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
19 * @author Aaron Schulz
22 use MediaWiki\Logger\LoggerFactory
;
25 * Prepare an edit in shared cache so that it can be reused on edit
27 * This endpoint can be called via AJAX as the user focuses on the edit
28 * summary box. By the time of submission, the parse may have already
29 * finished, and can be immediately used on page save. Certain parser
30 * functions like {{REVISIONID}} or {{CURRENTTIME}} may cause the cache
31 * to not be used on edit. Template and files used are check for changes
32 * since the output was generated. The cache TTL is also kept low for sanity.
37 class ApiStashEdit
extends ApiBase
{
38 const ERROR_NONE
= 'stashed';
39 const ERROR_PARSE
= 'error_parse';
40 const ERROR_CACHE
= 'error_cache';
41 const ERROR_UNCACHEABLE
= 'uncacheable';
43 const PRESUME_FRESH_TTL_SEC
= 30;
45 public function execute() {
46 $user = $this->getUser();
47 $params = $this->extractRequestParams();
49 if ( $user->isBot() ) { // sanity
50 $this->dieUsage( 'This interface is not supported for bots', 'botsnotsupported' );
53 $page = $this->getTitleOrPageId( $params );
54 $title = $page->getTitle();
56 if ( !ContentHandler
::getForModelID( $params['contentmodel'] )
57 ->isSupportedFormat( $params['contentformat'] )
59 $this->dieUsage( 'Unsupported content model/format', 'badmodelformat' );
62 // Trim and fix newlines so the key SHA1's match (see RequestContext::getText())
63 $text = rtrim( str_replace( "\r\n", "\n", $params['text'] ) );
64 $textContent = ContentHandler
::makeContent(
65 $text, $title, $params['contentmodel'], $params['contentformat'] );
67 $page = WikiPage
::factory( $title );
68 if ( $page->exists() ) {
69 // Page exists: get the merged content with the proposed change
70 $baseRev = Revision
::newFromPageId( $page->getId(), $params['baserevid'] );
72 $this->dieUsage( "No revision ID {$params['baserevid']}", 'missingrev' );
74 $currentRev = $page->getRevision();
76 $this->dieUsage( "No current revision of page ID {$page->getId()}", 'missingrev' );
78 // Merge in the new version of the section to get the proposed version
79 $editContent = $page->replaceSectionAtRev(
82 $params['sectiontitle'],
85 if ( !$editContent ) {
86 $this->dieUsage( 'Could not merge updated section.', 'replacefailed' );
88 if ( $currentRev->getId() == $baseRev->getId() ) {
89 // Base revision was still the latest; nothing to merge
90 $content = $editContent;
92 // Merge the edit into the current version
93 $baseContent = $baseRev->getContent();
94 $currentContent = $currentRev->getContent();
95 if ( !$baseContent ||
!$currentContent ) {
96 $this->dieUsage( "Missing content for page ID {$page->getId()}", 'missingrev' );
98 $handler = ContentHandler
::getForModelID( $baseContent->getModel() );
99 $content = $handler->merge3( $baseContent, $editContent, $currentContent );
102 // New pages: use the user-provided content model
103 $content = $textContent;
106 if ( !$content ) { // merge3() failed
107 $this->getResult()->addValue( null,
108 $this->getModuleName(), [ 'status' => 'editconflict' ] );
112 // The user will abort the AJAX request by pressing "save", so ignore that
113 ignore_user_abort( true );
115 // Use the master DB for fast blocking locks
116 $dbw = wfGetDB( DB_MASTER
);
118 // Get a key based on the source text, format, and user preferences
119 $key = self
::getStashKey( $title, $content, $user );
120 // De-duplicate requests on the same key
121 if ( $user->pingLimiter( 'stashedit' ) ) {
122 $status = 'ratelimited';
123 } elseif ( $dbw->lock( $key, __METHOD__
, 1 ) ) {
124 $status = self
::parseAndStash( $page, $content, $user );
125 $dbw->unlock( $key, __METHOD__
);
130 $this->getStats()->increment( "editstash.cache_stores.$status" );
132 $this->getResult()->addValue( null, $this->getModuleName(), [ 'status' => $status ] );
136 * @param WikiPage $page
137 * @param Content $content
139 * @return integer ApiStashEdit::ERROR_* constant
142 public static function parseAndStash( WikiPage
$page, Content
$content, User
$user ) {
143 $cache = ObjectCache
::getLocalClusterInstance();
