Extend Joomla Forms Using Plugins

Extend Joomla Forms
Using Plugins
Presentation “Extend Joomla Forms Using Plugins” - http://slideshare.net/yireo
Jisse Reitsma (jisse@yireo.com) - Twitter @yireo @jissereitsma #jwc14

My name is Jisse Reitsma
Developer
Owner of Yireo
Joomla! & Magento
Extensions & services
Tutorials & blogs
Sponsoring JWC2014

Plugins I wrote
Language Domains
Auto Login IP
Demo Site
Fancybox
HTTP Authenticatie
New Relic
Piwik
WebP
ScriptMerge
SEF Test
SSL Redirection
Static Content
Trademark
32+ MageBridge plugins
10+ SimpleLists plugins
8+ Dynamic404 plugins

Book release in November 2014
English
368 pages
Available through:
Yireo Shop (Europe)
Amazon (US & world wide)
#deadtreeformat (no ebook)

Extend Joomla Forms Using Plugins
Part I - Events & JForm
Part II - Code
Part III - Braindump
Presentation online: http://slideshare.net/yireo
Tweets: @yireo / @jissereitsma
Code: github.com/yireo/JoomlaPluginsBook

Part I:
Events & JForm

Extensions
Component
Modules
Plugins
Libraries
Language files

Plugin groups
Authentication
Content
System
User
Editors
Editor Buttons
Search
Finder
CAPTCHA
Extension
Quick Icon

Content events
onContentPrepareForm
onContentAfterSave
onContentAfterDelete
onContentBeforeDisplay

JForm
Joomla core library for handling forms
XML form definition + PHP logic
Tasks
Form generation (HTML)
Validation
Filtering

MVC
Model
View
Controller

MVC workflow (simple)
User requests page
Controller calls view
View fetches data from model
View shows page

MVC workflow (form)
User requests form
View shows form
User submits form (POST)
Controller picks up on POST
Controller validates & filters form
Model stores form data
Controller redirects back to form or other page

MVC workflow (form)
User requests form
View shows form (JForm)
User submits form (POST)
Controller picks up on POST
Controller validates & filters form (JForm)
Model stores form data
Controller redirects back to form or other page

Part II:
Code

Goal
Add a custom field to backends article form
Store that fields value in a separate database table
Show that fields value in the same form again
Show that fields value in the frontend

Goal

Goal
Add a custom field to backends article form
Store that fields value in a separate database table
onContentAfterSave
Show that fields value in the same form again
Show that fields value in the frontend

Content Plugin files
plugins/content/example/example.php
plugins/content/example/example.xml
plugins/content/exampe/form/default.xml
administrator/languages/en-GB/en-GB.plg_content_example.ini
administrator/languages/en-GB/en-GB.plg_content_example.sys.ini

Language files (1/2)
PLG_CONTENT_EXAMPLE="Content Example"
PLG_CONTENT_EXAMPLE_DESC="An example Content Plugin"
PLG_CONTENT_EXAMPLE_FIELD_EXAMPLE_LABEL=”Test”
PLG_CONTENT_EXAMPLE_FIELD_EXAMPLE_DESC=”New field”

Language files (2/2)
*.sys.ini = Always loaded
Add plugin title + description, but not much more
*.ini = Only loaded specifically
When editing a plugin in backend
When showing plugin in frontend ($autoLoadLanguage = true)
Add all language strings you need (backend + frontend)

XML manifest
<?xml version="1.0" encoding="utf8"?>
<extension version="3.0" type="plugin" group="content">
<name>PLG_CONTENT_EXAMPLE</name>
<description>PLG_CONTENT_EXAMPLE_DESC</description>
<version>0.0.1</version>
<files>
<filename plugin=”example”>example.php</filename>
<folder>form</folder>
</files>
<languages>
<language tag=”enGB”>
enGB.
plg_content_example.ini</language>
<language tag=”enGB”>
enGB.
plg_content_example.sys.ini</language>
</languages>
</extension>

XML form
<?xml version="1.0" encoding="utf8"?>
<form>
<fields>
<fieldset name="jmetadata">
<field name="example" type="text"
label="PLG_CONTENT_EXAMPLE_FIELD_EXAMPLE_LABEL"
description="PLG_CONTENT_EXAMPLE_FIELD_EXAMPLE_DESC"
/>
</fieldset>
</fields>
</form>

