ContentCachingResponseWrapper tworzy pustą odpowiedź

Question

Próbuję zaimplementować filtr do rejestrowania żądań i odpowiedzi w aplikacji Spring MVC. używam następujący kod:

@Component 
public class LoggingFilter extends OncePerRequestFilter { 

    private static final Logger LOGGER = LoggerFactory.getLogger(LoggingFilter.class); 

    @Override 
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { 

     ContentCachingRequestWrapper requestWrapper = new ContentCachingRequestWrapper(request); 
     ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper(response); 

     LOGGER.debug(REQUEST_MESSAGE_FORMAT, requestWrapper.getRequestURI(), requestWrapper.getMethod(), requestWrapper.getContentType(), 
       new ServletServerHttpRequest(requestWrapper).getHeaders(), IOUtils.toString(requestWrapper.getInputStream(), UTF_8)); 

     filterChain.doFilter(requestWrapper, responseWrapper); 

     LOGGER.debug(RESPONSE_MESSAGE_FORMAT, responseWrapper.getStatus(), responseWrapper.getContentType(), 
       new ServletServerHttpResponse(responseWrapper).getHeaders(), IOUtils.toString(responseWrapper.getContentInputStream(), UTF_8)); 
    } 
} 

Tak, mam moją prośbę i respone rejestrowane zgodnie z oczekiwaniami. Oto dzienniki:

2016-10-08 19:10:11.212 DEBUG 11072 --- [qtp108982313-19] by.kolodyuk.logging.LoggingFilter 
---------------------------- 
ID: 1 
URI: /resources/1 
Http-Method: GET 
Content-Type: null 
Headers: {User-Agent=[curl/7.41.0], Accept=[*/*], Host=[localhost:9015]} 
Body: 
-------------------------------------- 
2016-10-08 19:10:11.277 DEBUG 11072 --- [qtp108982313-19] by.kolodyuk.logging.LoggingFilter 
---------------------------- 
ID: 1 
Response-Code: 200 
Content-Type: application/json;charset=UTF-8 
Headers: {} 
Body: {"id":"1"} 
-------------------------------------- 

Jednak pusta odpowiedź jest zwracana. Oto dane wyjściowe z curl:

$ curl http://localhost:9015/resources/1 --verbose 
* Trying ::1... 
* Connected to localhost (::1) port 9015 (#0) 
> GET /resources/1 HTTP/1.1 
> User-Agent: curl/7.41.0 
> Host: localhost:9015 
> Accept: */* 
> 
< HTTP/1.1 200 OK 
< Date: Sat, 08 Oct 2016 17:10:11 GMT 
< Content-Type: application/json;charset=UTF-8 
< Content-Length: 0 
< 
* Connection #0 to host localhost left intact 

Wszelkie pomysły?

Dzięki

Answer 1

Po kilku godzinach zmagań, mam w końcu znaleźć rozwiązanie.

W skrócie, ContentCachingResponseWrapper.copyBodyToResponse() powinien zostać wywołany na końcu metody filtra.

ContentCachingResponseWrapper buforuje treść odpowiedzi, odczytując ją ze strumienia wyjściowego odpowiedzi. Strumień staje się pusty. Aby użyć odpowiedzi do strumienia wyjściowego ContentCachingResponseWrapper.copyBodyToResponse() należy użyć.

Answer 2

W końcu rozwiązano problem. Oto idealne rozwiązanie:

import com.fasterxml.jackson.databind.JsonNode; 
import com.fasterxml.jackson.databind.ObjectMapper; 
import org.apache.commons.io.IOUtils; 
import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.http.*; 
import org.springframework.stereotype.Component; 
import org.springframework.web.filter.OncePerRequestFilter; 
import org.springframework.web.util.ContentCachingRequestWrapper; 
import org.springframework.web.util.ContentCachingResponseWrapper; 

import javax.servlet.FilterChain; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.URI; 
import java.util.Enumeration; 
import java.util.Map; 

import static java.nio.charset.StandardCharsets.UTF_8; 
import static net.logstash.logback.marker.Markers.appendFields; 

@Component 
public class LoggingFilter extends OncePerRequestFilter { 

    private static final Logger LOGGER = LoggerFactory.getLogger(LoggingFilter.class); 

    @Autowired 
    private ObjectMapper objectMapper; 

    @Override 
    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException { 

    ContentCachingRequestWrapper requestWrapper = new ContentCachingRequestWrapper(httpServletRequest); 
    ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper(httpServletResponse); 

    filterChain.doFilter(requestWrapper, responseWrapper); 

    String requestUrl = requestWrapper.getRequestURL().toString(); 
    HttpHeaders requestHeaders = new HttpHeaders(); 
    Enumeration headerNames = requestWrapper.getHeaderNames(); 
    while (headerNames.hasMoreElements()) { 
     String headerName = (String) headerNames.nextElement(); 
     requestHeaders.add(headerName, requestWrapper.getHeader(headerName)); 
    } 
    HttpMethod httpMethod = HttpMethod.valueOf(requestWrapper.getMethod()); 
    Map<String, String[]> requestParams = requestWrapper.getParameterMap(); 

    String requestBody = IOUtils.toString(requestWrapper.getInputStream(),UTF_8); 
    JsonNode requestJson = objectMapper.readTree(requestBody); 

    RequestEntity<JsonNode> requestEntity = new RequestEntity<>(requestJson,requestHeaders, httpMethod, URI.create(requestUrl)); 
    LOGGER.info(appendFields(requestEntity),"Logging Http Request"); 


    HttpStatus responseStatus = HttpStatus.valueOf(responseWrapper.getStatusCode()); 
    HttpHeaders responseHeaders = new HttpHeaders(); 
    for (String headerName : responseWrapper.getHeaderNames()) { 
     responseHeaders.add(headerName, responseWrapper.getHeader(headerName)); 
    } 
    String responseBody = IOUtils.toString(responseWrapper.getContentInputStream(), UTF_8); 
    JsonNode responseJson = objectMapper.readTree(responseBody); 
    ResponseEntity<JsonNode> responseEntity = new ResponseEntity<>(responseJson,responseHeaders,responseStatus); 
    LOGGER.info(appendFields(responseEntity),"Logging Http Response"); 
    responseWrapper.copyBodyToResponse(); 
    } 
}