Plugin-Driven Frontend Views

J2Commerce app plugins can own complete frontend views — with menu items, SEF URLs, and full page rendering — without modifying any core component file. Two event hooks in the component enable this:

1. onJ2CommerceRegisterRouterViews — Register your view with the Router for SEF URL support.
2. onJ2CommerceBeforeDispatchView — Claim your view so the Dispatcher skips the MVC chain (no View class or template needed in the component).

Rendering happens in Joomla's standard onAfterDispatch event, where the plugin builds HTML and sets the component buffer. Joomla's Menu Manager discovers the view through a default.xml file the install script deploys to components/com_j2commerce/tmpl/{viewname}/.

The app_vendormanagement plugin (vendorapply view) is the reference implementation for this pattern.

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Architecture

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Event Reference

Event	Fired By	Arguments	Plugin Response
onJ2CommerceRegisterRouterViews	Router.php constructor	['router' => $routerInstance] (named)	Call $router->registerView(new RouterViewConfiguration('yourview'))
onJ2CommerceBeforeDispatchView	Dispatcher.php dispatch()	[$viewName] (positional, index 0)	Call $event->addResult(true) if view matches
onAfterRoute	Joomla kernel	None (standard Joomla event)	Handle POST form submissions
onAfterDispatch	Joomla kernel	None (standard Joomla event)	Render HTML, call setBuffer($html, 'component')

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What Your Plugin Needs

Requirement	How
SEF URL support	Subscribe to onJ2CommerceRegisterRouterViews, call $router->registerView()
Skip MVC dispatch	Subscribe to onJ2CommerceBeforeDispatchView, return true for your view
Page rendering	Subscribe to onAfterDispatch, render HTML, call setBuffer()
Menu item discovery	Deploy default.xml to components/com_j2commerce/tmpl/{viewname}/ via install script
POST handling	Subscribe to onAfterRoute, check task name, process form

Zero core file modifications required. The Router and Dispatcher events are generic — they fire for all J2Commerce plugins.

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Complete Working Example

File Structure

plugins/j2commerce/app_yourplugin/
├── app_yourplugin.xml                  # XML manifest
├── script.app_yourplugin.php           # Install/uninstall script
├── services/
│   └── provider.php                    # DI service provider
├── src/
│   └── Extension/
│       └── AppYourPlugin.php           # Main plugin class
├── tmpl/
│   ├── yourview/
│   │   └── default.php                 # Frontend page template
│   └── application/
│       └── default.xml                 # Menu item metadata (deployed to component)
├── media/
│   ├── css/
│   │   └── yourplugin.css              # Plugin styles
│   └── js/
│       └── yourplugin.js               # Plugin scripts
└── language/
    └── en-GB/
        ├── plg_j2commerce_app_yourplugin.ini
        └── plg_j2commerce_app_yourplugin.sys.ini

Plugin Extension Class

<?php
/**
 * @package     J2Commerce
 * @subpackage  plg_j2commerce_app_yourplugin
 */

declare(strict_types=1);

namespace YourCompany\Plugin\J2Commerce\AppYourPlugin\Extension;

defined('_JEXEC') or die;

use Joomla\CMS\Component\Router\RouterViewConfiguration;
use Joomla\CMS\Plugin\CMSPlugin;
use Joomla\CMS\Router\Route;
use Joomla\CMS\Session\Session;
use Joomla\Event\Event;
use Joomla\Event\SubscriberInterface;

final class AppYourPlugin extends CMSPlugin implements SubscriberInterface
{
    protected $autoloadLanguage = true;

    public static function getSubscribedEvents(): array
    {
        return [
            'onJ2CommerceRegisterRouterViews'  => 'onRegisterRouterViews',
            'onJ2CommerceBeforeDispatchView'   => 'onBeforeDispatchView',
            'onAfterRoute'                     => 'onAfterRoute',
            'onAfterDispatch'                  => 'onAfterDispatch',
        ];
    }

    // -----------------------------------------------------------------
    // Router: Register SEF route for this view
    // -----------------------------------------------------------------

    public function onRegisterRouterViews(Event $event): void
    {
        $router = $event->getArgument('router');
        $router->registerView(new RouterViewConfiguration('yourview'));
    }

