Creating modules - a tutorial: Drupal 7.x

This tutorial describes how to create a module for Drupal 7. If your goal is to convert a module from Drupal 6 or earlier to Drupal 7, see: Updating your modules.
A module is a collection of functions that link into Drupal, providing additional functionality for your Drupal installation. After reading this tutorial, you will be able to create a basic block module and use it as a template for more advanced modules.

Requirements

This tutorial assumes you have:

• Basic PHP knowledge, including syntax and the concept of PHP objects
• Basic understanding of database tables, fields, records and SQL statements
• A working Drupal 7 installation
• Drupal administration access
• Webserver access

This tutorial does not assume you have any knowledge about the inner workings of a Drupal module.
For more information on module development, see Module Development with Drupal.

When finished

This tutorial will not necessarily prepare you to write modules for public release. It does not cover important topics such as: caching, permissions, or security issues. Use this tutorial as a starting point and then extend your skills with other resources, including:

• Examples for Developers, modules written specifically to illustrate various aspects of Drupal development with verbose comments
• Other modules, including contrib and core
• Drupal documentation
• Writing secure code
• Coding standards

When you are finished developing a useful module, you may want to contribute it back to the community. If so follow the instructions for: creating a new full project.

• Getting started
• Telling Drupal about your module
• Writing comments and implementing your first hook
• Declaring the block
• Retrieving data
• Generating block content
• Testing and troubleshooting the module
• Preparing for a module configuration form
• Creating the configuration form
• Validating the data
• Specifying a custom permission for a new page
• Adapting the query
• Theming the page
• Adding a 'More' link
• Testing with SimpleTest
• Practicing patches