Regression: ShallowEtagHeaderFilter does not add Etag header for ResponseEntity returning methods [SPR-13717]

[spring-projects-issues]

Jan Gaedicke opened SPR-13717 and commented

As we updated our spring dependencies from 4.0.8.RELEASE to 4.2.3.RELEASE the ShallowEtagHeaderFilter stopped working for spring controller methods that return a ResponseEntity. The effect is that no "Etag" header is added to the response.

The problem is, that the HttpEntityMethodProcessor flushes the HttpServletResponse and the ShallowEtagHeaderFilter refuses to add the header if the response is committed.

As a workaround we have implemented the flushBuffer method in the ContentCachingResponseWrapper and delay the original flushBuffer call until copyBodyToResponse is called.

You can find a small spring-boot app using a tomcat to reproduce this bug at github:
https://github.com/jgaedicke/ShallowEtagHeaderFilter-bug-demo.

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Affects: 4.2.2, 4.2.3

Reference URL: https://github.com/jgaedicke/ShallowEtagHeaderFilter-bug-demo

Issue Links:

• Provide controller method level alternative to WebContentInterceptor [SPR-8550] #13194 Provide controller method level alternative to WebContentInterceptor

Referenced from: commits 9d9433a

[spring-projects-issues]

Juergen Hoeller commented

Looking at the version history, I assume this does not happen with 4.1.8, i.e. it's a regression in the 4.2 line?

Brian Clozel, this seems to be a side effect of your changes around #13194...

Juergen

[spring-projects-issues]

Brian Clozel commented

I fixed this issue by not delegating the flushBuffer call to the actual response.
Indeed, multiple parts of Spring can commit the response, making it impossible for the filter to act on it.

[spring-projects-issues]

Juergen Hoeller commented

Jan Gaedicke, could you please give a recent 4.2.4.BUILD-SNAPSHOT a try and let us know whether it works for you now?

Juergen

[spring-projects-issues]

Jan Gaedicke commented

Great, thanks for the quick fix. It works for me. Any ideas when the next release will be available?

[spring-projects-issues]

Brian Clozel commented

Thanks for the feedback!
For now it's scheduled on December 22nd; you can follow its status here: https://jira.spring.io/browse/SPR/fixforversion/15353/

[spring-projects-issues]

Juergen Hoeller commented

In this particular case, Dec 22 has to be seen "on Dec 22 at the latest". We might pull it forward by a week or so. In any case, we'll keep the release target on JIRA up to date.

Juergen