spring cloud gateway 修改responseBody全局过滤器

Posted 2020-12-05 soft.push("zzq")

public class ResponseBodyModifyGlobalFilter implements GlobalFilter, Ordered {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return chain.filter(exchange.mutate().response(decorate(exchange)).build());
    }

    ServerHttpResponse decorate(ServerWebExchange exchange) {
        return new ServerHttpResponseDecorator(exchange.getResponse()) {

            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {

                Class inClass = String.class;
                Class outClass = String.class;

                String originalResponseContentType = exchange.getAttribute(ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR);
                HttpHeaders httpHeaders = new HttpHeaders();

                httpHeaders.add(HttpHeaders.CONTENT_TYPE, originalResponseContentType);

                ClientResponse clientResponse = ClientResponse
                        .create(exchange.getResponse().getStatusCode())
                        .headers(headers -> headers.putAll(httpHeaders))
                        .body(Flux.from(body)).build();

                Mono modifiedBody = clientResponse.bodyToMono(inClass)
                        .flatMap(originalBody -> {
                            //TODO:此次可以对返回的body进行操作
                            System.out.println(originalBody + "123");
                            return Mono.just(originalBody + "123");
                        });

                BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody,
                        outClass);
                CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(
                        exchange, exchange.getResponse().getHeaders());
                return bodyInserter.insert(outputMessage, new BodyInserterContext())
                        .then(Mono.defer(() -> {
                            Flux<DataBuffer> messageBody = outputMessage.getBody();
                            HttpHeaders headers = getDelegate().getHeaders();
                            if (!headers.containsKey(HttpHeaders.TRANSFER_ENCODING)) {
                                messageBody = messageBody.doOnNext(data -> headers
                                        .setContentLength(data.readableByteCount()));
                            }
                            return getDelegate().writeWith(messageBody);
                        }));
            }

            @Override
            public Mono<Void> writeAndFlushWith(
                    Publisher<? extends Publisher<? extends DataBuffer>> body) {
                return writeWith(Flux.from(body).flatMapSequential(p -> p));
            }
        };
    }

    @Override
    public int getOrder() {
        return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER - 10;
    }
}