Symfony custom requests

What is it?

To help accomplish the "Thin controllers, fat models" ideal, this bundle allows you to create custom request objects that you can use for validating your input before it gets to the controller.

You can use these to make sure certain fields are set with certain dynamic values, or validate form data without having to add additional logic to your controller.

The aim is that your controller knows that it has the correct data and therefore can start working with it immediately, instead of having to double-check it's input is valid.

The new custom request object are defined via services, so can have any other services passed to them. This means your validation steps can use data-sources such as other APIs, databases, Elasticsearch, etc.

How to use it

The first step is to update your composer.json with dittto/symfony-custom-request. You may need to also specify the an entry in the repositories for the github repository.

After you've added and installed this bundle, you'll need to add it to the AppKernel.php file:

class AppKernel extends Kernel {
    public function registerBundles() {
        $bundles = [
            ...
            new \Dittto\CustomRequestBundle\DitttoCustomRequestBundle(),

Next we'll create our custom request. This is going to be a simple check that looks for a query string containing token=allowed. The test below is stored at AppBundle/Request/TestRequest.php.

use Dittto\CustomRequestBundle\Request\AbstractRequestType;

class TestRequest extends AbstractRequestType {
    public function validate():bool {
        return $this->getOriginalRequest()->query->get('token') === 'allowed';
    }
}

Update the services for our new TestRequest. The tag is important as this enables us to know this is a custom request and can be used as a controller parameter.

services:
    test_request:
        class: AppBundle\Request\TestRequest
        tags: [ { name: dittto.request } ]

Lastly, we need to tell our controller to use our custom request using it's parameters.

class DefaultController extends Controller {
    public function indexAction(TestRequest $request):Response {
        ...
    }
}

Filters

There is a filter chain available for altering how this code handles itself after the validate() method has been run. By default there is a filter in place that if a GET request fails, then a 400 exception is thrown.

You can add as many additional filters as you like to the chain to create automated responses based on certain request types.

New filters are added by creating a compatible filter (RequestFilterInterface) and adding a tag of dittto.request_filter when defining it as a service.

To make the filters run in a particular order, add a slot as a tag with a positive integer as it's value. These run in the order of lowest number first. If you assign 2 or more filters to the same slot, the first-assigned filter will take the slot and block any others from taking it's place.

How to override default filters

Slots in local configs seem to always install before vendor-defined configs, so you can use the following to replace the default filter.

services:
    override_exception_on_failed_get:
        class: Dittto\CustomRequestBundle\Request\Filter\NullFilterRequest
        tags: [ { name: dittto.request_filter, slot: 10 } ]