Devel is a popular developer module containing a variety of developer and debugging utilities that make it more efficient to perform common development tasks. The Devel module includes Devel Generate, a module for generating example content. Devel also features Drush integration and provides several custom Drush commands. Other modules such as Webprofiler and vardump-enhancement libraries such as Kint can be configured via Devel.
Example tasks
- Quickly generate dummy content (menu items, terms, and nodes) for a development site
- Get insight into variables under the hood
Confidence
Devel has been a popular developer module and suite of tools since Drupal 6. As such, learning materials exist for Devel that can be quite dated. For current features and compatibility see the Drush project page on drupal.org.
Drupalize.Me resources
Knowing how to inspect the variables available within a template file enables you to discover all of the dynamic content in a Twig file, not just that which is already being used.
In this tutorial, we'll learn how to use {{ dump() }}, kint(), vardumper(), and XDebug to inspect variables in a template file.
Set up a local development environment to practice Drupal theme development. In order to practice theme development, either on your own or following our Hands-On: Theming guide, you'll need a Drupal site up and running on your computer.
By the end of this tutorial, you should be able to:
- Install Drupal on your computer so you can modify files with a code editor of your choice.
- Generate dummy content so that you have different kinds of pages to theme.
In this tutorial, we'll continue to look under the hood of Drupal 8, this time using a tool bundled with Devel called Webprofiler. You'll learn how to use the web debug toolbar and the profiler. You'll also learn how to reverse engineer a page to find out the names of the controllers responsible for output on that page.
Note: Webprofiler is now a separate project from Devel but still has it as a dependency.
Note: In order to get the Webprofiler timeline view working you need to add some configuration to your settings.php file. See the README.md file included with the Webprofiler module for more information on how to do this.
Additional resources
Since we haven’t been creating much content on our site, the My Workbench page is rather empty. This can make it hard to understand what’s going on and to grasp the module’s possibilities. This is a situation that you’ll encounter often when developing a site: at a certain point, you need content to test a certain feature, or to verify what a certain section on your site will look like. The Devel Generate module, which comes with the Devel module allows us to quickly generate sample content, users, taxonomy, and menu items, so testing functionality on our new site becomes a lot easier, since it will more closely resemble an actual site. In this lesson we'll enable and configure Devel Generate, and then run it to get a bunch of filler content set up on our site.
Additional resources
External resources
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Devel (drupal.org)
- The project page for Devel, which describes the submodules and utilities contained within the project.
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Drupal 8 Module of the Week: Devel (dev.acquia.com)
- In this interview, project maintainer Moshe Weitzman describes the main modules inside Devel and how they can be used.