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   1  <?php
   2  /**
   3   * Basic search engine
   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   * @ingroup Search
  22   */
  23  
  24  /**
  25   * @defgroup Search Search
  26   */
  27  
  28  /**
  29   * Contain a class for special pages
  30   * @ingroup Search
  31   */
  32  class SearchEngine {
  33      /** @var string */
  34      public $prefix = '';
  35  
  36      /** @var int[] */
  37      public $namespaces = array( NS_MAIN );
  38  
  39      /** @var int */
  40      protected $limit = 10;
  41  
  42      /** @var int */
  43      protected $offset = 0;
  44  
  45      /** @var array|string */
  46      protected $searchTerms = array();
  47  
  48      /** @var bool */
  49      protected $showSuggestion = true;
  50  
  51      /** @var array Feature values */
  52      protected $features = array();
  53  
  54      /**
  55       * Perform a full text search query and return a result set.
  56       * If title searches are not supported or disabled, return null.
  57       * STUB
  58       *
  59       * @param string $term Raw search term
  60       * @return SearchResultSet|Status|null
  61       */
  62  	function searchText( $term ) {
  63          return null;
  64      }
  65  
  66      /**
  67       * Perform a title-only search query and return a result set.
  68       * If title searches are not supported or disabled, return null.
  69       * STUB
  70       *
  71       * @param string $term Raw search term
  72       * @return SearchResultSet|null
  73       */
  74  	function searchTitle( $term ) {
  75          return null;
  76      }
  77  
  78      /**
  79       * @since 1.18
  80       * @param string $feature
  81       * @return bool
  82       */
  83  	public function supports( $feature ) {
  84          switch ( $feature ) {
  85          case 'search-update':
  86              return true;
  87          case 'title-suffix-filter':
  88          default:
  89              return false;
  90          }
  91      }
  92  
  93      /**
  94       * Way to pass custom data for engines
  95       * @since 1.18
  96       * @param string $feature
  97       * @param mixed $data
  98       * @return bool
  99       */
 100  	public function setFeatureData( $feature, $data ) {
 101          $this->features[$feature] = $data;
 102      }
 103  
 104      /**
 105       * When overridden in derived class, performs database-specific conversions
 106       * on text to be used for searching or updating search index.
 107       * Default implementation does nothing (simply returns $string).
 108       *
 109       * @param string $string String to process
 110       * @return string
 111       */
 112  	public function normalizeText( $string ) {
 113          global $wgContLang;
 114  
 115          // Some languages such as Chinese require word segmentation
 116          return $wgContLang->segmentByWord( $string );
 117      }
 118  
 119      /**
 120       * Transform search term in cases when parts of the query came as different
 121       * GET params (when supported), e.g. for prefix queries:
 122       * search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 123       * @param string $term
 124       * @return string
 125       */
 126  	function transformSearchTerm( $term ) {
 127          return $term;
 128      }
 129  
 130      /**
 131       * If an exact title match can be found, or a very slightly close match,
 132       * return the title. If no match, returns NULL.
 133       *
 134       * @param string $searchterm
 135       * @return Title
 136       */
 137  	public static function getNearMatch( $searchterm ) {
 138          $title = self::getNearMatchInternal( $searchterm );
 139  
 140          wfRunHooks( 'SearchGetNearMatchComplete', array( $searchterm, &$title ) );
 141          return $title;
 142      }
 143  
 144      /**
 145       * Do a near match (see SearchEngine::getNearMatch) and wrap it into a
 146       * SearchResultSet.
 147       *
 148       * @param string $searchterm
 149       * @return SearchResultSet
 150       */
 151  	public static function getNearMatchResultSet( $searchterm ) {
 152          return new SearchNearMatchResultSet( self::getNearMatch( $searchterm ) );
 153      }
 154  
 155      /**
 156       * Really find the title match.
 157       * @param string $searchterm
 158       * @return null|Title
 159       */
 160  	private static function getNearMatchInternal( $searchterm ) {
 161          global $wgContLang, $wgEnableSearchContributorsByIP;
 162  
 163          $allSearchTerms = array( $searchterm );
 164  
 165          if ( $wgContLang->hasVariants() ) {
 166              $allSearchTerms = array_merge(
 167                  $allSearchTerms,
 168                  $wgContLang->autoConvertToAllVariants( $searchterm )
 169              );
 170          }
 171  
 172          $titleResult = null;
 173          if ( !wfRunHooks( 'SearchGetNearMatchBefore', array( $allSearchTerms, &$titleResult ) ) ) {
 174              return $titleResult;
 175          }
 176  
 177          foreach ( $allSearchTerms as $term ) {
 178  
 179              # Exact match? No need to look further.
