Custom Joomla Plugin Development

Joomla Custom Plugin Development

Joomla plugins react to system events. They intercept moments of the lifecycle: before/after saving an article, on authentication, on search, on form submission. This is the correct way to extend system behavior without core modification.

Plugin Groups

Plugin Structure

plg_content_synccrm/
├── plg_content_synccrm.php    # Entry point (for legacy)
├── plg_content_synccrm.xml    # Manifest
├── services/
│   └── provider.php           # DI Provider
└── src/
    └── Extension/
        └── SyncCrmPlugin.php  # Main class

Manifest

<?xml version="1.0" encoding="utf-8"?>
<extension version="4.0" type="plugin" group="content">
    <name>plg_content_synccrm</name>
    <author>Your Company</author>
    <version>1.0.0</version>
    <description>Sync content with CRM on publish</description>
    <namespace path="src">MyCompany\Plugin\Content\SyncCrm</namespace>

    <files>
        <filename plugin="plg_content_synccrm">plg_content_synccrm.php</filename>
        <folder>services</folder>
        <folder>src</folder>
    </files>

    <config>
        <fields name="params">
            <fieldset name="basic">
                <field name="crm_api_url" type="text" label="CRM API URL" />
                <field name="crm_api_key" type="password" label="CRM API Key" />
                <field name="sync_types" type="checkboxes" label="Sync Types">
                    <option value="article">Articles</option>
                    <option value="product">Products</option>
                </field>
            </fieldset>
        </fields>
    </config>
</extension>

DI Provider

// services/provider.php
use Joomla\CMS\Extension\PluginInterface;
use Joomla\DI\Container;
use MyCompany\Plugin\Content\SyncCrm\Extension\SyncCrmPlugin;

return new class implements \Joomla\DI\ServiceProviderInterface {
    public function register(Container $container): void {
        $container->set(PluginInterface::class, function (Container $container) {
            $dispatcher = $container->get(\Joomla\Event\DispatcherInterface::class);
            $plugin = new SyncCrmPlugin($dispatcher, []);
            $plugin->setApplication($container->get(\Joomla\CMS\Application\CMSApplicationInterface::class));
            return $plugin;
        });
    }
};

Main Plugin Class

// src/Extension/SyncCrmPlugin.php
namespace MyCompany\Plugin\Content\SyncCrm\Extension;

use Joomla\CMS\Plugin\CMSPlugin;
use Joomla\Event\Event;
use Joomla\Event\SubscriberInterface;

class SyncCrmPlugin extends CMSPlugin implements SubscriberInterface {
    public static function getSubscribedEvents(): array {
        return [
            'onContentAfterSave' => 'syncToCrm',
        ];
    }

    public function syncToCrm(Event $event): void {
        [$context, $article, $isNew] = array_values($event->getArguments());

        // Sync articles only
        if ($context !== 'com_content.article') return;

        // Only published
        if ((int) $article->state !== 1) return;

        $syncTypes = $this->params->get('sync_types', []);
        if (!in_array('article', (array) $syncTypes)) return;

        try {
            $this->sendToCrm([
                'type'       => 'article',
                'external_id'=> $article->id,
                'title'      => $article->title,
                'url'        => \Joomla\CMS\Router\Route::link('site', 'index.php?option=com_content&view=article&id=' . $article->id),
                'published'  => (bool) $article->state,
                'updated_at' => $article->modified,
            ]);
        } catch (\Exception $e) {
            $this->getApplication()->getLogger()->error('CRM sync failed: ' . $e->getMessage());
        }
    }

    private function sendToCrm(array $data): void {
        $apiUrl = rtrim($this->params->get('crm_api_url'), '/') . '/articles';
        $apiKey = $this->params->get('crm_api_key');

        $http = \Joomla\CMS\Factory::getContainer()
            ->get(\Joomla\Http\HttpFactory::class)
            ->getHttp();

        $response = $http->post($apiUrl, json_encode($data), [
            'Content-Type'  => 'application/json',
            'Authorization' => 'Bearer ' . $apiKey,
        ]);

        if ($response->code >= 400) {
            throw new \RuntimeException('CRM API error: ' . $response->code);
        }
    }
}

Authentication Plugin (External SSO)

public static function getSubscribedEvents(): array {
    return ['onUserAuthenticate' => 'authenticate'];
}

public function authenticate(Event $event): void {
    $credentials = $event->getArgument('credentials');
    $options     = $event->getArgument('options');
    $response    = $event->getArgument('response');

    // Check via external OAuth server
    $token = $this->verifyWithOAuthServer($credentials['username'], $credentials['password']);

    if ($token) {
        $response->status = \Joomla\CMS\Authentication\Authentication::STATUS_SUCCESS;
        $response->email  = $token['email'];
        $response->fullname = $token['name'];
        $response->type   = 'OAuth';
    } else {
        $response->status  = \Joomla\CMS\Authentication\Authentication::STATUS_FAILURE;
        $response->error_message = 'Invalid credentials';
    }
}

Timeline

Plugin development for one event group (content, user or system) with configurable parameters — 1–3 days.