Spring Cloud Gateway 獲取請求體(Request Body)的多種方法

一、直接在全局攔截器中獲取,偽代碼如下

private String resolveBodyFromRequest(ServerHttpRequest serverHttpRequest){
 
  Flux<DataBuffer> body = serverHttpRequest.getBody();
 
  AtomicReference<String> bodyRef = new AtomicReference<>();
 
  body.subscribe(buffer -> {
 
   CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
 
   DataBufferUtils.release(buffer);
 
   bodyRef.set(charBuffer.toString());
 
  });
 
  return bodyRef.get();
 
 }

存在的缺陷:其他攔截器無法再通過該方式獲取請求體(因為請求體已被消費),並且會拋出異常

Only one connection receive subscriber allowed.Caused by: java.lang.IllegalStateException: Only one connection receive subscriber allowed.

異常原因:實際上spring-cloud-gateway反向代理的原理是,首先讀取原請求的數據,然後構造一個新的請求,將原請求的數據封裝到新的請求中,然後再轉發出去。然而我們在他封裝之前讀取瞭一次request body,而request body隻能讀取一次。因此就出現瞭上面的錯誤。

再者受版本限制

這種方法在spring-boot-starter-parent 2.0.6.RELEASE + Spring Cloud Finchley.SR2 body 中生效,

但是在spring-boot-starter-parent 2.1.0.RELEASE + Spring Cloud Greenwich.M3 body 中不生效,總是為空

二、先在全局過濾器中獲取,然後再把request重新包裝,繼續向下傳遞傳遞

@Override
 public GatewayFilter apply(NameValueConfig nameValueConfig) {
  return (exchange, chain) -> {
   URI uri = exchange.getRequest().getURI();
   URI ex = UriComponentsBuilder.fromUri(uri).build(true).toUri();
   ServerHttpRequest request = exchange.getRequest().mutate().uri(ex).build();
   if("POST".equalsIgnoreCase(request.getMethodValue())){//判斷是否為POST請求
    Flux<DataBuffer> body = request.getBody();
    AtomicReference<String> bodyRef = new AtomicReference<>();
    body.subscribe(dataBuffer -> {
     CharBuffer charBuffer = StandardCharsets.UTF_8.decode(dataBuffer.asByteBuffer());
     DataBufferUtils.release(dataBuffer);
     bodyRef.set(charBuffer.toString());
    });//讀取request body到緩存
    String bodyStr = bodyRef.get();//獲取request body
    System.out.println(bodyStr);//這裡是我們需要做的操作
    DataBuffer bodyDataBuffer = stringBuffer(bodyStr);
    Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);
 
    request = new ServerHttpRequestDecorator(request){
     @Override
     public Flux<DataBuffer> getBody() {
      return bodyFlux;
     }
    };//封裝我們的request
   }
   return chain.filter(exchange.mutate().request(request).build());
  };
 }
 protected DataBuffer stringBuffer(String value) {
  byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
 
  NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(ByteBufAllocator.DEFAULT);
  DataBuffer buffer = nettyDataBufferFactory.allocateBuffer(bytes.length);
  buffer.write(bytes);
  return buffer;
 }

該方案的缺陷:request body獲取不完整(因為異步原因),隻能獲取1024B的數據。並且請求體超過1024B,會出現響應超慢(因為我是開啟瞭熔斷)。

三、過濾器加路線定位器

翻查源碼發現ReadBodyPredicateFactory裡面緩存瞭request body的信息,於是在自定義router中配置瞭ReadBodyPredicateFactory,然後在filter中通過cachedRequestBodyObject緩存字段獲取request body信息。

/**
 * @description: 獲取POST請求的請求體
 * ReadBodyPredicateFactory 發現裡面緩存瞭request body的信息,
 * 於是在自定義router中配置瞭ReadBodyPredicateFactory
 * @modified:
 */
@EnableAutoConfiguration
@Configuration
public class RouteLocatorRequestBoby{
   //自定義過濾器
 @Resource
 private ReqTraceFilter reqTraceFilter;
  
