[TASK] Add example: Display an Extbase plugin in a Fluid template

Documentation/ContentObjects/Extbaseplugin/Index.rst

@@ -52,8 +52,8 @@ Properties
 
 ..  _cobj-extbaseplugin-examples:
 
-Example
-=======
+Example: Display an Extbase plugin via TypoScript
+=================================================
 
 ..  code-block:: typoscript
     :caption: EXT:my_extension/Configuration/TypoScript/setup.typoscript
@@ -62,6 +62,43 @@ Example
     page.10.extensionName = MyExtension
     page.10.pluginName = MyPlugin
 
+..  _cobj-extbaseplugin-examples-fluid:
+
+Example: Display an Extbase plugin in a Fluid template
+======================================================
+
+It is possible to display an Extbase plugin in Fluid using the
+:ref:`CObject ViewHelper <f:cObject> <t3viewhelper:typo3-fluid-cobject>`:
+
+..  literalinclude:: _CodeSnippets/_SomeTemplate.html
+    :caption: EXT:my_extension/Resources/Private/Templates/Pages/SomeTemplate.html
+
+Create a lib object which utilizes the :typoscript:`EXTBASEPLUGIN` into
+a :typoscript:`lib` object:
+
+..  literalinclude:: _CodeSnippets/_libMyPlugin.typoscript
+    :caption: EXT:my_extension/Configuration/TypoScript/setup.typoscript
+
+For `extensionName` and `pluginName` use the names as configured in
+:php:`\TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin()`:
+
+..  literalinclude:: _CodeSnippets/_configurePlugin.php
+    :caption: EXT:my_extension/ext_localconf.php
+    :emphasize-lines: 9,10
+
+If you passed data to the ViewHelper, you can access the data in the controller's
+action by getting the currentContentObject from the request:
+
+..  literalinclude:: _CodeSnippets/_MyController.php
+    :caption: EXT:my_extension/Classes/Controller/MyController.php
+    :emphasize-lines: 16,17
+
+..  note::
+    You should treat all data from the
+    :php-short:`\TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer` as
+    potential user input. Do not use it unescaped and do not trust to receive
+    certain types.
+
 ..  _cobj-extbaseplugin-history:
 
 History

Documentation/ContentObjects/Extbaseplugin/_CodeSnippets/_MyController.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MyVendor\MyExtension\Controller;
+
+use Psr\Http\Message\ResponseInterface;
+use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
+use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
+
+class MyController extends ActionController
+{
+    public function listAction(): ResponseInterface
+    {
+        /** @var ContentObjectRenderer $contentObject */
+        $contentObject = $this->request->getAttribute('currentContentObject');
+        $dataFromTypoScript = $contentObject->data;
+        $someValue = (int)($dataFromTypoScript['someValue'] ?? 0);
+        $someSetting = $dataFromTypoScript['someSetting'] ?? '';
+        // Do something
+        return $this->htmlResponse();
+    }
+}

Documentation/ContentObjects/Extbaseplugin/_CodeSnippets/_SomeTemplate.html

@@ -0,0 +1,5 @@
+<!-- ... -->
+<f:cObject
+        typoscriptObjectPath="lib.myPlugin"
+        data="{someValue: page.pageRecord.someValue, someSetting: site.someSetting}"
+/>

Documentation/ContentObjects/Extbaseplugin/_CodeSnippets/_configurePlugin.php

@@ -0,0 +1,14 @@
+<?php
+
+use MyVendor\MyExtension\Controller\MyController;
+use TYPO3\CMS\Extbase\Utility\ExtensionUtility;
+
+defined('TYPO3') || die('Access denied.');
+
+ExtensionUtility::configurePlugin(
+    'MyExtension',
+    'MyPlugIn1',
+    [MyController::class => 'list, show'],
+    [],
+    ExtensionUtility::PLUGIN_TYPE_CONTENT_ELEMENT,
+);

Documentation/ContentObjects/Extbaseplugin/_CodeSnippets/_libMyPlugin.typoscript

@@ -0,0 +1,6 @@
+lib.myPlugin = EXTBASEPLUGIN
+lib.myPlugin {
+    extensionName = MyExtension
+    pluginName = MyPlugIn1
+    settings.detailPid = 42
+}