feat: [Validation] add method to get the validated data

[kenjis]

Description

• add Validation::getValidated()

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[iRedds]

I'd like to hear the reason for adding this method.
What is the real benefit of it?

[kenjis]

Security enhancement.
This method returns only validated data, so developers can be sure to use validated data.

[iRedds]

Let's say the script receives data, some of which do not need to be validated.
It turns out that after validation, the getValidated() method will return only part of the data, which will add an extra operation to manipulate the data further.
For me, this feature looks dubious.

[kenjis]

Let's say the script receives data, some of which do not need to be validated.

This method is intended for input validation like validation for HTML form.
What data don't you need to validate?

[ddevsr]

For me, currently develop upload batch by excel and will return callback failed excel with marker like alreadyExists in column description.

Upload:

1|John Doe|2023-02-01|
2|Maria|2024-04-14|

Callback:

1|John Doe|2023-02-01|DONE
2|Maria|2024-04-14|alreadyExists

I think this function can use for this case and combine failed validation

[kenjis]

Added the docs.

[michalsn]

This example is fine, but I would like to ask you to add an example that will cover controller validation (with the $this->validate() method). This is the place where this method is the most valuable.

[kenjis]

I have a plan to add a method to get validated data in Controller, and update all sample code with $this->validate().

[michalsn]

I don't think need a separate method in the controller for this, though.
Since we can get the errors via $this->validator->getErrors(), I see no problem with getting validated data the same way, via $this->validator->getValidated().

[kenjis]

Oh, I see. Thank you for opinion.

[kenjis]

See #7425