    // -----------------------------------------------------------------
    // Dispatcher: Claim the view so MVC chain is skipped
    // -----------------------------------------------------------------

    public function onBeforeDispatchView(Event $event): void
    {
        $view = $event->getArgument(0);

        if ($view === 'yourview') {
            $event->addResult(true);
        }
    }

    // -----------------------------------------------------------------
    // POST handling (form submissions)
    // -----------------------------------------------------------------

    public function onAfterRoute(): void
    {
        $app   = $this->getApplication();
        $input = $app->getInput();

        if ($input->getCmd('option') !== 'com_j2commerce') {
            return;
        }

        if ($app->isClient('site') && $input->getCmd('task') === 'yourplugin.submit') {
            Session::checkToken() or die;
            $this->handleFormSubmit();
            $app->redirect(Route::_('index.php?option=com_j2commerce&view=yourview'));
        }
    }

    // -----------------------------------------------------------------
    // Rendering: Build HTML and set component buffer
    // -----------------------------------------------------------------

    public function onAfterDispatch(): void
    {
        $app   = $this->getApplication();
        $input = $app->getInput();

        if ($input->getCmd('option') !== 'com_j2commerce') {
            return;
        }

        if ($app->isClient('site') && $input->getCmd('view') === 'yourview') {
            $this->renderFrontendView();
        }
    }

    private function renderFrontendView(): void
    {
        $app    = $this->getApplication();
        $user   = $app->getIdentity();
        $params = $this->params;

        // Register plugin assets via Web Asset Manager
        $wa = $app->getDocument()->getWebAssetManager();
        $wa->registerAndUseStyle(
            'plg_j2commerce_app_yourplugin',
            'media/plg_j2commerce_app_yourplugin/css/yourplugin.css'
        );
        $wa->registerAndUseScript(
            'plg_j2commerce_app_yourplugin',
            'media/plg_j2commerce_app_yourplugin/js/yourplugin.js',
            [],
            ['defer' => true]
        );

        // Resolve template (check for site template override first)
        $templateFile = $this->resolveTemplate();

        ob_start();
        include $templateFile;
        $html = ob_get_clean() ?: '';

        $app->getDocument()->setBuffer($html, 'component');
    }

    private function resolveTemplate(): string
    {
        $tpl      = $this->getApplication()->getTemplate();
        $override = JPATH_SITE . '/templates/' . $tpl
            . '/html/plg_j2commerce_app_yourplugin/yourview/default.php';

        if (is_file($override)) {
            return $override;
        }

        return __DIR__ . '/../../tmpl/yourview/default.php';
    }

    private function handleFormSubmit(): void
    {
        // Process form data here
    }
}

Service Provider

<?php
// File: plugins/j2commerce/app_yourplugin/services/provider.php

declare(strict_types=1);

defined('_JEXEC') or die;

use YourCompany\Plugin\J2Commerce\AppYourPlugin\Extension\AppYourPlugin;
use Joomla\CMS\Extension\PluginInterface;
use Joomla\CMS\Factory;
use Joomla\CMS\Plugin\PluginHelper;
use Joomla\DI\Container;
use Joomla\DI\ServiceProviderInterface;
use Joomla\Event\DispatcherInterface;

return new class () implements ServiceProviderInterface
{
    public function register(Container $container): void
    {
        $container->set(
            PluginInterface::class,
            function (Container $container) {
                $plugin = new AppYourPlugin(
                    $container->get(DispatcherInterface::class),
                    (array) PluginHelper::getPlugin('j2commerce', 'app_yourplugin')
                );

                $plugin->setApplication(Factory::getApplication());

                return $plugin;
            }
        );
    }
};

Install Script

The install script deploys the menu item XML to the component's tmpl/ directory so Joomla's Menu Manager discovers the view. On uninstall, it removes the deployed file.

