John K. VanDyk

Working with Users

After reading this chapter, you should be able to Understand how users are represented internally in Drupal. Understand how to store information associated with a user in several ways. Hook into the user registration process to obtain more information from a registering user. Hook into the user login process to run your own code at user login time. Understand how external user authentication works. Implement your own external authentication module.

How Drupal Works

In this chapter, I’ll give you an overview of Drupal. Details on how each part of the system works will be provided in later chapters. Here, we’ll cover the technology stack on which Drupal runs, the layout of the files that make up Drupal, and the various conceptual terms that Drupal uses, such as nodes, hooks, blocks, and themes.

Localization and Translation

In this chapter, you’ve learned the following: How the t() function works. How to customize built-in Drupal strings. How to export your customizations. What portable object and portable object template files are. How to download portable object template files and generate your own. How to import an existing Drupal translation. How to use style sheets for right-to-left language support. How language negotiation settings affect Drupal. How content translation works.

Working with Blocks

In this chapter, you learned the following: What blocks are and how they differ from nodes. How block visibility and placement settings work. How to define a block or multiple blocks. How to enable a block by default.

Working with Files

In this chapter, you learned The difference between public and private files. Contributed modules to use for image, video, and audio handling. The database schema for file storage. Common functions for manipulating files. Authentication hooks for private file downloading.

Working with Fields

In this chapter, I covered the basics of using Drupal 7’s core functionality to create a custom content type that contains additional fields beyond the title and body, how to create a custom field type, and how to programmatically add new fields to a module. In the next chapter, we’ll enter the realm of theming, learning how to apply visual styling to the content Drupal renders on our site.

The form API

Drupal features an application programming interface (API) for generating, validating, and processing HTML forms. The form API abstracts forms into a nested array of properties and values. The array is then rendered by the form rendering engine at the appropriate time while a page is being generated. There are several implications of this approach: Rather than output HTML, we create an array and let the engine generate the HTML. Since we are dealing with a representation of the form as structured data, we can add, delete, reorder, and change forms. This is especially handy when you want to modify a form created by a different module in a clean and unobtrusive way. Any form element can be mapped to any theme function. Additional form validation or processing can be added to any form. Operations with forms are protected against form injection attacks, where a user modifies a form and then tries to submit it. The learning curve for using forms is a little steeper!

Writing a Module

After reading this chapter, you should be able to perform the following tasks: Create a Drupal module from scratch. Understand how to hook into Drupal’s code execution. Store and retrieve module-specific settings. Create and process simple forms using Drupal’s forms API. Create a new administrative category on Drupal’s main administration page. Define a form for the site administrator to choose options using check boxes, text input fields, and radio buttons. Validate settings and present an error message if validation fails. Understand how Drupal stores and retrieves settings using the built-in persistent variable system.

Working with Taxonomy

After reading this chapter, you should be able to Understand what taxonomy is. Understand terms, vocabularies, and their different options. Differentiate between flat, hierarchical, and multiple hierarchical vocabularies. Construct URLs to do AND and OR searches of taxonomy terms. Construct URLs for RSS feeds of taxonomy terms and term combinations. Understand how taxonomies are stored. Know how to use vocabularies within your own module. Set up your module to receive notification of changes to taxonomies.

The Menu System

After reading this chapter, you should be able to Map URLs to functions in your module or other modules or .inc files. Understand how access control works. Understand how wildcards work in paths. Create pages with tabs (local tasks) that map to functions. Modify existing menu items and links programmatically.