 @Resource
 private RibbonLoadBalancerClient ribbonLoadBalancerClient;
 
 private static final String SERVICE = "/leap/**";
 
 private static final String HTTP_PREFIX = "http://";
 
 private static final String COLON = ":";
 
 @Bean
 public RouteLocator myRoutes(RouteLocatorBuilder builder) {
  //通過負載均衡獲取服務實例
  ServiceInstance instance = ribbonLoadBalancerClient.choose("PLATFORM-SERVICE");
  //拼接路徑
  StringBuilder forwardAddress = new StringBuilder(HTTP_PREFIX);
  forwardAddress.append(instance.getHost())
    .append(COLON)
    .append(instance.getPort());
  return builder.routes()
    //攔截請求類型為POST Content-Type application/json application/json;charset=UTF-8
    .route(r -> r
        .header(HttpHeaders.CONTENT_TYPE,
          MediaType.APPLICATION_JSON_VALUE + MediaType.APPLICATION_JSON_UTF8_VALUE)
        .and()
        .method(HttpMethod.POST)
        .and()
        //獲取緩存中的請求體
        .readBody(Object.class, readBody -> {
         return true;
        })
        .and()
        .path(SERVICE)
        //把請求體傳遞給攔截器reqTraceFilter
        .filters(f -> {
         f.filter(reqTraceFilter);
         return f;
        })
        .uri(forwardAddress.toString())).build();
 }
 
/**
 * @description: 過濾器,用於獲取請求體,和處理請求體業務,列如記錄日志
 * @modified:
 */
@Component
public class ReqTraceFilter implements GlobalFilter, GatewayFilter,Ordered {
 
 private static final String CONTENT_TYPE = "Content-Type";
 
 private static final String CONTENT_TYPE_JSON = "application/json";
  
 //獲取請求路由詳細信息Route route = exchange.getAttribute(GATEWAY_ROUTE_BEAN)
 private static final String GATEWAY_ROUTE_BEAN = "org.springframework.cloud.gateway.support.ServerWebExchangeUtils.gatewayRoute";
 
 private static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";
 @Override
 public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
  ServerHttpRequest request = exchange.getRequest();
  //判斷過濾器是否執行
  String requestUrl = RequestUtils.getCurrentRequest(request);
  if (!RequestUtils.isFilter(requestUrl)) {
   String bodyStr = "";
   String contentType = request.getHeaders().getFirst(CONTENT_TYPE);
   String method = request.getMethodValue();
   //判斷是否為POST請求
   if (null != contentType && HttpMethod.POST.name().equalsIgnoreCase(method) && contentType.contains(CONTENT_TYPE_JSON)) {
    Object cachedBody = exchange.getAttribute(CACHE_REQUEST_BODY_OBJECT_KEY);
    if(null != cachedBody){
     bodyStr = cachedBody.toString();
    }
   }
   if (HttpMethod.GET.name().equalsIgnoreCase(method)) {
    bodyStr = request.getQueryParams().toString();
   }
   
   log.info("請求體內容:{}",bodyStr);
  }
  return chain.filter(exchange);
 }
 
 
 @Override
 public int getOrder() {
  return 5;
 }
}

該方案優點:這種解決,一不會帶來重復讀取問題,二不會帶來requestbody取不全問題。三在低版本的Spring Cloud Finchley.SR2也可以運行。

缺點:不支持multipart/form-data(異常415),這個致命。

四、通過org.springframework.cloud.gateway.filter.factory.rewrite包下有個ModifyRequestBodyGatewayFilterFactory,顧名思義,這就是修改 Request Body 的過濾器工廠類。

@Component
@Slf4j
public class ReqTraceFilter implements GlobalFilter, GatewayFilter, Ordered {
 
 @Resource
 private IPlatformFeignClient platformFeignClient;
 
