CastTrait

Inside the controller scope (of MVC) you usually handle request data:

• posted data
• query string

You want to make sure your application gets the right type of data here. If you pass it along, you want it to match the signature of the method you pass it into. Especially if you introspect your code with static analyzers (like PHPStan), you will need this kind of additional type safety. Even more so if you enabled strict types.

Static-analyzer friendly

"PHPStan level 7" approved.

Add it at the top of your controller or globally in your AppController:

use Shim\Utility\CastTrait;

class TriggerController extends AppController {

    use CastTrait;

The following two type families are available to help keep your controller code clean.

Assert

The assert*() methods allow null values to be returned, making them "optional" input casting. Either the right type or null is guaranteed. If the type is completely wrong (array vs scalar) you even get an exception early on.

public function myAction() {
    // string|null
    $processName = $this->assertString($this->request->getQuery('process'));

    // int|null
    $limit = $this->assertInt($this->request->getQuery('limit'));
}

Cast

The cast*() methods will only return the desired type, defaulting falsy/empty values to the corresponding empty value of that type. If the type is completely wrong (array vs scalar) you even get an exception early on.

public function myAction() {
    // string
    $processName = $this->castString($this->request->getQuery('process'));

    // bool (also handles string "true"/"false")
    $redirectEnabled = $this->castBool($this->request->getQuery('redirect'));
}

Defaults

Why doesn't the CastTrait ship with a second $default argument like the core does in some places?

There are many different "ways" you want your default value to kick in — for example on null, or maybe on any empty value ('', false, ...).

For that reason PHP offers two different operators to use in ternary form:

// We want any empty input to get overwritten
$processName = $this->castString($this->request->getQuery('process')) ?: 'default';

// We only want null (not 0) to be overwritten
$limit = $this->assertInt($this->request->getQuery('limit')) ?? 100;

Just use those where needed to quickly confine your values to non-empty defaults. This is usually as readable as providing a default argument, and allows you to customize it more easily.

TIP

Always have some test cases backing up your asserting/casting.