@PostMapping("/plugin/rule/saveOrUpdate")
    public Mono<String> saveRule(@RequestBody final RuleData ruleData) {
        if (StringUtils.isEmpty(ruleData.getSelectorId())) {
            return Mono.just("Error: please add selectorId!");
        }
        subscriber.onRuleSubscribe(buildDefaultRuleData(ruleData));
        return Mono.just(ruleData.getId());
    }
Save rule mono.

@param ruleData the rule data
@return the mono
shenyu-web/src/main/java/org/apache/shenyu/web/controller/LocalPluginController.java