octobercms/october · error · October\Rain\Exception\ValidationException

Please specify a valid hostname

Error message

Please specify a valid hostname

What it means

Error "Please specify a valid hostname" thrown in octobercms/october.

Source

Thrown at modules/system/models/SiteDefinition.php:137

        $site->syncOriginal();
        return $site;
    }

    /**
     * beforeValidate
     */
    public function beforeValidate()
    {
        if ($this->is_custom_url && !Url::isValidUrl($this->app_url)) {
            throw new ValidationException(['app_url' => __("Please specify a valid URL")]);
        }

        if ($this->is_prefixed && (substr($this->route_prefix, 0, 1) !== '/' || $this->route_prefix === '/')) {
            throw new ValidationException(['route_prefix' => __("Route prefix must start with a forward slash (/)")]);
        }

        if ($this->is_host_restricted && !$this->isAllowHostsValid()) {
            throw new ValidationException(['allow_hosts' => __("Please specify a valid hostname")]);
        }

        $this->fallback_locale = $this->getFallbackLocale($this->locale);
    }

    /**
     * getFallbackLocale attempts to extract the fallback language from the locale.
     * @return string
     */
    protected function getFallbackLocale($locale)
    {
        if ($position = strpos($locale, '-')) {
            $target = substr($locale, 0, $position);
            $available = $this->getLocaleOptions();
            if (isset($available[$target])) {
                return $target;
            }
        }

View on GitHub (pinned to b608633a7e)

When it happens

Trigger: Thrown at modules/system/models/SiteDefinition.php:137 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/a0264e4674b5aad2. Report an issue: GitHub.