Custom data processors

When there is no fitting data processor to prepare variables needed for your content element or template, you can define a custom data processor by implementing the DataProcessorInterface.

You can find the example below in the TYPO3 Documentation Team extension examples.

Using a custom data processor in TypoScript

The data processor can be configured by a TypoScript setup configuration. A custom data processor can be used like this in the definition of a new custom content element:

tt_content {
   examples_dataproccustom =< lib.contentElement
   examples_dataproccustom {
      templateName = DataProcCustom
      dataProcessing.10 = T3docs\Examples\DataProcessing\CustomCategoryProcessor
      dataProcessing.10 {
         as = categories
         categoryList.field = tx_examples_main_category

In the extension examples you can find the code in typo3conf/ext/examples/Configuration/TypoScript/setup.typoscript.

Where tx_examples_main_category is the field in which the comma separated categories are being stored.


The custom data processor described here was intended to be kept as a simple example. It can therefore only work with comma separated values, not a m-n relationship as is used in the field categories of tables like tt_content. For that, further logic would need to be implemented.

Implementing the custom data processor

The custom data processor needs to implement DataProcessorInterface. The main function process gets called with the following parameters:

ContentObjectRenderer $cObj

Receives the data of the current TypoScript context, in this case the data of the calling content element.

array $contentObjectConfiguration

Contains the configuration of the calling content element. In this example all configuration of tt_content.examples_dataproccustom

array $processorConfiguration

Contains the configuration of the currently called dataprocessor. In this case the value of as and the stdWrap configuration of the categoryList

array $processedData

On calling, contains the processed data of all previously called data processors on this content element. Your custom data processor also stores the variables to be send to Fluid here.

This is an example implementation of a custom data processor:

namespace T3docs\Examples\DataProcessing;

use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer;
use TYPO3\CMS\Frontend\ContentObject\DataProcessorInterface;
use TYPO3\CMS\Extbase\Domain\Repository\CategoryRepository;

class CustomCategoryProcessor implements DataProcessorInterface
   public function process(
      ContentObjectRenderer $cObj,
      array $contentObjectConfiguration,
      array $processorConfiguration,
      array $processedData
   ) : array {
      if (isset($processorConfiguration['if.']) && !$cObj->checkIf($processorConfiguration['if.'])) {
         // leave $processedData unchanged in case there were previous other processors
         return $processedData;
      // categories by comma separated list
      $categoryIdList = $cObj->stdWrapValue('categoryList', $processorConfiguration ?? []);
      if ($categoryIdList) {
         $categoryIdList = GeneralUtility::intExplode(',', (string)$categoryIdList, true);

      /** @var CategoryRepository $categoryRepository */
      $categoryRepository = GeneralUtility::makeInstance(CategoryRepository::class);
      $categories = [];
      foreach ($categoryIdList as $categoryId) {
         $categories[] = $categoryRepository->findByUid($categoryId);
      // set the categories into a variable, default "categories"
      $targetVariableName = $cObj->stdWrapValue('as', $processorConfiguration, 'categories');
      $processedData[$targetVariableName] = $categories;
      return $processedData;

In the extension examples you can find the code in typo3conf/ext/examples/Classes/DataProcessing/CustomCategoryProcessor.php.

On being called, the CustomCategoryProcessor runs stdWrap on the calling ContentObjectRenderer, which has the data of the table tt_content in the calling content element.

Since the field categoryList got configured in TypoScript as follows:

categoryList.field = tx_examples_main_category

stdWrap fetches the value of categoryList from tt_content.tx_examples_main_category of the currently calling content element.

Now the custom data processor processes the comma separated values into an array of integers that represent uids of the table sys_category. It then fetches the category data from the CategoryRepository by calling findByUid.

The data of the category records then gets stored in the desired key in the $processedData array.

In order to make the data processor more configurable we test for a TypoScript if condition in the beginning, and make the name of the key that we use to store the data configurable by the configuration as;