includes/PageProps.php

   1 <?php
   2 /**
   3  * Access to properties of a page.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22 use Wikimedia\ScopedCallback;
  23
  24 /**
  25  * Gives access to properties of a page.
  26  *
  27  * @since 1.27
  28  */
  29 class PageProps {
  30
  31         /**
  32          * @var PageProps
  33          */
  34         private static $instance;
  35
  36         /**
  37          * Overrides the default instance of this class
  38          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  39          *
  40          * If this method is used it MUST also be called with null after a test to ensure a new
  41          * default instance is created next time getInstance is called.
  42          *
  43          * @since 1.27
  44          *
  45          * @param PageProps|null $store
  46          *
  47          * @return ScopedCallback to reset the overridden value
  48          * @throws MWException
  49          */
  50         public static function overrideInstance( PageProps $store = null ) {
  51                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  52                         throw new MWException(
  53                                 'Cannot override ' . __CLASS__ . 'default instance in operation.'
  54                         );
  55                 }
  56                 $previousValue = self::$instance;
  57                 self::$instance = $store;
  58                 return new ScopedCallback( function() use ( $previousValue ) {
  59                         self::$instance = $previousValue;
  60                 } );
  61         }
  62
  63         /**
  64          * @return PageProps
  65          */
  66         public static function getInstance() {
  67                 if ( self::$instance === null ) {
  68                         self::$instance = new self();
  69                 }
  70                 return self::$instance;
  71         }
  72
  73         /** Cache parameters */
  74         const CACHE_TTL = 10; // integer; TTL in seconds
  75         const CACHE_SIZE = 100; // integer; max cached pages
  76
  77         /** Property cache */
  78         private $cache = null;
  79
  80         /**
  81          * Create a PageProps object
  82          */
  83         private function __construct() {
  84                 $this->cache = new ProcessCacheLRU( self::CACHE_SIZE );
  85         }
  86
  87         /**
  88          * Ensure that cache has at least this size
  89          * @param int $size
  90          */
  91         public function ensureCacheSize( $size ) {
  92                 if ( $this->cache->getSize() < $size ) {
  93                         $this->cache->resize( $size );
  94                 }
  95         }
  96
  97         /**
  98          * Given one or more Titles and one or more names of properties,
  99          * returns an associative array mapping page ID to property value.
 100          * Pages in the provided set of Titles that do not have a value for
 101          * the given properties will not appear in the returned array. If a
 102          * single Title is provided, it does not need to be passed in an array,
 103          * but an array will always be returned. If a single property name is
 104          * provided, it does not need to be passed in an array. In that case,
 105          * an associative array mapping page ID to property value will be
 106          * returned; otherwise, an associative array mapping page ID to
 107          * an associative array mapping property name to property value will be
 108          * returned. An empty array will be returned if no matching properties
 109          * were found.
 110          *
 111          * @param Title[]|Title $titles
 112          * @param string[]|string $propertyNames
 113          * @return array associative array mapping page ID to property value
 114          */
 115         public function getProperties( $titles, $propertyNames ) {
 116                 if ( is_array( $propertyNames ) ) {
 117                         $gotArray = true;
 118                 } else {
 119                         $propertyNames = [ $propertyNames ];
 120                         $gotArray = false;
 121                 }
 122
 123                 $values = [];
 124                 $goodIDs = $this->getGoodIDs( $titles );
 125                 $queryIDs = [];
 126                 foreach ( $goodIDs as $pageID ) {
 127                         foreach ( $propertyNames as $propertyName ) {
 128                                 $propertyValue = $this->getCachedProperty( $pageID, $propertyName );
 129                                 if ( $propertyValue === false ) {
 130                                         $queryIDs[] = $pageID;
 131                                         break;
 132                                 } else {
 133                                         if ( $gotArray ) {
 134                                                 $values[$pageID][$propertyName] = $propertyValue;
 135                                         } else {
 136                                                 $values[$pageID] = $propertyValue;
 137                                         }
 138                                 }
 139                         }
 140                 }
 141
 142                 if ( $queryIDs ) {
 143                         $dbr = wfGetDB( DB_REPLICA );
 144                         $result = $dbr->select(
 145                                 'page_props',
 146                                 [
 147                                         'pp_page',
 148                                         'pp_propname',
 149                                         'pp_value'
 150                                 ],
 151                                 [
 152                                         'pp_page' => $queryIDs,
 153                                         'pp_propname' => $propertyNames
 154                                 ],
 155                                 __METHOD__
 156                         );
 157
 158                         foreach ( $result as $row ) {
 159                                 $pageID = $row->pp_page;
 160                                 $propertyName = $row->pp_propname;
 161                                 $propertyValue = $row->pp_value;
 162                                 $this->cacheProperty( $pageID, $propertyName, $propertyValue );
 163                                 if ( $gotArray ) {
 164                                         $values[$pageID][$propertyName] = $propertyValue;
 165                                 } else {
 166                                         $values[$pageID] = $propertyValue;
 167                                 }
 168                         }
 169                 }
 170
 171                 return $values;
 172         }
 173
 174         /**
 175          * Get all page property values.
