Add a universal table picker

[aschempp]

Replaces contao/core-bundle#1171 and contao/core-bundle#999

It's basically the same implementation as by @qzminski. It also adds a picker for articles and content elements in the respective content elements.

Example configuration:

$GLOBALS['TL_DCA']['tl_module']['fields']['article'] = [
    'label' => &$GLOBALS['TL_LANG']['tl_module']['article'],
    'exclude' => true,
    'foreignKey' => 'tl_article.title',
    'inputType' => 'picker',
    'eval' => [
        //'context' => 'event', // optional, use a custom picker provider
        //'multiple'    => true, // switch to checkbox selection
        //'orderField'     => 'articleOrder',
    ],
    'sql' => ['type' => 'integer', 'unsigned' => true],
];

Contrary to contao/core-bundle#1171, the foreignKey attribute is used to generate the value from the regular DCA callbacks. If that's not the desired result, implement a custom widget that takes over the rendering.

FYI this does not mean that any DCA table can be picked, it still always needs a valid picker provider. Now added a universal picker provider that can select from any DCA table 🎉

[Toflar]

LGTM 👍

[qzminski]

Looks good to me, just a few minor details that could be improved but without an impact on the picker itself.

[leofeyer]

As briefly discussed in Slack with @aschempp, we could add an universal picker provider for all pickers that return a database ID.

[aschempp]

@leofeyer I think we can merge this if there's no more feedback. I'll create a separate PR for the universal picker provider.

[aschempp]

PR updated with a universal picker provider to pick any DC record 🎉

[Toflar]

LGTM except for missing tests. I think they might influence the outcome again so I'll approve once this PR is completely ready.

[leofeyer]

I like the latest changes, however, the AbstractDataContainerPickerProvider class does not really make sense to me. It contains a lot of code that is only required for DC_Table and that would have to be overwritten to make it work with other DCAs.

I would prefer not to have an abstract class. Just rename it to TablePickerProvider and we are all set.

[aschempp]

I like the latest changes, however, the AbstractDataContainerPickerProvider class does not really make sense to me. It contains a lot of code that is only required for DC_Table and that would have to be overwritten to make it work with other DCAs.

How come you think that? Every custom DC I ever implemented did extend DC_Table and adjusted some fields. I don't think it's better to extend the TablePickerProvider, which would be the case if there's no abstract.

[leofeyer]

You should not extend the TablePickerProvider for a folder picker provider obviously.

An abstract class should contain code that is used by 90% of their child classes. In this case, however, only about 20% of the code is relevant for a folder picker, which indicates that the abstract class is too concrete. 🤷‍♂

[leofeyer]

Thank you @aschempp.

[fritzmg]

@aschempp I am trying to gather some documentation for this. However I noticed some discrepancies with the original description in this issue. If I try to implement a news picker like this:

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

$GLOBALS['TL_DCA']['tl_content']['fields']['news'] = [
    'label' => ['News', 'Choose a news article.'],
    'foreignKey' => 'tl_news.headline',
    'inputType' => 'picker',
    'eval' => ['tl_class' => 'clr'],
    'sql' => ['type' => 'integer', 'unsigned' => true, 'default' => 0],
];

PaletteManipulator::create()
    ->addField('news', 'text', PaletteManipulator::POSITION_AFTER)
    ->applyToPalette('text', 'tl_content')
;

Then the following error will occur:

Exception:
The table name must not be empty

  at vendor\contao\contao\core-bundle\src\Resources\contao\library\Contao\DcaLoader.php:50
  at Contao\DcaLoader->__construct()
  at ReflectionClass->newInstanceArgs()
     (vendor\contao\contao\core-bundle\src\Framework\ContaoFramework.php:177)
  at Contao\CoreBundle\Framework\ContaoFramework->createInstance()
     (vendor\contao\contao\core-bundle\src\Picker\AbstractTablePickerProvider.php:133)
  at Contao\CoreBundle\Picker\AbstractTablePickerProvider->supportsContext()
     (vendor\contao\contao\core-bundle\src\Picker\PickerBuilder.php:94)
  at Contao\CoreBundle\Picker\PickerBuilder->supportsContext()
     (vendor\contao\contao\core-bundle\src\Resources\contao\widgets\Picker.php:138)
  at Contao\Picker->generate()
     (vendor\contao\contao\core-bundle\src\Resources\contao\library\Contao\Widget.php:653)
  at Contao\Widget->generateWithError()
     (vendor\contao\contao\core-bundle\src\Resources\contao\templates\backend\be_widget.html5:3)
  at include('vendor/contao/contao/core-bundle/src/Resources/contao/templates/backend/be_widget.html5')
     (vendor\contao\contao\core-bundle\src\Resources\contao\library\Contao\TemplateInheritance.php:100)
  at Contao\Widget->inherit()
     (vendor\contao\contao\core-bundle\src\Resources\contao\library\Contao\Widget.php:600)
  at Contao\Widget->parse()
     (vendor\contao\contao\core-bundle\src\Resources\contao\classes\DataContainer.php:670)
  at Contao\DataContainer->row()
     (vendor\contao\contao\core-bundle\src\Resources\contao\drivers\DC_Table.php:2003)
  at Contao\DC_Table->edit()
     (vendor\contao\contao\core-bundle\src\Resources\contao\classes\Backend.php:648)
  at Contao\Backend->getBackendModule()
     (vendor\contao\contao\core-bundle\src\Resources\contao\controllers\BackendMain.php:167)
  at Contao\BackendMain->run()
     (vendor\contao\contao\core-bundle\src\Controller\BackendController.php:49)
  at Contao\CoreBundle\Controller\BackendController->mainAction()
     (vendor\symfony\http-kernel\HttpKernel.php:157)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw()
     (vendor\symfony\http-kernel\HttpKernel.php:79)
  at Symfony\Component\HttpKernel\HttpKernel->handle()
     (vendor\symfony\http-kernel\Kernel.php:195)
  at Symfony\Component\HttpKernel\Kernel->handle()
     (web\index.php:31)
  at require('web/index.php')
     (web\app.php:4)

However if I then add a relation with table then everything is fine. I can even remove foreignKey - in fact the foreignKey declaration does not seem to have an effect whatsoever.

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

$GLOBALS['TL_DCA']['tl_content']['fields']['news'] = [
    'label' => ['News', 'Choose a news article.'],
    'inputType' => 'picker',
    'eval' => ['tl_class' => 'clr'],
    'sql' => ['type' => 'integer', 'unsigned' => true, 'default' => 0],
    'relation' => ['type' => 'hasOne', 'load' => 'lazy', 'table' => 'tl_news'],
];

PaletteManipulator::create()
    ->addField('news', 'text', PaletteManipulator::POSITION_AFTER)
    ->applyToPalette('text', 'tl_content')
;

Is this correct?

[aschempp]

hmm. Did you build the internal cache? The relation table should be taken from the DcaExtractor data not the DCA, but that might be a bug …

[fritzmg]

No, the error was taken from the dev environment, without an internal cache being built.

[aschempp]

Can you try if it works with the cache? Then maybe that's the problem…

Anyway, looks like it deserves a bug report to me 😉

[fritzmg]

Right, but seeing as it works just with the relation... what advantages would the foreignKey definiton bring? Is it supposed to work with either or?

[aschempp]

The table relations fall back to foreignKey, so our picker should do that as well.