144 $logger = LoggerFactory
::getInstance( 'StashEdit' );
146 $format = $content->getDefaultFormat();
147 $editInfo = $page->prepareContentForEdit( $content, null, $user, $format, false );
149 if ( $editInfo && $editInfo->output
) {
150 $key = self
::getStashKey( $page->getTitle(), $content, $user );
152 // Let extensions add ParserOutput metadata or warm other caches
153 Hooks
::run( 'ParserOutputStashForEdit', [ $page, $content, $editInfo->output
] );
155 list( $stashInfo, $ttl ) = self
::buildStashValue(
156 $editInfo->pstContent
,
158 $editInfo->timestamp
,
163 $ok = $cache->set( $key, $stashInfo, $ttl );
165 $logger->debug( "Cached parser output for key '$key'." );
166 return self
::ERROR_NONE
;
168 $logger->error( "Failed to cache parser output for key '$key'." );
169 return self
::ERROR_CACHE
;
172 $logger->info( "Uncacheable parser output for key '$key'." );
173 return self
::ERROR_UNCACHEABLE
;
177 return self
::ERROR_PARSE
;
181 * Attempt to cache PST content and corresponding parser output in passing
183 * This method can be called when the output was already generated for other
184 * reasons. Parsing should not be done just to call this method, however.
185 * $pstOpts must be that of the user doing the edit preview. If $pOpts does
186 * not match the options of WikiPage::makeParserOptions( 'canonical' ), this
187 * will do nothing. Provided the values are cacheable, they will be stored
188 * in memcached so that final edit submission might make use of them.
190 * @param Page|Article|WikiPage $page Page title
191 * @param Content $content Proposed page content
192 * @param Content $pstContent The result of preSaveTransform() on $content
193 * @param ParserOutput $pOut The result of getParserOutput() on $pstContent
194 * @param ParserOptions $pstOpts Options for $pstContent (MUST be for prospective author)
195 * @param ParserOptions $pOpts Options for $pOut
196 * @param string $timestamp TS_MW timestamp of parser output generation
197 * @return bool Success
199 public static function stashEditFromPreview(
200 Page
$page, Content
$content, Content
$pstContent, ParserOutput
$pOut,
201 ParserOptions
$pstOpts, ParserOptions
$pOpts, $timestamp
203 $cache = ObjectCache
::getLocalClusterInstance();
204 $logger = LoggerFactory
::getInstance( 'StashEdit' );
206 // getIsPreview() controls parser function behavior that references things
207 // like user/revision that don't exists yet. The user/text should already
208 // be set correctly by callers, just double check the preview flag.
209 if ( !$pOpts->getIsPreview() ) {
210 return false; // sanity
211 } elseif ( $pOpts->getIsSectionPreview() ) {
212 return false; // short-circuit (need the full content)
215 // PST parser options are for the user (handles signatures, etc...)
216 $user = $pstOpts->getUser();
217 // Get a key based on the source text, format, and user preferences
218 $key = self
::getStashKey( $page->getTitle(), $content, $user );
220 // Parser output options must match cannonical options.
221 // Treat some options as matching that are different but don't matter.
222 $canonicalPOpts = $page->makeParserOptions( 'canonical' );
223 $canonicalPOpts->setIsPreview( true ); // force match
224 $canonicalPOpts->setTimestamp( $pOpts->getTimestamp() ); // force match
225 if ( !$pOpts->matches( $canonicalPOpts ) ) {
226 $logger->info( "Uncacheable preview output for key '$key' (options)." );
230 // Set the time the output was generated
231 $pOut->setCacheTime( wfTimestampNow() );
233 // Build a value to cache with a proper TTL
234 list( $stashInfo, $ttl ) = self
::buildStashValue( $pstContent, $pOut, $timestamp, $user );
236 $logger->info( "Uncacheable parser output for key '$key' (rev/TTL)." );
240 $ok = $cache->set( $key, $stashInfo, $ttl );
242 $logger->error( "Failed to cache preview parser output for key '$key'." );
244 $logger->debug( "Cached preview output for key '$key'." );
251 * Check that a prepared edit is in cache and still up-to-date
253 * This method blocks if the prepared edit is already being rendered,
254 * waiting until rendering finishes before doing final validity checks.
