gateway的ServerHttpResponseDecorator后不起作用?

Question

@Component
public class CypherFilter implements GlobalFilter, Ordered {

    private int order = 10;

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {

        System.out.println("====================================");
        ServerHttpResponse originalResponse = exchange.getResponse();
        ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                System.out.println("++++++++++++++++++++=");
                this.getHeaders().add("aaaaa", "xxxxx");
                return super.writeWith(body);
            }
        };
        return chain.filter(exchange.mutate().response(decoratedResponse).build());
    }

    @Override
    public int getOrder() {
        return this.order;
    }
}

基于网关gateway，想做个需求，拿到后端返回的值，进行修改然后返回给客户端。比如后端返回aaaa，拿到aaa然后进行加密返回给浏览器。做了个demo，写了这样的一个过滤器想做实验，但是writeWith方法却无法执行。

也就是 System.out.println("====================================");能打印。而

System.out.println("++++++++++++++++++++="); 却没执行。

整个demo里就写了这个一个过滤器，而且能正常跑，能返回给浏览器，后端返回的值。但是就是进不去writeWith。

尝试在writeWith里写各种东西都不被执行。不知道原因何在？

Answer 1

// 加一个这个呢
    @Override
    public int getOrder() {
        // -1 is response write filter, must be called before that
        return -2;
    }