How to limit showPrevNext in news to categories?

Question

In the TYPO3 CMS 9.5.18 LTS with tx_news 8.3.0 we use the following extension Typoscript:

plugin.tx_news.settings{
  # what is allowed to overwrite with TS
  overrideFlexformSettingsIfEmpty := addToList(categories)
  overrideFlexformSettingsIfEmpty := addToList(categoryConjunction)
  # ids of categories
  categories = 3
  # category conjunction mode
  categoryConjunction = or
}

I wonder why I have to add categories to overrideFlexformSettingsIfEmpty to get the result below. Never the less this post is more about how to achieve that the prev/next links (settings.detail.showPrevNext) does respect the category definition at all.

Our customer has 3 categories for news. If I go to a single page that does has a one category limitation (for the detail and the list page) I still eg can go "forward" to newer news in a total different category. However the list page only shows the news of that one selected category.

<f:if condition="{paginated.prev}">
    <n:link newsItem="{paginated.prev}" settings="{settings}" class="ts-prev">
        {paginated.prev.title}
    </n:link>
</f:if>

Wasn't that never the case? Do I have to add some Typoscript or make a change in Fluid? The original code uses this settings variable as argument which contains the category limitation.

Answer 1

Okay I've had a look into the GeorgRinger\News\ViewHelpers\SimplePrevNextViewHelper and there aren't any limitation for the current chosen categories.

So here is what I did:

1. register a new optional argument categories to the viewhelper
2. add categories="{settings.categories}" to the simplePrevNext tag in the Detail.html
3. add an 'extra where' for the main query in the getNeighbours function
4. add the content for the additional where ( I did that first in the getNeighbours function )

Extra where:

if( is_array($newsOfCategory) && count($newsOfCategory) > 0 ){
    $extraWhere[] = $queryBuilder->expr()->in('uid', $queryBuilder->createNamedParameter($newsOfCategory, Connection::PARAM_INT_ARRAY));
}

Content for the additional where:

if( is_string($categories) && preg_match('/^[0-9]+(,[0-9]+)*$/',$categories) ){
    $categories = explode(',', $categories);
    $tmpCon = GeneralUtility::makeInstance(ConnectionPool::class)->getConnectionForTable('sys_category_record_mm');
    $tmpQB = $tmpCon->createQueryBuilder();
    $rows = $tmpQB
        ->select('uid_foreign')
        ->from('sys_category_record_mm')
        ->where(
            $tmpQB->expr()->in('uid_local', $tmpQB->createNamedParameter($categories, Connection::PARAM_INT_ARRAY))
        )
        ->andWhere(
            $tmpQB->expr()->like('tablenames', $tmpQB->createNamedParameter('tx_news_domain_model_news'))
        )
        ->execute()->fetchAll();
    if( is_array($rows) && count($rows) > 0 ){
        foreach($rows as $row){
            $newsOfCategory[] = $row['uid_foreign'];
        }
    }
}

May be someone can use that in the future or the will integrate that to the repository.