256 * The cache is rejected if template or file changes are detected.
257 * Note that foreign template or file transclusions are not checked.
259 * The result is a map (pstContent,output,timestamp) with fields
260 * extracted directly from WikiPage::prepareContentForEdit().
262 * @param Title $title
263 * @param Content $content
264 * @param User $user User to get parser options from
265 * @return stdClass|bool Returns false on cache miss
267 public static function checkCache( Title
$title, Content
$content, User
$user ) {
268 if ( $user->isBot() ) {
269 return false; // bots never stash - don't pollute stats
272 $cache = ObjectCache
::getLocalClusterInstance();
273 $logger = LoggerFactory
::getInstance( 'StashEdit' );
274 $stats = RequestContext
::getMain()->getStats();
276 $key = self
::getStashKey( $title, $content, $user );
277 $editInfo = $cache->get( $key );
278 if ( !is_object( $editInfo ) ) {
279 $start = microtime( true );
280 // We ignore user aborts and keep parsing. Block on any prior parsing
281 // so as to use its results and make use of the time spent parsing.
282 // Skip this logic if there no master connection in case this method
283 // is called on an HTTP GET request for some reason.
285 $dbw = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
286 if ( $dbw && $dbw->lock( $key, __METHOD__
, 30 ) ) {
287 $editInfo = $cache->get( $key );
288 $dbw->unlock( $key, __METHOD__
);
291 $timeMs = 1000 * max( 0, microtime( true ) - $start );
292 $stats->timing( 'editstash.lock_wait_time', $timeMs );
295 if ( !is_object( $editInfo ) ||
!$editInfo->output
) {
296 $stats->increment( 'editstash.cache_misses.no_stash' );
297 $logger->debug( "No cache value for key '$key'." );
301 $age = time() - wfTimestamp( TS_UNIX
, $editInfo->output
->getCacheTime() );
302 if ( $age <= self
::PRESUME_FRESH_TTL_SEC
) {
303 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
304 $logger->debug( "Timestamp-based cache hit for key '$key' (age: $age sec)." );
305 return $editInfo; // assume nothing changed
306 } elseif ( isset( $editInfo->edits
) && $editInfo->edits
=== $user->getEditCount() ) {
307 // Logged-in user made no local upload/template edits in the meantime
308 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
309 $logger->debug( "Edit count based cache hit for key '$key' (age: $age sec)." );
311 } elseif ( $user->isAnon()
312 && self
::lastEditTime( $user ) < $editInfo->output
->getCacheTime()
314 // Logged-out user made no local upload/template edits in the meantime
315 $stats->increment( 'editstash.cache_hits.presumed_fresh' );
316 $logger->debug( "Edit check based cache hit for key '$key' (age: $age sec)." );
320 $dbr = wfGetDB( DB_SLAVE
);
322 $templates = []; // conditions to find changes/creations
323 $templateUses = 0; // expected existing templates
324 foreach ( $editInfo->output
->getTemplateIds() as $ns => $stuff ) {
325 foreach ( $stuff as $dbkey => $revId ) {
326 $templates[(string)$ns][$dbkey] = (int)$revId;
330 // Check that no templates used in the output changed...
331 if ( count( $templates ) ) {
334 [ 'ns' => 'page_namespace', 'dbk' => 'page_title', 'page_latest' ],
335 $dbr->makeWhereFrom2d( $templates, 'page_namespace', 'page_title' ),
339 foreach ( $res as $row ) {
340 $changed = $changed ||
( $row->page_latest
!= $templates[$row->ns
][$row->dbk
] );
343 if ( $changed ||
$res->numRows() != $templateUses ) {
344 $stats->increment( 'editstash.cache_misses.proven_stale' );
345 $logger->info( "Stale cache for key '$key'; template changed. (age: $age sec)" );
350 $files = []; // conditions to find changes/creations
351 foreach ( $editInfo->output
->getFileSearchOptions() as $name => $options ) {
352 $files[$name] = (string)$options['sha1'];
354 // Check that no files used in the output changed...
