Laravel slug mutator (most basic implementation)

ModelWithSlug.php

<?php

use Illuminate\Database\Eloquent\Model;

class ModelWithSlug extends Model
{
    public function setSlugAttribute($val)
    {
        $val = trim($val);
        $val = str_slug($val);

        // check empty (fallback with title)
        if ($val == '') {
            $val = str_slug($this->title);
        }

        // check unique (fallback with uniqid suffix)
        $duplicate = ModelWithSlug::whereSlug($val)->where('id', '<>', $this->id)->first();
        if ($duplicate) {
            $val = $val.uniqid();
        }

        // mutate
        $this->attributes['slug'] = $val;
    }
}