Fuzzy search feature (replaces full text search as default action when exact title...

diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 9cd9ab3..5266466 100644 (file)
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -187,6 +187,7 @@ $wgDebugFunctionEntry = 0; # Output debug message on every wfProfileIn/wfProfile
 
 $wgDisableCounters = false;
 $wgDisableTextSearch = false;
+$wgDisableFuzzySearch = false;
 $wgDisableSearchUpdate = false; # If you've disabled search semi-permanently, this also disables updates to the table. If you ever re-enable, be sure to rebuild the search table.
 $wgDisableUploads = true; # Uploads have to be specially set up to be secure
 $wgRemoteUploads = false; # Set to true to enable the upload _link_ while local uploads are disabled. Assumes that the special page link will be bounced to another server where uploads do work.

diff --git a/includes/SearchEngine.php b/includes/SearchEngine.php
index 95dd539..90e0f5b 100644 (file)
--- a/includes/SearchEngine.php
+++ b/includes/SearchEngine.php
@@ -458,30 +458,109 @@ class SearchEngine {
                        $wgOut->redirect( wfLocalUrl( $t->getPrefixedURL() ) );
                        return;
                }
+               $wgOut->addHTML( wfMsg("nogomatch", 
+                       htmlspecialchars( wfLocalUrl( ucfirst($this->mUsertext), "action=edit") ) )
+                       . "\n<p>" );
+
+               # Try a fuzzy title search
+               $anyhit = false;
+               global $wgDisableFuzzySearch;
+               if(! $wgDisableFuzzySearch ){
+                       foreach( array(NS_MAIN, NS_WP, NS_USER, NS_IMAGE, NS_MEDIAWIKI) as $namespace){
+                               $anyhit |= SearchEngine::doFuzzyTitleSearch( $search, $namespace );
+                       }
+               } 
+               if( ! $anyhit ){
+                       $wgOut->addHTML( wfMsg("notitlematches") );             
+               }
+       }
 
-               # Try a near match
-               #
-               if( !$wgDisableTextSearch ) {
-                       $this->parseQuery();                                                                            
-                       $sql = "SELECT cur_id,cur_title,cur_namespace,si_page FROM cur,searchindex " .
-                         "WHERE cur_id=si_page AND {$this->mTitlecond} ORDER BY cur_namespace LIMIT 1";
-       
-                       if ( "" != $this->mTitlecond ) {
-                               $res = wfQuery( $sql, DB_READ, $fname );
-                       }                               
-                       if ( isset( $res ) && 0 != wfNumRows( $res ) ) {
-                               $s = wfFetchObject( $res );
-       
-                               $t = Title::makeTitle( $s->cur_namespace, $s->cur_title );
-                               $wgOut->redirect( wfLocalUrl( $t->getPrefixedURL() ) );
-                               return;
+       /* static */ function doFuzzyTitleSearch( $search, $namespace ){
+               global $wgLang, $wgOut;
+               $sstr = ucfirst($search);
+               $sstr = str_replace(" ", "_", $sstr);
+               $fuzzymatches = SearchEngine::fuzzyTitles( $sstr, $namespace );
+               $fuzzymatches = array_slice($fuzzymatches, 0, 10);
+               $slen = strlen( $search );
+               $wikitext = "";
+               foreach($fuzzymatches as $res){
+                       $t = str_replace("_", " ", $res[1]);
+                       $tfull = $wgLang->getNsText( $namespace ) . ":$t|$t";
+                       if( $namespace == NS_MAIN )
+                               $tfull = "$t";
+                       $distance = $res[0];
+                       $closeness = (strlen( $search ) - $distance) / strlen( $search );
+                       $percent = intval( $closeness * 100 ) . "%";
+                       $stars = str_repeat("*", ceil(5 * $closeness) );
+                       $wikitext .= "* [[$tfull]] $percent ($stars)\n";        
+               }
+               if( $wikitext ){
+                       if( $namespace != NS_MAIN )
+                               $wikitext = "=== " . $wgLang->getNsText( $namespace ) . " ===\n" . $wikitext;
+                       $wgOut->addWikiText( $wikitext );
+                       return true;
+               }
+               return false;
+       }
+
+       /* static */ function fuzzyTitles( $sstr, $namespace = NS_MAIN ){
+               $span = 0.10; // weed on title length before doing levenshtein.
+               $tolerance = 0.35; // allowed percentage of erronous characters
+               $slen = strlen($sstr);
+               $tolerance_count = ceil($tolerance * $slen);
+               $spanabs = ceil($slen * (1 + $span)) - $slen;
+               # print "Word: $sstr, len = $slen, range = [$min, $max], tolerance_count = $tolerance_count<BR>\n";
+               $result = array();
+               for( $i=0; $i <= $spanabs; $i++ ){
+                       $titles = SearchEngine::getTitlesByLength( $slen + $i, $namespace );
+                       if( $i != 0)
+                               $titles = array_merge($titles, SearchEngine::getTitlesByLength( $slen - $i, $namespace ) );
+                       foreach($titles as $t){
+                               $d = levenshtein($sstr, $t);
+                               if($d < $tolerance_count) 
+                                       $result[] = array($d, $t);
+                               $cnt++;
                        }
+               }
+               usort($result, "SearchEngine_pcmp");
+               return $result;
+       }
+
+       /* static */ function getTitlesByLength($aLength, $aNamespace = 0){
+               global $wgMemc, $wgDBname;
+
+               $mkey = "$wgDBname:titlesbylength:$aLength:$aNamespace";
+               $mkeyts = "$wgDBname:titlesbylength:createtime";
+               $ts = $wgMemc->get( $mkeyts );
+               $result = $wgMemc->get( $mkey );
+
+               if( time() - $ts < 3600 ){
+                       // note: in case of insufficient memcached space, we return
+                       // an empty list instead of starting to hit the DB.
+                       return is_array( $result ) ? $result : array();
                }
-               $wgOut->addHTML( wfMsg("nogomatch", 
-                 htmlspecialchars( wfLocalUrl( ucfirst($this->mUsertext), "action=edit") ) )
-                 . "\n<p>" );
-               $this->showResults();
+
+               $wgMemc->set( $mkeyts, time() );
+               $res = wfQuery("SELECT cur_title, cur_namespace FROM cur", DB_READ);
+               $titles = array(); // length, ns, [titles]
+               while( $obj = wfFetchObject( $res ) ){
+                       $title = $obj->cur_title;
+                       $ns = $obj->cur_namespace;
+                       $len = strlen( $title );
+                       $titles[$len][$ns][] = $title;
+               } 
+               foreach($titles as $length => $length_arr){
+                       foreach($length_arr as $ns => $title_arr){
+                               $mkey = "$wgDBname:titlesbylength:$length:$ns";
+                               $wgMemc->set( $mkey, $title_arr, 3600 * 24 );
+                       }
+               }
+               return $titles[$aLength][$aNamespace];
        }
 }
 
+/* private static */ function SearchEngine_pcmp($a, $b){ return $a[0] - $b[0]; }
+
+
+
 ?>