public static String getSrcUserName(HttpServletRequest request) {
        IdentityContext identityContext = RequestContextHolder.getContext().getAuthContext().getIdentityContext();
        String result = StringUtils.EMPTY;
        if (null != identityContext) {
            result = (String) identityContext.getParameter(
                    com.alibaba.nacos.plugin.auth.constant.Constants.Identity.IDENTITY_ID);
        }
        // If auth is disabled, get username from parameters by agreed key
        return StringUtils.isBlank(result) ? request.getParameter(Constants.USERNAME) : result;
    }
@Test
    void testGetSrcUserNameFromRequest() {
        HttpServletRequest request = Mockito.mock(HttpServletRequest.class);
        Mockito.when(request.getParameter(eq(Constants.USERNAME))).thenReturn("parameterName");
        assertEquals("parameterName", RequestUtil.getSrcUserName(request));
    }