Parameters
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Login SubscribeEarlier, we talked about our container and all the service objects it has. To see them, we can run:
bin/console debug:container
But these services aren't the only things in our container. It also holds parameters. Run the same command as before, but this time, add the --parameters option:
bin/console debug:container --parameters
These are basically just variables that you can reference in your code. Most of these are internal, but there are some core parameters that you may find useful. For example, any of these that start with kernel., like kernel.environment, which is set to the APP_ENV environment variable. Or this kernel.project_dir that's set to the path to the project root directory.
Symfony Parameters
So how do we get this from our container? We actually have a special shortcut method for it in our controller. In the /src directory, open Controller/MainController.php. In the homepage() method, right at the beginning, write dd($this->getParameter()). And inside that, write the parameter name: 'kernel.project_dir'. As you can see, PhpStorm (with the Symfony plugin), has already autocompleted that for us. Nice.
| // ... lines 1 - 13 | |
| class MainController extends AbstractController | |
| { | |
| // ... line 16 | |
| public function homepage( | |
| // ... lines 18 - 20 | |
| ): Response { | |
| dd($this->getParameter('kernel.project_dir')); | |
| // ... lines 23 - 36 | |
| } | |
| } |
Back at the browser, refresh and... there's our path! Most of the time, we'll need to inject parameters into services and we can do that with a special syntax. I'll show you! Open config/packages/twig.yaml. You can see that we have twig.default_path that's set to %kernel.project_dir%/templates. This %[parameter name]% is a special syntax used to refer to a parameter in .yaml files.
| twig: | |
| default_path: '%kernel.project_dir%/templates' | |
| // ... lines 3 - 7 |
Next: Let's create a custom parameter and learn how to fetch it from the service container in different ways.
