Best practice for JSON foreign key references?

[Patrick Lightbody]

Suppose I have two models: Foo and Bar. Bar is already in the database with an instance with ID 123. In building out a REST API, I want to allow the API to accept a JSON representation of Foo, including the reference to the "123" instance of Bar.

This would obviously be bad:

{ fooProp1: "...", fooProp2: "...", bar: { id: 123, barProp1: "..." } }

Instead I'd prefer something like:

{ fooProp1: "...", fooProp2: "...", bar: 123 }

Of course, when I run this through Json.fromJson(json, Foo.class), it blows up complaining that "123" can't be converted to Bar. I have used Jackson directly before and what I'd normally do is register a converter that would do the mapping for me and call Bar.find.byId() on my behalf. So two questions:

1) Is this possible?

2) Is it a best practice? If not, what is the recommended way to do this kind of stuff.

Thanks!

Patrick

[Pascal Voitot Dev]

in scala or java?

Pascal

Patrick

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[Patrick Lightbody]

Apologies: this is Java using Play 2.0. Missed the request for subject line clarification until after I posted :)

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[Pascal Voitot Dev]

So I don't have your anwer and I'd say it's in Jackson IMO.
Maybe someone else has the answer in the community ;)

Pascal

[Guillaume Bort]

On Wed, Mar 6, 2013 at 4:11 PM, Patrick Lightbody <pat...@lightbody.net> wrote:

Of course, when I run this through Json.fromJson(json, Foo.class), it blows up complaining that "123" can't be converted to Bar. I have used Jackson directly before and what I'd normally do is register a converter that would do the mapping for me and call Bar.find.byId() on my behalf. So two questions:

1) Is this possible?

You are free to use Jackson directly. `Json.fromJson` is just a more direct helper for simple use cases.

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Guillaume Bort, http://guillaume.bort.fr