cURL PHP 7 Object Oriented

<?php
function getStr($string,$start,$end)
{
        $str = explode($start,$string);
        $str = explode($end,$str[1]);
        return $str[0];
}

class cURL
{
	var $callback = false;
    private function setCallback($func_name)
    {
        $this->callback = $func_name;
    }

	public function doRequest($method, $url)
	{
		global $email, $senha;

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_HEADER, FALSE);
        curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($ch, CURLOPT_ENCODING, 'gzip');
        curl_setopt($ch, CURLOPT_COOKIESESSION, TRUE);
        curl_setopt($ch, CURLOPT_COOKIEJAR, getcwd().'/cookie.txt');
        curl_setopt($ch, CURLOPT_COOKIEFILE, getcwd().'/cookie.txt');
        curl_setopt($ch, CURLOPT_REFERER, '');
        curl_setopt($ch, CURLOPT_VERBOSE, TRUE);
        if ($method == 'POST')
        {
        	curl_setopt($ch, CURLOPT_POST, 1);
        	curl_setopt($ch, CURLOPT_POSTFIELDS, "username=".$email."&password=".$senha."&recaptchaResponse=FALSE");
        }
        $data = curl_exec($ch);
        curl_close($ch);

        if ($data)
        {
            if ($this->callback)
            {
                $callback = $this->callback;
                $this->callback = false;
                return call_user_func($callback, $data);
            }
            else
            {
                return $data;
            }
        }
        else
        {
            return curl_error($ch);
        }
    }

    public function get($url)
    {
        return $this->doRequest('GET', $url, 'NULL');
    }

    public function post($url)
    {
        return $this->doRequest('POST', $url);
    }
}

$email = "rochtiecode@hotmail.com";
$senha = "Rochtie11@";

$cURL = new cURL();
echo $cURL->post('https://www.netshoes.com.br/login');