Registration of frontend plugins

When you want to use Extbase controllers in the frontend you need to define a so called frontend plugin. Extbase allows to define multiple frontend plugins for different use cases within one extension.

A frontend plugin can be defined as content element or as pure TypoScript frontend plugin.

Content element plugins can be added by editors to pages in the Page module while TypoScript frontend plugin can only be added via TypoScript or Fluid in a predefined position of the page. All content element plugins can also be used as TypoScript plugin.

Frontend plugin as content element

The plugins in the New Content Element wizard

Use the following steps to add the plugin as content element:

configurePlugin(): Make the plugin available in the frontend

EXT:blog_example/ext_localconf.php
```
<?php

declare(strict_types=1);

use FriendsOfTYPO3\BlogExample\Controller\CommentController;
use FriendsOfTYPO3\BlogExample\Controller\PostController;
use TYPO3\CMS\Extbase\Utility\ExtensionUtility;

defined('TYPO3') or die();

ExtensionUtility::configurePlugin(
    // extension name, matching the PHP namespaces (but without the vendor)
    'BlogExample',
    // arbitrary, but unique plugin name (not visible in the backend)
    'PostSingle',
    // all actions
    [PostController::class => 'show', CommentController::class => 'create'],
    // non-cacheable actions
    [CommentController::class => 'create'],
    ExtensionUtility::PLUGIN_TYPE_CONTENT_ELEMENT,
);
```
Copied!
Use the following parameters:
1. Extension key 'blog_example' or name BlogExample.
2. A unique identifier for your plugin in UpperCamelCase: 'PostSingle'
3. An array of allowed combinations of controllers and actions stored in an array
4. (Optional) an array of controller name and action names which should not be cached
5. Using any value but ExtensionUtility::PLUGIN_TYPE_CONTENT_ELEMENT is deprecated in TYPO3 v13.4.
Deprecated since version 13.4

Setting the fifth parameter to any value but ExtensionUtility::PLUGIN_TYPE_CONTENT_ELEMENT is deprecated. See Migration: list_type plugins to CType.

TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin() generates the necessary TypoScript to display the plugin in the frontend.

In the above example the actions show in the PostController and create in the CommentController are allowed. The later action should not be cached. This action can show different output depending on whether a comment was just added, there was an error in the input etc. Therefore the output of the action create of the CommentController should not be cached.

The action delete of the CommentController is not listed. This action is therefore not allowed in this plugin.

The TypoScript of the plugin will be available at tt_content.blogexample_postsingle. Additionally the lists of allowed and non-cacheable actions have been added to the according global variables.
registerPlugin(): Add the plugin as option to the field "Type" of the content element (column CType of table tt_content).

This makes the plugin available in the field Type of the content elements and automatically registers it for the New Content Element Wizard.

Changed in version 13.0

In TYPO3 13 this is now automatically registered by the TCA from the step above. See Feature: #102834 - Auto-registration of New Content Element Wizard via TCA

EXT:blog_example/Configuration/TCA/Overrides/tt_content.php
```
<?php

use TYPO3\CMS\Extbase\Utility\ExtensionUtility;

defined('TYPO3') or die();

(static function (): void {
    $pluginKey = ExtensionUtility::registerPlugin(
        // extension name, matching the PHP namespaces (but without the vendor)
        'BlogExample',
        // arbitrary, but unique plugin name (not visible in the backend)
        'PostSingle',
        // plugin title, as visible in the drop-down in the backend, use "LLL:" for localization
        'Single Post (BlogExample)',
    );
})();
```
Copied!
Use the following parameters:
1. Extension key 'blog_example' or name BlogExample.
2. A unique identifier for your plugin in UpperCamelCase: 'PostSingle', must be the same as used in configurePlugin() or the plugin will not render.
3. Plugin title in the backend: Can be a string or a localized string starting with LLL:.
4. (Optional) the icon identifier or file path prepended with "EXT:"

Frontend plugin as pure TypoScript

configurePlugin(): Make the plugin available in the frontend

Configure the plugin just like described in Frontend plugin as content element. This will create the basic TypoScript and the lists of allowed controller-action combinations.

In this example we define a plugin displaying a list of posts as RSS feed:

EXT:blog_example/ext_localconf.php

<?php

declare(strict_types=1);

use FriendsOfTYPO3\BlogExample\Controller\PostController;
use TYPO3\CMS\Extbase\Utility\ExtensionUtility;

defined('TYPO3') or die();

// RSS feed
ExtensionUtility::configurePlugin(
    'BlogExample',
    'PostListRss',
    [PostController::class => 'displayRssList'],
    [],
    ExtensionUtility::PLUGIN_TYPE_CONTENT_ELEMENT,
);

Display the plugin via TypoScript

The TypoScript EXTBASEPLUGIN object saved at tt_content.blogexample_postlistrss can now be used to display the frontend plugin. In this example we create a special page type for the RSS feed and display the plugin via TypoScript there:

EXT:blog_example/Configuration/TypoScript/RssFeed/setup.typoscript

# RSS rendering
tx_blogexample_rss = PAGE
tx_blogexample_rss {
  typeNum = {$plugin.tx_blogexample.settings.rssPageType}
  10 < tt_content.blogexample_postlistrss

  config {
    disableAllHeaderCode = 1
    xhtml_cleaning = none
    admPanel = 0
    debug = 0
    disablePrefixComment = 1
    metaCharset = utf-8
    additionalHeaders.10.header = Content-Type:application/rss+xml;charset=utf-8
    linkVars >
  }
}