Function: convertXMLtoJSON

    +

    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"
    }