Unable to create HEAD response with completely empty body

Spring-Boot Version: 1.5.22.RELEASE

When creating a route with the method HEAD in spring-boot, i.e.

@RequestMapping(value = "/", method = HEAD)

And you have chunked-encoding enabled by default, it doesn’t appear to be possible to return a response that is completely empty (which is required for HEAD requests). For example if you do something like this

return ResponseEntity.status(OK).contentLength(0).build();

And analyze the bytes in the bodies response you get "0\r\n\r\n" which indicates chunked encoding. This is illegal according to the RFC-spec, see https://tools.ietf.org/html/rfc7230#section-3.3 specifically

   Responses to the HEAD request method (Section 4.3.2
   of [RFC7231]) never include a message body because the associated
   response header fields (e.g., Transfer-Encoding, Content-Length,
   etc.), if present, indicate only what their values would have been if
   the request method had been GET (Section 4.3.1 of [RFC7231]).

In other words, the response body should be completely empty. This is causing issues with certain http clients such as akka-http client which expect there to be no response in the body when making a HEAD request. The related issue with akka-http can be seen here https://github.com/akka/akka-http/issues/2883#issuecomment-574070860

[mdedetrich]

So I just ran the app locally and I can confirm that its not spring-framework (by itself) that is adding these empty responses into the chunked body.

I will re-open the ticket if I find something to the contrary.

[spring-projects-issues]

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