InputStream consumed by DispatcherServlet logRequest

Affects: 5.2.1

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A few weeks ago I enabled debug logging for my application, today I had forgotten about but noticed that my injected InputStream was empty. After a debugging session (first assuming it again was related to the HiddenHttpMethodFilter) I ended up at

https://github.com/spring-projects/spring-framework/blob/8d846500eff3e51fc49846a969ae1a7f4671015d/spring-webmvc/src/main/java/org/springframework/web/servlet/DispatcherServlet.java#L955-L965

So every time I enable debug logging I cannot use my injected InputStream:

@PostMapping
public ResponseEntity<String> doPost(InputStream input, HttpServletRequest request) {
    ...

I do now get this logging:

2019-12-10T10:27:46,305 [http-nio-8082-exec-7] DEBUG org.springframework.web.servlet.DispatcherServlet - POST "/communication", parameters={masked}

But maybe it would make sense to auto-wrap the request in DEBUG when that logging is active or give a warning when injecting the consumed InputStream later and even report who did it 😄

Thanks!

Related to (but not covered by): #22985

[rstoyanchev]

Yes this is expected, and besides the logging of request details, any other code could cause a similar issue by accessing a request parameter.

Note that you can inject the content reliably as @RequestBody String or @RequestBody ByteArrayResource because we reconstruct the body from request parameters in ServletServerHttpRequest#getBody.

[rstoyanchev]

Yes, just use the standard multipart support in the Servlet container.