java - 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。目标是向客户端隐藏遗留 API。

我的想法是:客户端将带有对象 A 的 JSON 表示的 POST 请求发送到嵌入了 Zuul 的 API 网关。 API 网关将正文从 A 转换为 LegacyA，并将其发送到内部服务。

例如，我搜索了一种转换以下JSON的方法:

["hello","world"]

在这个 JSON 中:

{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")));

对于完整的类:

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