FE Searchfield in simpleblog extension doesn't work - typo3

Question

I am trying to going through the book "TYPO3 Extbase - Modern Extension Development" from P. Lobacher. There I am on the point with the searchfield. Here my Editor (PHPStorm) tells me that $search isn't defined.
I have a listAction with:
/**
* #internal param string $search
*/
public function listAction() {
if ($this->request->hasArgument('search')){
$search = $this->request->getArgument('search');
}
$limit = ($this->settings['blog']['max']) ?: NULL;
$this->view->assign('blogs', $this->blogRepository->findSearchForm($search,$limit));
$this->view->assign('search', $search);
}
In my repository i try to setup a query like that:
/**
* #param string $search
* #param int $limit
* #return array|\TYPO3\CMS\Extbase\Persistence\QueryResultInterface
*/
public function findSearchForm($search,$limit) {
$query = $this->createQuery();
$query->matching(
$query->like('title','%'.$search.'%')
);
$query->setOrderings(array('title' => \TYPO3\CMS\Extbase\Persistence\QueryInterface::ORDER_ASCENDING));
$limit = (int)$limit; if ($limit > 0) {
$query->setLimit($limit);
}
return $query->execute();
}
In my list view i have the searchform like that:
<f:form action="list" additionalAttributes="{role:'form'}"> <div class="form-inline">
<div class="form-group">
<f:form.textfield name="search" value="{search}" class="form-control" /> <f:form.submit value="Search!" class="btn-xs btn-primary" />
</div> </div>
</f:form>
If i change the assign to the view in my listAction to:
$this->view->assign('blogs', $this->blogRepository->findSearchForm('Testblog',$limit));
Then he shows me the blogs with the titlefragment "Testblog" in it. But dynamically it won't work.
I am using TYPO3 v8.5.1
Thx for your help.

Answer 1

at first you should change the $limit line because its hard to read. Change it to:
$limit = $this->settings['blog']['max'] ? $this->settings['blog']['max'] : 0;
I changed NULL to 0 because in the repository annotation the parameter should be an integer.
Then you should also change the two assign() functions to an assignMultiple()-Array.
Have you ever debugged $search in your controller using
\TYPO3\CMS\Extbase\Utility\DebuggerUtility::var_dump($search);
Because your is not bound to an object, you are may not able to get $search with getArgument(). Can you please give us the rendered HTML output of that form field?
EDIT: Because of your search you may not cache the list action. Change list action in ext_localconf.php to NOT CACHED.