Added support for "exact" searches

- Exact search = search terms in quotes using different search specs.

config/vufind/searchspecs.yaml

@@ -51,6 +51,12 @@
 #    #     for an example.  This is applied whether we use DismaxFields or
 #    #     QueryFields.
 #    FilterQuery: (optional Lucene filter query)
+#    ExactSettings:
+#      DismaxFields: ...
+#      QueryFields: ...
+#    # All the same settings as above, but for exact searches, i.e. search terms
+#    #     enclosed in quotes. Allows different fields or weights for exact
+#    #     searches. See below for commented-out examples.  
 #       
 # ...etc.
 #
@@ -208,6 +214,14 @@ Subject:
     era:
       - [and, 100]
       - [or, ~]
+#  ExactSettings:
+#    DismaxFields:
+#      - topic_unstemmed^150
+#    QueryFields:
+#      - topic_unstemmed:
+#        - [onephrase, 350]
+#        - [and, 150]
+#        - [or, ~]
 
 # This field definition is a compromise that supports both journal-level and
 # article-level data.  The disadvantage is that hits in article titles will
@@ -253,6 +267,14 @@ JournalTitle:
       - [onephrase, 50]
       - [and , ~]
   FilterQuery: "format:Journal OR format:Article"
+#  ExactSettings:
+#    DismaxFields:
+#      - title_full_unstemmed^450
+#    QueryFields:
+#      - title_full_unstemmed:
+#        - [onephrase, 450]
+#        - [and, 400]
+#    FilterQuery: "format:Journal OR format:Article"
 
 Title:
   DismaxFields:
@@ -288,6 +310,13 @@ Title:
     series2:
       - [onephrase, 50]
       - [and , ~]
+#  ExactSettings:
+#    DismaxFields:
+#      - title_full_unstemmed^450
+#    QueryFields:
+#      - title_full_unstemmed:
+#        - [onephrase, 450]
+#        - [and, 400]
 
 Series:
   DismaxFields:
@@ -382,6 +411,29 @@ AllFields:
       - [onephrase, ~]
     issn:
       - [onephrase, ~]
+#  ExactSettings:
+#    DismaxFields:
+#      - title_full_unstemmed^600
+#      - topic_unstemmed^550
+#      - allfields_unstemmed^10
+#      - fulltext_unstemmed^10
+#      - isbn
+#      - issn
+#    QueryFields:
+#      title_full_unstemmed:
+#        - [onephrase, 600]
+#        - [and, 500]
+#      topic_unstemmed:
+#        - [onephrase, 550]
+#        - [and, 500]
+#      allfields_unstemmed:
+#        - [or, 10]
+#      fulltext_unstemmed:
+#        - [or, 10]
+#      isbn:
+#        - [onephrase, ~]
+#      issn:
+#        - [onephrase, ~]
 
 # These are advanced searches that never use Dismax:
 id:

module/VuFindSearch/src/VuFindSearch/Backend/Solr/QueryBuilder.php

@@ -61,7 +61,14 @@ class QueryBuilder implements QueryBuilderInterface
      *
      * @var array
      */
-    protected $specs;
+    protected $specs = array();
+
+    /**
+     * Search specs for exact searches.
+     *
+     * @var array
+     */
+    protected $exactSpecs = array();
 
     /**
      * Should we create the hl.q parameter when appropriate?
@@ -128,7 +135,7 @@ class QueryBuilder implements QueryBuilderInterface
         }
 
         $string  = $query->getString() ?: '*:*';
-        $handler = $this->getSearchHandler($query->getHandler());
+        $handler = $this->getSearchHandler($query->getHandler(), $string);
 
         if (!($handler && $handler->hasExtendedDismax())
             && $this->getLuceneHelper()->containsAdvancedLuceneSyntax($string)
@@ -204,6 +211,12 @@ class QueryBuilder implements QueryBuilderInterface
     public function setSpecs(array $specs)
     {
         foreach ($specs as $handler => $spec) {
+            if (isset($spec['ExactSettings'])) {
+                $this->exactSpecs[strtolower($handler)] = new SearchHandler(
+                    $spec['ExactSettings'], $this->defaultDismaxHandler
+                );
+                unset($spec['ExactSettings']);
+            }
             $this->specs[strtolower($handler)]
                 = new SearchHandler($spec, $this->defaultDismaxHandler);
         }
@@ -239,18 +252,32 @@ class QueryBuilder implements QueryBuilderInterface
     /**
      * Return named search handler.
      *
-     * @param string $handler Search handler name
+     * @param string $handler      Search handler name
+     * @param string $searchString Search query
      *
      * @return SearchHandler|null
      */
-    protected function getSearchHandler($handler)
+    protected function getSearchHandler($handler, $searchString)
     {
         $handler = $handler ? strtolower($handler) : $handler;
-        if ($handler && isset($this->specs[$handler])) {
-            return $this->specs[$handler];
-        } else {
-            return null;
+        if ($handler) {
+            // Since we will rarely have exactSpecs set, it is less expensive
+            // to check for a handler first before doing multiple string
+            // operations to determine eligibility for exact handling.
+            if (isset($this->exactSpecs[$handler])) {
+                $searchString = isset($searchString) ? trim($searchString) : '';
+                if (strlen($searchString) > 1
+                    && substr($searchString, 0, 1) == '"'
+                    && substr($searchString, -1, 1) == '"'
+                ) {
+                    return $this->exactSpecs[$handler];
+                }
+            }
+            if (isset($this->specs[$handler])) {
+                return $this->specs[$handler];
+            }
         }
+        return null;
     }
 
     /**
@@ -292,7 +319,10 @@ class QueryBuilder implements QueryBuilderInterface
         } else {
             $searchString  = $this->getLuceneHelper()
                 ->normalizeSearchString($component->getString());
-            $searchHandler = $this->getSearchHandler($component->getHandler());
+            $searchHandler = $this->getSearchHandler(
+                $component->getHandler(),
+                $searchString
+            );
             if ($searchHandler) {
                 $searchString
                     = $this->createSearchString($searchString, $searchHandler);