FHIR Chat · OrderedJson

Hello, I am very new to FHIR. I met a guy from the German organization who explained me, that the JSON thas is used must have the key-value pairs in the right order. This seems to me quite strange, since the JSON RFC 7159 explicitly says, that JSON is unordered. Also most of the implementations I know are based on dictionaries, that are also unordered. Was he simply wrong in this point or did I miss something?

Lloyd McKenzie (Apr 27 2017 at 11:56):

There is no requirement that JSON elements be ordered - but if you convert to XML, ordering matters

Patrick Plattes (Apr 27 2017 at 19:01):

Okay, thank you very much

Grahame Grieve (May 01 2017 at 03:36):

the reference implementation carefully maintains order - perhaps that is where the claim comes from. But that is for the convenience of the readers, not because it actually matters

Brian Postlethwaite (May 03 2017 at 03:46):

When serializing into an object model from the json, need to process the resource_type before you can select the appropriate object serializer to inflate, so can't stream directly without that property coming first.

Brian Postlethwaite (May 03 2017 at 03:47):

I don't recall if the dotnet fhir client has this restriction or not (probably not though)
just a heads up for possible implementer issues.

Mattias Flodin (May 03 2017 at 10:37):

I'm working with the .Net implementation right now. It uses Json.NET internally which parses the entire json text into a document object model. I can't imagine that ordering would matter.
On the other hand, the reason I was looking into it was that I am working with potentially large objects and was looking for a way to stream them. I'd say it's likely that the order could matter to some implementations in the future, for this reason.