Allow request input to be retrieved as a collection (laravel#38832)

* Allow request input to be retrieved as a collection

* Fix docblock spacing -- styleci

* Remove default input value when collecting key

src/Illuminate/Http/Concerns/InteractsWithInput.php

@@ -296,6 +296,17 @@ public function boolean($key = null, $default = false)
         return filter_var($this->input($key, $default), FILTER_VALIDATE_BOOLEAN);
     }
 
+    /**
+     * Retrieve input from the request as a collection.
+     *
+     * @param  string|null  $key
+     * @return \Illuminate\Support\Collection
+     */
+    public function collect($key = null)
+    {
+        return collect($this->input($key));
+    }
+
     /**
      * Get a subset containing the provided keys with values from the input data.
      *

tests/Http/HttpRequestTest.php

@@ -6,6 +6,7 @@
 use Illuminate\Http\UploadedFile;
 use Illuminate\Routing\Route;
 use Illuminate\Session\Store;
+use Illuminate\Support\Collection;
 use Mockery as m;
 use PHPUnit\Framework\TestCase;
 use RuntimeException;
@@ -502,6 +503,26 @@ public function testBooleanMethod()
         $this->assertFalse($request->boolean('some_undefined_key'));
     }
 
+    public function testCollectMethod()
+    {
+        $request = Request::create('/', 'GET', ['users' => [1, 2, 3]]);
+
+        $this->assertInstanceOf(Collection::class, $request->collect('users'));
+        $this->assertTrue($request->collect('developers')->isEmpty());
+        $this->assertEquals([1, 2, 3], $request->collect('users')->all());
+        $this->assertEquals(['users' => [1, 2, 3]], $request->collect()->all());
+
+        $request = Request::create('/', 'GET', ['text-payload']);
+        $this->assertEquals(['text-payload'], $request->collect()->all());
+
+        $request = Request::create('/', 'GET', ['email' => 'test@example.com']);
+        $this->assertEquals(['test@example.com'], $request->collect('email')->all());
+
+        $request = Request::create('/', 'GET', []);
+        $this->assertInstanceOf(Collection::class, $request->collect());
+        $this->assertTrue($request->collect()->isEmpty());
+    }
+
     public function testArrayAccess()
     {
         $request = Request::create('/', 'GET', ['name' => null, 'foo' => ['bar' => null, 'baz' => '']]);