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
  23 /**
  24  * Gives access to properties of a page.
  25  *
  26  * @since 1.27
  27  *
  28  */
  29 class PageProps {
  30
  31         /**
  32          * @var PageProps
  33          */
  34         private static $instance;
  35
  36         /**
  37          * @return PageProps
  38          */
  39         public static function getInstance() {
  40                 if ( self::$instance === null ) {
  41                         self::$instance = new self();
  42                 }
  43                 return self::$instance;
  44         }
  45
  46         /** Cache parameters */
  47         const CACHE_TTL = 10; // integer; TTL in seconds
  48         const CACHE_SIZE = 100; // integer; max cached pages
  49
  50         /** Property cache */
  51         private $cache = null;
  52
  53         /**
  54          * Create a PageProps object
  55          */
  56         private function __construct() {
  57                 $this->cache = new ProcessCacheLRU( self::CACHE_SIZE );
  58         }
  59
  60         /**
  61          * Given one or more Titles and the name of a property, returns an
  62          * associative array mapping page ID to property value. Pages in the
  63          * provided set of Titles that do not have a value for the given
  64          * property will not appear in the returned array. If a single Title
  65          * is provided, it does not need to be passed in an array, but an array
  66          * will always be returned. An empty array will be returned if no
  67          * matching properties were found.
  68          *
  69          * @param array|Title $titles
  70          * @param string $propertyName
  71          *
  72          * @return array associative array mapping page ID to property value
  73          *
  74          */
  75         public function getProperty( $titles, $propertyName ) {
  76                 $values = array();
  77                 $goodIDs = $this->getGoodIDs( $titles );
  78                 $queryIDs = array();
  79                 foreach ( $goodIDs as $pageID ) {
  80                         $propertyValue = $this->getCachedProperty( $pageID, $propertyName );
  81                         if ( $propertyValue === false ) {
  82                                 $queryIDs[] = $pageID;
  83                         } else {
  84                                 $values[$pageID] = $propertyValue;
  85                         }
  86                 }
  87
  88                 if ( $queryIDs != array() ) {
  89                         $dbr = wfGetDB( DB_SLAVE );
  90                         $result = $dbr->select(
  91                                 'page_props',
  92                                 array(
  93                                         'pp_page',
  94                                         'pp_value'
  95                                 ),
  96                                 array(
  97                                         'pp_page' => $queryIDs,
  98                                         'pp_propname' => $propertyName
  99                                 ),
 100                                 __METHOD__
 101                         );
 102
 103                         foreach ( $result as $row ) {
 104                                 $pageID = $row->pp_page;
 105                                 $propertyValue = $row->pp_value;
 106                                 $this->cacheProperty( $pageID, $propertyName, $propertyValue );
 107                                 $values[$pageID] = $propertyValue;
 108                         }
 109                 }
 110
 111                 return $values;
 112         }
 113
 114         /**
 115          * Get all page property values.
 116          * Given one or more Titles, returns an associative array mapping page
 117          * ID to an associative array mapping property names to property
 118          * values. Pages in the provided set of Titles that do not have any
 119          * properties will not appear in the returned array. If a single Title
 120          * is provided, it does not need to be passed in an array, but an array
 121          * will always be returned. An empty array will be returned if no
 122          * matching properties were found.
