The document provides a comprehensive guide on writing a Drupal 8 module, detailing the structure, naming conventions, and essential files needed, such as the .info.yml and .routing.yml files. It explains the process of creating a basic controller, defining configurations, adding menu links, and implementing block plugins. Additionally, it outlines methods for handling configurations and ensuring proper functionalities within the module.

1. Writing your first Drupal 8
module with Router and
Block plugin
Vinay Abhang
(vinay.abhang@iksulaops.com)

2. Vinay Abhang
•I am a Drupal developer at Iksula
Services Pvt Ltd, based in
Mumbai, India.
•I have 2 years of experience in
building websites in Drupal.

3. Router
• Websites => Webpages => Paths (Routes)
• Routes => Controller (to display content)
• Routes => Permission (to restrict access)
• Routes => Menu link (to reach the route)

4. Naming and placing your D8
module
• Name your module
• It must start with an alphabet.
• It must contain only lower-case alphabets and underscores.
• It must not contain any spaces.
• It must be unique.
• It may not be any of the reserved terms, for e.g.: src, lib, js, css,
templates, vendor, images, files, includes, misc, assets, fixtures, Drupal
• Create a folder for your module
• /modules
• /sites/all/modules

5. Let D8 know about your
module
• {module_machine_name}.info.yml file.
• Three keys — name, type and core are required in
this file.
• This file stores the metadata about the module.
• name, package, type, core, description
• Provides criteria to control module activation and
deactivation.
• Can specify dependencies (if any) of other
contributed modules and Drupal core modules.

6. Debugging .info.yml files
• Module is not listed on ‘Extend’ page
• Ensure the file is named correctly
{module_machine_name}.info.yml and is located in
module’s root.
• Ensure that file has the line: “type: module”
• Module is listed but its checkbox is disabled
• Ensure that core compatibility is set to “core: 8.x”
• Ensure that all module dependencies are available

7. Adding a basic Controller
• Within your module folder, you should have the PSR-4
standard folder structure /src/Controller and inside this
folder you should have your BasicController.php
controller file.
• /src/Controller/BasicController.php
• Adding the Controller first, is part of a general D8
philosophy of, “Build a tool first, then wire it up”
• For wiring it up, we need to add a routing.yml file in
our module.

8. Add routing file
• In module’s root folder, where .info.yml file is
located, add a new file with following naming
convention:
• {module_machine_name}.routing.yml
• Required properties in defining a route.
• path, defaults and requirements

9. Traits
• Traits help you embed a set of properties and
methods in several independent classes that
could be living in different hierarchies.

10. Defining configuration in custom
module
• Configurations are defined in a file residing in
config/install sub-directory of module
• {module_machine_name}.settings.yml
• Name of the config file (minus the .yml
extension) is called the ‘configuration name’ in
the system, using which the configuration can be
referred.

11. Using configuration in custom
module
• Simplest way to use is via Drupal::config() static
method
$config = Drupal::config(‘d8_example.settings');
// Will print ‘Vinay Abhang'.
print $config->get(‘d8_example.name’);
// Will print 'en'.
print $config->get(‘d8_example.langcode’);
• Editing and updating the config can be done
using Drupal::service(‘config.factory’)-
>getEditable() method
$config = Drupal::service(‘config.factory')->getEditable('d8_example.settings');
// Set and save new message value.
$config->set(‘d8_example.name’, 'Vinay')->save();

12. Add a menu link
• Menu links are used to reach to the routes
defined in the routing file.
• These links are defined in the file residing in the
module’s root folder with following naming
convention:
• {module_machine_name}.links.menu.yml

13. Creating menu tabs
• This is similar to the concept of D7’s
‘MENU_LOCAL_TASK’ menu type in
hook_menu.
• In D8, we need to create a file with following
naming convention:
• {module_machine_name}.links.task.yml
• It is advised to name the plugin ID same as the
route name.

14. Block Plugin
• In D8, blocks are instances of the Block Plugin
• Drupal’s block manager scans all the modules for any classes that contain
a @Block Annotation
• @Block Annotation has properties
• id : machine name for the block
• admin_label : block name to be listed on the administrative block
configuration page
• The block file resides in the src/Plugin/Block folder structure in your
module
• To add a block, go to Structure > Block Layout and click on ‘Place Block’
button associated with each available region.

15. Add a form to Block Configuration
• Provides an ability to enter a piece of
configuration for each instance of custom block
• This makes the configuration exportable using
Configuration Management
• The form is first defined in the blockForm()
method with a reference to its parent class using
• $form = parent::blockForm($form, $form_state)

16. Process the Block Config
Form
• Adding following method means that the form will
process and the input to the form will be saved in
the configuration for that instance of the block.
/**
* {@inheritdoc}
*/
public function blockSubmit($form, FormStateInterface $form_state) {
$this->configuration['hello_name'] = $form_state->getValue('example_block_name');
}

17. Use Config in Block
Display
• To make use of the configuration of instances of
the block, the build() method of custom block
class is used
• $config = $this->getConfiguration()

18. Questions?

19. Thank You!