<?php
// File: plugins/j2commerce/app_yourplugin/script.app_yourplugin.php

declare(strict_types=1);

defined('_JEXEC') or die;

use Joomla\CMS\Installer\InstallerScript;
use Joomla\Filesystem\File;
use Joomla\Filesystem\Folder;
use Joomla\Filesystem\Path;

class plgJ2CommerceApp_yourpluginInstallerScript extends InstallerScript
{
    public function postflight(string $type, object $parent): bool
    {
        if ($type === 'uninstall') {
            return true;
        }

        $this->deployMenuItemXml();

        return true;
    }

    public function uninstall(object $parent): bool
    {
        // Remove the menu item XML from the component tmpl directory
        $targetDir = Path::clean(
            JPATH_SITE . '/components/com_j2commerce/tmpl/yourview'
        );

        if (is_dir($targetDir)) {
            Folder::delete($targetDir);
        }

        return true;
    }

    private function deployMenuItemXml(): void
    {
        $sourceFile = Path::clean(
            JPATH_PLUGINS . '/j2commerce/app_yourplugin/tmpl/application/default.xml'
        );
        $targetDir  = Path::clean(
            JPATH_SITE . '/components/com_j2commerce/tmpl/yourview'
        );
        $targetFile = $targetDir . '/default.xml';

        if (!is_file($sourceFile)) {
            return;
        }

        if (!is_dir($targetDir)) {
            Folder::create($targetDir);
        }

        File::copy($sourceFile, $targetFile);
    }
}

Menu Item Metadata

Stored in the plugin at tmpl/application/default.xml, deployed to components/com_j2commerce/tmpl/yourview/default.xml by the install script.

<?xml version="1.0" encoding="utf-8"?>
<metadata>
    <layout title="PLG_J2COMMERCE_APP_YOURPLUGIN_MENU_TITLE"
            option="PLG_J2COMMERCE_APP_YOURPLUGIN_MENU_OPTION">
        <message>
            <![CDATA[PLG_J2COMMERCE_APP_YOURPLUGIN_MENU_DESC]]>
        </message>
    </layout>

    <fields name="params">
        <fieldset name="page_display" label="JGLOBAL_FIELDSET_PAGE_OPTIONS">

            <field
                name="show_page_heading"
                type="radio"
                layout="joomla.form.field.radio.switcher"
                label="JGLOBAL_SHOW_PAGE_HEADING"
                default="1"
                filter="integer"
            >
                <option value="0">JNO</option>
                <option value="1">JYES</option>
            </field>

            <field
                name="page_heading"
                type="text"
                label="JGLOBAL_PAGE_HEADING"
                showon="show_page_heading:1"
                default=""
            />

        </fieldset>
    </fields>
</metadata>

Frontend Template

<?php
// File: plugins/j2commerce/app_yourplugin/tmpl/yourview/default.php

declare(strict_types=1);

defined('_JEXEC') or die;

use Joomla\CMS\Language\Text;
use Joomla\CMS\Router\Route;
use Joomla\CMS\Session\Session;
?>
<div class="j2commerce yourplugin-view">
    <h2><?php echo Text::_('PLG_J2COMMERCE_APP_YOURPLUGIN_PAGE_HEADING'); ?></h2>

    <?php if ($user->guest) : ?>
        <div class="alert alert-info">
            <?php echo Text::_('PLG_J2COMMERCE_APP_YOURPLUGIN_LOGIN_REQUIRED'); ?>
        </div>
    <?php else : ?>
        <form method="post"
              action="<?php echo Route::_('index.php?option=com_j2commerce&view=yourview'); ?>">

            <input type="hidden" name="task" value="yourplugin.submit" />
            <?php echo \Joomla\CMS\HTML\HTMLHelper::_('form.token'); ?>

            <!-- Your form fields here -->

            <button type="submit" class="btn btn-primary">
                <?php echo Text::_('JSUBMIT'); ?>
            </button>
        </form>
    <?php endif; ?>
</div>

---

How the Events Work Internally

onJ2CommerceRegisterRouterViews

Fired in components/com_j2commerce/src/Service/Router.php after all core views are registered but before parent::__construct() builds the view tree:

// Router.php constructor (after core view registrations)
JoomlaPluginHelper::importPlugin('j2commerce');
$app->getDispatcher()->dispatch(
    'onJ2CommerceRegisterRouterViews',
    new Event('onJ2CommerceRegisterRouterViews', ['router' => $this])
);

parent::__construct($app, $menu);  // Builds view tree including plugin views

The event passes the Router instance as a named argument. Plugins call $router->registerView() to add their views. The parent::__construct() call after the event builds the complete view tree, so plugin views are included in SEF URL generation and parsing.

