修改requestBody与responseBody

今天遇到个需求，业务系统(简称ABC)需要对requestBody加密与responseBody解密。网关实现如下
## 1.获取requestBody
```
    @Override
    protected Mono<Void> doExecute(ServerWebExchange exchange, ShenyuPluginChain chain, SelectorData selectorData, RuleData ruleData) {

List<HttpMessageReader<?>> MESSAGE_READERS = HandlerStrategies.builder().build().messageReaders();
        ServerRequest serverRequest = ServerRequest.create(exchange, MESSAGE_READERS);
        Mono<String> mono = serverRequest.bodyToMono(String.class).switchIfEmpty(Mono.defer(() -> Mono.just(""))).flatMap(originalBody -> {
            LOGGER.info("get body data success data:{}", originalBody);
            //process entity
            String modify = "lxl";
            return Mono.just(modify);
        });
    }
```
## 2.获取responseBody
```
    @Override
    protected Mono<Void> doExecute(ServerWebExchange exchange, ShenyuPluginChain chain, SelectorData selectorData, RuleData ruleData) {
        ShenyuContext shenyuContext = (ShenyuContext)exchange.getAttribute("context");
        assert shenyuContext != null;
        BankResponseSelectorHandle selectorDataHandle = BankResponsePluginSelectorDataHandler.CACHED_HANDLE.get().obtainHandle(CacheKeyUtils.INST.getKey(selectorData));
        return chain.execute(exchange.mutate().response(new ModifyResponseDecorator(exchange, selectorDataHandle)).build());
    }
	
	......
	......
	......
	
    static class ModifyResponseDecorator extends ServerHttpResponseDecorator {
        private final ServerWebExchange exchange;
        private final BankResponseSelectorHandle selectorHandle;

ModifyResponseDecorator(ServerWebExchange exchange, BankResponseSelectorHandle selectorHandle) {
            super(exchange.getResponse());
            this.exchange = exchange;
            this.selectorHandle = selectorHandle;
        }

@NonNull
        public Mono<Void> writeWith(@NonNull Publisher<? extends DataBuffer> body) {
            ClientResponse clientResponse = this.buildModifiedResponse(body);
            Mono<byte[]> modifiedBody = clientResponse.bodyToMono(byte[].class).flatMap((originalBody) -> {
                return Mono.just(this.modifyBody(originalBody));
            });
            return ResponseUtils.writeWith(clientResponse, this.exchange, modifiedBody, byte[].class);
        }

private ClientResponse buildModifiedResponse(Publisher<? extends DataBuffer> body) {
            HttpHeaders httpHeaders = new HttpHeaders();
            httpHeaders.addAll(this.getHeaders());

ClientResponse clientResponse = ResponseUtils.buildClientResponse(this.getDelegate(), body);
            HttpStatus statusCode = clientResponse.statusCode();
            this.getDelegate().getHeaders().clear();
            this.getDelegate().getHeaders().putAll(httpHeaders);
            int rowStatusCode = clientResponse.rawStatusCode();
            ExchangeStrategies strategies = clientResponse.strategies();
            return ClientResponse.create(statusCode, strategies).rawStatusCode(rowStatusCode).headers((headers) -> {
                headers.addAll(httpHeaders);
            }).cookies((cookies) -> {
                cookies.addAll(this.getCookies());
            }).body(Flux.from(body)).build();
        }

private byte[] modifyBody(byte[] responseBody) {
            try {
                String bodyStr = this.modifyBody(new String(responseBody, StandardCharsets.UTF_8));
                bodyStr = modifyResponseBody(bodyStr);
                LOGGER.info("the body string {}", bodyStr);
                return bodyStr.getBytes(StandardCharsets.UTF_8);
            } catch (Exception var3) {
                LOGGER.error("modify response error", var3);
                throw new ShenyuException(String.format("response modify failure. %s", var3.getLocalizedMessage()));
            }
        }

private String modifyBody(String jsonValue) {
            DocumentContext context = JsonPath.parse(jsonValue);
            return context.jsonString();
        }

private String modifyResponseBody(String responseBody) {
            JSONObject joEnc = JSONObject.parseObject(responseBody);
            String recv = joEnc.getString("data");
            try {
                recv = RC4Util.decryRC4String( recv, this.selectorHandle.getRc4Key(), "UTF-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            JSONObject jo = JSONObject.parseObject(recv);
            boolean signState = MD5SignUtil.checkSign(this.selectorHandle.getMd5Key(), jo);
            if (signState){
                LOGGER.info("回报验签: {}", signState);
            }else {
                throw new ShenyuException("回报验签验证失败！");
            }
            return recv;
        }
    }
```