src/Url.php
public static function isAbsolute($url)
    {
        $components = parse_url($url);

        return isset($components[self::SCHEME]) && isset($components[self::HOST]);
    }
public static function isAbsolute($url)
    {
        $components = parse_url($url);

        return isset($components[self::SCHEME]) && isset($components[self::HOST]);
    }
Check if url is absolute (based on scheme and host components)

@param string $url
@return bool