protected void insertStrictTransportSecurityHeader(final HttpServletResponse httpServletResponse,
                                                       final HttpServletRequest httpServletRequest,
                                                       final String strictTransportSecurityHeader) {
        if (httpServletRequest.isSecure()) {
            val uri = httpServletRequest.getRequestURI();

            httpServletResponse.addHeader("Strict-Transport-Security", strictTransportSecurityHeader);
            LOGGER.trace("Adding HSTS response headers for [{}]", uri);
        }
    }
Insert content security policy header.

@param httpServletResponse the http servlet response
@param httpServletRequest  the http servlet request
core/cas-server-core-web-api/src/main/java/org/apereo/cas/web/support/filters/ResponseHeadersEnforcementFilter.java