 180              $title = Title::newFromText( $term );
 181              if ( is_null( $title ) ) {
 182                  return null;
 183              }
 184  
 185              # Try files if searching in the Media: namespace
 186              if ( $title->getNamespace() == NS_MEDIA ) {
 187                  $title = Title::makeTitle( NS_FILE, $title->getText() );
 188              }
 189  
 190              if ( $title->isSpecialPage() || $title->isExternal() || $title->exists() ) {
 191                  return $title;
 192              }
 193  
 194              # See if it still otherwise has content is some sane sense
 195              $page = WikiPage::factory( $title );
 196              if ( $page->hasViewableContent() ) {
 197                  return $title;
 198              }
 199  
 200              if ( !wfRunHooks( 'SearchAfterNoDirectMatch', array( $term, &$title ) ) ) {
 201                  return $title;
 202              }
 203  
 204              # Now try all lower case (i.e. first letter capitalized)
 205              $title = Title::newFromText( $wgContLang->lc( $term ) );
 206              if ( $title && $title->exists() ) {
 207                  return $title;
 208              }
 209  
 210              # Now try capitalized string
 211              $title = Title::newFromText( $wgContLang->ucwords( $term ) );
 212              if ( $title && $title->exists() ) {
 213                  return $title;
 214              }
 215  
 216              # Now try all upper case
 217              $title = Title::newFromText( $wgContLang->uc( $term ) );
 218              if ( $title && $title->exists() ) {
 219                  return $title;
 220              }
 221  
 222              # Now try Word-Caps-Breaking-At-Word-Breaks, for hyphenated names etc
 223              $title = Title::newFromText( $wgContLang->ucwordbreaks( $term ) );
 224              if ( $title && $title->exists() ) {
 225                  return $title;
 226              }
 227  
 228              // Give hooks a chance at better match variants
 229              $title = null;
 230              if ( !wfRunHooks( 'SearchGetNearMatch', array( $term, &$title ) ) ) {
 231                  return $title;
 232              }
 233          }
 234  
 235          $title = Title::newFromText( $searchterm );
 236  
 237          # Entering an IP address goes to the contributions page
 238          if ( $wgEnableSearchContributorsByIP ) {
 239              if ( ( $title->getNamespace() == NS_USER && User::isIP( $title->getText() ) )
 240                  || User::isIP( trim( $searchterm ) ) ) {
 241                  return SpecialPage::getTitleFor( 'Contributions', $title->getDBkey() );
 242              }
 243          }
 244  
 245          # Entering a user goes to the user page whether it's there or not
 246          if ( $title->getNamespace() == NS_USER ) {
 247              return $title;
 248          }
 249  
 250          # Go to images that exist even if there's no local page.
 251          # There may have been a funny upload, or it may be on a shared
 252          # file repository such as Wikimedia Commons.
 253          if ( $title->getNamespace() == NS_FILE ) {
 254              $image = wfFindFile( $title );
 255              if ( $image ) {
 256                  return $title;
 257              }
 258          }
 259  
 260          # MediaWiki namespace? Page may be "implied" if not customized.
 261          # Just return it, with caps forced as the message system likes it.
 262          if ( $title->getNamespace() == NS_MEDIAWIKI ) {
 263              return Title::makeTitle( NS_MEDIAWIKI, $wgContLang->ucfirst( $title->getText() ) );
 264          }
 265  
 266          # Quoted term? Try without the quotes...
 267          $matches = array();
 268          if ( preg_match( '/^"([^"]+)"$/', $searchterm, $matches ) ) {
 269              return SearchEngine::getNearMatch( $matches[1] );
 270          }
 271  
 272          return null;
 273      }
 274  
 275  	public static function legalSearchChars() {
 276          return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 277      }
 278  
 279      /**
 280       * Set the maximum number of results to return
 281       * and how many to skip before returning the first.
