Book excerpt: If you’re a web programmer, your experiences have taught you certain lessons—and only some of them apply well to Drupal. Drupal has its own set of programming principles that require a different approach, and many programmers make mistakes when relying on skills they’ve used for other projects. This book will show you which programming techniques you can use—and which you should avoid—when building web applications with this popular content management framework. Updated to cover both Drupal 7 and Drupal 8, the guidelines in this book demonstrate which programming practices conform to the "Drupal way" and which don’t. The book also serves as an excellent guide for Drupal 7 programmers looking to make the transition to Drupal 8. Get an overview of Drupal, including Drupal core and add-on modules and themes Learn Drupal’s basic programming principles, such as the ability to customize behavior and output with hooks Compare Drupal 7 and Drupal 8 programming methods, APIs, and concepts Discover common Drupal programming mistakes—and why hacking is one of them Explore specific areas where you can put your programming skills to work Learn about the new object-oriented Drupal 8 API, including plugins and services