Remove hacky code.

People only really use json/xml so we can support a limited set of types and do away with fancy things.

lib/Cake/Network/Http/Client.php

@@ -13,6 +13,7 @@
  */
 namespace Cake\Network\Http;
 
+use Cake\Error;
 use Cake\Network\Http\Request;
 use Cake\Network\Http\Response;
 use Cake\Utility\Hash;
@@ -314,18 +315,17 @@ protected function _typeHeaders($type) {
 				'Content-Type' => $type
 			];
 		}
-		// Hacky as hell but I'll clean it up I promise
-		$reflection = new \ReflectionClass('Cake\Network\Response');
-		$properties = $reflection->getDefaultProperties();
-		if (isset($properties['_mimeTypes'][$type])) {
-			$mimeTypes = $properties['_mimeTypes'][$type];
-			$mimeType = is_array($mimeTypes) ? current($mimeTypes) : $mimeTypes;
-			return [
-				'Accept' => $mimeType,
-				'Content-Type' => $mimeType,
-			];
+		$typeMap = [
+			'json' => 'application/json',
+			'xml' => 'application/xml',
+		];
+		if (!isset($typeMap[$type])) {
+			throw new Error\Exception(__d('cake_dev', 'Unknown type alias.'));
 		}
-		return [];
+		return [
+			'Accept' => $typeMap[$type],
+			'Content-Type' => $typeMap[$type],
+		];
 	}
 
 }

lib/Cake/Test/TestCase/Network/Http/ClientTest.php

@@ -323,4 +323,22 @@ public function testPostWithTypeKey($type, $mime) {
 		]);
 		$http->post('/projects/add', $data, ['type' => $type]);
 	}
+
+/**
+ * Test that exceptions are raised on invalid types.
+ *
+ * @expectedException Cake\Error\Exception
+ * @return void
+ */
+	public function testExceptionOnUnknownType() {
+		$mock = $this->getMock('Cake\Network\Http\Adapter\Stream', ['send']);
+		$mock->expects($this->never())
+			->method('send');
+
+		$http = new Client([
+			'host' => 'cakephp.org',
+			'adapter' => $mock
+		]);
+		$http->post('/projects/add', 'it works', ['type' => 'invalid']);
+	}
 }