In this tutorial we're going to look at one the first files you will need in order to create a Drupal module: the info file. Each module is required to have a MODULE.info.yml file to help Drupal identify that a bundle of code is a unique module. This specially-formatted YAML file not only tells Drupal about the module, but also allows us to provide other useful metadata. In this tutorial, we'll walk through all of the metadata possibilities that can be included in an info file.

If you've ever built or administered a Drupal site, the permissions page (/admin/people/permissions) is probably quite familiar.

If you're new to module development, you may wonder where these permissions come from, and how you can specify your own permissions. In this tutorial we'll answer those questions.

Drupal provides module developers several different methods for creating the different types of links we see on a typical page. In this tutorial we'll see how these different types of links relate to each other, and when you might want to make use of them.

In this tutorial we'll provide an overview of the following concepts:

The Drupal plugin system allows a particular module or subsystem to provide functionality in an extensible, object-oriented way. The controlling module defines the basic framework (interface) for the functionality, and other modules can create plugins (implementing the interface) with particular behaviors. Plugins are grouped into plugin types. Each plugin type is managed by a plugin manager service, which uses a plugin discovery method to discover provided plugins of that type and instantiate them using a plugin factory.

Hooks allow modules to alter and extend the behavior of Drupal core, or another module. They are one of the various ways that code components in Drupal can communicate with one another. Using hooks a module developer can change how core or another module works -- without changing the existing code. As a Drupal developer, understanding how to implement and invoke hooks is essential.

In this tutorial we'll:

Drupal uses events to allow modules and various subsystems to communicate with one another in an object-oriented manner. Understanding how the Event API works is critical knowledge for all module developers. In this tutorial we'll:

• Explain what events are
• Discuss the use case for subscribing to events
• Give an example use-case for dispatching events

By the end of this tutorial you should be able to explain what events are, understand when to use them in your own code, and know where to learn more about how to do so.

It's best practice to access any of the services provided by Drupal via the service container to ensure the decoupled nature of these systems is respected. In order to do so, you need to know what services exists, and then, where possible, use dependency injection to use them in your code.

This tutorial walks through the process of:

The Render API consists of two parts: structured arrays that provide data and hints about how that data should be rendered, and a rendering pipeline that can be used to render these arrays into various output formats. Understanding at least the basics of how the Render API works, the difference between elements and properties, and the concept of callback functions is an integral part of learning Drupal.

In this tutorial we'll:

The core structure of Drupal's Render API is the render array, which is a hierarchical associative array containing data to be rendered and properties describing how the data should be rendered. As a module developer you'll use render arrays to describe the content your module controls in order to output it on a page as HTML, or as part of a response in another format like JSON. As a theme developer, you'll manipulate render arrays in order to affect the way content is output on the page.

In this tutorial we'll learn:

If you've ever created or edited a piece of content on a Drupal site you have already interacted with the Field API. The Field module (along with its user interface counterpart) is responsible for providing the forms and data components used to build up the content model that make up a Drupal site. Understanding how Drupal fields work and how they're constructed via the Field API is an important part of understanding how Drupal works.

One of the central components of Drupal's Render API is render elements. You can think of them as prepackaged render arrays or shortcuts you can use to describe common things, like tables, links, and form elements, in a consistent way. In this tutorial we'll take a more in-depth look at the use of the #type property in render arrays in order to answer questions like:

Many of the processes that Drupal performs when responding to a request are cached in order to increase performance. Creating the HTML for the page that a user sees or the JSON response to a REST request can require thousands of operations. Some operations are time consuming, memory heavy, CPU intense, or all 3. By performing the operation once, and then caching the result for next time, subsequent requests can be fulfilled faster. In order to make it easier to store, retrieve, and invalidate cached data, Drupal provides cache-related services you can use in your code.

Drupal's Form API is a set of interfaces, utility classes, and conventions that when combined together allow module developers to create forms that collect, validate, and process user-submitted data. The Form API is closely related to the Render API.

When learning Drupal development, it won't be long before you encounter the word "entity" and the Entity API. But what are entities in Drupal? How can you use them to build your site? When should you use the Entity API?

This tutorial will explain Drupal's Entity system from a high level. We'll look at:

Drupal's configuration system helps to solve the problem of moving changes in configuration from development to production. It does this in two ways: by providing a unified way to store configuration and by providing a process by which configuration changes can be imported and exported between instances of the same site. The configuration system is the result of work completed within the Configuration Management Initiative (CMI).

In this introduction, we'll provide:

Configuration entities are suitable for creating user-defined configuration, such as image styles, views, content types, etc. A configuration entity type is defined by a module, default configuration is provided by that module as well as any other module, and then users can create zero or more configuration entities through Drupal's administrative UI.

In this tutorial, you will learn about: