spring-boot - Spring Cloud 网关在过滤器中发送响应

Question

我正在使用 Spring Cloud Gateway 作为边缘服务器。
这是流量

如果请求有一个名为“x-foo”的 header ，则找到 header 值，从另一个服务器获取一个字符串并将该字符串作为响应发送，而不是实际代理请求。

这是过滤器 DSL 的代码

@Bean
    public RouteLocator routes(RouteLocatorBuilder builder) {
        return builder.routes()
                .route("foo-filter", r -> r.header('x-foo').and().header("x-intercepted").negate()
                        .filters(f -> f.filter(fooFilter))
                        .uri("http://localhost:8081")) // 8081 is self port, there are other proxy related configurations too
                .build();
    }

Foo 过滤器的代码

@Component
@Slf4j
public class FooFilter implements GatewayFilter {

    @Autowired
    private ReactiveRedisOperations<String, String> redisOps;

    @Value("${header-name}")
    private String headerName;

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        var foo = request.getHeaders().getFirst(headerName);

        return redisOps.opsForHash()
                .get("foo:" + foo, "response")
                .doOnSuccess(s -> {
                    log.info("data on success");
                    log.info(s.toString()); // I am getting proper response here
                    if (s != null) {
                        ServerHttpResponse response = exchange.getResponse();
                        response.setStatusCode(HttpStatus.OK);
                        response.getHeaders().set("x-intercepted", "true");

                        byte[] bytes = s.toString().getBytes(StandardCharsets.UTF_8);

                        DataBuffer buffer = response.bufferFactory().wrap(bytes);

                        response.writeWith(Mono.just(buffer));

                        response.setComplete();
                    }
                })
                .then(chain.filter(exchange));
    }

}

问题是，响应得到了正确的 200 代码，注入(inject)的 header 出现在响应中，但响应中的数据不可用。

Answer 1

这就是我开始工作的方式。

使用flatMap而不是 doOnSuccess

不要使用 then或 switchIfEmpty改为使用 onErrorResume

返回response.writeWith

    @Component
    @Slf4j
    public class FooFilter implements GatewayFilter {
    
        @Autowired
        private ReactiveRedisOperations<String, String> redisOps;
    
        @Value("${header-name}")
        private String headerName;
    
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            ServerHttpRequest request = exchange.getRequest();
            var foo = request.getHeaders().getFirst(headerName);
    
            return redisOps.opsForHash()
                    .get("foo:" + foo, "response")
                    .flatMap(s -> {
                        log.info("data on success");
                        log.info(s.toString()); // I am getting proper response here
                        if (s != null) {
                            ServerHttpResponse response = exchange.getResponse();
                            response.setStatusCode(HttpStatus.OK);
                            response.getHeaders().set("x-intercepted", "true");
    
                            byte[] bytes = s.toString().getBytes(StandardCharsets.UTF_8);
    
                            DataBuffer buffer = response.bufferFactory().wrap(bytes);
    
                            return response.writeWith(Mono.just(buffer));
   
                        }else{ return chain.filter(exchange).then(Mono.fromRunnable(() -> {log.info("It was empty")} }
                    })
                    .onErrorResume(chain.filter(exchange));
        }
    }