Spring zuul proxy appends extra json response along with service response json - spring-boot

Question

Spring zuul proxy appends extra json response along with service response json
Below is the zuul configuration
zuul:
sensitiveHeaders:
routes:
api-gateway:
url: http://localhost:8099
abc-management:
url: http://localhost:8098
Below is the response json
{
"status": "P200",
"message": "Orders fetched successfully",
"timeStamp": "2020-09-30T16:01:42.116275Z",
"data": {
"orders": [
{
"order_id": "11312553751504",
"status_reason": null
}
]
},
"requestId": 0
}{
"timestamp": "2020-09-30T16:01:42.122+0000",
"status": 200,
"error": "OK",
"message": "",
"path": "/api-gateway/orders"
}
The extra json
{
"timestamp": "2020-09-30T16:01:42.122+0000",
"status": 200,
"error": "OK",
"message": "",
"path": "/api-gateway/orders"
}
is appended by zuul proxy, is this a bug or a misconfiguration

Answer 1

was overriding PostFilter, when that part is removed. It fixed the issue

Answer 2

The reason is because an exception occurred in filter. and response has written twice, the response data and the /error response.
ApplicationFilterChain.java
} catch (IOException | ServletException | RuntimeException e) {
throw e;
} catch (Throwable e) {
e = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(e);
throw new ServletException(sm.getString("filterChain.filter"), e);
}
StandardWrapperValve.java
private void exception(Request request, Response response,
Throwable exception) {
request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, exception);
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
response.setError();
}
BasicErrorController.java
#RequestMapping
public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
HttpStatus status = this.getStatus(request);
if (status == HttpStatus.NO_CONTENT) {
return new ResponseEntity(status);
} else {
Map<String, Object> body = this.getErrorAttributes(request, this.getErrorAttributeOptions(request, MediaType.ALL));
return new ResponseEntity(body, status);
}
}
if these is an Error occurred in filter, then will be redirect to /error page.
this is a example:
#Component
public class MyFilter implements Filter {
#Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
filterChain.doFilter(servletRequest, servletResponse);
throw new RuntimeException("error");
}
}
#RestController
public class IndexController {
#GetMapping("/user")
public User user(#RequestParam int id) {
return new User(id, "user" + id);
}
}
Request from postman, the response:
{
"id": 2,
"name": "user2"
}{
"timestamp": "2022-02-15T11:06:16.094+00:00",
"status": 200,
"error": "OK",
"path": "/user"
}
image