 /**
  * httpheader,traceId的key名稱
  */
 private static final String REQUESTID = "traceId";
 
 private static final String CONTENT_TYPE = "Content-Type";
 
 private static final String CONTENT_TYPE_JSON = "application/json";
 
 private static final String GATEWAY_ROUTE_BEAN = "org.springframework.cloud.gateway.support.ServerWebExchangeUtils.gatewayRoute";
  
 
 @Override
 public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
  ServerHttpRequest request = exchange.getRequest();
  //判斷過濾器是否執行
  String requestUrl = RequestUtils.getCurrentRequest(request);
  if (!RequestUtils.isFilter(requestUrl)) {
   String bodyStr = "";
   String contentType = request.getHeaders().getFirst(CONTENT_TYPE);
   String method = request.getMethodValue();
   //判斷是否為POST請求
   if (null != contentType && HttpMethod.POST.name().equalsIgnoreCase(method) && contentType.contains(CONTENT_TYPE_JSON)) {
    ServerRequest serverRequest = new DefaultServerRequest(exchange);
    List<String> list = new ArrayList<>();
    // 讀取請求體
    Mono<String> modifiedBody = serverRequest.bodyToMono(String.class)
      .flatMap(body -> {
       //記錄請求體日志
       final String nId = saveRequestOperLog(exchange, body);
       //記錄日志id
       list.add(nId);
       return Mono.just(body);
      });
 
    BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody, String.class);
    HttpHeaders headers = new HttpHeaders();
    headers.putAll(exchange.getRequest().getHeaders());
    headers.remove(HttpHeaders.CONTENT_LENGTH);
 
    CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, headers);
    return bodyInserter.insert(outputMessage, new BodyInserterContext())
      .then(Mono.defer(() -> {
       ServerHttpRequestDecorator decorator = new ServerHttpRequestDecorator(
         exchange.getRequest()) {
        @Override
        public HttpHeaders getHeaders() {
         long contentLength = headers.getContentLength();
         HttpHeaders httpHeaders = new HttpHeaders();
         httpHeaders.putAll(super.getHeaders());
         httpHeaders.put(REQUESTID,list);
         if (contentLength > 0) {
          httpHeaders.setContentLength(contentLength);
         } else {
          httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
         }
         return httpHeaders;
        }
 
        @Override
        public Flux<DataBuffer> getBody() {
         return outputMessage.getBody();
        }
       };
 
       return chain.filter(exchange.mutate().request(decorator).build());
      }));
   }
   if (HttpMethod.GET.name().equalsIgnoreCase(method)) {
    bodyStr = request.getQueryParams().toString();
    String nId = saveRequestOperLog(exchange, bodyStr);
    ServerHttpRequest userInfo = exchange.getRequest().mutate()
      .header(REQUESTID, nId).build();
    return chain.filter(exchange.mutate().request(userInfo).build());
   }
 
  }
  return chain.filter(exchange);
 }
 
 
 /**
  * 保存請求日志
  *
  * @param exchange
  * @param requestParameters
  * @return
  */
 private String saveRequestOperLog(ServerWebExchange exchange, String requestParameters) {
  log.debug("接口請求參數:{}", requestParameters);
  ServerHttpRequest request = exchange.getRequest();
  String ip = Objects.requireNonNull(request.getRemoteAddress()).getAddress().getHostAddress();
  SaveOperLogVO vo = new SaveOperLogVO();
  vo.setIp(ip);
  vo.setReqUrl(RequestUtils.getCurrentRequest(request));
  vo.setReqMethod(request.getMethodValue());
  vo.setRequestParameters(requestParameters);
 
  Route route = exchange.getAttribute(GATEWAY_ROUTE_BEAN);
  //是否配置路由
  if (route != null) {
   vo.setSubsystem(route.getId());
  }
  ResEntity<String> res = platformFeignClient.saveOperLog(vo);
  log.debug("當前請求ID返回的數據:{}", res);
  return res.getData();
 }
 
 @Override
 public int getOrder() {
  return 5;
 }
}

該方案:完美解決以上所有問題

參考文檔:https://www.codercto.com/a/52970.html

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