Installing Drupal using the instructions in this tutorial will give you a working Drupal site that can be used for learning, or real-world project development.

Before you can work on a Drupal site locally (on your computer), you'll need to set up a local development environment. This includes all the system requirements like PHP and a web server, that Drupal needs in order to run. Our favorite way to accomplish this is using DDEV.

In this tutorial we'll learn:

• How to install and configure DDEV for use with a Drupal project.
• How to use DDEV's integrated Composer to download Drupal and Drush.
• How to install Drupal inside DDEV so you can access the site and start doing development.

By the end of this tutorial, you should be able to set up a local development environment for learning Drupal or working on a new Drupal project.

By default, individual forms in Drupal are not output using Twig template files. It's possible to associate a form with a Twig template file by creating a new theme hook, and then referencing that theme hook from the $form array that defines the form. Doing so allows theme developers to customize the layout of the elements in the form using HTML and CSS.

This is useful when you want to change the layout of the entire form. For example, putting the elements into 2 columns. If you want to change individual elements in the form, you can often do so by overriding element specific Twig template files.

In this tutorial, we'll:

• Learn how to create a new theme hook that can be used to theme an element in a render array.
• Associate the $form we want to theme with the new theme hook we created.
• Create a Twig template file for the theme hook that will allow us to lay out the form elements using custom HTML.

By the end of this tutorial, you should be able to associate a Twig template file with any form in Drupal, so that you can customize its layout using HTML and CSS.

Do you know some PHP and want to learn how to create a custom page at a custom URL in Drupal? You're in the right place.

Every web framework has the same job: provide a way for developers to map user-accessible URLs with code that builds the page. Routes, controllers, and responses are what module developers use to create pages at custom URLs in a Drupal site.

In this tutorial, we'll:

• Define what routes, controllers, and responses are.
• Explain the routing workflow that Drupal uses to match a URL to a route.
• Define routing system-related terms like parameter and upcasting.

By the end of this tutorial, you should be able to explain how a developer uses routes, controllers, and responses to create custom pages in a module.

If you want to define a new URL that a user can navigate to, and custom PHP code that will generate the content of the page, you need a route and a controller. Most of the time you'll want to do something more complex than hard code the content of the page. This will require using services in your controller. This can be accomplished in different ways.

In this tutorial we'll:

• Provide the definition for a new route which maps a path to the callback method of a controller class.
• Create a controller that returns a hard coded string.
• Look at examples of using both ControllerBase and dependency injection to access services from a controller, and discuss the benefits of both approaches.

By the end of this tutorial, you should be able to define a new route that maps to a controller and displays content on the page as a result of your custom logic.

The routing system can get dynamic values from the URL and pass them as arguments to the controller. This means a single route with a path of /node/{node} can be used to display any node entity. Route parameters can be validated, and upcast to complex data types via parameter conversion. If you ever want to pass arguments to the controller for a route, you'll use parameters to do so.

In this tutorial we'll:

• Define what parameters (slugs, placeholders) are and what they are used for in a route definition.
• Explain how URL parameters are passed to a controller.
• Define parameter upcasting.

By the end of this tutorial, you should be able to explain how to define a route that uses parameters to pass dynamic values to the route controller, and explain how parameter upcasting works.

Every route should define its access control parameters. When you define routes in a module, you can limit who has access to those routes via different access control options. Route-level access control applies to the path. If your route defines a path like /journey/example, the access control configuration will determine whether to show the current user the page at the path defined by the route, or to have Drupal serve an "HTTP 403 Access Denied" message instead.

In this tutorial we'll look at different ways of adding access control to a route including:

• Access based on the current user's roles and permissions
• Access based on custom logic in a callback method
• Logic in an access checker service

By the end of this tutorial, you should be able to add access control logic to your custom routes that will meet any requirement.

When defining a route and subsequently displaying the page, often we need to calculate the page title based on route parameters or other logic. In these cases, we can't just hard code the value into the _title configuration of the route. To set a dynamic title for a page, we'll use the route's _title_callback option, and point to a PHP callback that contains the logic that computes the title of the page.

In this tutorial we'll:

• Learn how to use the _title_callback route configuration option to dynamically set a page title
• Explain how arguments are provided to the title callback method
• Update the route and controller from a previous tutorial to use a dynamic title callback

By the end of this tutorial, you should be able to configure a route so that its title can be set dynamically using route parameters, instead of hard-coding the title with a static string of text.

Let's write some code that will allow us to see route parameters in action. We'll define a new route with a path like /journey/42/full but where 42 can be any node ID, and full can be any view mode. When a user accesses the path we'll pass the dynamic parameters from the URL to the controller. The controller will then load the corresponding node and render it using the provided view mode, and return that to display on the page.

By the end of this tutorial you should be able to:

• Use dynamic slugs in a route to pass parameters to the route controller.
• See how Drupal will upcast a value like the node ID, 42, to a Node object automatically.
• Explain what happens when you visit a URL that matches a route but the parameters don't pass validation.

By the end of this tutorial, you should be able to pass dynamic values from the URL to a route's controller.

Every web framework, including Drupal, has basically the same job: provide a way for developers to map URLs to the code that builds the corresponding pages. Drupal uses Symfony's HTTPKernel component. Kernel events are dispatched to coordinate the following tasks:

• Process the incoming request
• Figure out what to put on the page
• Create a response
• Deliver that response to the user's browser

Knowing a bit more about how Drupal handles the request-to-response workflow will help you better understand how to use routes and controllers to create your own custom pages or deal with authentication, access checking, and error handling in a Drupal module.

In this tutorial we'll:

• Walk through the process that Drupal uses to convert an incoming request into HTML that a browser can read
• See how the Symfony HTTPKernel helps orchestrate this process
• Learn about how the output from a custom controller gets incorporated into the final page

By the end of this tutorial, you should be able to describe the process that Drupal goes through to convert an incoming request for a URL into an HTML response displayed by the browser.

Sometimes we need the response returned from a controller to be something other than HTML content wrapped with the rest of a Drupal theme. Maybe we need to return plain text, or JSON structured data for an application to consume. Perhaps we need greater control over the HTTP headers sent in the response. This is possible by building on the fact that controllers can return generic Response objects instead of renderable arrays, allowing you to gain complete control over what is sent to the requesting agent.

In this tutorial we'll:

• Look at how to return a plain text response, and JSON data
• Show how to make your responses cacheable by adding cacheability metadata
• Learn about how to use a generic Symfony Response to gain greater control over what gets returned

By the end of this tutorial, you should be able to return responses from a controller in a Drupal module that are not HTML content wrapped in a Drupal theme.

When it's time to start a custom Drupal theme from scratch (especially if you're new to Drupal theming), we recommend using Starterkit. Starterkit helps you get a new theme up and running by scaffolding a set of theme files with sensible defaults, saving you from a bunch of repetitive work.

In this tutorial we'll:

• Learn what Starterkit is
• Discuss when you should--and should not--use Starterkit
• Walk through how to use Starterkit to generate a new Drupal theme

By the end of this tutorial you should be able to explain the use case for Starterkit and understand how to use it to start a new custom theme.