 176          * Given one or more Titles, returns an associative array mapping page
 177          * ID to an associative array mapping property names to property
 178          * values. Pages in the provided set of Titles that do not have any
 179          * properties will not appear in the returned array. If a single Title
 180          * is provided, it does not need to be passed in an array, but an array
 181          * will always be returned. An empty array will be returned if no
 182          * matching properties were found.
 183          *
 184          * @param Title[]|Title $titles
 185          * @return array associative array mapping page ID to property value array
 186          */
 187         public function getAllProperties( $titles ) {
 188                 $values = [];
 189                 $goodIDs = $this->getGoodIDs( $titles );
 190                 $queryIDs = [];
 191                 foreach ( $goodIDs as $pageID ) {
 192                         $pageProperties = $this->getCachedProperties( $pageID );
 193                         if ( $pageProperties === false ) {
 194                                 $queryIDs[] = $pageID;
 195                         } else {
 196                                 $values[$pageID] = $pageProperties;
 197                         }
 198                 }
 199
 200                 if ( $queryIDs != [] ) {
 201                         $dbr = wfGetDB( DB_REPLICA );
 202                         $result = $dbr->select(
 203                                 'page_props',
 204                                 [
 205                                         'pp_page',
 206                                         'pp_propname',
 207                                         'pp_value'
 208                                 ],
 209                                 [
 210                                         'pp_page' => $queryIDs,
 211                                 ],
 212                                 __METHOD__
 213                         );
 214
 215                         $currentPageID = 0;
 216                         $pageProperties = [];
 217                         foreach ( $result as $row ) {
 218                                 $pageID = $row->pp_page;
 219                                 if ( $currentPageID != $pageID ) {
 220                                         if ( $pageProperties != [] ) {
 221                                                 $this->cacheProperties( $currentPageID, $pageProperties );
 222                                                 $values[$currentPageID] = $pageProperties;
 223                                         }
 224                                         $currentPageID = $pageID;
 225                                         $pageProperties = [];
 226                                 }
 227                                 $pageProperties[$row->pp_propname] = $row->pp_value;
 228                         }
 229                         if ( $pageProperties != [] ) {
 230                                 $this->cacheProperties( $pageID, $pageProperties );
 231                                 $values[$pageID] = $pageProperties;
 232                         }
 233                 }
 234
 235                 return $values;
 236         }
 237
 238         /**
 239          * @param Title[]|Title $titles
 240          * @return array array of good page IDs
 241          */
 242         private function getGoodIDs( $titles ) {
 243                 $result = [];
 244                 if ( is_array( $titles ) ) {
 245                         foreach ( $titles as $title ) {
 246                                 $pageID = $title->getArticleID();
 247                                 if ( $pageID > 0 ) {
 248                                         $result[] = $pageID;
 249                                 }
 250                         }
 251                 } else {
 252                         $pageID = $titles->getArticleID();
 253                         if ( $pageID > 0 ) {
 254                                 $result[] = $pageID;
 255                         }
 256                 }
 257                 return $result;
 258         }
 259
 260         /**
 261          * Get a property from the cache.
 262          *
 263          * @param int $pageID page ID of page being queried
 264          * @param string $propertyName name of property being queried
 265          * @return string|bool property value array or false if not found
 266          */
 267         private function getCachedProperty( $pageID, $propertyName ) {
 268                 if ( $this->cache->has( $pageID, $propertyName, self::CACHE_TTL ) ) {
 269                         return $this->cache->get( $pageID, $propertyName );
 270                 }
 271                 if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
 272                         $pageProperties = $this->cache->get( 0, $pageID );
 273                         if ( isset( $pageProperties[$propertyName] ) ) {
 274                                 return $pageProperties[$propertyName];
 275                         }
 276                 }
 277                 return false;
 278         }
 279
 280         /**
 281          * Get properties from the cache.
 282          *
 283          * @param int $pageID page ID of page being queried
 284          * @return string|bool property value array or false if not found
 285          */
 286         private function getCachedProperties( $pageID ) {
 287                 if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
 288                         return $this->cache->get( 0, $pageID );
 289                 }
 290                 return false;
 291         }
 292
 293         /**
 294          * Save a property to the cache.
 295          *
 296          * @param int $pageID page ID of page being cached
 297          * @param string $propertyName name of property being cached
 298          * @param mixed $propertyValue value of property
 299          */
 300         private function cacheProperty( $pageID, $propertyName, $propertyValue ) {
 301                 $this->cache->set( $pageID, $propertyName, $propertyValue );
 302         }
 303
 304         /**
 305          * Save properties to the cache.
 306          *
 307          * @param int $pageID page ID of page being cached
 308          * @param string[] $pageProperties associative array of page properties to be cached
 309          */
 310         private function cacheProperties( $pageID, $pageProperties ) {
 311                 $this->cache->clear( $pageID );
 312                 $this->cache->set( 0, $pageID, $pageProperties );
 313         }
 314 }