如何在Spring Cloud Data Flow中使用过滤器？

Question

我想在Spring Cloud Data Flow（SCDF）中添加一个过滤器进行调试，并在接收到一些请求时查看其工作方式。

我已经尝试实现javax.servlet.Filter并重写doFilter方法，但是它似乎不起作用，因为在我的Filter类之前已经启动了一些默认的SCDF过滤器。

有没有办法为SCDF编写过滤器？如果我为此目的应用此link，是否可以？

这是我的过滤器类：

@Component
public class CustomFilter implements Filter {


    @Override
    public void destroy() {
        System.out.println("init fillter ");
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        try {
            HttpServletRequest req = (HttpServletRequest) arg0;
            ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper(
                    (HttpServletResponse) arg1);
            ResettableStreamHttpServletRequest wrappedRequest = new ResettableStreamHttpServletRequest(
                    (HttpServletRequest) req);
            logger.info(">>>>>link: " + req.getServletPath() + "?");
            for (Entry<String, String[]> entry : req.getParameterMap().entrySet()) {
                logger.info(">>>>>param: " + entry.getKey() + ":" + entry.getValue()[0]);
            }
            String bodyRequest = IOUtils.toString(wrappedRequest.getReader());
            logger.info(">>>>>link: " + req.getServletPath() + "?");
            for (Entry<String, String[]> entry : req.getParameterMap().entrySet()) {
                logger.info(">>>>>param: " + entry.getKey() + ":" + entry.getValue()[0]);
            }

            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            transformerFactory.setAttribute("indent-number", 2);
            javax.xml.transform.Transformer transformer = transformerFactory.newTransformer();
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
            try {

                logger.info("Request: " + bodyRequest);
            } catch (Exception e) {
                logger.info("Request: " + bodyRequest);
            }

            wrappedRequest.resetInputStream();
            arg2.doFilter(wrappedRequest, responseWrapper);
            logger.info("Response: " + IOUtils.toString(responseWrapper.getContentInputStream()));

            responseWrapper.copyBodyToResponse();
        } catch (Exception ex) {
            logger.info("doFilter: " + ex);
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        System.out.println("init fillter " + arg0);
    }

    private static class ResettableStreamHttpServletRequest extends HttpServletRequestWrapper {

        private byte[] rawData;
        private HttpServletRequest request;
        private ResettableServletInputStream servletStream;

        public ResettableStreamHttpServletRequest(HttpServletRequest request) {
            super(request);
            this.request = request;
            this.servletStream = new ResettableServletInputStream();
        }

        public void resetInputStream() {
            servletStream.stream = new ByteArrayInputStream(rawData);
        }

        @Override
        public ServletInputStream getInputStream() throws IOException {
            if (rawData == null) {
                rawData = IOUtils.toByteArray(this.request.getReader());
                servletStream.stream = new ByteArrayInputStream(rawData);
            }
            return servletStream;
        }

        @Override
        public BufferedReader getReader() throws IOException {
            if (rawData == null) {
                rawData = IOUtils.toByteArray(this.request.getReader());
                servletStream.stream = new ByteArrayInputStream(rawData);
            }
            return new BufferedReader(new InputStreamReader(servletStream));
        }

        private class ResettableServletInputStream extends ServletInputStream {

            private InputStream stream;

            @Override
            public int read() throws IOException {
                return stream.read();
            }

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener arg0) {

            }
        }
    }
}

Answer 1

Spring Cloud Data Flow服务器本质上是一个Spring Boot应用程序，因此，它允许您将特定的配置bean注入到Data Flow配置中以进行扩展/自定义。

在您的情况下，您可以创建扩展javax.servlet.http.HttpFilter或实现javax.servlet.Filter的bean，并将该bean注入SCDF配置。