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Injecting Dependencies into Drupal 8 plugins

As part of our code review process for a current project, it was suggested that rather than calling the static Drupal formBuilder function to insert a form into a custom block, we actually inject the *Form Builder service* directly into the module, and for bonus points also inject the renderer service. I'd previously had exposure to dependency injection earlier on the same project but hadn’t exactly grokked the concept fully and so with a few pointers in the right direction, I set about refactoring the code I’d written using dependency injection and Drupal services.

Drupal Developer

Refactoring Drupal batch API callbacks to increase testability

Drupal's Batch API is great, it allows you to easily perform long running processes with feedback to the user.

But during Drupal 8's development processes it was one of the remaining systems that didn't get the full object oriented, service-based architecture.

Much of the batch API is largely unchanged from Drupal 7.

But that doesn't mean you can't write unit-testable callbacks.

Let's get started.

Lee RowlandsSenior Developer

A quick gotcha with Drupal 8's libraries.info.yml and aggregated JavaScript

This one tripped me up on a recent Drupal 8 project.

Easy to miss when you're working in a development oriented environment with things like JavaScript preprocessing turned off.

A JavaScript file was being added just fine with aggregation turned off, but not getting added with it turned on.

Lee RowlandsSenior Developer

Making Drupal 8's menu active trail consider query arguments

On a recent Drupal 8 client project our client was building listing pages using views exposed filters and adding these to the menu.

This resulted in several menu URLs pointing to the same base path, but with the query arguments determining the difference.

However Drupal 8's default menu-trail calculation was resulting in the menu highlighting all instances when one of them was viewed.

Luckily the active trail calculation is done in a service and it was simple to modify the default behaviour.

Read on to see how we did it.

Lee RowlandsSenior Developer

Native PHPStorm Drupal Test Runner

PHPStorm has a lot of built in test runners, but it doesn't support Drupal's Simpletest test runner. In this blog post we'll see how we can execute Drupal tests inside PHPStorm using Drupal test runner.

Jibran IjazSenior Drupal Developer

Ensuring Drupal 8 Block Cache Tags bubble up to the Page

Whilst working on a Drupal 8 project, we found that cache tags for a Block Content entity embedded in the footer weren't bubbling up to the page cache.

Read on to find out how we debugged this and how you can ensure this doesn't happen to you too.

Lee RowlandsSenior Developer

Handling Errors in Complex Drupal Form Validation

Recently, I have been working on a site with a big multi-step form that is using a lot of custom form elements, custom auto-completes, custom form api states and ajax based sub-forms. It is all built using Drupal form api. The best thing about this form is that all the fields and sub-forms map to a data model.

Jibran IjazSenior Drupal Developer

Printing any Drupal Entity to PDF

Lead Drupal Developer

Skinning HTML emails with Drupal using an existing front-end

A requirement that comes up from time to time is being able to use content stored in Drupal and produce rich HTML emails. In a lot of cases the design of these emails matches the design of the existing, already implemented front-end website.

In a recent project, we explored ways of creating HTML email’s which wouldn’t require us to start from scratch and would also evolve as the website’s look and feel did. Our design goals were thus:

Use the existing website’s CSS to skin the emails.
Use existing Drupal site-building tools to construct the markup for these emails.
Allow admins to easily create and preview HTML emails.

Sam BeckerSenior Developer