XmlToJson.cpp

 
/* SPDX-License-Identifier: CC0-1.0 */
 
#include "XmlToJson.h"
#include "IException.h"
 
#include <nlohmann/json.hpp>
#include <iostream>
 
#include <QDomDocument>
#include <QDomElement>
#include <QFile>
#include <QString>
 
using json = nlohmann::json;
 
namespace Isis {
   json convertLastChildNodeToJson(QDomElement& element);
   json convertXmlToJson(QDomElement& element, json& output);
 
  json xmlToJson(QString xmlFile) {
    QDomDocument doc("xmlInput");
    QFile file(xmlFile);
 
    if (!file.open(QIODevice::ReadOnly)) {
      QString message = QString("Failed to open file for XML Input: [%1]").arg(xmlFile);
      throw IException(IException::Io, message, _FILEINFO_);
    }
 
    QString errMsg;
    int errLine, errCol;
    if (!doc.setContent(&file, &errMsg, &errLine, &errCol)) {
      file.close();
      QString message = QString("Failed to use file for XML Input: [%1]. %2 at line %3, column %4").arg(xmlFile).arg(errMsg).arg(errLine).arg(errCol);
      throw IException(IException::Io, message, _FILEINFO_);
    }
 
    file.close();
 
    return xmlToJson(doc);
  }
 
    
  json xmlToJson(QDomDocument& doc) {
    QDomElement docElem = doc.documentElement();
    json output;
    return convertXmlToJson(docElem, output);
  }
    
 
  json convertLastChildNodeToJson(QDomElement& element){
    json newJson;
    if (element.hasAttributes()) {
      // If there are attributes, add them
      // <tag attributeName="attributeValue">textValue</tag>
      json attributeSection;
      QDomNamedNodeMap attrMap = element.attributes();
      for (int i=0; i < attrMap.size(); i++) {
        QDomAttr attr = attrMap.item(i).toAttr(); 
        attributeSection["attrib_"+attr.name().toStdString()] = attr.value().toStdString();
      }
      // If there is no textValue, don't include it
      // <tag attributeName="attributeValue" />
      if (!element.text().isEmpty()) {
        attributeSection["_text"] = element.text().toStdString(); 
      }
      newJson[element.tagName().replace(":", "_").toStdString()] = attributeSection;
    }
    else {
      // Just add element and its value
      // <tag>value</tag>
      if (!element.text().isEmpty()) {
        newJson[element.tagName().replace(":", "_").toStdString()] = element.text().toStdString();
      }
      else {
        // <tag /> no value case
        newJson[element.tagName().replace(":", "_").toStdString()];
      }
    }
    return newJson;
  }
 
 
  json convertXmlToJson(QDomElement& element, json& output) {
    while (!element.isNull()) {
      QDomElement next = element.firstChildElement();
      if (next.isNull()){
        json converted = convertLastChildNodeToJson(element);
        // Simple case with no repeated tags at the same level
        if (!output.contains(element.tagName().toStdString())){
          output.update(converted);
        }
        else {
          // There is a repeated tag at the same level in the XML, i.e: <a>val1</a><a>val2</a>
          // Translated json goal: a:[val1, val2]
          // If the converted json has an array already, append, else make it an array
          if (!output[element.tagName().toStdString()].is_array()) {
            json repeatedArray;
            repeatedArray.push_back(output[element.tagName().toStdString()]);
            output[element.tagName().replace(":", "_").toStdString()] = repeatedArray;
          }
          output[element.tagName().replace(":", "_").toStdString()].push_back(converted[element.tagName().toStdString()]);
        }
      }
      else {
        // If there is already an element with this tag name at any level besides the same one,
        // add it to a list rather than 
        // overwriting. This is the following situation:
        // XML: <a> <first>value1</first> </a> <a> <second>value2</second></a>
        // JSON: a: [ {first:value1, second:value2} ]
        if (output.contains(element.tagName().toStdString())) {
          // If it's an array already, append, else make it an array
          json temporaryJson;
          convertXmlToJson(next, temporaryJson);
          if (!output[element.tagName().toStdString()].is_array()) {
            json repeatedArray;
            repeatedArray.push_back(output[element.tagName().toStdString()]);
            output[element.tagName().replace(":", "_").toStdString()] = repeatedArray;
          }
          output[element.tagName().replace(":", "_").toStdString()].push_back(temporaryJson);
        }
        else {
          if (element.hasAttributes()) {
            json tempArea;
            QDomNamedNodeMap attrMap = element.attributes();
            for (int j=0; j < attrMap.size(); j++) {
              QDomAttr attr = attrMap.item(j).toAttr(); 
              tempArea["attrib_"+attr.name().toStdString()] = attr.value().toStdString();
            }
            tempArea.update(
                convertXmlToJson(next, output[element.tagName().toStdString()]));
            output[element.tagName().replace(":", "_").toStdString()] = tempArea;
          }
          else {
            output[element.tagName().toStdString()] = 
              convertXmlToJson(next, output[element.tagName().replace(":", "_").toStdString()]);
          }
        }
      }
      element = element.nextSiblingElement();
    }
    return output;
  }
}