Introduction to Module Development John Fiala and Ezra Barnett Gildesgame
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Transcript of Introduction to Module Development John Fiala and Ezra Barnett Gildesgame
Introduction to Module Development
John Fiala and
Ezra Barnett Gildesgame
What is a module?
Apollo Lunar Service and Excursion Modules
What is a module?
A piece of software that adds or extends functionality on a Drupal website
Adds functionality
o Ubercart - Provides a sophisticated online store
o Fivestar - Provides a star rating widget for rating content
o Signup - Let's users sign up to attend events
Extends Functionality
• UC_Signup - Allows people to to pay for Ubercart Events• Token - Many modules rely on Token to provide
configurable messages including variable (like [user-name])
Often, adding a new feature entails extending or connecting existing
featuresYou usually don't have to start from scratch :)
• Fivestar stores data using the VotingAPI• UC_Signup connects Ubercart and Signup• Embedded Media Field provides a new field for use with the
Content Construction Kit
Core, Contrib & Custom
• Core - Part of the official Drupal package. Everyone using Drupal has it
• Contrib - Publicly available optional download, not specific to a particular website. (Though sometimes specific to a kind of feature)
• Custom - Specific to a particular website. Useful for that website, but not generally useful to the public.
Drupal Community
• Check out the issue queue• Find a related group on groups.drupal.org
Custom Modules
• Often avoidable
• Often necessary
• Usually cost more to maintaino API changes, version updateso Securityo Feature additionso Friends you lose when you duplicate their moduleo (We still <8 you)
You usually don't have to start from scratch!
Drupal Core and Contrib have nice systems thatyou can harness in your module
o Displaying and processing forms for user input
o Handling user accounts
o Handling Content (Core node, contrib CCK)
o Creating custom listings of content (Views)
And much, much more!
How do modules add or extend functionality?
How do modules add or extend functionality?
With hooksI'm performing a particular action.
Does anyone have anything to say about it?
• Person A: I'm getting up to get napkins. Does anybody want me to get anything else?
• Person B: Yes! Please get straws.
• Module A: I'm presenting a form to the user.• Module B: Please add a checkbox to the form!
A - The hook DefinitionB - The hook Implemenation
Examples of Hook Events
• Displaying a form to the user (hook_form_alter)o Add a custom checkbox
• A user signs up for an account (hook_user)o Display a friendly message
• Submitting a node (hook_nodeapi)o Store custom data in the database
• The website sends mail (o Connect to an SMTP sever
Writing a module
• Create a .info file - Tell Drupal your module exists• Create a .module file
o Implement one or more hooks• Create a .install file (optional)
Go to http://drupal.org/node/231036Your Basic Info File: ; $Id$name = Example moduledescription = "Gives an example of a module."core = 6.x
Optional: package = Viewsdependencies[] = viewsdependencies[] = panelsphp = 5.1
How Do I Interact with a Form?
hook_form_alter(&$form, $form_state, $form_id)
The $form Array:(We'll get to this)
The Form Status$form_state['values'] is what was entered
Which Form Is This?Step 1: Use dpm($form_id);to find out!
http://api.drupal.org/api/function/hook_form_alter/6
Form Array? What?Something like this:
$form['foo'] = array( '#type' => 'textfield', '#title' => t('bar'), '#default_value' => $object['foo'], '#size' => 60, '#maxlength' => 64, '#description' => t('baz'),);$form['submit'] = array( '#type' => 'submit', '#value' => t('Save'),);
QuickStart: http://api.drupal.org/api/file/developer/topics/forms_api.html/6
How do you Interact with nodes?hook_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL)
The node to change
What's happening to the node(There's a long list):delete/insert/update/view/validate
Extra data: if 'view', then $teaser, if 'validate', then $form.
Extra data: if 'view' then $page
http://api.drupal.org/api/function/hook_nodeapi/6
What about interacting with User accouts.
hook_user($op, &$edit, &$account, $category = NULL)
What the User is Doing(Again, a list, but...)delete/insert/load/login/logout/register/update /etc, etc, etc
Form Values submitted
The User's User Object(Why isn't it $user?)
$category - the category of User Info being changed
So, let's throw something together...
Modules That Help Build Modules
Token
Image Credits
• Tube Man• http://www.flickr.com/photos/redherring1up• NASA Toys
http://www.silentthundermodels.com/nasa_space_models/apollo.html
• Updating Modules from 5.x to 6.xhttp://drupal.org/node/114774
• Form API Reference - http://api.drupal.org/api/file/developer/topics/forms_api_reference.html/6
• Form API Quickstart -http://api.drupal.org/api/file/developer/topics/forms_api.html• "Easy" d.o Newbie taghttp://drupal.org/project/issues/search?text=&projects=&assigned=&submitted=&participant=&status%5B%5D=Open&issue_tags=Newbie