1.
evolvingweb.ca @evolvingweb
Dipping Your Toe into Drupal
8 Module Development
WITH SUZANNE DERGACHEVA

2.
• Co-founded Evolving Web in
2007
• Experienced Drupal themer,
developer, project lead
• Loves teaching DrupalSuzanne Dergacheva
CO-FOUNDER AND FRONT-END LEAD

3.
Creating great websites
with Drupal
TRAINING WEB DEVELOPMENT WEB CONSULTING

4.
Some of our happy clients

5.
Should I Create a Module?
PROS
• You get a flexible solution
• Might be simpler than installing
a complex module
CONS
• Takes time/skills to develop
• You have to maintain the code
• Can introduce bugs

6.
Simple Module Examples
• Change a form
• Add a programmatic block
• Add a programmatic page
• Add a menu link
• Create a field formatter
• Add custom validation

7.
Before You Start
• Use the local.settings.php file and development.services.yml files
(https://www.drupal.org/node/2598914)
• Enables errors and warnings
• Disables some caching
• Disables aggregation of CSS/JS
• Install the Devel module
• Make sure your editor has syntax highlighting set up

8.
Step 1: Research
• Is there already a module that does this?
• If not, is there something similar. Look for an example:
• Drupal core
• Contrib modules
• Examples module
• Try and find the code that does the thing you want
• Figure out how it integrates with Drupal (usually a hook or a Class)

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Step 2: Create the Scaffolding
• Use the Drupal Console to write the scaffolding code or use
examples from other modules to see what structure you need
• Create a module folder, and an .info.yml file
• Then, add a Class or hook to your module
drupal generate:module
drupal generate:controller

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Step 3: Fill in the Custom Code
• Write the logical part of your code that does the custom work
• Look for exmaples of what you’re trying to do
• You can copy and paste code snippets
• … But make sure you read/understand each line of code!

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Step 4: Testing
• Easy to forget to test when you’re doing something simple
• QA Tips:
• Read error messages
• Make sure you understand what you’re testing (what is supposed
to change on the site)
• Also test that your code doesn’t break other use cases. You might
need to add an ‘if’ statement

12.
Essential Terminology
• Yml - File format used to define modules/theme, permissions, paths,
menu items, and exported configuration
• Class - Group of properties and methods that define an object. Used
to extend parts of Drupal so you can create your own Forms, Blocks,
Fields, Entities, Webform Elements, etc.
• Plugin - Class that is ‘discoverable’ by Drupal. Examples: Blocks,
Fields
• Hook - Function that allows you to alter how something works in
Drupal. Examples: altering forms, emails, adding things to cron

13.
Let’s Build a Module

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Real Example Module

15.
Link to the Edit Account Page

16.
Link to the Edit Account Page
• Define a new path
• The path points to a Controller
• The controller redirects you to the path /user/[uid] but fills in the uid
of the current User
drupal generate:controller
drupal generate:module

17.
Changing a Form

18.
Changing a Form
• Find the form ID
• Implement hook_form_alter
• Add/remove/update elements of the form
• Use this reference: https://api.drupal.org/api/drupal/elements/8.2.x
drupal generate:form:alter
drupal generate:module

19.
Useful Code Snippets
http://bit.ly/d8-snippets

20.
Next Steps
• Drupal Docs for Creating Custom Modules: https://www.drupal.org/
docs/8/creating-custom-modules
• Try this tutorial: https://www.drupal.org/docs/8/creating-custom-
modules/a-hello-world-custom-page-module
• Download the Examples module: http://drupal.org/project/examples

21.
Upcoming Drupal
Trainings
MAY 7-11, IN-PERSON
Drupal 8 Training in Princeton NJ
FEB 5-8, ONLINE
Drupal 8 Module Development
FEB 20-23, ONLINE
Migrate to Drupal 8
MARCH 1-2, ONLINE
Drupal 8 Site Building
MARCH 12-15, ONLINE
Drupal 8 Theming
evolvingweb.ca/training
training@evolvingweb.ca

22.
@suzanne_kennedy
evolvingweb.ca @evolvingweb
Thank you!