std::string AdfsCredentialsProvider::GetSAMLAssertion()

in src/authentication/adfs/adfs.cc [30:80]
42 lines of code
7 McCabe index (conditional complexity)

std::string AdfsCredentialsProvider::GetSAMLAssertion(std::string& err_info) {
    std::string url = get_signin_url();
    LOG(INFO) << "Got ADFS URL: " << url;

    std::shared_ptr<Aws::Http::HttpRequest> req = Aws::Http::CreateHttpRequest(url, Aws::Http::HttpMethod::HTTP_GET, Aws::Utils::Stream::DefaultResponseStreamFactoryMethod);
    std::shared_ptr<Aws::Http::HttpResponse> response = http_client->MakeRequest(req);

    std::string retval;
    // check response code
    if (response->GetResponseCode() != Aws::Http::HttpResponseCode::OK) {
        LOG(WARNING) << "ADFS request returned bad HTTP response code: " << response->GetResponseCode();
        err_info = "Adfs signOnPageRequest failed.";
        if (response->HasClientError()) {
            err_info += "Client error: '" + response->GetClientErrorMessage() + "'.";
        }
        return retval;
    }

    std::istreambuf_iterator<char> eos;
    std::string body(std::istreambuf_iterator<char>(response->GetResponseBody().rdbuf()), eos);
    DLOG(INFO) << "Signout response body: " << body;

    // retrieve SAMLResponse value
    std::smatch matches;
    std::string action;
    if (std::regex_search(body, matches, std::regex(FORM_ACTION_PATTERN))) {
        action = HtmlUtil::EscapeHtmlEntity(matches.str(1));
    } else {
        err_info = "Could not extract action from the response body";
        return retval;
    }

    if (!action.empty() && action[0]=='/') {
        url = "https://";
        url += std::string(cfg.idp_endpoint);
        url += ":";
        url += std::string(cfg.idp_port);
        url += action;
    }
    DLOG(INFO) << "Updated URL [" << url << "] using Action [" << action << "]";

    std::map<std::string, std::string> params = get_para_from_html_body(body);
    std::string content = get_form_action_body(url, params);

    if (std::regex_search(content, matches, std::regex(SAML_RESPONSE_PATTERN))) {
        DLOG(INFO) << "SAML Response: " << matches.str(1);
        return matches.str(1);
    }
    LOG(WARNING) << "Failed SAML Asesertion";
    return retval;
}