school of information university of michigan si.umich.edu drupal: configuration and customization...

SCHOOL OF INFORMATION

UNIVERSITY OF MICHIGANsi.umich.edu

Drupal: Configuration and Customization

Week 4: Installation, Module Development

January 25, 2007

Professor Paul Resnick

(with help from Michael Hess, as usual)



Today’s Learning Objectives At the end of this week, students should

be able to:– Debug minor installation and upgrade

problems– Explain the major differences between

Drupal 4.7 and 5.0– Explore the code behind a contributed

module– Create small custom modules



Drupal 4.7 Installation

If you don’t have an auto-installer (e.g., fantastico)… Download and extract the tar.gz file

– Place in a web-accessible folder on your server• E.g., htdocs

Edit sites/default/settings.php file– Directions in the comments in this file– location of your database – $base_url path

Import the database– Get directions from your ISP– E.g., mysql dbname –u dbuser –ppassword < drupaldb_file



Drupal 5.0 Installation

If you don’t have an auto-installer (e.g., fantastico)…

Download and extract the tar.gz file– Place in a web-accessible folder on your server

• E.g., htdocs

Change perms on /sites/default/settings.php to 666– Owner, group, and other all read/write privileges

Access your Drupal install via web and follow the directions



Upgrading 4.7 to 5

See Lullabot screencast Note: you can’t do this on cms.si.umich

– We have a multi-site installation



Drupal Security

If you’re the site maintainer…– Join the security mailing list

• Login to drupal.org• My account >> my newsletters

– When you get a security alert for a module you’re using

• Upgrade as soon as you can

– When you get a security alert for Drupal core• Follow the suggested action ASAP

Do NOT install modules not found on Drupal.org– No security alerting system



Drupal 5.0 Preview

Key changes– Installation is easier– Administration interface changes– Themes

• New: Garland• Some color changes without changing code

– CCK is part of core– Installation Profiles

See Lullabot screencast



Some PHP Basics

Semi-colon at end of statements { } enclose collection of statements Variables If-statements Functions Arrays For loops



PHP Variables

Variables begin with $ Set using =

$x = 23; Local unless you specify global

global $user;



PHP If/Else and Switch/Caseif ($op == "list") {

stm1; stm2; …}else {}

switch ($section) { case “a”: stmt; break; case “b”: stmt; }



PHP Function Definition

function onthisdate_help($section='') { $output = ''; switch ($section) { case "admin/modules#description": $output = t("Displays links to nodes created on this date");

break; } return $output;} // function onthisdate_help



PHP Arrays

Example: an array whose first/only item is an array

$items = array(); $items[] = array('path' => 'onthisdate', 'title' => t('on this date'), 'callback' => 'onthisdate_all', 'access' => user_access('access

content'), 'type' => MENU_CALLBACK);



PHP Foreach Loops

<?php$arr = array(1, 2, 3, 4);foreach ($arr as &$value) { $value = $value * 2;}// $arr is now array(2, 4, 6, 8)?>



Extensibility Concepts: Defining Add-ons

Adding new names– Only problem is name collisions

• Variables in programs– local and global• XML markup tags– XML Namespaces

Defining meaning of named items– Set variable values– Define functions



Extensibility Concepts: Integrating Add-ons

Hooks/callbacks– Base calls the add-on

Function libraries– Add-on calls the base



What Programmers Need to Know About Callbacks

How to register the callback so it will be invoked

When the callback will be invoked Parameters passed and returned



Drupal Callbacks (Hooks)

Registering a hook– Define a function with the right name

• <modulename>_hookname

– No separate registration process; will automatically be invoked

When hook will be invoked– Check documentation; look at source code

Parameters passed and returned– api.drupal.org



Drupal Naming Conventions One big namespace Don’t define a module that has same

name as any other module All functions in module begin with prefix

– <module-name>_• For functions that may be invoked from other

files

– _<module-name>_• For private functions



What Programmers Need to Know About Library Functions Parameters passed and returned

– See api.drupal.org Any side effects of the function

– E.g., saving a node in the database



Some Useful Hooks

Documentation hook_access hook_block hook_cron hook_menu hook_settings (4.7; use hook_menu in 5.0) hook_nodeapi



Cron.php

When cron.php is executed– Executes the cron hooks for all contributed

modules Set up a UNIX cron job to cause cron.php to

be executed periodically– Done for you on cms.si

• Once per hour

Poormanscron module if you can’t run a cron job on your installation– Checks on each user access whether it’s time to

run cron.php



Some Useful Drupal library functions Documentation at http://api.drupal.org/ Theme related

– l(), t() Node functions

– node_load(), node_save() Database functions

– Db_query() et al Forms API Access control

– User_access()



Drupal Licensing

Drupal Core is Distributed under GPL– You can modify and redistribute it– You can’t prevent others from doing so– You don’t have to distribute your modifications

If you distribute modifications, must be under GPL– Wiggle room about whether a consultant who

gives the module only to a client who paid for its production is distributing it

• Consult an attorney



Module Development

Tutorial OnThisDate– http://drupal.org/node/22801

A Sign-me-up custom feature for AARecon



Devel Module

Menu block– Clear the cache– View variable values

PHP block to execute some code Display SQL queries used in building a

page Object structure display for current node



OnThisDate Tutorial

http://drupal.org/node/22801 Final version of 4.7 code (rename it to

OnThisDate.module)



Making module information visible hook_help



Permission Actions

hook_perm



Create Block(s) in a Module hook_block

– List op– View op



Create Module Settings

hook_settings– Add a new variable that can be set through

administer >> settings >> this_module



Create a Page

Define a function that outputs a page Give it a URL path and/or add it to a

menu



SignMeUp Custom Module Adds a link to sign up as the closer For production we’ll do better

– A custom field type using CCK’s API• Copy and edit userreference

– Button in each of the fields where user can sign up

• Access controls; don’t allow double sign-up, etc.

– Display sign-ups with photos



Exercises

Which hook would you use? Write or modify a module

school of information university of michigan si.umich.edu drupal: configuration and customization...

Documents