Merge pull request #128 from leroy-merlin-br/settable-read-preference

Allows Cursor to choose a member of the ReplicaSet

src/Mongolid/Cursor/Cursor.php

@@ -3,6 +3,7 @@
 namespace Mongolid\Cursor;
 
 use IteratorIterator;
+use MongoDB\Driver\ReadPreference;
 use Serializable;
 use Traversable;
 use MongoDB\Collection;
@@ -147,6 +148,24 @@ public function disableTimeout(bool $flag = true)
         return $this;
     }
 
+    /**
+     * This describes how the Cursor route the future read operations to the members of a replica set.
+     *
+     * @see http://php.net/manual/pt_BR/class.mongodb-driver-readpreference.php
+     *
+     * @param int $mode preference mode that the Cursor will use
+     *
+     * @see ReadPreference::class To get a glance of the constants available
+     *
+     * @return $this
+     */
+    public function setReadPreference(int $mode)
+    {
+        $this->params[1]['readPreference'] = new ReadPreference($mode);
+
+        return $this;
+    }
+
     /**
      * Counts the number of results for this cursor.
      *

tests/Mongolid/Cursor/CursorTest.php

@@ -8,6 +8,7 @@
 use Mockery as m;
 use MongoDB\Collection;
 use MongoDB\Driver\Exception\LogicException;
+use MongoDB\Driver\ReadPreference;
 use Mongolid\ActiveRecord;
 use Mongolid\Connection\Connection;
 use Mongolid\Connection\Pool;
@@ -82,6 +83,19 @@ public function testShouldSetNoCursorTimeoutToTrue()
         );
     }
 
+    public function testShouldSetReadPreferenceParameterAccordingly()
+    {
+        // Arrange
+        $cursor = $this->getCursor();
+        $mode = ReadPreference::RP_SECONDARY;
+        $cursor->setReadPreference($mode);
+        $readPreferenceParameter = $this->getProtected($cursor, 'params')[1]['readPreference'];
+
+        // Assert
+        $this->assertInstanceOf(ReadPreference::class, $readPreferenceParameter);
+        $this->assertSame($readPreferenceParameter->getMode(), $mode);
+    }
+
     public function testShouldCountDocuments()
     {
         // Arrange