Re: [netmod] RFC7952 JSON streaming decoding efficiency?

["Rob Wilton (rwilton)" <[e-mail]>]

Hi Robert,

Isn't this just a limitation of JSON, in that the elements in an object are unordered (RFC 8259)?

Thanks,
Rob

-----Original Message-----
From: netmod <[e-mail]> On Behalf Of Robert Varga
Sent: 27 February 2019 22:26
To: [e-mail]
Subject: [netmod] RFC7952 JSON streaming decoding efficiency?

Hello,

reading RFC7952 sections 5.2.2-5.2.4, it would seem that metadata object
(5.2.2) can occur at any position in a JSON object, as well as metadata attachments to leaf/leaf-list/anyxml (5.2.3, 5.2.4) can occur any distance (before or after) from the data element they attach to.

The examples list the metadata object as the first item, and attachments immediately after the data element, but I could find no text which would make this required or recommended for document producers.

While this is completely workable when the parsing state is received into a mutable structure, it requires full parser event buffering in streaming setups.

One example would be JSON->XML transformation using token streaming interfaces (like GSON's JsonReader and
javax.xml.stream.XMLStreamWriter): since metadata can occur at any place in JSON, but is required to be emitted just after opening XML element, we must completely parse the JSON document before we can start emitting the XML document.

Is this intentional or just an omission?

Thanks,
Robert