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1 | <?php |
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2 | /** |
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3 | * This program is free software; you can redistribute it and/or modify |
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4 | * it under the terms of the GNU General Public License as published by |
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5 | * the Free Software Foundation; either version 2 of the License, or |
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6 | * (at your option) any later version. |
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7 | * |
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8 | * This program is distributed in the hope that it will be useful, |
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9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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11 | * GNU General Public License for more details. |
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12 | * |
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13 | * You should have received a copy of the GNU General Public License along |
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14 | * with this program; if not, write to the Free Software Foundation, Inc., |
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15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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16 | * http://www.gnu.org/copyleft/gpl.html |
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17 | * |
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18 | * @file |
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19 | * @author Aaron Schulz |
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20 | */ |
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21 | |||
22 | use MediaWiki\Logger\LoggerFactory; |
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23 | use MediaWiki\MediaWikiServices; |
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24 | use Wikimedia\ScopedCallback; |
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25 | |||
26 | /** |
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27 | * Prepare an edit in shared cache so that it can be reused on edit |
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28 | * |
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29 | * This endpoint can be called via AJAX as the user focuses on the edit |
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30 | * summary box. By the time of submission, the parse may have already |
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31 | * finished, and can be immediately used on page save. Certain parser |
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32 | * functions like {{REVISIONID}} or {{CURRENTTIME}} may cause the cache |
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33 | * to not be used on edit. Template and files used are check for changes |
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34 | * since the output was generated. The cache TTL is also kept low for sanity. |
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35 | * |
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36 | * @ingroup API |
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37 | * @since 1.25 |
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38 | */ |
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39 | class ApiStashEdit extends ApiBase { |
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40 | const ERROR_NONE = 'stashed'; |
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41 | const ERROR_PARSE = 'error_parse'; |
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42 | const ERROR_CACHE = 'error_cache'; |
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43 | const ERROR_UNCACHEABLE = 'uncacheable'; |
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44 | const ERROR_BUSY = 'busy'; |
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45 | |||
46 | const PRESUME_FRESH_TTL_SEC = 30; |
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47 | const MAX_CACHE_TTL = 300; // 5 minutes |
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48 | |||
49 | public function execute() { |
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50 | $user = $this->getUser(); |
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51 | $params = $this->extractRequestParams(); |
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52 | |||
53 | if ( $user->isBot() ) { // sanity |
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54 | $this->dieUsage( 'This interface is not supported for bots', 'botsnotsupported' ); |
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55 | } |
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56 | |||
57 | $cache = ObjectCache::getLocalClusterInstance(); |
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58 | $page = $this->getTitleOrPageId( $params ); |
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59 | $title = $page->getTitle(); |
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60 | |||
61 | if ( !ContentHandler::getForModelID( $params['contentmodel'] ) |
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62 | ->isSupportedFormat( $params['contentformat'] ) |
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63 | ) { |
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64 | $this->dieUsage( 'Unsupported content model/format', 'badmodelformat' ); |
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65 | } |
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66 | |||
67 | $text = null; |
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68 | $textHash = null; |
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69 | if ( strlen( $params['stashedtexthash'] ) ) { |
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70 | // Load from cache since the client indicates the text is the same as last stash |
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71 | $textHash = $params['stashedtexthash']; |
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72 | $textKey = $cache->makeKey( 'stashedit', 'text', $textHash ); |
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73 | $text = $cache->get( $textKey ); |
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74 | if ( !is_string( $text ) ) { |
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75 | $this->dieUsage( 'No stashed text found with the given hash', 'missingtext' ); |
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76 | } |
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77 | } elseif ( $params['text'] !== null ) { |
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78 | // Trim and fix newlines so the key SHA1's match (see WebRequest::getText()) |
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79 | $text = rtrim( str_replace( "\r\n", "\n", $params['text'] ) ); |
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80 | $textHash = sha1( $text ); |
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81 | } else { |
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82 | $this->dieUsage( |
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83 | 'The text or stashedtexthash parameter must be given', 'missingtextparam' ); |
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84 | } |
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85 | |||
86 | $textContent = ContentHandler::makeContent( |
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87 | $text, $title, $params['contentmodel'], $params['contentformat'] ); |
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88 | |||
89 | $page = WikiPage::factory( $title ); |
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90 | if ( $page->exists() ) { |
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91 | // Page exists: get the merged content with the proposed change |
