[Data objects] Default value generator service for URL Slugs

[weisswurstkanone]

as an addition to #5069

[solverat]

@weisswurstkanone @BlackbitNeueMedien: I just tested this feature and I'm not sure if I'm getting this right (No specific documentation about this).

This will trigger (getValue via DefaultValueGeneratorInterface service) only if a new object gets generated, right? But at this point, no information about the object is available.

Imagine a customer wants to create a blog entry - the (localized) title is available after an update because it's not possible to add those fields in an object creation state...

I came up with a proposal some years ago (#1048) and I think that's still a thing. The slug field is an "unsuable" field in a business point of view, since a user needs to add a complete path to it (/en/xxy).

[BlackbitDevs]

I have not retested it now but as I remember I tried to implement it so that the default values are generated every time an object gets saved if the field is empty. This is done in getDataForResource() in all Pimcore\Model\DataObject\ClassDefinition\Data subclasses. getDataForResource() gets called in

pimcore/models/DataObject/Concrete/Dao.php

Lines 245 to 264 in 7669a92

	if ($fd instanceof ResourcePersistenceAwareInterface) {
	// pimcore saves the values with getDataForResource
	if (is_array($fd->getColumnType())) {
	$insertDataArray = $fd->getDataForResource($this->model->$getter(), $this->model,
	[
	'isUpdate' => $isUpdate,
	'owner' => $this->model
	]);
	if (is_array($insertDataArray)) {
	$data = array_merge($data, $insertDataArray);
	}
	} else {
	$insertData = $fd->getDataForResource($this->model->$getter(), $this->model,
	[
	'isUpdate' => $isUpdate,
	'owner' => $this->model
	]);
	$data[$key] = $insertData;
	}
	}

For example for the input fields:

pimcore/models/DataObject/ClassDefinition/Data/Input.php

Lines 119 to 124 in 7669a92

	public function getDataForResource($data, $object = null, $params = [])
	{
	$data = $this->handleDefaultValue($data, $object, $params);
	return $data;
	}

The handleDefaultValue() then returns the default value if the field is empty.

Sadly Pimcore\Model\DataObject\ClassDefinition\Data\UrlSlug does not implement Pimcore\Model\DataObject\ClassDefinition\Data\ResourcePersistenceAwareInterface and for this reason above description does not work for this datatype.
Is this on purpose, @weisswurstkanone ?

[solverat]

UrlSlug

This save() method does not get executed if the field hasn't been marked as dirty - so this field will never gets prefilled by default.

pimcore/models/DataObject/ClassDefinition/Data/UrlSlug.php

Lines 243 to 251 in 1f9d0ff

	public function save($object, $params = [])
	{
	if (isset($params['isUntouchable']) && $params['isUntouchable']) {
	return;
	}
	$data = $this->getDataFromObjectParam($object, $params);
	if (!is_array($data) || count($data) === 0) {

Also, the method getDataForResource is not available within the UrlSlug data type.

Handle Default Value

This method does not get dispatched in update processes:

pimcore/models/DataObject/Traits/DefaultValueTrait.php

Lines 52 to 57 in 672b674

	/**
	* 1. only for create, not on update. otherwise there is no way to null it out anymore.
	*/
	if ($isUpdate) {
	return $data;
	}

[weisswurstkanone]

UrlSlug uses the CustomResourcePersistingInterface (not the ResourcePersistenceAwareInterface) so there is no getDataForResource.

[BlackbitDevs]

Hmm, does a default value generator make any sense then for URL slug datatype, @weisswurstkanone ? Because - as @solverat said - originally default value generators had two intentions:

1. Generate IDs like article numbers which do not depend on other fields' contents
2. Generate values based on other fields' values

Imho, with the current implementation URL slugs can only fulfill 1. but not 2.

[dpfaffenbauer]

Currently not, but the goal should be to make sense ;) URL Slugs is something a user will never manually input, so it has to be generated somehow.

[nicklassandell]

I just stumbled upon this issue while trying to figure it out myself, and in the end I opted for a calculated data type. The benefit is that it runs on every save, but the downside is that the user can't manually edit the slug, which in my experience, they do want the option to do. A workaround for that would be to have a second input field where they can manually enter a slug, but that isn't very nice. Anyway, just thought I'd leave this here for anyone else who stumbles across the issue.