Relationship validation

[dclucas]

(disclaimer: maybe we want to split this in more than one issue. I'd get started with 'required' validations).

When describing an entity with a relationship (eg: a product has a brand), we need a way to say that relationship is mandatory (eg: a product must have a link to a brand).

[kristofsajdak]

Currently we already have a more extended format for relationships in case they reference a remote API

e.g.

{
       type: 'posts',
       attributes: {},
       relationships: {
            author: {type: 'people', baseUri: 'http://localhost:9999'},
            comments: ['comments'],
            topic: 'topics'
       }
}

How about we extend that with a required attribute?

{
       type: 'posts',
       attributes: {},
       relationships: {
            author: {type: 'people', baseUri: 'http://localhost:9999', required: false},
            comments: ['comments'],
            topic: 'topics'
       }
}

Not sure whether we want to default to 'false' or 'true' here, perhaps we could make that configurable at the plugin level?

[dclucas]

Sounds like a good plan to me. I would assume 'required' as false by default...

[kristofsajdak]

Hey Diogo, perhaps you could submit a PR for this? Would be nice to get you in as a committer

[dclucas]

resisting... the urge... not to jump in that code.

ok, I will have a look. but please don't wait on me for this one -- I might be too swamped to be able to help.