Mongo Collection "group" and "mapReduce" functions fixed.

extensions/mongo/Collection.php

@@ -365,7 +365,7 @@ class Collection extends Object
 	}
 
 	/**
-	 * Performs aggregation using Mongo Map Reduce mechanism.
+	 * Performs aggregation using Mongo "group" command.
 	 * @param mixed $keys fields to group by. If an array or non-code object is passed,
 	 * it will be the key used to group results. If instance of [[\MongoCode]] passed,
 	 * it will be treated as a function that returns the key to group by.
@@ -377,12 +377,14 @@ class Collection extends Object
 	 *  - condition - criteria for including a document in the aggregation.
 	 *  - finalize - function called once per unique key that takes the final output of the reduce function.
 	 * @return array the result of the aggregation.
-	 * @see http://docs.mongodb.org/manual/core/map-reduce/
+	 * @see http://docs.mongodb.org/manual/reference/command/group/
+	 * @throws Exception on failure.
 	 */
-	public function mapReduce($keys, $initial, $reduce, $options = [])
+	public function group($keys, $initial, $reduce, $options = [])
 	{
-		$token = 'Map reduce from ' . $this->getFullName();
+		$token = 'Grouping from ' . $this->getFullName();
 		Yii::info($token, __METHOD__);
+		try {
 			Yii::beginProfile($token, __METHOD__);
 
 			if (!($reduce instanceof \MongoCode)) {
@@ -402,6 +404,7 @@ class Collection extends Object
 			} else {
 				$result = $this->mongoCollection->group($keys, $initial, $reduce, $options);
 			}
+			$this->tryResultError($result);
 
 			Yii::endProfile($token, __METHOD__);
 			if (array_key_exists('retval', $result)) {
@@ -409,6 +412,58 @@ class Collection extends Object
 			} else {
 				return [];
 			}
+		} catch (\Exception $e) {
+			Yii::endProfile($token, __METHOD__);
+			throw new Exception($e->getMessage(), (int)$e->getCode(), $e);
+		}
+	}
+
+	/**
+	 * Performs aggregation using Mongo "map reduce" mechanism.
+	 * Note: this function will not return the aggregation result, instead it will
+	 * write it inside the another Mongo collection specified by "out" parameter.
+	 * @param \MongoCode|string $map function, which emits map data from collection.
+	 * Argument will be automatically cast to [[\MongoCode]].
+	 * @param \MongoCode|string $reduce function that takes two arguments (the map key
+	 * and the map values) and does the aggregation.
+	 * Argument will be automatically cast to [[\MongoCode]].
+	 * @param string|array $out output collection name. It could be a string for simple output
+	 * ('outputCollection'), or an array for parametrized output (['merge' => 'outputCollection'])
+	 * @param array $condition criteria for including a document in the aggregation.
+	 * @return string the map reduce output collection name.
+	 * @throws Exception on failure.
+	 */
+	public function mapReduce($map, $reduce, $out, $condition = [])
+	{
+		$token = 'Map reduce from ' . $this->getFullName();
+		Yii::info($token, __METHOD__);
+
+		try {
+			Yii::beginProfile($token, __METHOD__);
+			if (!($map instanceof \MongoCode)) {
+				$map = new \MongoCode((string)$map);
+			}
+			if (!($reduce instanceof \MongoCode)) {
+				$reduce = new \MongoCode((string)$reduce);
+			}
+			$command = [
+				'mapReduce' => $this->getName(),
+				'map' => $map,
+				'reduce' => $reduce,
+				'out' => $out
+			];
+			if (!empty($condition)) {
+				$command['query'] = $this->buildCondition($condition);
+			}
+
+			$result = $this->mongoCollection->db->command($command);
+			$this->tryResultError($result);
+			Yii::endProfile($token, __METHOD__);
+			return $result['result'];
+		} catch (\Exception $e) {
+			Yii::endProfile($token, __METHOD__);
+			throw new Exception($e->getMessage(), (int)$e->getCode(), $e);
+		}
 	}
 
 	/**

tests/unit/extensions/mongo/CollectionTest.php

@@ -10,6 +10,7 @@ class CollectionTest extends MongoTestCase
 	protected function tearDown()
 	{
 		$this->dropCollection('customer');
+		$this->dropCollection('mapReduceOut');
 		parent::tearDown();
 	}
 
@@ -157,7 +158,7 @@ class CollectionTest extends MongoTestCase
 	/**
 	 * @depends testBatchInsert
 	 */
-	public function testMapReduce()
+	public function testGroup()
 	{
 		$collection = $this->getConnection()->getCollection('customer');
 		$rows = [
@@ -175,12 +176,65 @@ class CollectionTest extends MongoTestCase
 		$keys = ['address' => 1];
 		$initial = ['items' => []];
 		$reduce = "function (obj, prev) { prev.items.push(obj.name); }";
-		$result = $collection->mapReduce($keys, $initial, $reduce);
+		$result = $collection->group($keys, $initial, $reduce);
 		$this->assertEquals(2, count($result));
 		$this->assertNotEmpty($result[0]['address']);
 		$this->assertNotEmpty($result[0]['items']);
 	}
 
+	/**
+	 * @depends testBatchInsert
+	 */
+	public function testMapReduce()
+	{
+		$collection = $this->getConnection()->getCollection('customer');
+		$rows = [
+			[
+				'name' => 'customer 1',
+				'status' => 1,
+				'amount' => 100,
+			],
+			[
+				'name' => 'customer 2',
+				'status' => 1,
+				'amount' => 200,
+			],
+			[
+				'name' => 'customer 2',
+				'status' => 2,
+				'amount' => 400,
+			],
+			[
+				'name' => 'customer 2',
+				'status' => 3,
+				'amount' => 500,
+			],
+		];
+		$collection->batchInsert($rows);
+
+		$result = $collection->mapReduce(
+			'function () {emit(this.status, this.amount)}',
+			'function (key, values) {return Array.sum(values)}',
+			'mapReduceOut',
+			['status' => ['$lt' => 3]]
+		);
+		$this->assertEquals('mapReduceOut', $result);
+
+		$outputCollection = $this->getConnection()->getCollection($result);
+		$rows = $outputCollection->findAll();
+		$expectedRows = [
+			[
+				'_id' => 1,
+				'value' => 300,
+			],
+			[
+				'_id' => 2,
+				'value' => 400,
+			],
+		];
+		$this->assertEquals($expectedRows, $rows);
+	}
+
 	public function testCreateIndex()
 	{
 		$collection = $this->getConnection()->getCollection('customer');