 282       *
 283       * @param int $limit
 284       * @param int $offset
 285       */
 286  	function setLimitOffset( $limit, $offset = 0 ) {
 287          $this->limit = intval( $limit );
 288          $this->offset = intval( $offset );
 289      }
 290  
 291      /**
 292       * Set which namespaces the search should include.
 293       * Give an array of namespace index numbers.
 294       *
 295       * @param array $namespaces
 296       */
 297  	function setNamespaces( $namespaces ) {
 298          $this->namespaces = $namespaces;
 299      }
 300  
 301      /**
 302       * Set whether the searcher should try to build a suggestion.  Note: some searchers
 303       * don't support building a suggestion in the first place and others don't respect
 304       * this flag.
 305       *
 306       * @param bool $showSuggestion Should the searcher try to build suggestions
 307       */
 308  	function setShowSuggestion( $showSuggestion ) {
 309          $this->showSuggestion = $showSuggestion;
 310      }
 311  
 312      /**
 313       * Parse some common prefixes: all (search everything)
 314       * or namespace names
 315       *
 316       * @param string $query
 317       * @return string
 318       */
 319  	function replacePrefixes( $query ) {
 320          global $wgContLang;
 321  
 322          $parsed = $query;
 323          if ( strpos( $query, ':' ) === false ) { // nothing to do
 324              return $parsed;
 325          }
 326  
 327          $allkeyword = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 328          if ( strncmp( $query, $allkeyword, strlen( $allkeyword ) ) == 0 ) {
 329              $this->namespaces = null;
 330              $parsed = substr( $query, strlen( $allkeyword ) );
 331          } elseif ( strpos( $query, ':' ) !== false ) {
 332              $prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
 333              $index = $wgContLang->getNsIndex( $prefix );
 334              if ( $index !== false ) {
 335                  $this->namespaces = array( $index );
 336                  $parsed = substr( $query, strlen( $prefix ) + 1 );
 337              }
 338          }
 339          if ( trim( $parsed ) == '' ) {
 340              $parsed = $query; // prefix was the whole query
 341          }
 342  
 343          return $parsed;
 344      }
 345  
 346      /**
 347       * Make a list of searchable namespaces and their canonical names.
 348       * @return array
 349       */
 350  	public static function searchableNamespaces() {
 351          global $wgContLang;
 352          $arr = array();
 353          foreach ( $wgContLang->getNamespaces() as $ns => $name ) {
 354              if ( $ns >= NS_MAIN ) {
 355                  $arr[$ns] = $name;
 356              }
 357          }
 358  
 359          wfRunHooks( 'SearchableNamespaces', array( &$arr ) );
 360          return $arr;
 361      }
 362  
 363      /**
 364       * Extract default namespaces to search from the given user's
 365       * settings, returning a list of index numbers.
 366       *
 367       * @param user $user
 368       * @return array
 369       */
 370  	public static function userNamespaces( $user ) {
 371          $arr = array();
 372          foreach ( SearchEngine::searchableNamespaces() as $ns => $name ) {
 373              if ( $user->getOption( 'searchNs' . $ns ) ) {
 374                  $arr[] = $ns;
 375              }
 376          }
 377  
 378          return $arr;
 379      }
 380  
 381      /**
 382       * Find snippet highlight settings for all users
 383       *
 384       * @return array Contextlines, contextchars
 385       */
 386  	public static function userHighlightPrefs() {
 387          $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 388          $contextchars = 75; // same as above.... :P
 389          return array( $contextlines, $contextchars );
 390      }
 391  
 392      /**
 393       * An array of namespaces indexes to be searched by default
 394       *
 395       * @return array
 396       */
 397  	public static function defaultNamespaces() {
 398          global $wgNamespacesToBeSearchedDefault;
 399  
 400          return array_keys( $wgNamespacesToBeSearchedDefault, true );
 401      }
 402  
 403      /**
 404       * Get a list of namespace names useful for showing in tooltips
 405       * and preferences
 406       *
 407       * @param array $namespaces
 408       * @return array
 409       */
 410  	public static function namespacesAsText( $namespaces ) {
 411          global $wgContLang;
 412  
 413          $formatted = array_map( array( $wgContLang, 'getFormattedNsText' ), $namespaces );
 414          foreach ( $formatted as $key => $ns ) {
 415              if ( empty( $ns ) ) {
 416                  $formatted[$key] = wfMessage( 'blanknamespace' )->text();
 417              }
 418          }
 419          return $formatted;
 420      }
 421  
 422      /**
 423       * Load up the appropriate search engine class for the currently
 424       * active database backend, and return a configured instance.
