Consider setting ExecutionInput.Locale property automatically

[spring-projects]

Consider setting ExecutionInput.Locale property automatically

[jurriaan]

@rstoyanchev In WebFlux I use the AcceptHeaderLocaleContextResolver which makes the locale available via the ServerWebExchangeMethodArgumentResolver.

Can we somehow use this or a similar ArgumentResolver in Spring-GraphQL as well, so that we can inject the locale (which is stored in the LocaleContext on the ServerWebExchange) into @SchemaMapping and @BatchMapping annotated methods?

[rstoyanchev]

For Spring MVC this can be probably be based on AcceptHeaderLocaleResolver, i.e. "Accept-Language" header via request.getLocales() with a fallback on Boot's "spring.mvc.locale" property. For WebFlux, similar logic based directly on the "Accept-Language" request header.

[rstoyanchev]

Yes, I think we'll first make sure that it's extracted in Spring MVC and WebFlux and set on the ExecutionContext, and then add support for Locale as a method argument that's sourced from the DataFetchingEnvironment.