优雅地记录http请求和响应的数据
不装逼的程序员 今天
经常会遇到需要处理 http 请求以及响应 body 的场景。
而这里比较大的一个问题是 servle t的 requestBody 或 responseBody 流一旦被读取了就无法二次读取了。
针对这个问题，spring本身提供了解决方案，即：
ContentCachingRequestWrapper ContentCachingResponseWrapper。
我们编写一个过滤器:
public abstract class HttpBodyRecorderFilter extends OncePerRequestFilter {
private static final int DEFAULT_MAX_PAYLOAD_LENGTH = 1024 * 512;
private int maxPayloadLength = DEFAULT_MAX_PAYLOAD_LENGTH;
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
boolean isFirstRequest = !isAsyncDispatch(request);
HttpServletRequest requestToUse = request;
if (isFirstRequest && !(request instanceof ContentCachingRequestWrapper) && (request.getMethod().equals(HttpMethod.PUT.name()) || request.getMethod().equals(HttpMethod.POST.name()))) { requestToUse = new ContentCachingRequestWrapper(request); }
HttpServletResponse responseToUse = response;
if (!(response instanceof ContentCachingResponseWrapper) && (request.getMethod().equals(HttpMethod.PUT.name()) || request.getMethod().equals(HttpMethod.POST.name()))) { responseToUse = new ContentCachingResponseWrapper(response); }
boolean hasException = false;
try { filterChain.doFilter(requestToUse, responseToUse); } catch (final Exception e) { hasException = true; throw e; } finally { int code = hasException ? 500 : response.getStatus();
if (!isAsyncStarted(requestToUse) && (this.codeMatched(code, AdvancedHunterConfigManager.recordCode()))) { recordBody(createRequest(requestToUse), createResponse(responseToUse)); } else { writeResponseBack(responseToUse); }
}
}
protected String createRequest(HttpServletRequest request) { String payload = "";
ContentCachingRequestWrapper wrapper = WebUtils.getNativeRequest(request, ContentCachingRequestWrapper.class);
if (wrapper != null) { byte[] buf = wrapper.getContentAsByteArray(); payload = genPayload(payload, buf, wrapper.getCharacterEncoding()); }
return payload; }
protected String createResponse(HttpServletResponse resp) { String response = "";
ContentCachingResponseWrapper wrapper = WebUtils.getNativeResponse(resp, ContentCachingResponseWrapper.class);
if (wrapper != null) { byte[] buf = wrapper.getContentAsByteArray();
try { wrapper.copyBodyToResponse(); } catch (IOException e) { e.printStackTrace(); }
response = genPayload(response, buf, wrapper.getCharacterEncoding()); }
return response;
}
protected void writeResponseBack(HttpServletResponse resp) { ContentCachingResponseWrapper wrapper = WebUtils.getNativeResponse(resp, ContentCachingResponseWrapper.class);
if (wrapper != null) { try { wrapper.copyBodyToResponse(); } catch (IOException e) { LOG.error("Fail to write response body back", e); } }
}
private String genPayload(String payload, byte[] buf, String characterEncoding) {
if (buf.length > 0 && buf.length < getMaxPayloadLength()) { try { payload = new String(buf, 0, buf.length, characterEncoding); } catch (UnsupportedEncodingException ex) { payload = "[unknown]"; } }
return payload;
}
public int getMaxPayloadLength() { return maxPayloadLength; }
private boolean codeMatched(int responseStatus, String statusCode) {
if (statusCode.matches("^[0-9,]*$")) { String[] filteredCode = statusCode.split(","); return Stream.of(filteredCode).map(Integer::parseInt).collect(Collectors.toList()).contains(responseStatus); } else { return false; }
}
protected abstract void recordBody(String payload, String response);
protected abstract String recordCode();
}这样自定义一个filter继承HttpBodyRecorderFilter，重写recordBody方法就能自定义自己的处理逻辑了。
另外，recordCode方法可用于定义在请求响应码为多少的时候才会去记录body，例如可以定义为只有遇到400或500时才记录body，用于错误侦测。
过滤器的匹配规则比较简单，如果想要像springmvc那样进行匹配，我们可以使用：AntPathMatcher。
class PatternMappingFilterProxy implements Filter {
private final Filter delegate;
private final List<String> pathUrlPatterns = new ArrayList();
private PathMatcher pathMatcher;
public PatternMappingFilterProxy(Filter delegate, String... urlPatterns) { Assert.notNull(delegate, "A delegate Filter is required"); this.delegate = delegate; int length = urlPatterns.length; pathMatcher = new AntPathMatcher(); for (int index = 0; index < length; ++index) { String urlPattern = urlPatterns[index]; this.pathUrlPatterns.add(urlPattern); }
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest httpRequest = (HttpServletRequest) request;
String path = httpRequest.getRequestURI();
if (this.matches(path)) { this.delegate.doFilter(request, response, filterChain); } else { filterChain.doFilter(request, response); }
}
private boolean matches(String requestPath) {
for (String pattern : pathUrlPatterns) { if (pathMatcher.match(pattern, requestPath)) { return true; } }
return false; }
@Override public void init(FilterConfig filterConfig) throws ServletException { this.delegate.init(filterConfig); }
@Override
public void destroy() { this.delegate.destroy(); }
public List<String> getPathUrlPatterns() { return pathUrlPatterns; }
public void setPathUrlPatterns(List<String> urlPatterns) { pathUrlPatterns.clear(); pathUrlPatterns.addAll(urlPatterns); }
}这样子，PatternMappingFilterProxy装饰了真正的HttpBodyRecorderFilter，支持传入urlPatterns，从而实现像springmvc那样的ant style的匹配。例如对于以下接口：
@PostMapping("/test/{id}")public Object test(@PathVariable(value = "id",required = true) final Integer index) {
//do something
}可以设置urlPattern为/test/{id:[0-9]+}
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