HEAD response has "Content-Length: 0" for @RestController @GetMapping methods [SPR-15337]

[spring-projects-issues]

David Goblirsch opened SPR-15337 and commented

When including ShallowEtagHeaderFilter in a REST application, HEAD responses no longer include an ETag header as of 4.3.7, but they still have zero for the Content-Length header. If I do not activate a ShallowEtagHeaderFilter, the response to HEAD has the Content-Length header value set to the size of the response body that GET would have returned, which is the desired behavior.

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Affects: 4.3.7

Reference URL: #19826

Referenced from: commits spring-attic/spring-framework-issues@6a1802f

[spring-projects-issues]

Brian Clozel commented

I've looked at this and this doesn't seem to be strictly related to ShallowEtagHeaderFilter, since the Servlet response has its internal "Content-Length" value set already after the filter chain has been called. This has something to do with the dispatching/handling of the response, then.

I'll report back once I've narrowed down the origin of this behavior.

[spring-projects-issues]

Brian Clozel commented

Hi David Goblirsch!

Sorry about the late reply.
I was sure I had reproduced this, but looking back at my repro project, I can't see the issue anymore.

I've created a repro project here that you can run with mvn package cargo:run.

I'm getting the following result on the CLI:

➜  ~ http :8080/SPR-15337/
HTTP/1.1 200
Content-Length: 4
Content-Type: text/plain;charset=ISO-8859-1
Date: Thu, 08 Mar 2018 13:34:32 GMT
ETag: "0033bd94b1168d7e4f0d644c3c95e35bf"

TEST

➜  ~ http HEAD :8080/SPR-15337/
HTTP/1.1 200
Content-Length: 4
Content-Type: text/plain;charset=ISO-8859-1
Date: Thu, 08 Mar 2018 13:34:37 GMT

Did I miss something here?

[spring-projects-issues]

David Goblirsch commented

In my case I was trying to get XML and JSON payloads.  Your example returns a simple string. I wonder if that has something to do with it.

I am behind a firewall and I cannot pull your example in to elaborate on it.