onJ2CommerceBeforeDispatchView

Fired in components/com_j2commerce/src/Dispatcher/Dispatcher.php before parent::dispatch() calls the MVC chain:

// Dispatcher.php dispatch() — before parent::dispatch()
$claimed = J2CommerceHelper::plugin()->eventWithArray(
    'BeforeDispatchView',
    [$view]
);

if (\in_array(true, $claimed, true)) {
    return;  // Skip MVC chain — onAfterDispatch will still fire
}

parent::dispatch();

Uses J2Commerce's eventWithArray() helper which fires onJ2CommerceBeforeDispatchView with [$viewName] as arguments. If any plugin returns true via $event->addResult(true), the Dispatcher returns early — skipping parent::dispatch() which would require a View class and template. Joomla's onAfterDispatch event still fires afterward, allowing the plugin to render.

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Template Overrides

Site templates can override your plugin's frontend output using the standard Joomla template override path:

templates/{template}/html/plg_j2commerce_app_yourplugin/yourview/default.php

Implement priority resolution in your renderFrontendView() method as shown in the example above. Check the active template's override directory first, then fall back to the plugin's own template.

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Troubleshooting

View returns a 404

1. Verify your plugin is enabled in System → Manage → Plugins.
2. Confirm onJ2CommerceRegisterRouterViews is in your getSubscribedEvents() array and the handler calls $router->registerView().
3. Confirm onJ2CommerceBeforeDispatchView is subscribed and returns true for your view name. Without this, the Dispatcher tries to load a View class that doesn't exist.
4. Test with the non-SEF URL first: index.php?option=com_j2commerce&view=yourview. If this works but the SEF URL doesn't, the issue is in Router registration.

Page loads but the component area is blank

1. Verify onAfterDispatch is subscribed and the handler guards on $input->getCmd('view') === 'yourview' — the check is case-sensitive.
2. A PHP error inside ob_start() / ob_get_clean() suppresses output silently. Enable Joomla error reporting temporarily.
3. Confirm the template file path in include is correct — use __DIR__ relative paths.

Menu Manager does not list the view type

1. Confirm default.xml exists at components/com_j2commerce/tmpl/yourview/default.xml.
2. Clear Joomla's cache and reload the Menu Manager.
3. Language keys in <layout title="..."> must be loaded during admin requests. Deploy your .sys.ini to administrator/language/en-GB/ or register with the J2Commerce language registry (see app_vendormanagement for the pattern).

POST submissions not processed

1. onAfterRoute fires on every request including GET. Always guard with a task check.
2. Pass the CSRF token as a hidden <input> field, not in the query string.
3. Always call $app->redirect() after processing to prevent onAfterDispatch from rendering over the POST response.

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Checklist

Before releasing a plugin that uses this pattern:

• getSubscribedEvents() includes all four events
• onRegisterRouterViews registers the view with RouterViewConfiguration
• onBeforeDispatchView returns true only for your view name
• onAfterDispatch guards on both option=com_j2commerce and isClient('site')
• Install script deploys default.xml to tmpl/{viewname}/
• Uninstall script removes tmpl/{viewname}/ directory
• .sys.ini language keys available for Menu Manager discovery
• POST handlers verify CSRF token via Session::checkToken()
• POST handlers end with $app->redirect()
• Template override resolution checks active site template first
• Tested with SEF URLs both enabled and disabled

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Reference Implementation

The app_vendormanagement plugin is the canonical reference:

File	Role
plugins/j2commerce/app_vendormanagement/src/Extension/AppVendorManagement.php	Subscribes to all four events
plugins/j2commerce/app_vendormanagement/script.app_vendormanagement.php	deployMenuItemXml() and uninstall() cleanup
plugins/j2commerce/app_vendormanagement/tmpl/application/default.xml	Menu item metadata deployed to tmpl/vendorapply/
plugins/j2commerce/app_vendormanagement/tmpl/application/default.php	Frontend application form template

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Related

• Apps View Hook — Register your plugin in the J2Commerce admin Apps view.
• Payment Plugin Development — Full guide for payment gateway plugins.
• Shipping & Payment Template Overrides — Override checkout templates from plugins.