/**
     * Deletes documents matching the specified search parameters.
     *
     * @param request The HTTP servlet request
     * @param params The search request parameters to identify documents to delete
     * @return Number of documents deleted
     */
    public long deleteByQuery(final HttpServletRequest request, final SearchRequestParams params) {

                        return processCallback(request, code);
                    }
                }
            }

            return new ActionResponseCredential(() -> HtmlResponse.fromRedirectPathAsIs(getAuthUrl(request)));
        }).orElse(null);
    }

    /**
     * Gets the authorization URL for OpenID Connect.
     *
     * @param request the HTTP servlet request
     * @return the authorization URL
     */

        }).orElse(null);
    }

    /**
     * Creates a login credential.
     * @param request The HTTP request.
     * @param response The HTTP response.
     * @param auth The SAML authentication.
     * @return The login credential.
     */
    protected LoginCredential createLoginCredential(final HttpServletRequest request, final HttpServletResponse response, final Auth auth) {

     *
     * @return The username, or "guest" if not logged in.
     */
    public String getUsername() {
        return getRequestManager().findUserBean(FessUserBean.class).map(FessUserBean::getUserId).orElse(Constants.GUEST_USER);
    }

    /**
     * Gets the request manager.
     *
     * @return The request manager.
     */
    protected RequestManager getRequestManager() {