes before doing final validity checks.
*
* The cache is rejected if template or file changes are detected.
* Note that foreign template or file transclusions are not checked.
*
* The result is a map (pstContent,output,timestamp) with fields
* extracted directly from WikiPage::prepareContentForEdit().
*
* @param Title $title
* @param Content $content
* @param User $user User to get parser options from
* @return stdClass|bool Returns false on cache miss
*/
public static function checkCache(Title $title, Content $content, User $user)
{
if ($user->isBot()) {
return false;
// bots never stash - don't pollute stats
}
$cache = ObjectCache::getLocalClusterInstance();
$logger = LoggerFactory::getInstance('StashEdit');
$stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
$key = self::getStashKey($title, self::getContentHash($content), $user);
$editInfo = $cache->get($key);
if (!is_object($editInfo)) {
$start = microtime(true);
// We ignore user aborts and keep parsing. Block on any prior parsing
// so as to use its results and make use of the time spent parsing.
// Skip this logic if there no master connection in case this method
// is called on an HTTP GET request for some reason.
$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
$dbw = $lb->getAnyOpenConnection($lb->getWriterIndex());
if ($dbw && $dbw->lock($key, __METHOD__, 30)) {
$editInfo = $cache->get($key);
$dbw->unlock($key, __METHOD__);
}
$timeMs = 1000 * max(0, microtime(true) - $start);
$stats->timing('editstash.lock_wait_time', $timeMs);
}
if (!is_object($editInfo) || !$editInfo->output) {
$stats->increment('editstash.cache_misses.no_stash');
$logger->debug("Empty cache for key '{$key}' ('{$title}'); user '{$user->getName()}'.");
return false;
}
$age = time() - wfTimestamp(TS_UNIX, $editInfo->output->getCacheTime());
if ($age <= self::PRESUME_FRESH_TTL_SEC) {
// Assume nothing changed in this time
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Timestamp-based cache hit for key '{$key}' (age: {$age} sec).");
} elseif (isset($editInfo->edits) && $editInfo->edits === $user->getEditCount()) {
// Logged-in user made no local upload/template edits in the meantime
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Edit count based cache hit for key '{$key}' (age: {$age} sec).");
} elseif ($user->isAnon() && self::lastEditTime($user) < $editInfo->output->getCacheTime()) {
// Logged-out user made no local upload/template edits in the meantime
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Edit check based cache hit for key '{$key}' (age: {$age} sec).");
} else {
// User may have changed included content
$editInfo = false;
}
if (!$editInfo) {
$stats->increment('editstash.cache_misses.proven_stale');
$logger->info("Stale cache for key '{$key}'; old key with outside edits. (age: {$age} sec)");
} elseif ($editInfo->output->getFlag('vary-revision')) {
// This can be used for the initial parse, e.g. for filters or doEditContent(),
// but a second parse will be triggered in doEditUpdates(). This is not optimal.
$logger->info("Cache for key '{$key}' ('{$title}') has vary_revision.");
} elseif ($editInfo->output->getFlag('vary-revision-id')) {
// Similar to the above if we didn't guess the ID correctly.
$logger->info("Cache for key '{$key}' ('{$title}') has vary_revision_id.");
}
return $editInfo;
}
/**
* Check that a prepared edit is in cache and still up-to-date
*
* This method blocks if the prepared edit is already being rendered,
* waiting until rendering finishes before doing final validity checks.
*
* The cache is rejected if template or file changes are detected.
* Note that foreign template or file transclusions are not checked.
*
* The result is a map (pstContent,output,timestamp) with fields
* extracted directly from WikiPage::prepareContentForEdit().
