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.
Concept: Testing
FreeTesting 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
ForecastClientservice 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.
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.
Customizing the available regions in your theme is one of the first things you'll do when creating your own themes. Doing so gives you complete control over where content is displayed on the page, and the markup involved. Adding regions to a theme is a two-step process that involves editing your theme's THEMENAME.info.yml file and updating your page.html.twig file.
In this tutorial we'll:
- Declare one or more new regions in our themes THEMENAME.info.yml file.
- Output the content of those regions in our theme via the page.html.twig file.
By the end of this tutorial you should be able to add or edit the regions a theme provides. Also, you'll ensure that blocks placed into regions are displayed by outputting the regions in the page template.
Contributed and custom themes can ship with a thumbnail screenshot that will be used to represent the theme when listing themes in the administration UI.
In this tutorial you'll learn how to:
- Prepare your site for the screenshot
- Create a screenshot of your theme
- Define a screenshot file for your theme in the THEMENAME.info.yml file
Preprocess functions are specially-named functions that can be used to add new variables to a Twig template file. They are commonly used by themes to add new variables based on custom PHP logic and simplify accessing the data contained in complex entity structures. For example: adding a variable to all node.html.twig template files that contains the combined content a couple of specific fields under a meaningful name like {{ call_to_action }}. Modules use preprocess functions to expose the dynamic data they manage to Twig template files, or to alter data provided by another module based on custom logic.
In this tutorial we'll learn how to:
- Use PHP to perform some complex logic in our theme.
- Store the resulting calculation in a variable.
- Make that variable available to a Twig template file.
Example use cases for adding variables with preprocess functions include:
- Anytime calculating the value to output in a template requires logic more complex than an if/else statement.
- Anytime the desired value requires additional string manipulation beyond what can be easily accomplished using an existing Twig filter or function.
By the end of this tutorial you should be able to expose new variables to a Twig template file by defining a preprocess function in either a module or a theme.
Twig has a special syntax for accessing array keys and objects, also known in Twig as variable attributes. In this tutorial, we'll cover the period or dot (.) operator to access a variable attribute, as well as subscript or square-bracket syntax, useful for when the key of the array contains special characters, like a dash (-) or pound sign (#). We'll also look at the logic Twig uses to find the matching attribute in an array or object.
Once you've defined an asset library you'll need to tell Drupal when you want to add the CSS and JavaScript that it includes to the page. Ideally you'll do so in a way that allows Drupal to only add the corresponding assets on pages where they are needed.
You can attach a library to all pages, a subset of pages, or to elements in a render array. This allows you to have some assets that are global, and others that get loaded on an as-needed basis. To attach a library you'll need to know both its name and prefix, and then use one of the techniques outlined below to let Drupal know when to include it.
In this tutorial, we'll look at attaching asset libraries:
- Globally, via your THEMENAME.info.yml file
- Conditionally, via a preprocess function using the
#attachedrender array property - Inside of a Twig template file
By the end of this tutorial you should be able to attach asset libraries in various different ways depending on your use case.
It's probably not too surprising that a library called Backbone aims to provide structure to your front-end JavaScript code and applications. In this tutorial we'll take a look at how Backbone.js goes about achieving that goal, and how you can make use of it on your Drupal site. We'll first take a high-level look at the main components that make up the Backbone.js library. With that basic understanding in place we'll look at an example of how you might integrate Backbone.js into a Drupal site.
Drupal's Breakpoint module defines a "breakpoint" plugin type that modules or themes can implement via a breakpoints configuration file. So, in order to make their breakpoints discoverable, themes and modules define their breakpoints in a THEME-OR-MODULE.breakpoints.yml file located in the root of their directory.
In this tutorial, you'll learn about the structure of a breakpoints configuration file and why you would want to use one. We’ll cover the kinds of metadata you can include in a breakpoint file, including key, label, mediaQuery, weight, multipliers, and breakpoint group. Throughout, we'll look at some examples of breakpoint configuration files available in Drupal themes and modules.
You've got a slick responsive theme for your Drupal site that's been implemented in CSS using media queries. But the content and images on your site will regularly be updated and you want to use the Responsive Images module to create responsive image style field formatters that you can apply to image field display settings.
In this lesson, we'll review the concepts of breakpoints and media queries so that you can better understand what's going on when you encounter them in non-CSS file contexts like configuration forms for responsive image styles or breakpoint YAML files.
By the end of this tutorial, you should have an understanding of what breakpoints are, how they are expressed in media queries, and how they are relevant in the context of Drupal.
Some, but not all, themes come with administrator-configurable settings that you can change through the UI. These might allow you to upload your own logo, choose between a couple of different pre-defined layouts, or turn features of a theme on or off. In this tutorial we’ll look at where you can find these theme settings if they exist, and how to go about changing them.