 123          *
 124          * @param array|Title $titles
 125          *
 126          * @return array associative array mapping page ID to property value array
 127          *
 128          */
 129         public function getProperties( $titles ) {
 130                 $values = array();
 131                 $goodIDs = $this->getGoodIDs( $titles );
 132                 $queryIDs = array();
 133                 foreach ( $goodIDs as $pageID ) {
 134                         $pageProperties = $this->getCachedProperties( $pageID );
 135                         if ( $pageProperties === false ) {
 136                                 $queryIDs[] = $pageID;
 137                         } else {
 138                                 $values[$pageID] = $pageProperties;
 139                         }
 140                 }
 141
 142                 if ( $queryIDs != array() ) {
 143                         $dbr = wfGetDB( DB_SLAVE );
 144                         $result = $dbr->select(
 145                                 'page_props',
 146                                 array(
 147                                         'pp_page',
 148                                         'pp_propname',
 149                                         'pp_value'
 150                                 ),
 151                                 array(
 152                                         'pp_page' => $queryIDs,
 153                                 ),
 154                                 __METHOD__
 155                         );
 156
 157                         $currentPageID = 0;
 158                         $pageProperties = array();
 159                         foreach ( $result as $row ) {
 160                                 $pageID = $row->pp_page;
 161                                 if ( $currentPageID != $pageID ) {
 162                                         if ( $pageProperties != array() ) {
 163                                                 $this->cacheProperties( $currentPageID, $pageProperties );
 164                                                 $values[$currentPageID] = $pageProperties;
 165                                         }
 166                                         $currentPageID = $pageID;
 167                                         $pageProperties = array();
 168                                 }
 169                                 $pageProperties[$row->pp_propname] = $row->pp_value;
 170                         }
 171                         if ( $pageProperties != array() ) {
 172                                 $this->cacheProperties( $pageID, $pageProperties );
 173                                 $values[$pageID] = $pageProperties;
 174                         }
 175                 }
 176
 177                 return $values;
 178         }
 179
 180         /**
 181          * @param array|Title $titles
 182          *
 183          * @return array array of good page IDs
 184          *
 185          */
 186         private function getGoodIDs( $titles ) {
 187                 $result = array();
 188                 if ( is_array( $titles ) ) {
 189                         foreach ( $titles as $title ) {
 190                                 $pageID = $title->getArticleID();
 191                                 if ( $pageID > 0 ) {
 192                                         $result[] = $pageID;
 193                                 }
 194                         }
 195                 } else {
 196                         $pageID = $titles->getArticleID();
 197                         if ( $pageID > 0 ) {
 198                                 $result[] = $pageID;
 199                         }
 200                 }
 201                 return $result;
 202         }
 203
 204         /**
 205          * Get a property from the cache.
 206          *
 207          * @param int $pageID page ID of page being queried
 208          * @param string $propertyName name of property being queried
 209          *
 210          * @return string|bool property value array or false if not found
 211          *
 212          */
 213         private function getCachedProperty( $pageID, $propertyName ) {
 214                 if ( $this->cache->has( $pageID, $propertyName, self::CACHE_TTL ) ) {
 215                         return $this->cache->get( $pageID, $propertyName );
 216                 }
 217                 if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
 218                         $pageProperties = $this->cache->get( 0, $pageID );
 219                         if ( isset( $pageProperties[$propertyName] ) ) {
 220                                 return $pageProperties[$propertyName];
 221                         }
 222                 }
 223                 return false;
 224         }
 225
 226         /**
 227          * Get properties from the cache.
 228          *
 229          * @param int $pageID page ID of page being queried
 230          *
 231          * @return string|bool property value array or false if not found
 232          *
 233          */
 234         private function getCachedProperties( $pageID ) {
 235                 if ( $this->cache->has( 0, $pageID, self::CACHE_TTL ) ) {
 236                         return $this->cache->get( 0, $pageID );
 237                 }
 238                 return false;
 239         }
 240
 241         /**
 242          * Save a property to the cache.
 243          *
 244          * @param int $pageID page ID of page being cached
 245          * @param string $propertyName name of property being cached
 246          * @param mixed $propertyValue value of property
 247          *
 248          */
 249         private function cacheProperty( $pageID, $propertyName, $propertyValue ) {
 250                 $this->cache->set( $pageID, $propertyName, $propertyValue );
 251         }
 252
 253         /**
 254          * Save properties to the cache.
 255          *
 256          * @param int $pageID page ID of page being cached
 257          * @param array $pageProperties associative array of page properties to be cached
 258          *
 259          */
 260         private function cacheProperties( $pageID, $pageProperties ) {
 261                 $this->cache->clear( $pageID );
 262                 $this->cache->set( 0, $pageID, $pageProperties );
 263         }
 264 }