*
* @param Title $title
* @param Content $content
* @param User $user User to get parser options from
* @return stdClass|bool Returns false on cache miss
*/
public static function checkCache(Title $title, Content $content, User $user)
{
if ($user->isBot()) {
return false;
// bots never stash - don't pollute stats
}
$cache = ObjectCache::getLocalClusterInstance();
$logger = LoggerFactory::getInstance('StashEdit');
$stats = RequestContext::getMain()->getStats();
$key = self::getStashKey($title, $content, $user);
$editInfo = $cache->get($key);
if (!is_object($editInfo)) {
$start = microtime(true);
// We ignore user aborts and keep parsing. Block on any prior parsing
// so as to use its results and make use of the time spent parsing.
// Skip this logic if there no master connection in case this method
// is called on an HTTP GET request for some reason.
$lb = wfGetLB();
$dbw = $lb->getAnyOpenConnection($lb->getWriterIndex());
if ($dbw && $dbw->lock($key, __METHOD__, 30)) {
$editInfo = $cache->get($key);
$dbw->unlock($key, __METHOD__);
}
$timeMs = 1000 * max(0, microtime(true) - $start);
$stats->timing('editstash.lock_wait_time', $timeMs);
}
if (!is_object($editInfo) || !$editInfo->output) {
$stats->increment('editstash.cache_misses.no_stash');
$logger->debug("No cache value for key '{$key}'.");
return false;
}
$age = time() - wfTimestamp(TS_UNIX, $editInfo->output->getCacheTime());
if ($age <= self::PRESUME_FRESH_TTL_SEC) {
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Timestamp-based cache hit for key '{$key}' (age: {$age} sec).");
return $editInfo;
// assume nothing changed
} elseif (isset($editInfo->edits) && $editInfo->edits === $user->getEditCount()) {
// Logged-in user made no local upload/template edits in the meantime
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Edit count based cache hit for key '{$key}' (age: {$age} sec).");
return $editInfo;
} elseif ($user->isAnon() && self::lastEditTime($user) < $editInfo->output->getCacheTime()) {
// Logged-out user made no local upload/template edits in the meantime
$stats->increment('editstash.cache_hits.presumed_fresh');
$logger->debug("Edit check based cache hit for key '{$key}' (age: {$age} sec).");
return $editInfo;
}
$dbr = wfGetDB(DB_SLAVE);
$templates = [];
// conditions to find changes/creations
$templateUses = 0;
// expected existing templates
foreach ($editInfo->output->getTemplateIds() as $ns => $stuff) {
foreach ($stuff as $dbkey => $revId) {
$templates[(string) $ns][$dbkey] = (int) $revId;
++$templateUses;
}
}
// Check that no templates used in the output changed...
if (count($templates)) {
$res = $dbr->select('page', ['ns' => 'page_namespace', 'dbk' => 'page_title', 'page_latest'], $dbr->makeWhereFrom2d($templates, 'page_namespace', 'page_title'), __METHOD__);
$changed = false;
foreach ($res as $row) {
$changed = $changed || $row->page_latest != $templates[$row->ns][$row->dbk];
}
if ($changed || $res->numRows() != $templateUses) {
$stats->increment('editstash.cache_misses.proven_stale');
$logger->info("Stale cache for key '{$key}'; template changed. (age: {$age} sec)");
return false;
}
}
$files = [];
// conditions to find changes/creations
foreach ($editInfo->output->getFileSearchOptions() as $name => $options) {
$files[$name] = (string) $options['sha1'];
}
// Check that no files used in the output changed...
if (count($files)) {
$res = $dbr->select('image', ['name' => 'img_name', 'img_sha1'], ['img_name' => array_keys($files)], __METHOD__);
$changed = false;
foreach ($res as $row) {
$changed = $changed || $row->img_sha1 != $files[$row->name];
}
if ($changed || $res->numRows() != count($files)) {
$stats->increment('editstash.cache_misses.proven_stale');
$logger->info("Stale cache for key '{$key}'; file changed. (age: {$age} sec)");
return false;
}
}
$stats->increment('editstash.cache_hits.proven_fresh');
$logger->debug("Verified cache hit for key '{$key}' (age: {$age} sec).");
return $editInfo;
}
