[11.x] Allows Unit & Backed Enums for registering named RateLimiter & RateLimited middleware

[sethsandaru]

Hi team,

This PR enables us to use both BackedEnum & UnitEnum to register named RateLimiter, and the RateLimited middleware.

I believe many of us really want to use Enum for this case and avoid using hardcoded strings across our codebase.

[devfrey]

What problem does this solve, as opposed to using string constants?

class GlobalRateLimitEnum
{
    public const HUBSPOT = 'hubspot';
}

public function middleware(): array
{
    return [
        new RateLimited(GlobalRateLimitEnum::HUBSPOT),
    ];
}

Exact same syntax, same "type safety" (or lack thereof), and requires no changes the framework.

[sethsandaru]

it doesn't solve any typing problems here. It gives devs the flexibility to use Enum 🤷‍♂️ depending on people's taste I guess. Many parts of Laravel already support Enum.

And I'm a fan of UnitEnum for this (BackedEnum - nice to have). And enums are special, don't treat them like a simple place to hold strings or integers, they can do more than that.

===

Going forward, I can even do something like this:

enum GlobalNamedLimiter
{
    case API; // short and simple

    public function getLimit(): Closure
    {
        return fn () => match ($this) {
            self::API => Limit::perMinute(100)
        };
    }
}

RateLimiter::for(
    GlobalNamedLimiter::API, 
    GlobalNamedLimiter::API->getLimit() // return () => Limit::perMinute(100);
);

or even this

public function middleware(): array
{
    return [GlobalNamedLimiter::API->middleware()];
}

🤷‍♂️

[siarheipashkevich]

@sethsandaru what about supporting enum for Illuminate\Support\Fluent?

https://laravel.com/docs/11.x/validation#complex-conditional-array-validation