diff --git a/lib/Cake/Network/CakeRequest.php b/lib/Cake/Network/CakeRequest.php
index 307066299..01179cb9d 100644
--- a/lib/Cake/Network/CakeRequest.php
+++ b/lib/Cake/Network/CakeRequest.php
@@ -112,8 +112,8 @@ class CakeRequest implements ArrayAccess {
 			'webOS', 'Windows CE', 'Windows Phone OS', 'Xiino'
 		)),
 		'requested' => array('param' => 'requested', 'value' => 1),
-		'json' => array('header' => array('application/json')),
-		'xml' => array('header' => array('application/xml', 'text/xml')),
+		'json' => array('accept' => array('application/json'), 'param' => 'ext', 'value' => 'json'),
+		'xml' => array('accept' => array('application/xml', 'text/xml'), 'param' => 'ext', 'value' => 'xml'),
 	);
 
 /**
@@ -506,6 +506,9 @@ class CakeRequest implements ArrayAccess {
 		if (isset($detect['header']) && $this->_headerDetector($detect)) {
 			return true;
 		}
+		if (isset($detect['accept']) && $this->_acceptHeaderDetector($detect)) {
+			return true;
+		}
 		if (isset($detect['param']) && $this->_paramDetector($detect)) {
 			return true;
 		}
@@ -528,6 +531,38 @@ class CakeRequest implements ArrayAccess {
 		return $headers;
 	}
 
+/**
+ * Detects if an URL extension is present.
+ *
+ * @param array $detect Detector options array.
+ * @return bool Whether or not the request is the type you are checking.
+ */
+	protected function _extensionDetector($detect) {
+		if (is_string($detect['extension'])) {
+			$detect['extension'] = array($detect['extension']);
+		}
+		if (in_array($this->params['ext'], $detect['extension'])) {
+			return true;
+		}
+		return false;
+	}
+
+/**
+ * Detects if a specific accept header is present.
+ *
+ * @param array $detect Detector options array.
+ * @return bool Whether or not the request is the type you are checking.
+ */
+	protected function _acceptHeaderDetector($detect) {
+		$acceptHeaders = $this->getAcceptHeaders();
+		foreach ($detect['accept'] as $header) {
+			if (in_array($header, $acceptHeaders)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 /**
  * Detects if a specific header is present.
  *
@@ -535,10 +570,13 @@ class CakeRequest implements ArrayAccess {
  * @return bool Whether or not the request is the type you are checking.
  */
 	protected function _headerDetector($detect) {
-		$acceptHeaders = $this->getAcceptHeaders();
-		foreach ($detect['header'] as $header) {
-			if (in_array($header, $acceptHeaders)) {
-				return true;
+		foreach ($detect['header'] as $header => $value) {
+			$header = 'HTTP_' . strtoupper($header);
+			if (isset($_SERVER[$header])) {
+				if (is_callable($value)) {
+					return call_user_func($value, $_SERVER[$header]);
+				}
+				return ($_SERVER[$header] === $value);
 			}
 		}
 		return false;
diff --git a/lib/Cake/Test/Case/Network/CakeRequestTest.php b/lib/Cake/Test/Case/Network/CakeRequestTest.php
index 14a3d63f4..f9d8c5842 100644
--- a/lib/Cake/Test/Case/Network/CakeRequestTest.php
+++ b/lib/Cake/Test/Case/Network/CakeRequestTest.php
@@ -52,16 +52,6 @@ class TestCakeRequest extends CakeRequest {
 		$this->here = $this->base . '/' . $this->url;
 	}
 
-/**
- * Detects if a specific header is present.
- *
- * @param $detect Detector options array.
- * @return bool Whether or not the request is the type you are checking.
- */
-	public function headerDetector($detect) {
-		return $this->_headerDetector($detect);
-	}
-
 }
 
 /**
@@ -105,15 +95,42 @@ class CakeRequestTest extends CakeTestCase {
  * @return void
  */
 	public function testHeaderDetector() {
-		$request = $this->getMock('TestCakeRequest', array('getAcceptHeaders'));
+		$request = new CakeRequest('some/path');
+		$request->addDetector('host', array('header' => array('host' => 'cakephp.org')));
+
+		$_SERVER['HTTP_HOST'] = 'cakephp.org';
+		$this->assertTrue($request->is('host'));
+
+		$_SERVER['HTTP_HOST'] = 'php.net';
+		$this->assertFalse($request->is('host'));
+	}
+
+/**
+ * Test the accept header detector.
+ *
+ * @return void
+ */
+	public function testExtensionDetector() {
+		$request = new CakeRequest('some/path');
+		$request->params['ext'] = 'json';
+		$this->assertTrue($request->is('json'));
+
+		$request->params['ext'] = 'xml';
+		$this->assertFalse($request->is('json'));
+	}
+
+/**
+ * Test the accept header detector.
+ *
+ * @return void
+ */
+	public function testAcceptHeaderDetector() {
+		$request = new CakeRequest('some/path');
 		$_SERVER['HTTP_ACCEPT'] = 'application/json, text/plain, */*';
-		$detector = array('header' => array('application/json'), 'param' => 'ext', 'value' => 'json');
-		$request->expects($this->once())
-			->method('getAcceptHeaders')
-			->will($this->returnValue(array(
-				'application/json'
-			)));
-		$this->assertTrue($request->headerDetector($detector));
+		$this->assertTrue($request->is('json'));
+
+		$_SERVER['HTTP_ACCEPT'] = 'text/plain, */*';
+		$this->assertFalse($request->is('json'));
 	}
 
 /**