Lae/app/Rules/Domain.php

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class Domain implements Rule
{
    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     */
    public function passes($attribute, $value): bool
    {
        return filter_var($value, FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME) !== false;
    }

    /**
     * Get the validation error message.
     */
    public function message(): string
    {
        return '域名格式不正确。';
    }
}