3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
21 use MediaWiki\Logger\LoggerFactory
;
22 use MediaWiki\MediaWikiServices
;
23 use Wikimedia\ScopedCallback
;
26 * Prepare an edit in shared cache so that it can be reused on edit
28 * This endpoint can be called via AJAX as the user focuses on the edit
29 * summary box. By the time of submission, the parse may have already
30 * finished, and can be immediately used on page save. Certain parser
31 * functions like {{REVISIONID}} or {{CURRENTTIME}} may cause the cache
32 * to not be used on edit. Template and files used are check for changes
33 * since the output was generated. The cache TTL is also kept low for sanity.
38 class ApiStashEdit
extends ApiBase
{
39 const ERROR_NONE
= 'stashed';
40 const ERROR_PARSE
= 'error_parse';
41 const ERROR_CACHE
= 'error_cache';
42 const ERROR_UNCACHEABLE
= 'uncacheable';
43 const ERROR_BUSY
= 'busy';
45 const PRESUME_FRESH_TTL_SEC
= 30;
46 const MAX_CACHE_TTL
= 300; // 5 minutes
47 const MAX_SIGNATURE_TTL
= 60;
49 public function execute() {
50 $user = $this->getUser();
51 $params = $this->extractRequestParams();
53 if ( $user->isBot() ) { // sanity
54 $this->dieWithError( 'apierror-botsnotsupported' );
57 $cache = ObjectCache
::getLocalClusterInstance();
58 $page = $this->getTitleOrPageId( $params );
59 $title = $page->getTitle();
61 if ( !ContentHandler
::getForModelID( $params['contentmodel'] )
62 ->isSupportedFormat( $params['contentformat'] )
65 [ 'apierror-badformat-generic', $params['contentformat'], $params['contentmodel'] ],
70 $this->requireAtLeastOneParameter( $params, 'stashedtexthash', 'text' );
74 if ( strlen( $params['stashedtexthash'] ) ) {
75 // Load from cache since the client indicates the text is the same as last stash
76 $textHash = $params['stashedtexthash'];
77 if ( !preg_match( '/^[0-9a-f]{40}$/', $textHash ) ) {
78 $this->dieWithError( 'apierror-stashedit-missingtext', 'missingtext' );
80 $textKey = $cache->makeKey( 'stashedit', 'text', $textHash );
81 $text = $cache->get( $textKey );
82 if ( !is_string( $text ) ) {
83 $this->dieWithError( 'apierror-stashedit-missingtext', 'missingtext' );
85 } elseif ( $params['text'] !== null ) {
86 // Trim and fix newlines so the key SHA1's match (see WebRequest::getText())
87 $text = rtrim( str_replace( "\r\n", "\n", $params['text'] ) );
88 $textHash = sha1( $text );
90 $this->dieWithError( [
91 'apierror-missingparam-at-least-one-of',
92 Message
::listParam( [ '<var>stashedtexthash</var>', '<var>text</var>' ] ),
97 $textContent = ContentHandler
::makeContent(
98 $text, $title, $params['contentmodel'], $params['contentformat'] );
100 $page = WikiPage
::factory( $title );
101 if ( $page->exists() ) {
102 // Page exists: get the merged content with the proposed change
103 $baseRev = Revision
::newFromPageId( $page->getId(), $params['baserevid'] );
105 $this->dieWithError( [ 'apierror-nosuchrevid', $params['baserevid'] ] );
107 $currentRev = $page->getRevision();
108 if ( !$currentRev ) {
109 $this->dieWithError( [ 'apierror-missingrev-pageid', $page->getId() ], 'missingrev' );
111 // Merge in the new version of the section to get the proposed version
112 $editContent = $page->replaceSectionAtRev(
115 $params['sectiontitle'],
118 if ( !$editContent ) {
119 $this->dieWithError( 'apierror-sectionreplacefailed', 'replacefailed' );
121 if ( $currentRev->getId() == $baseRev->getId() ) {
122 // Base revision was still the latest; nothing to merge
123 $content = $editContent;
125 // Merge the edit into the current version
126 $baseContent = $baseRev->getContent();
127 $currentContent = $currentRev->getContent();
128 if ( !$baseContent ||
!$currentContent ) {
129 $this->dieWithError( [ 'apierror-missingcontent-pageid', $page->getId() ], 'missingrev' );
131 $handler = ContentHandler
::getForModelID( $baseContent->getModel() );
132 $content = $handler->merge3( $baseContent, $editContent, $currentContent );
