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Drupal Architecture Basics

Drupal Architecture Basics

21 December 2016

Drupal is one of the most powerful open-source content management systems (CMS), widely known for its flexibility and scalability. To work effectively with Drupal, it’s important to understand its architecture and how its different layers interact to deliver dynamic websites and applications.

1. Core Concept of Entities and Nodes

At the heart of Drupal lies the Entity System. An entity is a container for structured data, and each entity has multiple fields to hold specific types of information. For example:

  • Nodes are entities that represent content, such as an article or a blog post.

  • Users, taxonomy terms, and files are also entities.

This system makes Drupal highly flexible because you can define custom entities and fields to model any type of data your project requires.

2. Content Types and Taxonomy

Drupal organizes content using Content Types. A content type defines a structure for a specific kind of data (e.g., articles, pages, events). Each content type can have its own fields like title, image, or date.

To categorize and relate content, Drupal provides Taxonomy—a system for creating vocabularies and terms. For example, you can have a “Tags” vocabulary with terms like “Drupal,” “PHP,” and “CMS” to classify articles.

3. Theming Layer with Twig

The theme layer controls how content is displayed. Drupal uses Twig, a modern PHP-based templating engine, to render output. Twig templates allow developers to design flexible, reusable HTML structures while maintaining clean separation from business logic.

Themes in Drupal typically include:

  • .info.yml files to define theme metadata.

  • CSS & JavaScript for styling and interactions.

  • Twig templates to structure page rendering.

4. Module System for Extensibility

Drupal’s functionality can be extended through modules. There are two types:

  • Core Modules (shipped with Drupal) – e.g., Views, Path, Taxonomy.

  • Contributed Modules (downloaded from Drupal.org) – e.g., Paragraphs, Webform.

You can also build custom modules to implement project-specific features. The module system ensures that Drupal is not just a CMS but a framework that adapts to your business needs.

5. Configuration Management

Drupal 8 and above introduced Configuration Management (CMI) to handle site settings systematically. Configurations (like content types, views, and roles) can be exported to YAML files, version-controlled, and imported across environments. This makes deploying changes much more reliable.

6. Database and Storage

Drupal follows a database-driven architecture. Content and configuration are stored in a relational database (like MySQL, MariaDB, or PostgreSQL). Drupal’s database abstraction layer ensures compatibility across different systems. Files and images, on the other hand, are managed through the file system and linked to entities.

7. Caching and Performance

To ensure fast page loads, Drupal comes with multiple caching layers:

  • Page Cache for anonymous users.

  • Dynamic Page Cache for logged-in users.

  • Render Cache for reusable components.

This caching system makes Drupal scalable, capable of handling high-traffic sites.

Drupal’s architecture is built to be modular, flexible, and robust. From entities and fields to theming and caching, each layer plays a critical role in delivering dynamic and secure digital experiences. Understanding these basics helps developers and site builders leverage Drupal to its fullest potential.