Typo3 8.7 return a GLOBAL be_user value from a TCA Override page

Question

I have created a new back-end variable called "userval". I can reference this value in any controller by simply calling:

$GLOBALS['BE_USER']->user['userval']

However I need to get this value from another extensions, via the TCA/Overrides/tt_content.php page. The above code doesn't work here (I receive an empty value). Is it possible to access the BE_USER values from tt_content.php?

Answer 1

Update - I didn't manage to figure it out but I found a better solution that might work for others.

I needed this information because I wanted to return a list of items from a table that was linked to the field "userval". But the example below has been simplified for more general use..

I discovered that tt_content.php can have data passed directly to it via a controller. In the tt_content.php file, add the following:

'tx_some_example' =>
 array(
   'config' =>
   array(
     'type' => 'select',
     'renderType' => 'selectSingle',
     'items' => array (),      
     'itemsProcFunc' => 'SomeDomain\SomeExtensionName\Controller\ExampleController->getItems',
     'selicon_cols' => 8,
     'size' => 1,
     'minitems' => 0,
     'maxitems' => 1,       
   ),
   'exclude' => '1',
   'label' => 'Some example',

),

...note the "itemsProcFunc" line. This references returned data from the ExampleController.

In the ExampleController, here's how you can send the data into tt_content.php:

public function getItems($config){         
        
     //Sample data - this could be a DB call, a list in a folder, or a simple array like this
     $sampleArray[
        "id1" => "ID 1 Label",            
        "id2" => "ID 2 Label",            
        "id3" => "ID 3 Label",
     ];  
      
     $optionList = [];
     $count=0;


     //Cycle through each item, and add it to the desired dropdown list
     foreach ($sampleArray as $id => $label) {
          $optionList[$count] = [0 => $label, 1 => $id];
          $count++;
     }

     //Pass the data back to the tt_content.php page
     $config['items'] = array_merge($config['items'], $optionList);
     return $config;

}