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92 | $baseRev = Revision::newFromPageId( $page->getId(), $params['baserevid'] ); |
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93 | if ( !$baseRev ) { |
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94 | $this->dieUsage( "No revision ID {$params['baserevid']}", 'missingrev' ); |
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95 | } |
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96 | $currentRev = $page->getRevision(); |
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97 | if ( !$currentRev ) { |
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98 | $this->dieUsage( "No current revision of page ID {$page->getId()}", 'missingrev' ); |
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99 | } |
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100 | // Merge in the new version of the section to get the proposed version |
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101 | $editContent = $page->replaceSectionAtRev( |
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102 | $params['section'], |
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103 | $textContent, |
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104 | $params['sectiontitle'], |
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105 | $baseRev->getId() |
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106 | ); |
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107 | if ( !$editContent ) { |
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108 | $this->dieUsage( 'Could not merge updated section.', 'replacefailed' ); |
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109 | } |
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110 | if ( $currentRev->getId() == $baseRev->getId() ) { |
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111 | // Base revision was still the latest; nothing to merge |
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112 | $content = $editContent; |
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113 | } else { |
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114 | // Merge the edit into the current version |
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115 | $baseContent = $baseRev->getContent(); |
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116 | $currentContent = $currentRev->getContent(); |
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117 | if ( !$baseContent || !$currentContent ) { |
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118 | $this->dieUsage( "Missing content for page ID {$page->getId()}", 'missingrev' ); |
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119 | } |
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120 | $handler = ContentHandler::getForModelID( $baseContent->getModel() ); |
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121 | $content = $handler->merge3( $baseContent, $editContent, $currentContent ); |
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122 | } |
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123 | } else { |
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124 | // New pages: use the user-provided content model |
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125 | $content = $textContent; |
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126 | } |
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127 | |||
128 | if ( !$content ) { // merge3() failed |
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129 | $this->getResult()->addValue( null, |
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130 | $this->getModuleName(), [ 'status' => 'editconflict' ] ); |
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131 | return; |
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132 | } |
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133 | |||
134 | // The user will abort the AJAX request by pressing "save", so ignore that |
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135 | ignore_user_abort( true ); |
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136 | |||
137 | if ( $user->pingLimiter( 'stashedit' ) ) { |
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138 | $status = 'ratelimited'; |
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139 | } else { |
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140 | $status = self::parseAndStash( $page, $content, $user, $params['summary'] ); |
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141 | $textKey = $cache->makeKey( 'stashedit', 'text', $textHash ); |
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142 | $cache->set( $textKey, $text, self::MAX_CACHE_TTL ); |
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143 | } |
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144 | |||
145 | $stats = MediaWikiServices::getInstance()->getStatsdDataFactory(); |
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146 | $stats->increment( "editstash.cache_stores.$status" ); |
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147 | |||
148 | $this->getResult()->addValue( |
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149 | null, |
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150 | $this->getModuleName(), |
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151 | [ |
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152 | 'status' => $status, |
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153 | 'texthash' => $textHash |
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154 | ] |
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155 | ); |
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156 | } |
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157 | |||
158 | /** |
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159 | * @param WikiPage $page |
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160 | * @param Content $content Edit content |
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161 | * @param User $user |
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162 | * @param string $summary Edit summary |
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163 | * @return integer ApiStashEdit::ERROR_* constant |
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164 | * @since 1.25 |
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165 | */ |
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166 | public static function parseAndStash( WikiPage $page, Content $content, User $user, $summary ) { |
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167 | $cache = ObjectCache::getLocalClusterInstance(); |
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168 | $logger = LoggerFactory::getInstance( 'StashEdit' ); |
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169 | |||
170 | $title = $page->getTitle(); |
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171 | $key = self::getStashKey( $title, self::getContentHash( $content ), $user ); |
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172 | |||
173 | // Use the master DB for fast blocking locks |
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174 | $dbw = wfGetDB( DB_MASTER ); |
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175 | if ( !$dbw->lock( $key, __METHOD__, 1 ) ) { |
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176 | // De-duplicate requests on the same key |
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177 | return self::ERROR_BUSY; |
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178 | } |
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179 | /** @noinspection PhpUnusedLocalVariableInspection */ |
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180 | $unlocker = new ScopedCallback( function () use ( $dbw, $key ) { |
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181 | $dbw->unlock( $key, __METHOD__ ); |
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182 | } ); |
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183 | |||
