Drupal offers module developers several methods for creating different types of links, all defined by module configuration. This tutorial explores these types of links, how they relate to each other, and when to use them.

In this tutorial, we'll learn:

• The nature of menu items, action links, and local task links.
• Examples of each link type in Drupal's UI and their application in our scenario.
• Criteria for selecting the appropriate link type for adding the weather page to site navigation.

By the end of this tutorial, you'll understand the different types of links in Drupal and how they apply to adding navigational elements for custom module pages.

Permissions in Drupal control access to features and functions. Modules define permissions, which allow site administrators to grant or restrict access based on user roles. As a module developer, you'll create new permissions to restrict access to your module's custom features, independent of existing permissions defined by other modules.

In this tutorial, we'll:

• Explore how and where permissions are defined within a module.
• Discuss the concept of static and dynamic permissions in Drupal.

By the end of this tutorial, you'll have a clear understanding of how permissions function in Drupal and their implementation in modules.

Modules can define custom permissions to restrict access to specific routes or page sections. This control allows module developers to provide granular access while enabling site administrators to manage user privileges. We'll add a view weekly weather permission via the anytown module to limit access to the weather page.

In this tutorial, we'll:

• Create an MODULE_NAME.permissions.yml file.
• Define a new permission.
• Use the new permission to restrict access to a route.

By the end of this tutorial, you should be able to define a new permission in a module and use it to control access to a route.

Custom services in Drupal modules encapsulate specific business logic or functionality. In our example, we'll demonstrate moving code required to access a weather forecast API from a controller into a service. This will help make our controller thin and our module code more reusable, testable, and maintainable.

In this tutorial, we'll:

• Explore the advantages of custom services for managing business logic.
• Define the components of a custom service.

By the end of this tutorial, you'll understand why creating custom services is a beneficial practice in Drupal module development.

To access services in Drupal through the service container, you'll need to know the unique machine name of the service. We'll use the example of making HTTP requests to a weather forecast API in the anytown module to demonstrate several methods you can use to identify an existing service's ID.

In this tutorial, we'll:

• Discover existing services and their machine names.
• Take a look at an example service definition.

By the end of this tutorial, you should be able to locate and use existing services in your Drupal module.

Testing ensures that code remains reliable and functional. This tutorial introduces the primary types of tests in Drupal: Unit, Kernel, Functional, and FunctionalJavascript -- all executed via PHPUnit. We'll clarify the differences between each type of test and appropriate use cases. As module developers, understanding what to test and how to write tests is vital for robust and maintainable code.

In this tutorial, we'll:

• Identify the primary test types in Drupal and their use cases.
• Emphasize the importance of functional tests in custom module development.
• Introduce the basics of authoring tests in a custom module.

By the end of this tutorial, you should recognize the different types of tests Drupal uses and when and how to use each kind.

Before you can run tests, you'll need to configure your local environment. This setup involves Drupal-specific configuration for PHPUnit and ensuring your environment supports Functional JavaScript tests with a WebDriver client and a compatible browser. The setup process varies based on the development environment. In this tutorial, we're using DDEV as the local environment.

In this tutorial, we'll:

• Install all required dependencies.
• Configure PHPUnit specific to our environment.
• Validate the setup by running a Drupal core test.

By the end of this tutorial, you'll be equipped to run Drupal's PHPUnit tests locally using DDEV.

Functional tests simulate user interactions with Drupal applications, which enables us to test user interfaces and complex workflows. This tutorial guides you through writing functional tests for the anytown module, focusing on custom user registration workflow enhancements.

In this tutorial, we'll:

• Examine functional test structure.
• Test anytown_form_user_register_form_alter() customizations.
• Discuss the functional test execution environment.

By the end of this tutorial, you'll know how to write functional tests that emulate browser interactions with your Drupal application.

Kernel tests in Drupal enable module integration testing with Drupal core systems in a bootstrapped environment. Kernel tests bridge the gap between unit and functional tests. This tutorial focuses on writing kernel tests for the anytown module, specifically to test the ForecastClient service's caching logic and custom username validation.

In this tutorial, we'll:

• Explore the parts of a kernel test.
• Write kernel tests for anytown module features.
• Use mocks and the Drupal container in kernel tests.

By the end of this tutorial, you should be able to get started writing kernel tests to verify your module's integration with Drupal core.

Unit tests are the simplest among Drupal's test types, ideal for verifying code that performs computations. This tutorial guides through writing unit tests for the anytown module, focusing on the ForecastClient service, and illustrates how to use mocks for dependencies.

In this tutorial, we'll:

• List potential unit tests for the anytown module.
• Write tests for ForecastClient service logic.
• Demonstrate how to mock services in unit tests.

By the end of this tutorial you should be able to write PHPUnit Unit tests for logic in the anytown module.

As of Drupal 10.2, most plugin types use PHP attributes for discovery and metadata.

In this tutorial, we'll:

• Provide a recipe for implementing PHP attribute-based plugins.
• Demonstrate how to figure out where the code and metadata should live for PHP attribute-based plugins.

By the end of this tutorial you should have a recipe for getting started with implementing PHP attribute-based plugins, and a better understanding of how to figure out the details required to implement a given plugin type.

PHP attributes are a native PHP language feature, introduced in PHP 8.0, that provide a way to add metadata to classes, methods, properties, and functions in PHP code.

