Merge pull request #455 from ArthurHoaro/improved-search-454

Improved search: combine AND, exact terms and exclude search.

1 files changed, 49 insertions, 39 deletions

diff --git a/application/LinkFilter.php b/application/LinkFilter.php
index ceb47d16..17594e8f 100644
--- a/application/LinkFilter.php
+++ b/application/LinkFilter.php
@@ -120,7 +120,9 @@ class LinkFilter
      *
      * Searches:
      *  - in the URLs, title and description;
-     *  - are case-insensitive.
+     *  - are case-insensitive;
+     *  - terms surrounded by quotes " are exact terms search.
+     *  - terms starting with a dash - are excluded (except exact terms).
      *
      * Example:
      *    print_r($mydb->filterFulltext('hollandais'));
@@ -136,19 +138,30 @@ class LinkFilter
      */
     private function filterFulltext($searchterms, $privateonly = false)
     {
+        $filtered = array();
         $search = mb_convert_case(html_entity_decode($searchterms), MB_CASE_LOWER, 'UTF-8');
-        $explodedSearch = explode(' ', trim($search));
-        $keys = array('title', 'description', 'url', 'tags');
-        $found = true;
-        $searchExactPhrase = false;
-
-        // Check if we're using double-quotes to search for the exact string
-        if ($search[0] == '"' && $search[strlen($search) - 1] == '"') {
-            $searchExactPhrase = true;
-            
-            // Remove the double-quotes as they are not what we search for
-            $search = substr($search, 1, -1);
+        $exactRegex = '/"([^"]+)"/';
+        // Retrieve exact search terms.
+        preg_match_all($exactRegex, $search, $exactSearch);
+        $exactSearch = array_values(array_filter($exactSearch[1]));
+
+        // Remove exact search terms to get AND terms search.
+        $explodedSearchAnd = explode(' ', trim(preg_replace($exactRegex, '', $search)));
+        $explodedSearchAnd = array_values(array_filter($explodedSearchAnd));
+
+        // Filter excluding terms and update andSearch.
+        $excludeSearch = array();
+        $andSearch = array();
+        foreach ($explodedSearchAnd as $needle) {
+            if ($needle[0] == '-' && strlen($needle) > 1) {
+                $excludeSearch[] = substr($needle, 1);
+            } else {
+                $andSearch[] = $needle;
+            }
         }
+
+        $keys = array('title', 'description', 'url', 'tags');
+
         // Iterate over every stored link.
         foreach ($this->links as $link) {
 
@@ -157,35 +170,32 @@ class LinkFilter
                 continue;
             }
 
-            // Iterate over searchable link fields.
+            // Concatenate link fields to search across fields.
+            // Adds a '\' separator for exact search terms.
+            $content = '';
             foreach ($keys as $key) {
-                // Be optimistic
-                $found = true;
-                
-                // FIXME: Find a better word for where you're searching in 
-                $haystack = mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8');
-
-                // When searching for the phrase, check if it's in the haystack...
-                if ( $searchExactPhrase && strpos($haystack, $search) !== false) {
-                    break;
-                }
-                else {
-                    // Iterate over keywords, if keyword is not found,
-                    // no need to check for the others. We want all or nothing.
-                    foreach($explodedSearch as $keyword) {
-                         if(strpos($haystack, $keyword) === false) {
-                           $found = false;
-                           break;
-                      }
-                    }
-                }
-                
-                // One of the fields of the link matches, no need to check the other.
-                if ($found) {
-                    break;
-                }
+                $content .= mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8') . '\\';
+            }
+
+            // Be optimistic
+            $found = true;
+
+            // First, we look for exact term search
+            for ($i = 0; $i < count($exactSearch) && $found; $i++) {
+                $found = strpos($content, $exactSearch[$i]) !== false;
             }
-            
+
+            // Iterate over keywords, if keyword is not found,
+            // no need to check for the others. We want all or nothing.
+            for ($i = 0; $i < count($andSearch) && $found; $i++) {
+                $found = strpos($content, $andSearch[$i]) !== false;
+            }
+
+            // Exclude terms.
+            for ($i = 0; $i < count($excludeSearch) && $found; $i++) {
+                $found = strpos($content, $excludeSearch[$i]) === false;
+            }
+
             if ($found) {
                 $filtered[$link['linkdate']] = $link;
             }