JSON - Hypermedia or references support?

[bclozel]

See issue https://github.com/resthub/resthub-spring-stack/issues/45 for the server part.

How should we consider support for:

• JSON references - (de)serializing object graphs and preventing duplication or circular references, using references.
• Hypermedia - adding metadata to serialized objects to allow lazy loading through additional API calls on the client side.

We should consider only one of those options.

JSON reference

On the client side, several libs achieved this:

• json-ref coffeescript
• dojox.json.ref (see this article).

There are problems on the server side: Jackson doesn't support the json-ref syntax "$ref" and only relies on having typed objects on both client/server sides (see ObjectIdentity).

There are also problems on the client side; javascript client libs duplicate data, i.e. they expand the object graph with their values. This can be problematic when updating data on the client side.

Hypermedia

We could consider HAL and/or json-ld formats and integrate those on the client side for lazy-loading and metadata.

We could integrate those within backbone using:

• backbone model getters/setters
• proxies using ES6 Proxy API

Of course, I'm all for Hypermedia!

[manosbatsis]

Regarding references, why not use Jackson's @JsonIdentityInfo[1]? It just works as far as the spring stack goes, but needs support on the backbone stack side. Perhaps something as simple as an identity map [2]. I'd surely vote for this as a core resthub feature.

[1] http://wiki.fasterxml.com/JacksonFeatureObjectIdentity [2] http://blog.shinetech.com/2012/12/24/an-identity-map-for-backbone-js/