`application/hal+json` is used, but it's non-standard

[Tachi107]

Hi,

spring-hateoas uses the application/hal+json media type, but no such media type is registered with IANA. The standard media type is application/vnd.hal+json (note the "vnd." prefix).

The docs mention that if the client sets the Accept header to application/hal+json, Spring will return the HAL representation of the resource. In my opinion, such representation should be returned also if the (registered) application/vnd.hal+json media type is used instead.

Here's the relevant documentation section:

spring-hateoas/src/main/asciidoc/fundamentals.adoc

Line 157 in b19f7de

If you returned such an instance from a Spring MVC or WebFlux controller and the client sent an `Accept` header set to `application/hal+json`, the response would look as follows:

Bye!

[odrotbohm]

I've been following the RFC primarily and that only mentions the application/hal+json. I think we can introduce an additional constant VND_HAL_JSON to capture the registered media type.

[Tachi107]

Hi, thanks for the reply!

the RFC [...] only mentions the `application/hal+json`

Yeah, that's the "ideal" media type. But as HAL (unfortunately) is not a standard, nor an offical RFC (only an expired draft), IANA hasn't assigned that ideal media type. It is hence possible (but somewhat unlikely) that the `application/hal` media type might get registered in the future with a completely different meaning. Applications making use of the system's media types database might also get confused: $ grep hal /etc/mime.types application/vnd.hal+json application/vnd.hal+xml hal

I think we can introduce an additional constant `VND_HAL_JSON` to capture the registered media type.

That's be a nice starting point indeed. It'd also be nice if that media type would be recognized and accepted by default.

[odrotbohm]

This is now in. Configuration, we apply is augmented to also support the new official media type (link discoverers etc.). I've also tweaked Spring Data REST accordingly.