Contributed by Ruud Kamphuis
in #49134.

In Symfony 6.3 we introduced a feature to map request data into typed objects
using the #[MapRequestPayload] and #[MapQueryString] attributes. However,
sometimes you want to map individual request data to specific controller arguments.
Symfony has allowed to map route parameters to controller arguments since its
first version. In Symfony 6.3 you will also be able to map query string parameters
to specific controller arguments. To do so, use the new #[MapQueryParameter]
attribute:

#[Route(path: '/', name: 'admin_dashboard')]
public function indexAction(
#[MapQueryParameter] array $ids,
#[MapQueryParameter] string $firstName,
#[MapQueryParameter] bool $required,
#[MapQueryParameter] int $age,
#[MapQueryParameter] string $category = '',
#[MapQueryParameter] ?string $theme = null,
)

If the query string of the incoming request is /?ids[]=1&ids[]=2&firstName=Ruud&required=3&age=123,
this code will make the controller arguments to have these values:

$ids = ['1', '2']
$firstName = "Ruud"
$required = false
$age = 123
$category = ''
$theme = null

The #[MapQueryParameter] attribute makes the conversion of the query string
parameter(which is always a string) into the proper PHP type according to the
types of your controller arguments (it's similar to calling
$request->query->getInt('...'), $request->query->getAlpha('...'), etc.
but automated by Symfony).
For more advanced use cases, you can use the filter option of the attribute
to validate the data type details:

// this ensures that the array only contains integer values
#[MapQueryParameter(filter: \FILTER_VALIDATE_INT)]
array $ids

// this ensures that the string follows some specific pattern
#[MapQueryParameter(filter: \FILTER_VALIDATE_REGEXP, options: ['regexp' => '/^\w++$/'])]
string $name

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