should honor use-hal-as-default-json-media-type

[rainoko]

Spring boot introduced configuration use-hal-as-default-json-media-type which helps fallback from hal format links. spring-hateoas should honor this otherwise it is not compatible with boot anymore.

[odrotbohm]

There's nothing in Spring HATEOAS that it could honor here as it doesn't know anything about Spring Boot. When you say "anymore" can you please clarify what you mean by that? Has something worked before that now doesn't anymore? Would you mind getting a bit more precise on what works and what doesn't? Maybe through a test case/project?

[rainoko]

I tried to migrate from 0.18 to 0.23 (0.22 had bug with context)
problem is that 0.23 registretes HAL support for jackson converter.

In general spring-boot autoconfiguration doing same thing but honors flag use-hal-as-default-json-media-type. This registration adds application/json as supported media type for jackson configuration and causing HAL format by default.
org.springframework.boot.autoconfigure.hateoas.HypermediaHttpMessageConverterConfiguration

Now it seems that spring-hateoas doing it also in
org.springframework.hateoas.config.HypermediaSupportBeanDefinitionRegistrar
But seems that I cant drive it or I'm not clever enough to drive it.

[rainoko]

any news about this?

[rainoko]

seems that issue not appears anymore.

[abobwhite]

@rainoko I am still seeing this issue. I am having a problem with getting links on GETs but _links on POST and PUT responses. I want it to always be one or the other.

[gregturn]

Can you please list:

• Version of Spring Boot
• Version of Spring HATEOAS
• Are you using Spring Data REST (sometimes people use SDR, but open their issues here as related project).
• Any custom configurations you are doing involving message converters, @EnableHypermediaSupport
• Do you have a Spring MVC controller and some linkTo(methodOn() type code you are using that is yielding awkward stuff?
• What are the two operations you are performing and where (RestTemplate/curl) that yield different JSON formats?

We need this level of detail to pinpoint what is happening.

[abobwhite]

Hi @gregturn,

Thanks for the response. I am trying to use use-hal-as-default-json-media-type to make sure I get links consistently and not links for GET requests and _links for POST and PUT requests. I'd be happy if it was either as long as it's consistent.

• Spring Boot 1.5.7.RELEASE
• Spring HATEOAS 1.5.7.RELEASE
• Spring Data REST - yes
• No @EnableHypermediaSupport but using Gson instead of Jackson so I have this: @EnableAutoConfiguration(exclude = [JacksonAutoConfiguration.class])
• All my controllers a @RestControllers and I'm using ControllerLinkBuilder.linkTo and manually adding .slash parts, nothing awkward (and working fine for GETs)
• GET yields links and POST yields _links on the same Resource

[gregturn]

Gson is probably the issue right there. Spring HATEOAS is designed with a vendor neutral format and the actual styling into various forms of hypermedia is done through Jackson annotations and customized Jackson serializers/deserializers/mixins.

This is definitely an area NOT tested with Spring HATEOAS, so I wouldn't expect to work if you disable Jackson and remove its autoconfiguration.

[abobwhite]

Thanks for the tip. I have completely removed Gson from my app (pom, configuration, etc.) and I still see the same issue.

[abobwhite]

@gregturn UPDATE: The problem is not related to POST or GET but rather a list of resources vs a single resource. It appears that I am getting links for a list of resources and _links for a single resource. I discovered this after seeing #493

[gregturn]

Show me the method signature. If you are returning a list you're doing it wrong. If you return Resources, that should do the trick.

[abobwhite]

@gregturn Yes that was the issue! I didn't see that anywhere in an example so had no clue that wouldn't work correctly.

[gregturn]

Well, there are, in fact, unit tests that breach this rule. It's why I've drafted #629, to either log a warning or cause your controller to fail fast if you return a type that you can't expect the HAL (or any future serializer) to handle.