55 lines
2 KiB
Markdown
55 lines
2 KiB
Markdown
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[<< previous](07-dispatching-to-a-class.md) | [next >>](09-dependency-injector.md)
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### Inversion of Control
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In the last part you have set up a controller class and generated our Http-Response-object in that class, but if we
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want to switch to a more powerfull Http-Implementation later, or need to create our own for some special purposes, then
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we would need to edit every one of our request handlers to call a different constructor of the class.
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The sane option is to use [inversion of control](http://en.wikipedia.org/wiki/Inversion_of_control). This means that
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instead of giving the class the responsiblity of creating the object it needs, you just ask for them. This is done
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with [dependency injection](http://en.wikipedia.org/wiki/Dependency_injection).
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If this sounds a little complicated right now, don't worry. Just follow the tutorial and once you see how it is
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implemented, it will make sense.
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Change your `Hello` action to the following:
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```php
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<?php declare(strict_types = 1);
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namespace Lubian\NoFramework\Action;
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use Psr\Http\Server\RequestHandlerInterface;
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use Psr\Http\Message\ServerRequestInterface as Request;
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use Psr\Http\Message\ResponseInterface as Response;
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final class Hello implements \Psr\Http\Server\RequestHandlerInterface;
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{
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public function __construct(
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private Response $response
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) {}
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public function handle(Request $request): Response
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{
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$name = $request->getAttribute('name', 'Stranger');
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$body = $this->response->getBody();
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$body->write('Hello ' . $name . '!');
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return $this->response
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->withBody($body)
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->withStatus(200);
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}
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}
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```
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Now the code will result in an error because we are not actually injecting anything. So let's fix that in the `Bootstrap.php` where we dispatch when a route was found:
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```php
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$handler = new $className($response);
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```
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Of course we need to also update all the other handlers.
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[<< previous](07-dispatching-to-a-class.md) | [next >>](09-dependency-injector.md)
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