135 // New pages: use the user-provided content model
136 $content = $textContent;
139 if ( !$content ) { // merge3() failed
140 $this->getResult()->addValue( null,
141 $this->getModuleName(), [ 'status' => 'editconflict' ] );
145 // The user will abort the AJAX request by pressing "save", so ignore that
146 ignore_user_abort( true );
148 if ( $user->pingLimiter( 'stashedit' ) ) {
149 $status = 'ratelimited';
151 $status = self
::parseAndStash( $page, $content, $user, $params['summary'] );
152 $textKey = $cache->makeKey( 'stashedit', 'text', $textHash );
153 $cache->set( $textKey, $text, self
::MAX_CACHE_TTL
);
156 $stats = MediaWikiServices
::getInstance()->getStatsdDataFactory();
157 $stats->increment( "editstash.cache_stores.$status" );
159 $this->getResult()->addValue(
161 $this->getModuleName(),
164 'texthash' => $textHash
170 * @param WikiPage $page
171 * @param Content $content Edit content
173 * @param string $summary Edit summary
174 * @return string ApiStashEdit::ERROR_* constant
177 public static function parseAndStash( WikiPage
$page, Content
$content, User
$user, $summary ) {
178 $cache = ObjectCache
::getLocalClusterInstance();
179 $logger = LoggerFactory
::getInstance( 'StashEdit' );
181 $title = $page->getTitle();
182 $key = self
::getStashKey( $title, self
::getContentHash( $content ), $user );
184 // Use the master DB to allow for fast blocking locks on the "save path" where this
185 // value might actually be used to complete a page edit. If the edit submission request
186 // happens before this edit stash requests finishes, then the submission will block until
187 // the stash request finishes parsing. For the lock acquisition below, there is not much
188 // need to duplicate parsing of the same content/user/summary bundle, so try to avoid
189 // blocking at all here.
190 $dbw = wfGetDB( DB_MASTER
);
191 if ( !$dbw->lock( $key, __METHOD__
, 0 ) ) {
192 // De-duplicate requests on the same key
193 return self
::ERROR_BUSY
;
195 /** @noinspection PhpUnusedLocalVariableInspection */
196 $unlocker = new ScopedCallback( function () use ( $dbw, $key ) {
197 $dbw->unlock( $key, __METHOD__
);
200 $cutoffTime = time() - self
::PRESUME_FRESH_TTL_SEC
;
202 // Reuse any freshly build matching edit stash cache
203 $editInfo = $cache->get( $key );
204 if ( $editInfo && wfTimestamp( TS_UNIX
, $editInfo->timestamp
) >= $cutoffTime ) {
205 $alreadyCached = true;
207 $format = $content->getDefaultFormat();
208 $editInfo = $page->prepareContentForEdit( $content, null, $user, $format, false );
209 $alreadyCached = false;
212 if ( $editInfo && $editInfo->output
) {
213 // Let extensions add ParserOutput metadata or warm other caches
214 Hooks
::run( 'ParserOutputStashForEdit',
215 [ $page, $content, $editInfo->output
, $summary, $user ] );
217 $titleStr = (string)$title;
218 if ( $alreadyCached ) {
219 $logger->debug( "Already cached parser output for key '{cachekey}' ('{title}').",
220 [ 'cachekey' => $key, 'title' => $titleStr ] );
221 return self
::ERROR_NONE
;
224 list( $stashInfo, $ttl, $code ) = self
::buildStashValue(
225 $editInfo->pstContent
,
227 $editInfo->timestamp
,
232 $ok = $cache->set( $key, $stashInfo, $ttl );
234 $logger->debug( "Cached parser output for key '{cachekey}' ('{title}').",
235 [ 'cachekey' => $key, 'title' => $titleStr ] );
236 return self
::ERROR_NONE
;
238 $logger->error( "Failed to cache parser output for key '{cachekey}' ('{title}').",
239 [ 'cachekey' => $key, 'title' => $titleStr ] );
240 return self
::ERROR_CACHE
;
243 $logger->info( "Uncacheable parser output for key '{cachekey}' ('{title}') [{code}].",
244 [ 'cachekey' => $key, 'title' => $titleStr, 'code' => $code ] );
245 return self
::ERROR_UNCACHEABLE
;
249 return self
::ERROR_PARSE
;
253 * Check that a prepared edit is in cache and still up-to-date
255 * This method blocks if the prepared edit is already being rendered,
256 * waiting until rendering finishes before doing final validity checks.