184 | $cutoffTime = time() - self::PRESUME_FRESH_TTL_SEC; |
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185 | |||
186 | // Reuse any freshly build matching edit stash cache |
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187 | $editInfo = $cache->get( $key ); |
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188 | if ( $editInfo && wfTimestamp( TS_UNIX, $editInfo->timestamp ) >= $cutoffTime ) { |
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189 | $alreadyCached = true; |
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190 | } else { |
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191 | $format = $content->getDefaultFormat(); |
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192 | $editInfo = $page->prepareContentForEdit( $content, null, $user, $format, false ); |
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193 | $alreadyCached = false; |
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194 | } |
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195 | |||
196 | if ( $editInfo && $editInfo->output ) { |
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197 | // Let extensions add ParserOutput metadata or warm other caches |
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198 | Hooks::run( 'ParserOutputStashForEdit', |
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199 | [ $page, $content, $editInfo->output, $summary, $user ] ); |
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200 | |||
201 | if ( $alreadyCached ) { |
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202 | $logger->debug( "Already cached parser output for key '$key' ('$title')." ); |
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203 | return self::ERROR_NONE; |
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204 | } |
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205 | |||
206 | list( $stashInfo, $ttl, $code ) = self::buildStashValue( |
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207 | $editInfo->pstContent, |
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208 | $editInfo->output, |
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209 | $editInfo->timestamp, |
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210 | $user |
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211 | ); |
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212 | |||
213 | if ( $stashInfo ) { |
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214 | $ok = $cache->set( $key, $stashInfo, $ttl ); |
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215 | if ( $ok ) { |
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216 | $logger->debug( "Cached parser output for key '$key' ('$title')." ); |
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217 | return self::ERROR_NONE; |
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218 | } else { |
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219 | $logger->error( "Failed to cache parser output for key '$key' ('$title')." ); |
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220 | return self::ERROR_CACHE; |
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221 | } |
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222 | } else { |
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223 | $logger->info( "Uncacheable parser output for key '$key' ('$title') [$code]." ); |
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224 | return self::ERROR_UNCACHEABLE; |
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225 | } |
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226 | } |
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227 | |||
228 | return self::ERROR_PARSE; |
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229 | } |
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230 | |||
231 | /** |
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232 | * Check that a prepared edit is in cache and still up-to-date |
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233 | * |
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234 | * This method blocks if the prepared edit is already being rendered, |
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235 | * waiting until rendering finishes before doing final validity checks. |
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236 | * |
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237 | * The cache is rejected if template or file changes are detected. |
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238 | * Note that foreign template or file transclusions are not checked. |
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239 | * |
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240 | * The result is a map (pstContent,output,timestamp) with fields |
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241 | * extracted directly from WikiPage::prepareContentForEdit(). |
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242 | * |
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243 | * @param Title $title |
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244 | * @param Content $content |
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245 | * @param User $user User to get parser options from |
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246 | * @return stdClass|bool Returns false on cache miss |
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247 | */ |
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248 | public static function checkCache( Title $title, Content $content, User $user ) { |
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249 | if ( $user->isBot() ) { |
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250 | return false; // bots never stash - don't pollute stats |
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251 | } |
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252 | |||
253 | $cache = ObjectCache::getLocalClusterInstance(); |
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254 | $logger = LoggerFactory::getInstance( 'StashEdit' ); |
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255 | $stats = MediaWikiServices::getInstance()->getStatsdDataFactory(); |
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256 | |||
257 | $key = self::getStashKey( $title, self::getContentHash( $content ), $user ); |
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258 | $editInfo = $cache->get( $key ); |
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259 | if ( !is_object( $editInfo ) ) { |
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260 | $start = microtime( true ); |
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261 | // We ignore user aborts and keep parsing. Block on any prior parsing |
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262 | // so as to use its results and make use of the time spent parsing. |
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263 | // Skip this logic if there no master connection in case this method |
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264 | // is called on an HTTP GET request for some reason. |
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265 | $lb = MediaWikiServices::getInstance()->getDBLoadBalancer(); |
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266 | $dbw = $lb->getAnyOpenConnection( $lb->getWriterIndex() ); |
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267 | if ( $dbw && $dbw->lock( $key, __METHOD__, 30 ) ) { |
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268 | $editInfo = $cache->get( $key ); |
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269 | $dbw->unlock( $key, __METHOD__ ); |
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270 | } |
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271 | |||
272 | $timeMs = 1000 * max( 0, microtime( true ) - $start ); |
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273 | $stats->timing( 'editstash.lock_wait_time', $timeMs ); |
