PayPal\Auth\Oauth\OAuthRequest::get_signable_parameters PHP Method

    public function get_signable_parameters()
    {
        // Grab all parameters
        $params = $this->parameters;
        ksort($params);
        // Remove oauth_signature if present
        // Ref: Spec: 9.1.1 ("The oauth_signature parameter MUST be excluded.")
        if (isset($params['oauth_signature'])) {
            unset($params['oauth_signature']);
        }
        foreach ($params as $key => $value) {
            $res[] = $key . "=" . $value;
        }
        return implode('&', $res);
        //return OAuthUtil::build_http_query($params);
    }