XML <--> JSON

xml-rules.md

XML Rules

Questions

• Shall we take into account XML or XML Schema (see issues below)

Links

• TD issue #139
• SAP guidelines for XML
• NPM Libraries
  • MOST of the libs support one-way only, we need bi-directional
  • https://www.npmjs.com/package/xml2json -> bidirectional (Last updated 3 years ago) -> tested: does not seem to work properly
  • https://www.npmjs.com/package/jxon -> bidirectional (Last updated 6 years ago) -> tested: works better
  • https://github.com/nashwaan/xml-js -> bidirectional (Last updated4 years ago) -> to be tested!
  • https://github.com/Leonidas-from-XIV/node-xml2js -> bidirectional (Last updated 3 years ago) -> to be tested!
  • https://github.com/buglabs/node-xml2json -> bidirectional (Last updated 4 years ago) -> to be tested!
  • https://github.com/NaturalIntelligence/fast-xml-parser -> bidirectional (Last updated 1 month ago) -> Works GREAT!

Tools

• https://www.freeformatter.com/xml-to-json-converter.html
• https://codebeautify.org/xmltojson
• https://www.utilities-online.info/xmltojson OR https://www.utilities-online.info/jsontoxml
• https://www.convertjson.com/xml-to-json.htm
• http://badgerfish.ning.com/
• Related Tools / Information / Links
  • A beginner’s guide to parse and create XML with Node.js

Rules

• JSON members whose names start with @ (or $) are transformed to XML attributes (TBD)
• #text (or _) used for text content (TBD)
• Simple types are always nested in a term
• What about namespaces?
• Multiple roots NOT possible in XML -> add outer root? Starting with XML this should not be an issue
• need to always wrap JSON in root? Starting with XML this should not be an issue

XML to JSON

e.g., for reading XML int using JSON in scripts that then get converted to XML on the wire

XML		JSON
<foo>1</foo>	->	{"foo": "1"}
<root att="X">1</root>	->	{"root": {"@att": "X", "#text": "1"}} OR {"root":{"$att":"X","_":"1"}}
<root><a>A</a><b>B</b></root>	->	{"root": {"a": "A", "b": "B"}}
<root><a>A1</a><b>B1</b><a>A2</a><b>B2</b></root>	->	{"root": {"a": ["A1", "A2"], "b": ["B1", "B2"]}} OR {"root": [{"a": "A1","b": "B1"},{"a": "A2","b": "B2"}]}
		XML schema could tell that there can be multiple a+b sequences. Returning from JSON to XML might result in different result (first a's and then b's which is not the same).
		<root at="dd"><a>A1</a><a>A2</a><b>B1</b><b>B2</b></root>
<nsX:Name xmlns:nsX="http://mycompany">Widget A</nsX:Name>	->	{"nsX:Name":{"$xmlns:nsX":"http://mycompany","_":"Widget A"}}
...	->	...

JSON to XML

e.g., for using JSON in scripts that then get converted to XML on the wire

Note: ONLY specific JSON can be transformed to XML (see some fail below).

JSON		XML
"string"	->	FAIL given that XML needs surrounding element Starting with XML this should not be an issue
{"el": 123}	->	<el>123</el>
{"el": 123, "@at": true}	->	<el at="true">123</el> ??? at on this level or outside in root ??? Sample not valid, needs outer nesting for @? --> Fail Starting with XML this should not be an issue
{"el1": 1, "el2": 2, "@at": true}	->	<root at="true"><el1>1</el1><el2>2</el2></root> root added because there cannot be multipe roots in XML!?! Starting with XML this should not be an issue
{"root":{"$att":"X","_":"1"}}	->	<root att="X">1</root>
{"nsX:Name":{"$xmlns:nsX":"http://mycompany","_":"Widget A"}}	->	<nsX:Name xmlns:nsX="http://mycompany">Widget A</nsX:Name>
...	->	...