cognito code to token 1

public function exchangeAuthorizationCodeForToken($code)
    {
        $token_url = $this->domain_url ."/oauth2/token";
        $params = array(
            'grant_type' => 'authorization_code',
            'client_id' => $this->client_id,
            'code' => $code,
            'redirect_uri' => $this->redirect_uri,
        );
        $headers = [];
        $headers[] = 'Content-Type: application/x-www-form-urlencoded';
        $headers[] = 'Authorization: Basic ' . base64_encode($this->client_id . ':' . Yii::$app->params['aws']['client_secret']);

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $token_url);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params));
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $response = curl_exec($ch);
        curl_close($ch);
        return json_decode($response, true);
    }