When developing custom modules, there are several scenarios where the developer is required to add a composer.json file to the module. Some of these scenarios depend on whether the custom module is intended to be shared with the community as a project on drupal.org.

If a module developer wants to use a PHP library hosted on packagist.org, they must add a composer.json file to their project.

In the next section, we will look at creating a simple module. There is a long-standing tradition that the first program you write in any new system displays "Hello World!" on the screen.

Although Drupal is one of the boldest and most progressive open source projects, it is also deeply rooted in long-standing scientific and technical traditions.

The content() function in the HelloController class will return markup text when the routing system calls the page.

In your module folder, you should have the standard PSR-4 folder structure /src/Controller, and inside this folder, you should have the controller file HelloController.php.
Thus, your controller file will be located at
/src/Controller/HelloController.php

You have the following code in the HelloController.php file:

Return to the root folder of your module where the .info.yml file is located, add a new file named hello_world.routing.yml, and add the following content to it:

Now that we've created a placeholder for our module's settings page, let's add a menu link. The instructions below show how to create a menu link for the hello_world module under the “Development” section on the “Admin > Configuration” page (http://example.com/admin/config).

In the root folder of your module, create a new file named hello_world.links.menu.yml and add the following:

This guide continues with the Hello World module, demonstrating how to gradually add custom blocks (and more).

If you're feeling adventurous, you can jump straight to the Examples module. The Examples module contains many more code samples used in this guide. If you're new here, keep following this tutorial and check out the Examples modules when you're ready to dive deeper.

By adding a single YAML settings file to our module, Drupal will automatically load the contents of this YAML file, and we’ll be able to access it to provide default configuration. From the root folder of your module, create a new folder called “config.” Inside that folder, create another one named “install.” Finally, inside config/install, create a new file and name it hello_world.settings.yml.

Introduction

Much has been said—and debated—about the latest version of Drupal—Drupal 8, and one thing is certain: the way modules are built has changed significantly. There are numerous tutorials addressing the new concepts, and many of them encourage developers to stay updated as the codebase evolves.

Introduction

Much has been said—and debated—about the latest version of Drupal—Drupal 8, and one thing is certain: building modules has changed significantly. There are many tutorials focusing on the new concepts, and in each one, the authors advise developers to expect even more changes as the codebase evolves.

Part II of the Practical Guide to Creating Basic Drupal 8 Modules
From .info to Tests, Just the Basics