Function: convertXMLtoJSON

Enterprise Edition

Goal: Recursively and generically convert simple XML strings into JSON.

This function convertXMLtoJSON shows how to convert simple XML strings into JSON.
If you need to also convert XML attributes refer to convertAdvXMLtoJSON
Requires Eventing Storage (or metadata collection) and a "source" collection.
Will operate on any mutation where the KEY or meta.id starts with "xml:".
Will enrich the source document with a new JSON object representing the XML data.
Maintains a checksum to prevent the overhead of conversion if the in_xml property is unchanged.

convertXMLtoJSON
Input Data/Mutation
Output Data/Mutation

// To run configure the settings for this Function, convertXMLtoJSON, as follows:
//
// Version 7.0+
//   "Listen to Location"
//     bulk.data.source
//   "Eventing Storage"
//     rr100.eventing.metadata
//   Binding(s)
//    1. "binding type", "alias name...", "bucket.scope.collection", "Access"
//       "bucket alias", "src_col",       "bulk.data.source",        "read and write"
//
// Version 6.X
//   "Source Bucket"
//     source
//   "MetaData Bucket"
//     metadata
//   Binding(s)
//    1. "binding type", "alias name...", "bucket",     "Access"
//       "bucket alias", "src_col",       "source",     "read and write"

function OnUpdate(doc, meta) {
    // filter out non XML
    if (!meta.id.startsWith("xml:")) return;
    // The KEY started with "xml" try to process it
    // ===========================================================
    // *** Do other  work required here on non .in_xml changes ***
    // ===========================================================
    // let's see if we need to re-create our json representation.
    var xmlchksum = crc64(doc.in_xml);
    // ===========================================================
    // Don't reprocess if the doc.in_xml has not changed this could be
    // a big performance win if the doc has other fields that mutate.
    // We do this via a checksum of the .in_xml property.
    if (doc.xmlchksum && doc.xmlchksum === xmlchksum) return;
    // Either this is the first pass, or the .in_xml property changed.
    var jsonDoc = parseXmlToJson(doc.in_xml);
    log(meta.id,"1. INPUT  xml doc.in_xml :", doc.in_xml);
    log(meta.id,"2. CHECKSUM doc.in_xml   :", xmlchksum);
    log(meta.id,"3. OUTPUT doc.out_json   :", jsonDoc);
    doc.out_json = jsonDoc;
    doc.xmlchksum = xmlchksum;
    // ===========================================================
    // enrich the source collection with .out_json and .xmlchksum
    src_col[meta.id] = doc;
}

// 7.0.0 version uses String.matchAll eliminates the need to make our own MatchAll function
function parseXmlToJson(xml) {
    const json = {};
    for (const res of xml.matchAll(/(?:<(\w*)(?:\s[^>]*)*>)((?:(?!<\1).)*)(?:<\/\1>)|<(\w*)(?:\s*)*\/>/gm)) {
        const key = res[1] || res[3];
        const value = res[2] && parseXmlToJson(res[2]);
        json[key] = ((value && Object.keys(value).length) ? value : res[2]) || null;
    }
    return json;
}

/*
// need this for 6.6.0 version
function* MatchAll(str, regExp) {
  if (!regExp.global) {
    throw new TypeError('Flag /g must be set!');
  }
  const localCopy = new RegExp(regExp, regExp.flags);
  let match;
  while (match = localCopy.exec(str)) {
    yield match;
  }
}

// 6.6.0 version no String.matchAll need our own MatchAll function
function parseXmlToJson(xml) {
    const json = {};
    for (const res of MatchAll(xml,/(?:<(\w*)(?:\s[^>]*)*>)((?:(?!<\1).)*)(?:<\/\1>)|<(\w*)(?:\s*)*\/>/gm)) {
        const key = res[1] || res[3];
        const value = res[2] && parseXmlToJson(res[2]);
        json[key] = ((value && Object.keys(value).length) ? value : res[2]) || null;
    }
    return json;
}
*/

INPUT: KEY xml::1

{
  "type": "xml",
  "id": 1,
  "in_xml": "<CD><TITLE>EmpireBurlesque</TITLE><ARTIST>BobDylan</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Columbia</COMPANY><PRICE>10.90</PRICE><YEAR>1985</YEAR></CD>"
}

UPDATED/OUTPUT: KEY xml::1

{
  "type": "xml",
  "id": 2,
  "in_xml": "<CD><TITLE>EmpireBurlesque</TITLE><ARTIST>BobDylan</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Columbia</COMPANY><PRICE>10.90</PRICE><YEAR>1985</YEAR></CD>",
  "out_json": {
    "CD": {
      "TITLE": "EmpireBurlesque",
      "ARTIST": "BobDylan",
      "COUNTRY": "USA",
      "COMPANY": "Columbia",
      "PRICE": "10.90",
      "YEAR": "1985"
    }
  },
  "xmlchksum": "02087b7be275d0d8"
}