As per http://jsonapi.org/format/#fetching-sparse-fieldsets a response must not contain extra fields.
What about, if the request contains fields that aren’t available? Do we respond with an empty struct? No Content Status Code? An error?
I believe this depends in whether you consider it an error and want to fail the request (since they’re all or none)
See error discussion in the index page
I’m pretty sure @bf4 is correct. That is, server can either ignore the unknown field names (i.e. just not output a key for them in the returned resource objects), which I think is often the best approach, or return an error (probably a 400).
Thank you guys, I think we are going for an error 400. Let’s see how it works out 