Adding ability to pass params to the decoding function.

lib/Cake/Network/CakeRequest.php

@@ -676,15 +676,29 @@ class CakeRequest implements ArrayAccess {
 /**
  * Read data from `php://stdin`. Useful when interacting with XML or JSON
  * request body content.
+ * 
+ * Getting input with a decoding function:
+ *
+ * `$this->request->input('json_decode');`
+ *
+ * Getting input using a decoding function, and additional params:
+ *
+ * `$this->request->input('Xml::build', array('return' => 'DOMDocument'));`
+ *
+ * Any additional parameters are applied to the callback in the order they are given.
  *
  * @param string $callback A decoding callback that will convert the string data to another
- *     representation. Leave empty to access the raw input data.
+ *     representation. Leave empty to access the raw input data. You can also
+ *     supply additional parameters for the decoding callback using var args, see above.
  * @return The decoded/processed request data.
  */
 	public function input($callback = null) {
 		$input = $this->_readStdin();
-		if ($callback) {
-			return call_user_func($callback, $input);
+		$args = func_get_args();
+		if (!empty($args)) {
+			$callback = array_shift($args);
+			array_unshift($args, $input);
+			return call_user_func_array($callback, $args);
 		}
 		return $input;
 	}

lib/Cake/tests/Case/Network/CakeRequestTest.php

@@ -18,6 +18,7 @@
  */
 
 App::uses('Dispatcher', 'Routing');
+App::uses('Xml', 'Utility');
 App::uses('CakeRequest', 'Network');
 
 class CakeRequestTestCase extends CakeTestCase {
@@ -1462,6 +1463,32 @@ class CakeRequestTestCase extends CakeTestCase {
 		$result = $request->input('json_decode');
 		$this->assertEquals(array('name' => 'value'), (array)$result);
 	}
+
+/** 
+ * Test input() decoding with additional arguments.
+ *
+ * @return void
+ */
+	function testInputDecodeExtraParams() {
+		$xml = <<<XML
+<?xml version="1.0" encoding="utf-8"?>
+<post>
+	<title id="title">Test</title>
+</post>
+XML;
+
+		$request = $this->getMock('CakeRequest', array('_readStdin'));
+		$request->expects($this->once())->method('_readStdin')
+			->will($this->returnValue($xml));
+
+		$result = $request->input('Xml::build', array('return' => 'domdocument'));
+		$this->assertInstanceOf('DOMDocument', $result);
+		$this->assertEquals(
+			'Test', 
+			$result->getElementsByTagName('title')->item(0)->childNodes->item(0)->wholeText
+		);
+	}
+
 /**
  * loadEnvironment method
  *