Palette Manipulator

The PaletteManipulator is the way to go if you want to edit the palette of a DCA, e.g. add fields to the back end of an existing DCA.

Introduction

Before we use the PaletteManipulator, lets have a look at how palettes are defined.

// tl_user.php

$GLOBALS['TL_DCA']['tl_user'] = [
    …
    // Palettes
    'palettes' => [
        …
        'default' => '{name_legend},username,name,email;{backend_legend:hide},language,uploader,showHelp,thumbnails,useRTE,useCE;{theme_legend:hide},backendTheme,fullscreen;{password_legend:hide},pwChange,password;{admin_legend},admin;{groups_legend},groups,inherit;{account_legend},disable,start,stop'
        …
    ],
    …
];

The palette is a string. The PaletteManipulator is a utility class to help you manipulate that string.

Adding fields

Let’s assume we have the following DCA configuration:

// contao/dca/tl_user.php
$GLOBALS['TL_DCA']['tl_user']['fields']['custom_field'] = [
    'label' => &$GLOBALS['TL_LANG']['tl_user']['custom_field'],
    'inputType' => 'text',
    'eval' => […],
    'sql' => ['type' => 'string', 'length' => 255, 'default' => '']
];

At this moment, the field is not visible in the back end. The field now has to be added to the palette. This could happen via concatenation or something like str_replace():

// contao/dca/tl_user.php

// appending custom_field to the palette
$GLOBALS['TL_DCA']['tl_user']['palettes']['default'] .= ';{custom_legend},custom_field';

// using str_replace() to insert the field after the username
str_replace('username', 'username,custom_field', $GLOBALS['TL_DCA']['tl_user']['palettes']['default']);

These two methods are a bit complicated and prone to error.

Another method is by using the PaletteManipulator:

// contao/dca/tl_user.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    // apply the field "custom_field" after the field "username"
    ->addField('custom_field', 'username')

    // now the field is registered in the PaletteManipulator
    // but it still has to be registered in the globals array:
    ->applyToPalette('admin', 'tl_user') 
;

Each time you call an applyTo*() method, the fields you applied for this instance will not be cleared. If you do not want this behaviour, you can create a new instance:

// contao/dca/tl_user.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    ->addField('custom_field', 'username')
    ->applyToPalette('admin', 'tl_user') 
;

PaletteManipulator::create()
    ->removeField('username', 'name_legend')
    ->applyToPalette('admin', 'tl_user') 
;

Adding Legends

It is also possible to create new groups, i.e. “legends” (see the reference) via the addLegend method. As with addField, it takes the name of the legend, the “parent” field or legend and the position it is supposed to be added relative to the parent.

// contao/dca/tl_news.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    // add a new "custom_legend" before the "date_legend"
    ->addLegend('custom_legend', 'date_legend', PaletteManipulator::POSITION_BEFORE)

    // directly add new fields to the new legend
    ->addField('custom_field', 'custom_legend', PaletteManipulator::POSITION_APPEND)
    ->addField('foo_field', 'custom_legend', PaletteManipulator::POSITION_APPEND)
    
    // then apply it to the palette as usual
    ->applyToPalette('default', 'tl_news')
;

If you do not provide a parent (and position), the legend will simply be appended at the end.

Removing fields

This feature is only available in Contao 4.7 and later.

// contao/dca/tl_user.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    // remove the field "custom_field" from the "name_legend"
    ->removeField('custom_field', 'name_legend')

    // again, the change is registered in the PaletteManipulator
    // but it still has to be applied to the globals:
    ->applyToPalette('admin', 'tl_user')
;

Working with subpalettes

The same logic can be applied to subpalettes. Let’s assume custom_field is configured in tl_content:

// contao/dca/tl_content.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    // adding the field as usual
    ->addField('custom_field', 'singleSRC')

    // remove a field from the subpalette
    ->removeField('floating')

    // applying the new configuration to the "addImage" subpalette
    ->applyToSubpalette('addImage', 'tl_content')
;

Advanced configuration

By default, fields is added after the parent. You can alter the behaviour by using one of the predefined constants as third parameter:

parameter behaviour
PaletteManipulator::POSITION_BEFORE Adds the new field before the defined parent field
PaletteManipulator::POSITION_AFTER Adds the new field after the defined parent field
PaletteManipulator::POSITION_PREPEND Adds the new field before the defined parent legend
PaletteManipulator::POSITION_APPEND Adds the new field after the defined parent legend

Example

This example adds two fields custom_field and custom_field_2 and removes the username field from the palette.

// contao/dca/tl_example.php
use Contao\CoreBundle\DataContainer\PaletteManipulator;

PaletteManipulator::create()
    ->addField('custom_field', 'username', PaletteManipulator::POSITION_AFTER)
    ->addField('custom_field_2', 'name_legend', PaletteManipulator::POSITION_APPEND)
    ->removeField('username', 'name_legend')
    ->applyToPalette('default', 'tl_example')
;