added content to the controller part

6-controllers.md

@@ -4,4 +4,52 @@
 
 When I talk about a controller in this tutorial then I am just referring to a class that has handler methods. I am not talking about [MVC (Model-View-Controller)](http://martinfowler.com/eaaCatalog/modelViewController.html) controllers. MVC can't be implemented properly in PHP anyway, at least not in the way it was originally conceived. So forget about MVC and instead let's worry about [separation of concerns](http://en.wikipedia.org/wiki/Separation_of_concerns).
 
+Create a new folder inside the `src/` folder with the name `HelloWorld`. This will be where all your hello world related code will end up in. In there, create `HelloWorldController.php`.
+
+```
+<?php
+
+namespace Example\HelloWorld;
+
+class HelloWorldController
+{
+    public function helloWorld()
+    {
+        echo 'Hello World';
+    }
+}
+```
+
+The autoloader will only work if the namespace of a class matches the file path and the file name equals the class name. At the beginning I defined `Example` as the root namespace of the application so this is referring to the `src/` folder.
+
+Now let's change the hello world route so that it calls your new controller method instead of the closure. Change your `Routes.php` to this:
+
+```
+return [
+    ['GET', '/hello-world', [
+        'Example\HelloWorld\HelloWorldController', 
+        'helloWorld',
+    ]],
+];
+```
+
+Instead of just a callable you are now passing an array. The first value is the fully namespaced controller classname, the second one the method name that you want to call.
+
+To make this work, you will also have to do a small refactor to the routing part of the `Bootstrap.php`:
+
+```
+case \FastRoute\Dispatcher::FOUND:
+    $className = $routeInfo[1][0];
+    $method = $routeInfo[1][1];
+    $vars = $routeInfo[2];
+    
+    $class = new $className;
+    $class->$method($vars);
+    break;
+```
+
+So instead of just calling a handler method you are now instantiating the controller object and then calling the method on it.
+
+Now if you visit `http://localhost:8000/hello-world` everything should work. If not, go back and debug. And of course don't forget to commit your changes.
+
 to be continued...