TYPO3 TCA value as a variable on Fluid - php

Question

I have a base extension so i can version my website. That means i have not a controller or a repository on the extension. So what i want to do, is to create my own settings on existing elements. I was experimenting around with a text align values on the header content element.
Keep in mind, there is already a setting for this, but i am just
experimenting.
I figured out how to add them and the values are saved on the database.
What i now want to do, is to take the values and add them as a class on FLUID. This is where i stuck. I can not get the values. Any idea how to do it?
After this guide How to enable header_position in TYPO3 7.6
i manage to get my code that far:
On the folder /Configuration/TCA/Overrides/tt_content.php
use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;
ExtensionManagementUtility::addTCAcolumns('tt_content',[
'header_position_custom' => [
'exclude' => 1,
'label' => 'header position',
'config' => [
'type' => 'select',
'renderType' => 'selectSingle',
'items' => [
['left', 'left'],
['right', 'right'],
['center', 'center']
]
]
]
]);
ExtensionManagementUtility::addFieldsToPalette('tt_content', 'header', '--linebreak--,header_position_custom', 'after:header_layout');
ExtensionManagementUtility::addFieldsToPalette('tt_content', 'headers', '--linebreak--,header_position_custom', 'after:header_layout');
On the folder /Configuration/Typoscript/Constants/Base.typoscript
styles.templates.templateRootPath = EXT:my_website_base/Resources/Private/Extensions/Fluid_styled_content/Resources/Private/Templates/
styles.templates.partialRootPath = EXT:my_website_base/Resources/Private/Extensions/Fluid_styled_content/Resources/Private/Partials/
styles.templates.layoutRootPath = EXT:my_website_base/Resources/Private/Extensions/Fluid_styled_content/Resources/Private/Layouts/
On the /Resources/Private/Extensions/Fluid_styled_content/Resourcs/Private/Partials/Header.html
<h1 class="{positionClass} {header_position_custom} {data.header_position_custom} showed">
<f:link.typolink parameter="{link}">{header}</f:link.typolink>
</h1>
I 've put the class showed just to make sure that i am reading the
file from the path i gave on the constants
File ext_tables.php
TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addStaticFile($_EXTKEY,'Configuration/TypoScript', 'Website Base');
File ext_tables.sql
CREATE TABLE tt_content (
header_position_custom varchar(255) DEFAULT '' NOT NULL,
);
With all these i get my selectbox where i wanted to be and i get the values on the database. That means that if i select the value "Center" in the selectbox, then it will be saved on the database. How can i get this value and use it as class on the FLUID?
Thanks in advance,

Answer 1

You will find your field in the data object.
For inspecting your fluid variables you can use the f:debug-VH:
<f:debug title="the data">{data}</f:debug>
for inspecting all (in the current context) available variables you can debug _all:
<f:debug title="all data">{_all}</f:debug>
Hint: use the title attribute to identify the output
and don't forget to write a get* and set* function for new fields!