如何使用 zuul 过滤器转换客户端请求主体？

Question

我想使用 Zuul 来验证、转换和转发来自客户端的请求到内部服务。目标是向客户隐藏遗留 API.

我的想法是：客户端向嵌入 Zuul 的 API 网关发送一个带有对象 A 的 JSON 表示的 POST 请求。 API 网关将正文从 A 转换为 LegacyA，并将其发送到内部服务。

例如，我搜索了一种方法来转换如下JSON：

["hello","world"]

在此JSON:

{hashCode("hello"):"hello", hashCode("world"):"world")}

我想使用前置过滤器。但是我在重写有效请求时遇到问题。

你知道我该怎么做吗？

我写了这个过滤器：

public class RestZuulFilter extends ZuulFilter {

    private final ObjectMapper objectMapper;

    @Autowired
    public RestZuulFilter(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }

    @Override
    public String filterType() {
        return "pre";
    }

    @Override
    public int filterOrder() {
        return 100;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() {
        RequestContext ctx = RequestContext.getCurrentContext();

        HttpServletRequestWrapper wrapper = new MyWrapper(ctx.getRequest());
        ctx.setRequest(wrapper);

        return null;
    }

    class MyWrapper extends HttpServletRequestWrapper {

        /**
         * Constructs a request object wrapping the given request.
         *
         * @param request The request to wrap
         * @throws IllegalArgumentException if the request is null
         */
        public MyWrapper(HttpServletRequest request) {
            super(request);
        }

        @Override
        public ServletInputStream getInputStream() throws IOException {
            ServletInputStream inputStream = this.getRequest().getInputStream();

            List<String> test = objectMapper.readValue(inputStream, new TypeReference<List<String>>() {
            });
            Map<Integer, String> result = test.stream()
                    .collect(Collectors.toMap(String::hashCode, str -> str));

            byte[] json = objectMapper.writeValueAsBytes(result);
            ServletInputStream response = new ServletInputStreamWrapper(json);

            return response;
        }
    }
}

我遇到的问题是 Content-Length 没有相应更新。

Answer 1

查看以下正在转换的请求正文示例。我想这应该适合你。

    InputStream in = (InputStream) context.get("requestEntity");
    if (in == null) {
        in = context.getRequest().getInputStream();
    }
    String body = StreamUtils.copyToString(in, Charset.forName("UTF-8"));
    body = body.toUpperCase();
    context.set("requestEntity", new ByteArrayInputStream(body.getBytes("UTF-8")));

完整的class:

https://github.com/spring-cloud-samples/sample-zuul-filters/blob/master/src/main/java/org/springframework/cloud/samplezuulfilters/UppercaseRequestEntityFilter.java

Answer 2

最快的方法是在过滤器中使用 HttpServletRequestWrapper 类

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.http.ServletInputStreamWrapper;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.IOException;
import static com.netflix.zuul.context.RequestContext.getCurrentContext;

public class ModifyBodyFilter extends ZuulFilter {

@Override
public String filterType() {
    return "pre";
}

@Override
public int filterOrder() {
    return 0;
}

@Override
public boolean shouldFilter() {
    return true;
}

@Override
public Object run() {

    RequestContext ctx = getCurrentContext();

    String newBody = "{\"key\":\"value\"}";
    byte[] bytes = newBody.getBytes();

    ctx.setRequest(new HttpServletRequestWrapper(getCurrentContext().getRequest()) {
        @Override
        public ServletInputStream getInputStream() throws IOException {
            return new ServletInputStreamWrapper(bytes);
        }

        @Override
        public int getContentLength() {
            return bytes.length;
        }

        @Override
        public long getContentLengthLong() {
            return bytes.length;
        }
    });

    return null;
}

}

如何使用 zuul 过滤器转换客户端请求主体？

How to transform client request body with a zuul filter?

java

spring

netflix-zuul