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274 | } |
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275 | |||
276 | if ( !is_object( $editInfo ) || !$editInfo->output ) { |
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277 | $stats->increment( 'editstash.cache_misses.no_stash' ); |
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278 | $logger->debug( "Empty cache for key '$key' ('$title'); user '{$user->getName()}'." ); |
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279 | return false; |
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280 | } |
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281 | |||
282 | $age = time() - wfTimestamp( TS_UNIX, $editInfo->output->getCacheTime() ); |
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283 | if ( $age <= self::PRESUME_FRESH_TTL_SEC ) { |
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284 | // Assume nothing changed in this time |
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285 | $stats->increment( 'editstash.cache_hits.presumed_fresh' ); |
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286 | $logger->debug( "Timestamp-based cache hit for key '$key' (age: $age sec)." ); |
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287 | } elseif ( isset( $editInfo->edits ) && $editInfo->edits === $user->getEditCount() ) { |
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288 | // Logged-in user made no local upload/template edits in the meantime |
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289 | $stats->increment( 'editstash.cache_hits.presumed_fresh' ); |
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290 | $logger->debug( "Edit count based cache hit for key '$key' (age: $age sec)." ); |
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291 | } elseif ( $user->isAnon() |
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292 | && self::lastEditTime( $user ) < $editInfo->output->getCacheTime() |
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293 | ) { |
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294 | // Logged-out user made no local upload/template edits in the meantime |
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295 | $stats->increment( 'editstash.cache_hits.presumed_fresh' ); |
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296 | $logger->debug( "Edit check based cache hit for key '$key' (age: $age sec)." ); |
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297 | } else { |
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298 | // User may have changed included content |
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299 | $editInfo = false; |
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300 | } |
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301 | |||
302 | if ( !$editInfo ) { |
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303 | $stats->increment( 'editstash.cache_misses.proven_stale' ); |
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304 | $logger->info( "Stale cache for key '$key'; old key with outside edits. (age: $age sec)" ); |
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305 | } elseif ( $editInfo->output->getFlag( 'vary-revision' ) ) { |
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306 | // This can be used for the initial parse, e.g. for filters or doEditContent(), |
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307 | // but a second parse will be triggered in doEditUpdates(). This is not optimal. |
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308 | $logger->info( "Cache for key '$key' ('$title') has vary_revision." ); |
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309 | } elseif ( $editInfo->output->getFlag( 'vary-revision-id' ) ) { |
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310 | // Similar to the above if we didn't guess the ID correctly. |
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311 | $logger->info( "Cache for key '$key' ('$title') has vary_revision_id." ); |
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312 | } |
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313 | |||
314 | return $editInfo; |
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315 | } |
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316 | |||
317 | /** |
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318 | * @param User $user |
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319 | * @return string|null TS_MW timestamp or null |
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320 | */ |
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321 | private static function lastEditTime( User $user ) { |
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322 | $time = wfGetDB( DB_REPLICA )->selectField( |
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323 | 'recentchanges', |
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324 | 'MAX(rc_timestamp)', |
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325 | [ 'rc_user_text' => $user->getName() ], |
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326 | __METHOD__ |
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327 | ); |
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328 | |||
329 | return wfTimestampOrNull( TS_MW, $time ); |
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330 | } |
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331 | |||
332 | /** |
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333 | * Get hash of the content, factoring in model/format |
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334 | * |
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335 | * @param Content $content |
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336 | * @return string |
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337 | */ |
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338 | private static function getContentHash( Content $content ) { |
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339 | return sha1( implode( "\n", [ |
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340 | $content->getModel(), |
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341 | $content->getDefaultFormat(), |
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342 | $content->serialize( $content->getDefaultFormat() ) |
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343 | ] ) ); |
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344 | } |
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345 | |||
346 | /** |
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347 | * Get the temporary prepared edit stash key for a user |
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348 | * |
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349 | * This key can be used for caching prepared edits provided: |
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350 | * - a) The $user was used for PST options |
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351 | * - b) The parser output was made from the PST using cannonical matching options |
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352 | * |
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353 | * @param Title $title |
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354 | * @param string $contentHash Result of getContentHash() |
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355 | * @param User $user User to get parser options from |
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356 | * @return string |
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357 | */ |
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358 | private static function getStashKey( Title $title, $contentHash, User $user ) { |
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359 | return ObjectCache::getLocalClusterInstance()->makeKey( |
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360 | 'prepared-edit', |
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361 | md5( $title->getPrefixedDBkey() ), |
