Difference between revisions of "X3D JSON Encoding"
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Revision as of 15:29, 10 September 2014
Preliminary notes on the creation of an X3D JSON encoding.
- This page is to understand the conversion process so that a high-quality encoding definition can be created
- Don Brutzman started a thread on the X3D-Public list.
Conversion Issues
Primary design criterion: round-trippable lossless representation of X3D scene.
Conversion approach of greatest interest: XML to/from JSON. Issues:
- How to convert attribute names to distinguish them from child elements
- JSON handling of container elements to preserve parent/child relationships, distinguishing child elements from attributes
- Creation of JSON elements with datatypes appropriate to content (e.g., integer, float, strings, etc.)
- Inclusion of XML namespaces
- Handing of comments in the source
- {LD} I don't see an issue of dropping comments during conversion. This is not suppose to be a conversion of files to maintain an archive, but a conversion for use. JSON does provide comment mechanisms.
- {DPB} Each X3D encoding needs an option for inclusion of comments in order to ensure 100% round-trip conversion capabilities.
- Support for singleton (self-closing) tags also needed
Discussion points
Here are suggested discussion points for the X3D teleconference and future followups.
- What are the use cases for having X3D JSON available in JavaScript? It would be good to spell them out and understand them well.
- Is there a good/consistent way for X3DOM to utilize such capabilities?
- Is there a way for Three.js or other javascript libraries to utilize such capabilities?
- Is there a single authoritative reference for JSON itself? and for JSON-XML conversions?
- Compare compression of a TestMesh.x3d.json.gz to TestMesh.x3db and TestMesh.x3d.exi (EXI will likely win because it includes data typing)
- Once a canonical form for X3D as JSON is established, add conversion capabilities to X3D-Edit and also autoconvert, test and publish JSON for all of the 3800+ scenes in the X3D Examples Archives
- Decide if this capability needs to be defined in one of the X3D standards, or perhaps as an X3D best practice.
- Probably lots more... What else?
Contributors
- LD - Leonard Daly
- DPB - Don Brutzman
References
- XML to JSON Converter (provides option to assign a prefix to JSON attributes, default is @ character) [3]
- Apache Camel, XML JSON Data Format (camel-xmljson) [4]
- JSON Markup Language (JsonML) [5]
- XSLTJSON: Transforming XML to JSON using XSLT [6]
- Converting Between XML and JSON [7]
- XML/JSON Perl Converter [8]
- IBM's PHP converter [9]
- Java Converter [10]
- Google Code Library [11]
