Backport Session consume()

lib/Cake/Model/Datasource/CakeSession.php

@@ -432,6 +432,24 @@ public static function write($name, $value = null) {
 		return true;
 	}
 
+/**
+ * Reads and deletes a variable from session.
+ *
+ * @param string $name The key to read and remove (or a path as sent to Hash.extract).
+ * @return mixed The value of the session variable, null if session not available,
+ *   session not started, or provided name not found in the session.
+ */
+	public static function consume($name) {
+		if (empty($name)) {
+			return null;
+		}
+		$value = self::read($name);
+		if ($value !== null) {
+			self::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
+		}
+		return $value;
+	}
+
 /**
  * Helper method to destroy invalid sessions.
  *

lib/Cake/Test/Case/Model/Datasource/CakeSessionTest.php

@@ -328,6 +328,28 @@ public function testWriteOverwriteStringValue() {
 		);
 	}
 
+/**
+ * Test consuming session data.
+ *
+ * @return void
+ */
+	public function testConsume() {
+		TestCakeSession::write('Some.string', 'value');
+		TestCakeSession::write('Some.array', array('key1' => 'value1', 'key2' => 'value2'));
+		$this->assertEquals('value', TestCakeSession::read('Some.string'));
+		$value = TestCakeSession::consume('Some.string');
+		$this->assertEquals('value', $value);
+		$this->assertFalse(TestCakeSession::check('Some.string'));
+		$value = TestCakeSession::consume('');
+		$this->assertNull($value);
+		$value = TestCakeSession::consume(null);
+		$this->assertNull($value);
+		$value = TestCakeSession::consume('Some.array');
+		$expected = array('key1' => 'value1', 'key2' => 'value2');
+		$this->assertEquals($expected, $value);
+		$this->assertFalse(TestCakeSession::check('Some.array'));
+	}
+
 /**
  * testId method
  *