Spring Cloud Gateway 之 请求应答日志打印

请求应答日志时在日常开发调试问题的重要手段之一，那么如何基于Spring Cloud Gateway做呢，请看我上代码。

第一步：

创建RecorderServerHttpRequestDecorator，缓存请求参数，解决body只能读一次问题。

public class RecorderServerHttpRequestDecorator extends ServerHttpRequestDecorator {

    private final List<DataBuffer> dataBuffers = new ArrayList<>();

    public RecorderServerHttpRequestDecorator(ServerHttpRequest delegate) {
        super(delegate);
        super.getBody().map(dataBuffer -> {
            dataBuffers.add(dataBuffer);
            return dataBuffer;
        }).subscribe();
    }

    @Override
    public Flux<DataBuffer> getBody() {
        return copy();
    }

    private Flux<DataBuffer> copy() {
        return Flux.fromIterable(dataBuffers)
                .map(buf -> buf.factory().wrap(buf.asByteBuffer()));
    }


}

第二步:

创建访问日志全局过滤器,然后在此过滤器进行日志构造。

@Slf4j
public class AccessLogGlobalFilter implements GlobalFilter , Ordered {

    private static final String REQUEST_PREFIX = "Request Info [ ";

    private static final String REQUEST_TAIL = " ]";

    private static final String RESPONSE_PREFIX = "Response Info [ ";

    private static final String RESPONSE_TAIL = " ]";

    private StringBuilder normalMsg = new StringBuilder();

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        RecorderServerHttpRequestDecorator requestDecorator = new RecorderServerHttpRequestDecorator(request);
        InetSocketAddress address = requestDecorator.getRemoteAddress();
        HttpMethod method = requestDecorator.getMethod();
        URI url = requestDecorator.getURI();
        HttpHeaders headers = requestDecorator.getHeaders();
        Flux<DataBuffer> body = requestDecorator.getBody();
        //读取requestBody传参
        AtomicReference<String> requestBody = new AtomicReference<>("");
        body.subscribe(buffer -> {
            CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
            requestBody.set(charBuffer.toString());
        });
        String requestParams = requestBody.get();
        normalMsg.append(REQUEST_PREFIX);
        normalMsg.append(";header=").append(headers);
        normalMsg.append(";params=").append(requestParams);
        normalMsg.append(";address=").append(address.getHostName() + address.getPort());
        normalMsg.append(";method=").append(method.name());
        normalMsg.append(";url=").append(url.getPath());
        normalMsg.append(REQUEST_TAIL);

        ServerHttpResponse response = exchange.getResponse();

        DataBufferFactory bufferFactory = response.bufferFactory();
        normalMsg.append(RESPONSE_PREFIX);
        ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(response) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(fluxBody.map(dataBuffer -> {
                        // probably should reuse buffers
                        byte[] content = new byte[dataBuffer.readableByteCount()];
                        dataBuffer.read(content);
                        String responseResult = new String(content, Charset.forName("UTF-8"));
                        normalMsg.append("status=").append(this.getStatusCode());
                        normalMsg.append(";header=").append(this.getHeaders());
                        normalMsg.append(";responseResult=").append(responseResult);
                        normalMsg.append(RESPONSE_TAIL);
                        log.info(normalMsg.toString());
                        return bufferFactory.wrap(content);
                    }));
                }
                return super.writeWith(body); // if body is not a flux. never got there.
            }
        };

        return chain.filter(exchange.mutate().request(requestDecorator).response(decoratedResponse).build());
    }

    @Override
    public int getOrder() {
        return -2;
    }

}

最后结果：

Request Info [ ;header={cache-control=[no-cache], Postman-Token=[790488a5-a284-4a0e-968f-1b588cb26688], Content-Type=[application/json], User-Agent=[PostmanRuntime/3.0.9], Accept=[*/*], Host=[localhost:8084], cookie=[JSESSIONID=E161AC22204E626FBE6E96EE7B62EE70], accept-encoding=[gzip, deflate], content-length=[13], Connection=[keep-alive]};params={"name":"ss"};address=0:0:0:0:0:0:0:159621;method=POST;url=/account/testBody ]Response Info [ ;status=200;header={Content-Type=[text/plain;charset=UTF-8], Content-Length=[41], Date=[Mon, 18 Mar 2019 08:21:57 GMT]};responseResult=account hellowordAccountEntity{name='ss'} ]

基于以上代码即可完成请求应答日志打印功能。