Added custom filter "ProductStoreFilter" for Catalog Product API to enable store-filtering via REST API

app/code/Magento/Catalog/Model/Api/SearchCriteria/CollectionProcessor/FilterProcessor/ProductStoreFilter.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * Copyright © 2013-2017 Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Catalog\Model\Api\SearchCriteria\CollectionProcessor\FilterProcessor;
+
+use Magento\Catalog\Model\ResourceModel\Product\Collection;
+use Magento\Framework\Api\Filter;
+use Magento\Framework\Api\SearchCriteria\CollectionProcessor\FilterProcessor\CustomFilterInterface;
+use Magento\Framework\Data\Collection\AbstractDb;
+
+class ProductStoreFilter implements CustomFilterInterface
+{
+    /**
+     * Apply store Filter to Product Collection
+     *
+     * @param Filter $filter
+     * @param AbstractDb $collection
+     * @return bool Whether the filter is applied
+     */
+    public function apply(Filter $filter, AbstractDb $collection)
+    {
+        $conditionType = $filter->getConditionType() ? $filter->getConditionType() : 'eq';
+        $storeFilter = [$conditionType => [$filter->getValue()]];
+
+        /** @var Collection $collection */
+        $collection->addStoreFilter($storeFilter);
+
+        return true;
+    }
+}

app/code/Magento/Catalog/Test/Unit/Model/Api/SearchCriteria/CollectionProcessor/FilterProcessor/ProductStoreFilterTest.php

@@ -0,0 +1,73 @@
+<?php
+/**
+ * Copyright © 2013-2017 Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Catalog\Test\Unit\Model\Api\SearchCriteria\CollectionProcessor\FilterProcessor;
+
+use Magento\Catalog\Model\Api\SearchCriteria\CollectionProcessor\FilterProcessor\ProductStoreFilter;
+use Magento\Catalog\Model\ResourceModel\Product\Collection;
+use Magento\Framework\Api\Filter;
+
+class ProductStoreFilterTest extends \PHPUnit_Framework_TestCase
+{
+    /** @var ProductStoreFilter */
+    private $model;
+
+    protected function setUp()
+    {
+        $this->model = new ProductStoreFilter();
+    }
+
+    public function testApply()
+    {
+        /** @var Filter|\PHPUnit_Framework_MockObject_MockObject $filterMock */
+        $filterMock = $this->getMockBuilder(Filter::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        /** @var Collection|\PHPUnit_Framework_MockObject_MockObject $collectionMock */
+        $collectionMock = $this->getMockBuilder(Collection::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $filterMock->expects($this->exactly(2))
+            ->method('getConditionType')
+            ->willReturn('condition');
+        $filterMock->expects($this->once())
+            ->method('getValue')
+            ->willReturn('value');
+
+        $collectionMock->expects($this->once())
+            ->method('addStoreFilter')
+            ->with(['condition' => ['value']]);
+
+        $this->assertTrue($this->model->apply($filterMock, $collectionMock));
+    }
+
+    public function testApplyWithoutCondition()
+    {
+        /** @var Filter|\PHPUnit_Framework_MockObject_MockObject $filterMock */
+        $filterMock = $this->getMockBuilder(Filter::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        /** @var Collection|\PHPUnit_Framework_MockObject_MockObject $collectionMock */
+        $collectionMock = $this->getMockBuilder(Collection::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $filterMock->expects($this->once())
+            ->method('getConditionType')
+            ->willReturn(null);
+        $filterMock->expects($this->once())
+            ->method('getValue')
+            ->willReturn('value');
+
+        $collectionMock->expects($this->once())
+            ->method('addStoreFilter')
+            ->with(['eq' => ['value']]);
+
+        $this->assertTrue($this->model->apply($filterMock, $collectionMock));
+    }
+}

app/code/Magento/Catalog/etc/di.xml

@@ -826,6 +826,7 @@
         <arguments>
             <argument name="customFilters" xsi:type="array">
                 <item name="category_id" xsi:type="object">Magento\Catalog\Model\Api\SearchCriteria\CollectionProcessor\FilterProcessor\ProductCategoryFilter</item>
+                <item name="store" xsi:type="object">Magento\Catalog\Model\Api\SearchCriteria\CollectionProcessor\FilterProcessor\ProductStoreFilter</item>
             </argument>
         </arguments>
     </virtualType>