Obtain search results for a particular subsite when the request comes from a query (#136)

* Allow a user to obtain search results for a particular subsite when the request comes from a query

When attempting to do this in project code, SearchVariantSubsites kicks in and replaces any filter you've applied with the current subsite ID, which prevents you from searching for filtered results in another subsite.

This fix prevents the module from doing this if a filter is applied on the query

TODO  write unit tests for the filter() and exclude() behaviours

README.md

@@ -1,3 +1,4 @@
+
 # FullTextSearch module
 
 [![Build Status](https://secure.travis-ci.org/silverstripe/silverstripe-fulltextsearch.png?branch=master)](http://travis-ci.org/silverstripe/silverstripe-fulltextsearch)

code/search/SearchVariantSubsites.php

@@ -60,9 +60,21 @@ class SearchVariantSubsites extends SearchVariant
         ));
     }
 
-
+    /**
+     * This field has been altered to allow a user to obtain search results for a particular subsite
+     * When attempting to do this in project code, SearchVariantSubsites kicks and overwrites any filter you've applied
+     * This fix prevents the module from doing this if a filter is applied on the index or the query, or if a field is
+     * being excluded specifically before being executed.
+     *
+     * A pull request has been raised for this issue. Once accepted this forked module can be deleted and the parent
+     * project should be used instead.
+     */
     public function alterQuery($query, $index)
     {
+        if ($this->isFieldFiltered('_subsite', $query)) {
+            return;
+        }
+
         $subsite = Subsite::currentSubsiteID();
         $query->filter('_subsite', array($subsite, SearchQuery::$missing));
     }
@@ -109,4 +121,19 @@ class SearchVariantSubsites extends SearchVariant
             $writes[$key]['statefulids'] = $next;
         }
     }
+
+    /**
+     * Determine if a field with a certain name is filtered by the search query or on the index
+     * This is the equivalent of saying "show me the results that do ONLY contain this value"
+     * @param $field string name of the field being filtered
+     * @param $query SearchQuery currently being executed
+     * @param $index SearchIndex which specifies a filter field
+     * @return bool true if $field is being filtered, false if it is not being filtered
+     */
+    protected function isFieldFiltered($field, $query)
+    {
+        $queryHasFilter = !empty($query->require[$field]);
+
+        return $queryHasFilter;
+    }
 }

tests/SearchVariantSubsitesTest.php

@@ -0,0 +1,91 @@
+<?php
+
+class SearchVariantSubsiteTest extends SapphireTest
+{
+
+    private static $index = null;
+
+
+    public function setUp()
+    {
+        parent::setUp();
+
+        // Check versioned available
+        if (!class_exists('Subsite')) {
+            return $this->markTestSkipped('The subsites module is not installed');
+        }
+
+        if (self::$index === null) {
+            self::$index = singleton('SearchVariantSubsiteTest');
+        }
+
+        SearchUpdater::bind_manipulation_capture();
+
+        Config::inst()->update('Injector', 'SearchUpdateProcessor', array(
+            'class' => 'SearchUpdateImmediateProcessor'
+        ));
+
+        FullTextSearch::force_index_list(self::$index);
+        SearchUpdater::clear_dirty_indexes();
+    }
+
+    public function testQueryIsAlteredWhenSubsiteNotSet()
+    {
+        $index = new SolrIndexTest_FakeIndex();
+        $query = new SearchQuery();
+
+        //typical behaviour: nobody is explicitly filtering on subsite, so the search variant adds a filter to the query
+        $this->assertArrayNotHasKey('_subsite', $query->require);
+        $variant = new SearchVariantSubsites();
+        $variant->alterDefinition('SearchUpdaterTest_Container', $index);
+        $variant->alterQuery($query, $index);
+
+        //check that the "default" query has been put in place: it's not empty, and we're searching on Subsite ID:0 and
+        // an object of SearchQuery::missing
+        $this->assertNotEmpty($query->require['_subsite']);
+        $this->assertEquals(0, $query->require['_subsite'][0]);
+
+        //check that SearchQuery::missing is set (by default, it is an object of stdClass)
+        $this->assertInstanceOf('stdClass', $query->require['_subsite'][1]);
+    }
+
+
+    public function testQueryIsAlteredWhenSubsiteIsSet()
+    {
+        //now we want to test if somebody has already applied the _subsite filter to the query
+        $index = new SolrIndexTest_FakeIndex();
+        $query = new SearchQuery();
+
+        //check that _subsite is not applied yet
+        //this key should not be exist until the SearchVariant applies it later
+        $this->assertArrayNotHasKey('_subsite', $query->require);
+
+        //apply the subsite filter on the query (for example, if it's passed into a controller and set before searching)
+        //we've chosen an arbirary value of 2 here, to check if it is changed later
+        $query->filter('_subsite', 2);
+        $this->assertNotEmpty($query->require['_subsite']);
+
+        //apply the search variant's definition and query
+        $variant = new SearchVariantSubsites();
+        $variant->alterDefinition('SearchUpdaterTest_Container', $index);
+
+        //the protected function isFieldFiltered is implicitly tested here
+        $variant->alterQuery($query, $index);
+
+        //confirm that the query has been altered, but NOT with default values
+        //first check that _subsite filter is not empty
+        $this->assertNotEmpty($query->require['_subsite']);
+        //subsite filter first value is not 0
+        $this->assertNotEquals(0, $query->require['_subsite'][0]);
+
+        //subsite filter SearchQuery::missing should not be set so its expected location is empty
+        $this->assertArrayNotHasKey(1, $query->require['_subsite']);
+
+        //subsite filter has been modified with our arbitrary test value. The second value is not set
+        //this proves that the query has not been altered by the variant
+        $this->assertEquals(2, $query->require['_subsite'][0]);
+
+    }
+
+}
+