355 if ( count( $files ) ) {
358 [ 'name' => 'img_name', 'img_sha1' ],
359 [ 'img_name' => array_keys( $files ) ],
363 foreach ( $res as $row ) {
364 $changed = $changed ||
( $row->img_sha1
!= $files[$row->name
] );
367 if ( $changed ||
$res->numRows() != count( $files ) ) {
368 $stats->increment( 'editstash.cache_misses.proven_stale' );
369 $logger->info( "Stale cache for key '$key'; file changed. (age: $age sec)" );
374 $stats->increment( 'editstash.cache_hits.proven_fresh' );
375 $logger->debug( "Verified cache hit for key '$key' (age: $age sec)." );
382 * @return string|null TS_MW timestamp or null
384 private static function lastEditTime( User
$user ) {
385 $time = wfGetDB( DB_SLAVE
)->selectField(
388 [ 'rc_user_text' => $user->getName() ],
392 return wfTimestampOrNull( TS_MW
, $time );
396 * Get the temporary prepared edit stash key for a user
398 * This key can be used for caching prepared edits provided:
399 * - a) The $user was used for PST options
400 * - b) The parser output was made from the PST using cannonical matching options
402 * @param Title $title
403 * @param Content $content
404 * @param User $user User to get parser options from
407 private static function getStashKey( Title
$title, Content
$content, User
$user ) {
408 $hash = sha1( implode( ':', [
409 $content->getModel(),
410 $content->getDefaultFormat(),
411 sha1( $content->serialize( $content->getDefaultFormat() ) ),
412 $user->getId() ?
: md5( $user->getName() ), // account for user parser options
413 $user->getId() ?
$user->getDBTouched() : '-' // handle preference change races
416 return wfMemcKey( 'prepared-edit', md5( $title->getPrefixedDBkey() ), $hash );
420 * Build a value to store in memcached based on the PST content and parser output
422 * This makes a simple version of WikiPage::prepareContentForEdit() as stash info
424 * @param Content $pstContent
425 * @param ParserOutput $parserOutput
426 * @param string $timestamp TS_MW
428 * @return array (stash info array, TTL in seconds) or (null, 0)
430 private static function buildStashValue(
431 Content
$pstContent, ParserOutput
$parserOutput, $timestamp, User
$user
433 // If an item is renewed, mind the cache TTL determined by config and parser functions.
434 // Put an upper limit on the TTL for sanity to avoid extreme template/file staleness.
435 $since = time() - wfTimestamp( TS_UNIX
, $parserOutput->getTimestamp() );
436 $ttl = min( $parserOutput->getCacheExpiry() - $since, 5 * 60 );
438 if ( $ttl > 0 && !$parserOutput->getFlag( 'vary-revision' ) ) {
439 // Only store what is actually needed
440 $stashInfo = (object)[
441 'pstContent' => $pstContent,
442 'output' => $parserOutput,
443 'timestamp' => $timestamp,
444 'edits' => $user->getEditCount()
446 return [ $stashInfo, $ttl ];
452 public function getAllowedParams() {
455 ApiBase
::PARAM_TYPE
=> 'string',
456 ApiBase
::PARAM_REQUIRED
=> true
459 ApiBase
::PARAM_TYPE
=> 'string',
462 ApiBase
::PARAM_TYPE
=> 'string'
465 ApiBase
::PARAM_TYPE
=> 'text',
466 ApiBase
::PARAM_REQUIRED
=> true
469 ApiBase
::PARAM_TYPE
=> ContentHandler
::getContentModels(),
470 ApiBase
::PARAM_REQUIRED
=> true
473 ApiBase
::PARAM_TYPE
=> ContentHandler
::getAllContentFormats(),
474 ApiBase
::PARAM_REQUIRED
=> true
477 ApiBase
::PARAM_TYPE
=> 'integer',
478 ApiBase
::PARAM_REQUIRED
=> true
483 public function needsToken() {
487 public function mustBePosted() {
491 public function isWriteMode() {
495 public function isInternal() {