 425       *
 426       * @param string $type Type of search backend, if not the default
 427       * @return SearchEngine
 428       */
 429  	public static function create( $type = null ) {
 430          global $wgSearchType;
 431          $dbr = null;
 432  
 433          $alternatives = self::getSearchTypes();
 434  
 435          if ( $type && in_array( $type, $alternatives ) ) {
 436              $class = $type;
 437          } elseif ( $wgSearchType !== null ) {
 438              $class = $wgSearchType;
 439          } else {
 440              $dbr = wfGetDB( DB_SLAVE );
 441              $class = $dbr->getSearchEngine();
 442          }
 443  
 444          $search = new $class( $dbr );
 445          return $search;
 446      }
 447  
 448      /**
 449       * Return the search engines we support. If only $wgSearchType
 450       * is set, it'll be an array of just that one item.
 451       *
 452       * @return array
 453       */
 454  	public static function getSearchTypes() {
 455          global $wgSearchType, $wgSearchTypeAlternatives;
 456  
 457          $alternatives = $wgSearchTypeAlternatives ?: array();
 458          array_unshift( $alternatives, $wgSearchType );
 459  
 460          return $alternatives;
 461      }
 462  
 463      /**
 464       * Create or update the search index record for the given page.
 465       * Title and text should be pre-processed.
 466       * STUB
 467       *
 468       * @param int $id
 469       * @param string $title
 470       * @param string $text
 471       */
 472  	function update( $id, $title, $text ) {
 473          // no-op
 474      }
 475  
 476      /**
 477       * Update a search index record's title only.
 478       * Title should be pre-processed.
 479       * STUB
 480       *
 481       * @param int $id
 482       * @param string $title
 483       */
 484  	function updateTitle( $id, $title ) {
 485          // no-op
 486      }
 487  
 488      /**
 489       * Delete an indexed page
 490       * Title should be pre-processed.
 491       * STUB
 492       *
 493       * @param int $id Page id that was deleted
 494       * @param string $title Title of page that was deleted
 495       */
 496  	function delete( $id, $title ) {
 497          // no-op
 498      }
 499  
 500      /**
 501       * Get OpenSearch suggestion template
 502       *
 503       * @return string
 504       */
 505  	public static function getOpenSearchTemplate() {
 506          global $wgOpenSearchTemplate, $wgCanonicalServer;
 507  
 508          if ( $wgOpenSearchTemplate ) {
 509              return $wgOpenSearchTemplate;
 510          } else {
 511              $ns = implode( '|', SearchEngine::defaultNamespaces() );
 512              if ( !$ns ) {
 513                  $ns = "0";
 514              }
 515  
 516              return $wgCanonicalServer . wfScript( 'api' )
 517                  . '?action=opensearch&search={searchTerms}&namespace=' . $ns;
 518          }
 519      }
 520  
 521      /**
 522       * Get the raw text for updating the index from a content object
 523       * Nicer search backends could possibly do something cooler than
 524       * just returning raw text
 525       *
 526       * @todo This isn't ideal, we'd really like to have content-specific handling here
 527       * @param Title $t Title we're indexing
 528       * @param Content $c Content of the page to index
 529       * @return string
 530       */
 531  	public function getTextFromContent( Title $t, Content $c = null ) {
 532          return $c ? $c->getTextForSearchIndex() : '';
 533      }
 534  
 535      /**
 536       * If an implementation of SearchEngine handles all of its own text processing
 537       * in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
 538       * rather silly handling, it should return true here instead.
 539       *
 540       * @return bool
 541       */
 542  	public function textAlreadyUpdatedForIndex() {
 543          return false;
 544      }
 545  }
 546  
 547  /**
 548   * Dummy class to be used when non-supported Database engine is present.
 549   * @todo FIXME: Dummy class should probably try something at least mildly useful,
 550   * such as a LIKE search through titles.
 551   * @ingroup Search
 552   */
 553  class SearchEngineDummy extends SearchEngine {
 554      // no-op
 555  }