CacheBodyGatewayFilter.java

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

/**
 * 全局缓存body
 *
 * @author Gsealy
 * @date 2018/11/22 13:42
 */
@Component
public class CacheBodyGatewayFilter implements Ordered, GlobalFilter {

  private static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";

  @Override
  public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
    return DataBufferUtils.join(exchange.getRequest().getBody())
        .flatMap(dataBuffer -> {
          DataBufferUtils.retain(dataBuffer);
          Flux<DataBuffer> cachedFlux = Flux
              .defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));
          ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(exchange.getRequest()) {
            @Override
            public Flux<DataBuffer> getBody() {
              return cachedFlux;
            }

          };
          exchange.getAttributes().put(CACHE_REQUEST_BODY_OBJECT_KEY, cachedFlux);

          return chain.filter(exchange.mutate().request(mutatedRequest).build());
        });
  }

  /**
   * 缓存为最高优先级
   * <p>
   * 1
   *
   * @return
   */
  @Override
  public int getOrder() {
    return Ordered.HIGHEST_PRECEDENCE;
  }
}