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362 | // Account for the edit model/text |
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363 | $contentHash, |
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364 | // Account for user name related variables like signatures |
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365 | md5( $user->getId() . "\n" . $user->getName() ) |
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366 | ); |
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367 | } |
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368 | |||
369 | /** |
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370 | * Build a value to store in memcached based on the PST content and parser output |
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371 | * |
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372 | * This makes a simple version of WikiPage::prepareContentForEdit() as stash info |
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373 | * |
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374 | * @param Content $pstContent Pre-Save transformed content |
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375 | * @param ParserOutput $parserOutput |
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376 | * @param string $timestamp TS_MW |
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377 | * @param User $user |
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378 | * @return array (stash info array, TTL in seconds, info code) or (null, 0, info code) |
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379 | */ |
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380 | private static function buildStashValue( |
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381 | Content $pstContent, ParserOutput $parserOutput, $timestamp, User $user |
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382 | ) { |
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383 | // If an item is renewed, mind the cache TTL determined by config and parser functions. |
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384 | // Put an upper limit on the TTL for sanity to avoid extreme template/file staleness. |
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385 | $since = time() - wfTimestamp( TS_UNIX, $parserOutput->getTimestamp() ); |
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386 | $ttl = min( $parserOutput->getCacheExpiry() - $since, self::MAX_CACHE_TTL ); |
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387 | if ( $ttl <= 0 ) { |
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388 | return [ null, 0, 'no_ttl' ]; |
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389 | } |
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390 | |||
391 | // Only store what is actually needed |
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392 | $stashInfo = (object)[ |
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393 | 'pstContent' => $pstContent, |
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394 | 'output' => $parserOutput, |
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395 | 'timestamp' => $timestamp, |
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396 | 'edits' => $user->getEditCount() |
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397 | ]; |
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398 | |||
399 | return [ $stashInfo, $ttl, 'ok' ]; |
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400 | } |
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401 | |||
402 | public function getAllowedParams() { |
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403 | return [ |
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404 | 'title' => [ |
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405 | ApiBase::PARAM_TYPE => 'string', |
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406 | ApiBase::PARAM_REQUIRED => true |
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407 | ], |
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408 | 'section' => [ |
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409 | ApiBase::PARAM_TYPE => 'string', |
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410 | ], |
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411 | 'sectiontitle' => [ |
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412 | ApiBase::PARAM_TYPE => 'string' |
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413 | ], |
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414 | 'text' => [ |
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415 | ApiBase::PARAM_TYPE => 'text', |
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416 | ApiBase::PARAM_DFLT => null |
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417 | ], |
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418 | 'stashedtexthash' => [ |
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419 | ApiBase::PARAM_TYPE => 'string', |
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420 | ApiBase::PARAM_DFLT => null |
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421 | ], |
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422 | 'summary' => [ |
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423 | ApiBase::PARAM_TYPE => 'string', |
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424 | ], |
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425 | 'contentmodel' => [ |
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426 | ApiBase::PARAM_TYPE => ContentHandler::getContentModels(), |
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427 | ApiBase::PARAM_REQUIRED => true |
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428 | ], |
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429 | 'contentformat' => [ |
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430 | ApiBase::PARAM_TYPE => ContentHandler::getAllContentFormats(), |
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431 | ApiBase::PARAM_REQUIRED => true |
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432 | ], |
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433 | 'baserevid' => [ |
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434 | ApiBase::PARAM_TYPE => 'integer', |
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435 | ApiBase::PARAM_REQUIRED => true |
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436 | ] |
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437 | ]; |
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438 | } |
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439 | |||
440 | public function needsToken() { |
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441 | return 'csrf'; |
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442 | } |
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443 | |||
444 | public function mustBePosted() { |
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445 | return true; |
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446 | } |
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447 | |||
448 | public function isWriteMode() { |
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449 | return true; |
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450 | } |
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451 | |||
452 | public function isInternal() { |
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453 | return true; |
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454 | } |
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455 | } |
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456 |
Let’s assume that you have a directory layout like this:
and let’s assume the following content of
Bar.php
:If both files
OtherDir/Foo.php
andSomeDir/Foo.php
are loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.php
However, as
OtherDir/Foo.php
does not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php
, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: