Creating Drupal A Module

Creating Drupal Modules
A somewhat less then definitive guide to

Who is this bozo?
Adam A. Gregory
Drupal Developer for 4 years
PHP developer for 8+ years
Contribute and maintains modules on Drupal.org
Currently work as a freelance Drupal ninja.
Worked on Drupal sites large and small.
http://AdamAGregory.com

Why create a module?
New functionality
Override existing functionality
Forms
Nodes
Users
Search
Theming
Combination of the two
Almost every site needs a custom module

Before you start
Is there an existing module
Drupal.org (http://drupal.org/project/Modules/name)
IRC
Mailing list (development@drupal.org)
What you need
PHP/SQL/HTML/CSS skill
IDE
Test site
Drupal API (http://api.lullabot.com)

Setting up
File Structure
Module Folder (custom_pub)
.info file (custom_pub.info)
.module file (custom_pub.module)
.install file (custom_pub.install)
Other files/folders
Theme folder
.tpl.php files
Css/js folders
.inc files

.info File
Where Drupal gathers all the knowledge about your module
Contains module name, decsription, group, version, requirements and dependencies

;$Id: $
name=Custom Publishing Options
description=Adds the ability to add Custom publishing options to the node Add/Edit form.
core=6.x
package=Other

.module File
Must have the same name is .info file
Contains the PHP code for your module
All core hooks must be included in this file to work
Should be kept small as it is loaded on every page load
Dynamically loading inc files either via hook_menu or by loading them when a hook is called

.install File
Only needed if you module makes ANY sort of DB changes
Invokes hook_install, hook_uninstall, hook_update_##, and hook_schema

<?php
//;$Id: custom_pub.install,v 1.1 2010/01/20 21:13:05 arcaneadam Exp $
/**
* Implementation of hook_uninstall()
*/
function custom_pub_uninstall() {
$types = variable_get('custom_pub_types', array());
$ret=array();
foreach ($types as $type => $name) {
db_drop_field($ret,'node',$type);
}
variable_del('custom_pub_types');
}

Theres a hook for that
Drupal works off a hooking system similar to an Observer pattern.
Main hooks most modules use
Hook_menu
Hook_help
Hook_form_alter
Hook_user
Hook_nodeapi
API site can help you find other hooks

Organizing Your Code
.info and .module are the only required files for a module
Keep html/css/js in separate files and not hard coded into .module files
Functions for specific pages should moved into .inc files & loaded dynamically
Any calls to module files(.inc, .css, .js) should use drupal_get_path($type, $name) for css/js or module_load_include for php

Organizing your code cont.
Remember you shouldn’t hard code things like internal links, file paths, etc as you don’t know what sites will use your module and how. Keep your code dynamic and reusable
Keep file sizes small and load them when needed for better performance

Finishing Up
Load you module into a test site and enable it.
Test! Test! Test!
Stuff won’t work, you’ll have errors, and things will go crazy
DON’T PANIC!
It happens, take your time and debug the issues. Use Google, the API, IRC, Forums, Lists, Groups, etc. that are available for help.

A few words about security?
Never, ever under any circumstances trust User Input.
Drupal provides many functions and resources to properly secure your code.
Visit http://drupal.org/writing-secure-code for more info.

Contributing Back
http://drupal.org/contribute
If you have created something that will be widely useful, or al least you think it will be, you may want to get it listed on Drupal.org, but how?
The process can be painful, long, and hit and miss. Remember the D.o maintainers are volunteers.
Requires knowledge of CVS(Blah!)

Resources
API: http://api.lullabot.comhttp://api.drupal.org
Security and coding standards: http://drupal.org/node/360052
Module Developers Guide: http://drupal.org/developing/modules
Developing for Drupal: http://drupal.org/contributors-guide
IRC: #drupal, #drupal-nc
Mailing list: development@drupal.org

Creating Drupal A Module

by arcaneadam on May 14, 2010

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Creating Drupal A Module — Presentation Transcript

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