Dynamic Model Attribute Mutators

[tylernathanreed]

I came across a use-case where I wanted a model to have a series of magic attributes based on an array. In this scenario, I had a preferences json object, but I wanted the values in this object to be accessible as if they were properties on the model itself. I had a fixed list of allowable preference attribute names, so it seemed possible.

However, when I tried to implement this, I came into a snag that I felt could be handled better. If I wanted, say, 3 different preferences, I would have to add the names of these preferences as methods to the model. Sure, I could do that as a trait, but now, if I wanted to add another preference type, I needed to update both my list of allowed preferences, and my magic attribute methods.

I played around with the internals of Laravel, and ended up creating something I'm dubbing "Dynamic Model Attribute Mutators". Essentially, I can programmatically add new attributes to a model:

enum Preference: string
{
    case Timezone = 'timezone';
    case Language = 'lang';
    /* ... */
}

class User extends Model
{
    public static function boot()
    {
        foreach (Preference::cases() as $preference) {
            static::addDynamicAttribute($preference->value, Attribute::make(
                get: fn ($value, $attributes) => $attributes['preferences'][$preference->value] ?? null,
                set: function ($value, $attributes) => {
                    $preferences = $attributes['preferences'] ?? [];
                    $preferences[$preference->value] = $value;
                    return ['preferences' => json_encode($preferences)]
                }
            ));
        }
    }
}

It's possible that there's more applications for something like this, but it seems like a neat idea.

I've created PR #50770 as an attempt to implement this idea.

[iazaran]

Please take a look at this part of your PR:

if ($method->getNumberOfRequiredParameters() > 0) {
    return false;
}

An attribute function, even without a constructor, needs return an empty attr. It seems that part caused some failed tests.

[tylernathanreed]

That wasn't the issue. I had created a getMarkedAttribute() function to return dynamically registered attributes, but the old-style attributes detected this as a marked magic accessor. Renaming the method fixed the issue.