Moving accepts() into CakeRequest.

Adding test cases.

cake/libs/cake_request.php

@@ -410,6 +410,7 @@ public function referer($local = false) {
  * @param string $name The method called
  * @param array $params Array of parameters for the method call
  * @return mixed
+ * @throws BadMethodCallException when an invalid method is called.
  */
 	public function __call($name, $params) {
 		if (strpos($name, 'is') === 0) {
@@ -545,6 +546,29 @@ public function header($name) {
 		}
 		return false;
 	}
+
+/**
+ * Find out which content types the client accepts or check if they accept a 
+ * particular type of content.
+ *
+ * @param string $type The content type to check for.  Leave null to get all types a client accepts.
+ * @return mixed Either an array of all the types the client accepts or a boolean if they accept the
+ *   provided type.
+ */
+	public function accepts($type = null) {
+		$acceptTypes = explode(',', $this->header('accept'));
+		foreach ($acceptTypes as $i => $accepted) {
+			if (strpos($accepted, ';') !== false) {
+				list($accepted, $prefValue) = explode(';', $accepted);
+				$acceptTypes[$i] = $accepted;
+			}
+		}
+		if ($type === null) {
+			return $acceptTypes;
+		}
+		return in_array($type, $acceptTypes);
+	}
+
 /**
  * Array access read implementation
  *

cake/tests/cases/libs/cake_request.test.php

@@ -668,6 +668,28 @@ function testHeader() {
 		$this->assertEquals($_SERVER['HTTP_USER_AGENT'], $request->header('User-Agent'));
 	}
 
+/**
+ * test accepts() with and without parameters
+ *
+ * @return void
+ */
+	function testAccepts() {
+		$_SERVER['HTTP_ACCEPT'] = 'text/xml,application/xml;q=0.9,application/xhtml+xml,text/html,text/plain,image/png';
+		$request = new CakeRequest('/', false);
+
+		$result = $request->accepts();
+		$expected = array(
+			'text/xml', 'application/xml', 'application/xhtml+xml', 'text/html', 'text/plain', 'image/png'
+		);
+		$this->assertEquals($expected, $result, 'Content types differ.');
+
+		$result = $request->accepts('text/html');
+		$this->assertTrue($result);
+
+		$result = $request->accepts('image/gif');
+		$this->assertFalse($result);
+	}
+
 /**
  * testBaseUrlAndWebrootWithModRewrite method
  *