限制基于 CXF JAX-RS 的服务中的输出有效负载响应

Question

我有多个使用cxf/spring构建的jax-rs服务。我想控制所有服务的输出负载响应大小。为了简单起见，假设任何服务中的api都不应该返回超过500个字符的JSON响应有效负载，我希望在一个地方控制这一点，而不是依赖单个服务来遵守这一要求。(我们已经在所有服务所依赖的定制框架/基础组件中内置了其他功能)。

我已经尝试使用JAX-RS的< code>WriterInterceptor 、< code > ContainerResponseFilter 和CXF的< code>Phase Interceptor来实现这一点，但是这些方法似乎都不能完全满足我的要求。更多关于我目前所做的细节:

选项 1：（WriterInteceptor）在重写的方法中，我获取输出流并将缓存的最大大小设置为 500。当我调用在响应负载中返回超过 500 个字符的 api 时，我得到一个 HTTP 400 错误请求状态，但响应正文包含整个 JSON 有效负载。

@Provider
public class ResponsePayloadInterceptor implements WriterInterceptor {
    private static final Logger LOGGER = LoggerFactory.getLogger(ResponsePayloadInterceptor.class);

    @Override
    public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {
        final OutputStream outputStream = context.getOutputStream();

        CacheAndWriteOutputStream cacheAndWriteOutputStream = new CacheAndWriteOutputStream(outputStream);
        cacheAndWriteOutputStream.setMaxSize(500);
        context.setOutputStream(cacheAndWriteOutputStream);

        context.proceed();
    }
}

选项2a：（CXF相位Inteceptor）在覆盖的方法中，我从ouputstream中获取作为String的响应并检查它的大小，如果大于500，我创建一个新的响应对象，其中只有数据太多的数据并在消息中设置它。即使响应是

@Provider
public class ResponsePayloadInterceptor extends AbstractPhaseInterceptor<Message> {
    private static final Logger LOGGER = LoggerFactory.getLogger(ResponsePayloadInterceptor.class);

    public ResponsePayloadInterceptor() {
        super(Phase.POST_MARSHAL);
    }

    @Override
    public void handleMessage(Message message) throws Fault {
        LOGGER.info("handleMessage() - Response intercepted");
        try {
            OutputStream outputStream = message.getContent(OutputStream.class);
...
            CachedOutputStream cachedOutputStream = (CachedOutputStream) outputStream;
            String responseBody = IOUtils.toString(cachedOutputStream.getInputStream(), "UTF-8");
...
            LOGGER.info("handleMessage() - Response: {}", responseBody);
            LOGGER.info("handleMessage() - Response Length: {}", responseBody.length());
            if (responseBody.length() > 500) {
                Response response = Response.status(Response.Status.BAD_REQUEST)
                                            .entity("Too much data").build();
                message.getExchange().put(Response.class, response);
            }
        } catch (IOException e) {
            LOGGER.error("handleMessage() - Error");
            e.printStackTrace();
        }
    }
}

选项2b：（CXF相位接收器）与上述相同，但仅更改if块的内容。若响应长度大于500，我将创建一个新的输出流，其中包含字符串“太多数据”，并在消息中设置它。但是如果响应有效载荷为

        if (responseBody.length() > 500) {
            InputStream inputStream = new ByteArrayInputStream("Too much data".getBytes("UTF-8"));
            outputStream.flush();
            IOUtils.copy(inputStream, outputStream);

            OutputStream out = new CachedOutputStream();
            out.write("Too much data".getBytes("UTF-8"));
            message.setContent(OutputStream.class, out);
        }

选项 3：（ContainerResponseFilter）使用 ContainerResponseFilter，我添加了一个值为 500 的内容长度响应标头。如果响应长度为

@Provider
public class ResponsePayloadFilter implements ContainerResponseFilter {
    private static final Logger LOGGER = LoggerFactory.getLogger(ResponsePayloadFilter.class);

    @Override
    public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext) throws IOException {
        LOGGER.info("filter() - Response intercepted");
        CachedOutputStream cos = (CachedOutputStream) responseContext.getEntityStream();
        StringBuilder responsePayload = new StringBuilder();
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        if (cos.getInputStream().available() > 0) {
            IOUtils.copy(cos.getInputStream(), out);
            byte[] responseEntity = out.toByteArray();
            responsePayload.append(new String(responseEntity));
        }

        LOGGER.info("filter() - Content: {}", responsePayload.toString());
        responseContext.getHeaders().add("Content-Length", "500");
    }
}

关于如何调整上述方法以获得我想要的或任何其他不同指针的建议？

Answer 1

我使用这个答案的帮助部分解决了这个问题。我说部分原因是因为我能够成功控制有效负载，但不是响应状态代码。理想情况下，如果响应长度大于 500 并且我修改了消息内容，则我想发送不同的响应状态代码（200 OK 除外）。但是，对于我来说，这是一个足够好的解决方案，可以在这一点上继续进行。如果我弄清楚如何更新状态代码，我会回来更新这个答案。

import org.apache.commons.io.IOUtils;
import org.apache.cxf.interceptor.Fault;
import org.apache.cxf.io.CachedOutputStream;
import org.apache.cxf.message.Message;
import org.apache.cxf.phase.AbstractPhaseInterceptor;
import org.apache.cxf.phase.Phase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class ResponsePayloadInterceptor extends AbstractPhaseInterceptor<Message> {
    private static final Logger LOGGER = LoggerFactory.getLogger(ResponsePayloadInterceptor.class);

    public ResponsePayloadInterceptor() {
        super(Phase.PRE_STREAM);
    }

    @Override
    public void handleMessage(Message message) throws Fault {
        LOGGER.info("handleMessage() - Response intercepted");
        try {
            OutputStream outputStream = message.getContent(OutputStream.class);
            CachedOutputStream cachedOutputStream = new CachedOutputStream();
            message.setContent(OutputStream.class, cachedOutputStream);

            message.getInterceptorChain().doIntercept(message);

            cachedOutputStream.flush();
            cachedOutputStream.close();

            CachedOutputStream newCachedOutputStream = (CachedOutputStream) message.getContent(OutputStream.class);
            String currentResponse = IOUtils.toString(newCachedOutputStream.getInputStream(), "UTF-8");
            newCachedOutputStream.flush();
            newCachedOutputStream.close();

            if (currentResponse != null) {
                LOGGER.info("handleMessage() - Response: {}", currentResponse);
                LOGGER.info("handleMessage() - Response Length: {}", currentResponse.length());

                if (currentResponse.length() > 500) {
                    InputStream replaceInputStream = IOUtils.toInputStream("{\"message\":\"Too much data\"}", "UTF-8");

                    IOUtils.copy(replaceInputStream, outputStream);
                    replaceInputStream.close();

                    message.setContent(OutputStream.class, outputStream);
                    outputStream.flush();
                    outputStream.close();
                } else {
                    InputStream replaceInputStream = IOUtils.toInputStream(currentResponse, "UTF-8");

                    IOUtils.copy(replaceInputStream, outputStream);
                    replaceInputStream.close();

                    message.setContent(OutputStream.class, outputStream);
                    outputStream.flush();
                    outputStream.close();
                }
            }
        } catch (IOException e) {
            LOGGER.error("handleMessage() - Error", e);
            throw new RuntimeException(e);
        }
    }