Adding query projections, fixes #267

README.md

@@ -564,6 +564,12 @@ Update or insert a document. Additional options for the update method are passed
     DB::collection('users')->where('name', 'John')
                            ->update($data, array('upsert' => true));
 
+**Projections**
+
+You can apply projections to your queries using the `project()` method.
+
+    DB::collection('items')->project(array('tags' => array('$slice' => 1)))->get();
+
 **Push**
 
 Add an items to an array.

src/Jenssegers/Mongodb/Query/Builder.php

@@ -18,6 +18,13 @@ class Builder extends \Illuminate\Database\Query\Builder {
      */
     protected $collection;
 
+    /**
+     * The column projections.
+     *
+     * @var array
+     */
+    public $projections;
+
     /**
      * All of the available clause operators.
      *
@@ -59,6 +66,19 @@ class Builder extends \Illuminate\Database\Query\Builder {
         $this->connection = $connection;
     }
 
+    /**
+     * Set the projections.
+     *
+     * @param  array  $columns
+     * @return $this
+     */
+    public function project($columns)
+    {
+        $this->projections = is_array($columns) ? $columns : func_get_args();
+
+        return $this;
+    }
+
     /**
      * Execute a query for a single record by ID.
      *
@@ -155,6 +175,7 @@ class Builder extends \Illuminate\Database\Query\Builder {
             if ($this->orders)      $pipeline[] = array('$sort' => $this->orders);
             if ($this->offset)      $pipeline[] = array('$skip' => $this->offset);
             if ($this->limit)       $pipeline[] = array('$limit' => $this->limit);
+            if ($this->projections) $pipeline[] = array('$project' => $this->projections);
 
             // Execute aggregation
             $results = $this->collection->aggregate($pipeline);
@@ -179,11 +200,19 @@ class Builder extends \Illuminate\Database\Query\Builder {
         else
         {
             $columns = array();
+
+            // Convert select columns to simple projections.
             foreach ($this->columns as $column)
             {
                 $columns[$column] = true;
             }
 
+            // Add custom projections.
+            if ($this->projections)
+            {
+                $columns = array_merge($columns, $this->projections);
+            }
+
             // Execute query and get MongoCursor
             $cursor = $this->collection->find($wheres, $columns);
 
@@ -543,8 +572,6 @@ class Builder extends \Illuminate\Database\Query\Builder {
      */
     public function pull($column, $value = null)
     {
-        var_dump($value);
-
         // Check if we passed an associative array.
         $multipleValues = (is_array($value) and array_keys($value) === range(0, count($value) - 1));
 

tests/QueryBuilderTest.php

@@ -611,4 +611,20 @@ class QueryBuilderTest extends TestCase {
 		$this->assertEquals(1, $user['age']);
 	}
 
+	public function testProjections()
+	{
+		DB::collection('items')->insert(array(
+			array('name' => 'fork',  'tags' => array('sharp', 'pointy')),
+			array('name' => 'spork', 'tags' => array('sharp', 'pointy', 'round', 'bowl')),
+			array('name' => 'spoon', 'tags' => array('round', 'bowl')),
+		));
+
+		$results = DB::collection('items')->project(array('tags' => array('$slice' => 1)))->get();
+
+		foreach ($results as $result)
+		{
+			$this->assertEquals(1, count($result['tags']));
+		}
+	}
+
 }