A little trait to add to models that will have Uuids

HasUuid.php

<?php

// Example usage in a model:

class ExampleModel extends Model
{
    use HasUuid;

    protected $primaryKey = 'uuid';

    public $incrementing = false;
}

// The Trait:

trait HasUuid
{
    public static function bootHasUuid()
    {
        static::creating(function ($model) {
            if (! $model->{$model->getKeyName()}) {
                $model->{$model->getKeyName()} = static::generateUuid();
            }
        });
    }

    public static function generateUuid()
    {
        return (string) Illuminate\Support\Str::uuid();
    }
}

Also you need to specify key type and incrementing. And you can do it in trait, like:

trait HasUuid
{
    public static function bootHasUuid()
    {
        $callback = function (Model $model) {
            $model->setKeyType('string');
            $model->setIncrementing(false);
        
            if (! $model->getKey()) {
                $model->{$model->getKeyName()} = static::nextIdentity();
            }
        };

        static::creating($callback);
        static::retrieved($callback);
    }

    public static function nextIdentity()
    {
        return Illuminate\Support\Str::uuid()->toString();
    }
}

Didn't work for me. Ended up using:

<?php
namespace App\Traits;

trait Uuids
{
    /**
     * Boot function from laravel.
     */
    protected static function boot()
    {
        parent::boot();

        static::creating(function ($model) {
            $model->{$model->getKeyName()} = (string) \Illuminate\Support\Str::uuid();
        });
    }
}