Content Plugin - basic structure
<?php
defined('_JEXEC') or die();
class plgContentExample extends JPlugin
{
}

Content Plugin - basic structure
<?php
defined('_JEXEC') or die();
class plgContentExample extends JPlugin
{
public function onContentPrepareForm($form, $data) {}
public function onContentAfterSave($context, $item, $isNew) {}
public function onContentBeforeDisplay($context, $item, $params, $page) {}
}

public function onContentPrepareForm($form, $data)
{
...
JForm::addFormPath(__DIR__.'/form'); // subfolder “form”
$form>
loadFile('default'); // file “form/default.xml”
...
return true;
}

public function onContentPrepareForm($form, $data)
{
if (!($form instanceof JForm))
{
$this>_
subject>
setError('JERROR_NOT_A_FORM');
return false;
}
$name = $form>
getName();
if (!in_array($name, array('com_content.article')))
{
return true;
}
...

...
if(!empty($data>
id))
{
$data = $this>
loadExample($data);
}
return true;
}

loadExample
protected function loadExample($data)
{
$db = JFactory::getDbo();
$query = $db>
getQuery(true);
$query>
select('*')
>
from($db>
quoteName('#__example'))
>
where($db>
quoteName('content_id') . ' = '.$data>
id);
$db>
setQuery($query);
$exampleData = $db>
loadAssoc();
$data>
example = $exampleData['example'];
return $data;
}

onContentAfterSave
public function onContentAfterSave(
$context, $article, $isNew
)
{
if (!in_array($context, array('com_content.article')))
{
return true;
}
...

onContentAfterSave
...
$jinput = JFactory::getApplication()>
input;
$form = $jinput>
post>
get('jform', null, 'array');
if (is_array($form) && isset($form['example']))
{
$example = $form['example'];
}
else
{
return true;
}
...

onContentAfterSave
...
$content_id = $article>
id;
$this>
saveExample($content_id, $context, $example);
return true;
}

saveExample
protected function saveExample($content_id, $context, $test)
{
$db = JFactory::getDbo();
$query = $db>
getQuery(true);
$query>
select($db>
quoteName('content_id'))
>
from($db>
quoteName('#__example'))
>
where($db>
quoteName('content_id').'='.$content_id);
$db>
setQuery($query);
$db>
execute()
$exists = (bool)$db>
getNumRows();
...

saveExample
...
$data = new stdClass();
$data>
content_id = $content_id;
$data>
context = $context;
$data>
example = $example;
if($exists) {
$result = $db>
updateObject('#__example', $data,
'content_id');
} else {
$result = $db>
insertObject('#__example', $data);
}
return true;
}

public function onContentBeforeDisplay(
$context, &$row, &$params, $page = 0)
{
if(!empty($row>
id))
{
$row = $this>
loadExample($row);
}
if (!empty($row>
example))
{
$row>
text .= '<p>EXAMPLE: '.$row>
example.'<p>';
}
}

Part 3:
Braindump

Forms are everywhere
Article form
Category form
User profile form
Menu-Item form
Contact form

JForm manipulation
$form->load($xml)
$form->loadFile($file)
$form->bind($data)
$form->getField($name, $group, $value)
$form->removeField($field)
$form->setField($xml)

JForm output
$form->getInput($field, $group)
$form->getLabel($field, $group)
$form->getName($field, $group)
$form->getValue($field, $group)
$form->renderField($field, $group)
$form->getFieldset($fieldset)
$form->getFieldsets($group)

Showing new field values
4 times the same event
onContentPrepare
onContentAfterTitle
onContentAfterDisplay
Template override

Loading a language file - Joomla! 2.5
public function __construct(& $subject, $config)
{
parent::__construct($subject, $config);
$this>
loadLanguage();
}

Loading a language file - Joomla! 3.x
protected $autoloadLanguage = true;

github.com
/yireo
/JoomlaPluginsBook
/chapter05
https://github.com/yireo/JoomlaPluginsBook/tree/master/chapter05

@yireo
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