In Drupal, this metadata is used by the plugin system to aid in the discovery and configuration of plugin instances. As a Drupal developer, it's important to understand how to recognize, read, and write PHP attributes, as you'll encounter them when working with plugins.

In this tutorial we'll look at:

• What PHP attributes are
• The use case for attributes in Drupal
• An overview of the attribute syntax

By the end of this tutorial, you should understand how attributes are used in Drupal and how to write them in your own code.

Prior to Drupal 10.2 most plugin implementations required the use of annotations alongside a PHP class. Now Drupal supports and recommends the use of PHP attributes instead. During the transition, most developers will still need to know how to recognize and implement annotation-based plugins.

In this tutorial we'll:

• Provide a recipe for implementing annotation-based plugins.
• Demonstrate how to figure out where the code and metadata should live for annotation-based plugins.

By the end of this tutorial you should have a recipe for getting started with implementing annotation-based plugins, and a better understanding of how to figure out the details required to implement a given plugin type.

Many of Drupal's APIs that look like a bunch of configuration in a YAML file (migrations, menu links, etc.) are actually plugins in disguise. The YAML from these files is used as arguments to a generic PHP plugin class which then behaves differently depending on the provided values. As a developer, you probably don't need to know that menu links are plugins, but it can be helpful when debugging or just trying to get a better understanding of the big picture.

In this tutorial, we'll:

• Learn about how YAML-based plugins work
• Discuss how to find the implementation details for YAML-based plugins
• Walk through an example of implementing a YAML-based plugin

By the end of this tutorial, you should be able to recognize a YAML-based plugin definition, and author your own.

In this tutorial, you’ll create and render a simple single directory component (SDC) in Drupal. You’ll set up the required files, call the component from a template, and confirm that Drupal renders it with its styles automatically attached.

By following along, you will:

• Scaffold the files for a basic card component.
• Reference the component in a node template.
• See how Drupal renders the component’s HTML and CSS together.

When you’re done, you’ll have a complete working example of a Drupal single directory component.

As a module developer, you output themed content from your module in the form of renderable arrays. When doing so, you can make use of single directory components (SDCs) by using the #type => 'component' render element type. This allows modules to dynamically select and configure a component based on configuration or specific PHP logic. You'll use this as the return value of a controller, or a configurable plugin related to display building, like custom blocks or field formatters. As an example, we'll author a custom block plugin that loads a specific node and outputs it using the card SDC we defined in a previous tutorial. We'll build a render array that supplies the values for the component's props and slots, and add some caching logic to the output.

In this tutorial, we will:

• Build a render array that targets an SDC via the #component property.
• Pass data into the component's props and slots, and demonstrate optional #propsAlter and #slotsAlter callbacks.
• Validate the output and cache it properly.

By the end of this tutorial, you'll be able to render any SDC via a module's PHP code using a well-structured and cache-friendly render array.

A Drupal single directory component (SDC) is Drupal's way of packaging the markup, metadata, styles, and behavior for a UI element in one self-contained folder inside a theme or module. This structure helps front-end developers and site builders keep all related files together for easier theming and reuse. A Drupal single directory component directory must be located in a specific place and its files named with a particular convention so that the system can discover it and use its assets.

In this tutorial, we'll:

• Show where Drupal discovers single directory components in your codebase.
• Explain the naming and organization conventions for Drupal single directory component directories and files.
• Outline key files for a component—both required and optional.

By the end of this tutorial, you'll be able to identify an SDC directory in a Drupal module or theme and know exactly what you're looking at.

Props and slots are the two ways that data can be provided to a single directory component (SDC). They are part of a component's schema definition, and are used to determine the names of variables passed to a component's template file. Props pass structured, validated data into a component, while slots allow us to inject flexible content such as HTML or nested components. Understanding when and how to use each ensures you can build reusable and adaptable components.

In this tutorial, we'll:

• Learn what props and slots are, and how they differ.
• Discuss how using one or the other impacts the developer experience and use of your components in a UI.
• Practice deciding when to use each for component design.

By the end of this tutorial, you'll know how to choose between props and slots when building components.

Learn how to generate menu links dynamically with plugin derivatives in a custom module. This tutorial walks through creating a single base menu link plugin definition and a deriver class that expands that definition into one menu link per content entity. The code will automatically generate links for all published basic pages, placing dynamic menu links in the main menu.

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

• Understand which files you need in order to define menu link plugin derivatives, also known as dynamic menu links
• Create the necessary code to define menu link plugin derivatives for an example use case

This reference document contains a detailed list of available properties for the #[ContentEntityType] attribute in Drupal 11. The current documentation in the Drupal 11 code base lists, but doesn't always describe, each of these properties. Or, in many cases, the property is an associative array where the nested key/value pairs are important, but what they should be isn't well documented. So we've created this helpful reference. Most of the properties listed here will also apply to #[ConfigEntityType] attributes. These properties define the metadata and behavior of custom entity types.

In this tutorial, we'll:

• Look at an example of how to use #[ContentEntityType] attributes.
• Provide a comprehensive list of available properties and a description of each.
• Show detailed examples of using nested array properties like handlers[].

By the end of this tutorial, you should be able to understand how and when to use any of the properties of a #[ContentEntityType] attribute in order to modify the behavior of a custom entity type.