Implement sparse fieldset

[ghunti]

Hi.

This is a first proposal to implement the sparse fieldset feature. The idea is to discuss the current implementation to improve on what was done :-)

This are the "major features" in order to respect JSON API spec:

• If no field param is specified current behavior is kept
• If one or more fieldsets are provided then, only the fields on those fieldsets are returned (only exception to this is the id field, that will NEVER be removed)
• If one or more fieldsets are provided, relationship names MUST also be provided, otherwise the relationship object will not hold those relations

To mimic the behavior of includes, we need to call a method parseFieldsets() in order filter the response fields.

The fieldset filter is respecting the JSON API, but it's also affecting the other serializers (just like the included relations work right now)

Don't accept the commit, because it's still missing unit test

[willishq]

Hey, I'll merge this in if you write some tests for it! Thanks!

[dennisoderwald]

+1

[ghunti]

@willishq @dennisoderwald Working on them, but been very busy lately.

[ghunti]

Unit tests pushed.

[mdwheele]

@willishq Any updates on the merge-ability of this feature?

[marcaube]

@greydnls it seems like @willishq is missing in action 😛 What's the status of this PR ?

[LavaToaster]

@greydnls @willishq @philsturgeon Is there anything blocking this? (Not sure who to ping, sorry!)

[Indemnity83]

Would really love to use this in a project under development; its been months with no update though 😞

[greydnls]

I'm sorry about the delay on this, life has been hectic. This PR looks good and the tests are passing. I need to resolve conflicts and I'll merge it.

[rollbackpt]

+1
I was just looking for this feature on the documentation. Any predictions on this merge?

[greydnls]

Thank you @ghunti 👏 👏 This was merged in manually, not sure why GH didn't mark the PR as closed. Changes are on master. I'll cut a new release shortly.

[ghunti]

Thanks for everything @greydnls !!!