258 * The cache is rejected if template or file changes are detected.
259 * Note that foreign template or file transclusions are not checked.
261 * The result is a map (pstContent,output,timestamp) with fields
262 * extracted directly from WikiPage::prepareContentForEdit().
264 * @param Title $title
265 * @param Content $content
266 * @param User $user User to get parser options from
267 * @return stdClass|bool Returns false on cache miss
269 public static function checkCache( Title
$title, Content
$content, User
$user ) {
270 if ( $user->isBot() ) {
271 return false; // bots never stash - don't pollute stats
274 $cache = ObjectCache
::getLocalClusterInstance();
275 $logger = LoggerFactory
::getInstance( 'StashEdit' );
276 $stats = MediaWikiServices
::getInstance()->getStatsdDataFactory();
278 $key = self
::getStashKey( $title, self
::getContentHash( $content ), $user );
279 $editInfo = $cache->get( $key );
280 if ( !is_object( $editInfo ) ) {
281 $start = microtime( true );
282 // We ignore user aborts and keep parsing. Block on any prior parsing
283 // so as to use its results and make use of the time spent parsing.
284 // Skip this logic if there no master connection in case this method
285 // is called on an HTTP GET request for some reason.
286 $lb = MediaWikiServices
::getInstance()->getDBLoadBalancer();
287 $dbw = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
288 if ( $dbw && $dbw->lock( $key, __METHOD__
, 30 ) ) {
289 $editInfo = $cache->get( $key );
290 $dbw->unlock( $key, __METHOD__
);
293 $timeMs = 1000 * max( 0, microtime( true ) - $start );
294 $stats->timing( 'editstash.lock_wait_time', $timeMs );
297 if ( !is_object( $editInfo ) ||
!$editInfo->output
) {
298 $stats->increment( 'editstash.cache_misses.no_stash' );
299 $logger->debug( "Empty cache for key '$key' ('$title'); user '{$user->getName()}'." );
303 $age = time() - wfTimestamp( TS_UNIX
, $editInfo->output
->getCacheTime() );
304 if ( $age <= self
::PRESUME_FRESH_TTL_SEC
) {
305 // Assume nothing changed in this time
306 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
307 $logger->debug( "Timestamp-based cache hit for key '$key' (age: $age sec)." );
308 } elseif ( isset( $editInfo->edits
) && $editInfo->edits
=== $user->getEditCount() ) {
309 // Logged-in user made no local upload/template edits in the meantime
310 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
311 $logger->debug( "Edit count based cache hit for key '$key' (age: $age sec)." );
312 } elseif ( $user->isAnon()
313 && self
::lastEditTime( $user ) < $editInfo->output
->getCacheTime()
315 // Logged-out user made no local upload/template edits in the meantime
316 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
317 $logger->debug( "Edit check based cache hit for key '$key' (age: $age sec)." );
319 // User may have changed included content
324 $stats->increment( 'editstash.cache_misses.proven_stale' );
325 $logger->info( "Stale cache for key '$key'; old key with outside edits. (age: $age sec)" );
326 } elseif ( $editInfo->output
->getFlag( 'vary-revision' ) ) {
327 // This can be used for the initial parse, e.g. for filters or doEditContent(),
328 // but a second parse will be triggered in doEditUpdates(). This is not optimal.
329 $logger->info( "Cache for key '$key' ('$title') has vary_revision." );
330 } elseif ( $editInfo->output
->getFlag( 'vary-revision-id' ) ) {
331 // Similar to the above if we didn't guess the ID correctly.
332 $logger->info( "Cache for key '$key' ('$title') has vary_revision_id." );
340 * @return string|null TS_MW timestamp or null
342 private static function lastEditTime( User
$user ) {
343 $time = wfGetDB( DB_REPLICA
)->selectField(
346 [ 'rc_user_text' => $user->getName() ],
350 return wfTimestampOrNull( TS_MW
, $time );
354 * Get hash of the content, factoring in model/format
356 * @param Content $content
359 private static function getContentHash( Content
$content ) {
360 return sha1( implode( "\n", [
361 $content->getModel(),
362 $content->getDefaultFormat(),
363 $content->serialize( $content->getDefaultFormat() )
368 * Get the temporary prepared edit stash key for a user
370 * This key can be used for caching prepared edits provided:
371 * - a) The $user was used for PST options
372 * - b) The parser output was made from the PST using cannonical matching options
374 * @param Title $title
375 * @param string $contentHash Result of getContentHash()
376 * @param User $user User to get parser options from
379 private static function getStashKey( Title
$title, $contentHash, User
$user ) {
380 return ObjectCache
::getLocalClusterInstance()->makeKey(
382 md5( $title->getPrefixedDBkey() ),
383 // Account for the edit model/text
385 // Account for user name related variables like signatures
386 md5( $user->getId() . "\n" . $user->getName() )
391 * Build a value to store in memcached based on the PST content and parser output
393 * This makes a simple version of WikiPage::prepareContentForEdit() as stash info
395 * @param Content $pstContent Pre-Save transformed content
396 * @param ParserOutput $parserOutput
397 * @param string $timestamp TS_MW
399 * @return array (stash info array, TTL in seconds, info code) or (null, 0, info code)
401 private static function buildStashValue(
402 Content
$pstContent, ParserOutput
$parserOutput, $timestamp, User
$user
404 // If an item is renewed, mind the cache TTL determined by config and parser functions.
405 // Put an upper limit on the TTL for sanity to avoid extreme template/file staleness.
406 $since = time() - wfTimestamp( TS_UNIX
, $parserOutput->getTimestamp() );
407 $ttl = min( $parserOutput->getCacheExpiry() - $since, self
::MAX_CACHE_TTL
);
409 // Avoid extremely stale user signature timestamps (T84843)
410 if ( $parserOutput->getFlag( 'user-signature' ) ) {
411 $ttl = min( $ttl, self
::MAX_SIGNATURE_TTL
);
415 return [ null, 0, 'no_ttl' ];
418 // Only store what is actually needed
419 $stashInfo = (object)[
420 'pstContent' => $pstContent,
421 'output' => $parserOutput,
422 'timestamp' => $timestamp,
423 'edits' => $user->getEditCount()
426 return [ $stashInfo, $ttl, 'ok' ];
429 public function getAllowedParams() {
432 ApiBase
::PARAM_TYPE
=> 'string',
433 ApiBase
::PARAM_REQUIRED
=> true
436 ApiBase
::PARAM_TYPE
=> 'string',
439 ApiBase
::PARAM_TYPE
=> 'string'
442 ApiBase
::PARAM_TYPE
=> 'text',
443 ApiBase
::PARAM_DFLT
=> null
445 'stashedtexthash' => [
446 ApiBase
::PARAM_TYPE
=> 'string',
447 ApiBase
::PARAM_DFLT
=> null
450 ApiBase
::PARAM_TYPE
=> 'string',
453 ApiBase
::PARAM_TYPE
=> ContentHandler
::getContentModels(),
454 ApiBase
::PARAM_REQUIRED
=> true
457 ApiBase
::PARAM_TYPE
=> ContentHandler
::getAllContentFormats(),
458 ApiBase
::PARAM_REQUIRED
=> true
461 ApiBase
::PARAM_TYPE
=> 'integer',
462 ApiBase
::PARAM_REQUIRED
=> true
467 public function needsToken() {
471 public function mustBePosted() {
475 public function isWriteMode() {
479 public function isInternal() {