.XML

Task 839: .XML File Format

thinkmelt@protonmail.com

Dec 21, 2025 • 6 min read

Expanded Code for Full XML Parsing

The following sections expand upon the previously provided code to support full XML parsing. This includes not only extracting and handling the prolog properties (XML version, character encoding, and standalone status) but also parsing the entire document structure. For each language, the class now incorporates methods to traverse and print the hierarchical structure of elements, attributes, and text content. This enables a comprehensive representation of the XML document.

Parsing libraries or built-in facilities are utilized where appropriate to ensure robust handling:

Python: Enhanced use of xml.etree.ElementTree for tree traversal.
Java: Enhanced use of org.w3c.dom.Document for DOM traversal.
JavaScript: Enhanced use of xmldom for DOM traversal.
C++: Integrated basic parsing using pugixml (a lightweight XML library; assume it is included or linked, as standard C++ lacks built-in XML parsing). If pugixml is not available, a note is provided for alternatives.

The print_properties method now includes printing the full parsed structure in a readable, indented format. The write_file method remains focused on updating prolog properties but preserves the full document.

4. Expanded Python Class for Full XML Parsing

The class now includes a method to recursively traverse and print the XML tree structure.

import re import xml.etree.ElementTree as ET class XMLHandler: def __init__(self, filepath): self.filepath = filepath self.version = '1.0' self.encoding = 'UTF-8' self.standalone = 'no' self.tree = None self.root = None self._read_and_decode() def _read_and_decode(self): with open(self.filepath, 'r', encoding='utf-8') as f: content = f.read() # Extract declaration properties using regex declaration_match = re.search(r'<\?xml\s+(.*?) \?>', content) if declaration_match: attrs = declaration_match.group(1) version_match = re.search(r'version\s*=\s*["\'](.*?)["\']', attrs) if version_match: self.version = version_match.group(1) encoding_match = re.search(r'encoding\s*=\s*["\'](.*?)["\']', attrs) if encoding_match: self.encoding = encoding_match.group(1) standalone_match = re.search(r'standalone\s*=\s*["\'](.*?)["\']', attrs) if standalone_match: self.standalone = standalone_match.group(1) # Parse the XML content self.tree = ET.parse(self.filepath) self.root = self.tree.getroot() def _print_element(self, element, indent=0): print(' ' * indent + f"Element: {element.tag}") if element.attrib: print(' ' * (indent + 1) + f"Attributes: {element.attrib}") if element.text and element.text.strip(): print(' ' * (indent + 1) + f"Text: {element.text.strip()}") for child in element: self._print_element(child, indent + 1) def print_properties(self): print("XML Properties:") print(f"- XML Version: {self.version}") print(f"- Character Encoding: {self.encoding}") print(f"- Standalone Status: {self.standalone}") print("\nFull XML Structure:") if self.root: self._print_element(self.root) else: print("No root element found.") def write_file(self, output_filepath, new_version=None, new_encoding=None, new_standalone=None): if new_version: self.version = new_version if new_encoding: self.encoding = new_encoding if new_standalone: self.standalone = new_standalone declaration = f'\n' with open(output_filepath, 'w', encoding=self.encoding) as f: f.write(declaration) self.tree.write(f, encoding=self.encoding, xml_declaration=False) # Example usage: # handler = XMLHandler('example.xml') # handler.print_properties() # handler.write_file('output.xml', new_standalone='yes')

5. Expanded Java Class for Full XML Parsing

The class now includes a recursive method to traverse and print the DOM tree structure.

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.io.File;

public class XMLHandler {
    private String filepath;
    private String version;
    private String encoding;
    private String standalone;
    private Document document;

    public XMLHandler(String filepath) {
        this.filepath = filepath;
        this.version = "1.0";
        this.encoding = "UTF-8";
        this.standalone = "no";
        readAndDecode();
    }

    private void readAndDecode() {
        try {
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            document = builder.parse(new File(filepath));
            if (document.getXmlVersion() != null) {
                version = document.getXmlVersion();
            }
            if (document.getXmlEncoding() != null) {
                encoding = document.getXmlEncoding();
            }
            standalone = document.getXmlStandalone() ? "yes" : "no";
        } catch (Exception e) {
            System.err.println("Error parsing XML: " + e.getMessage());
        }
    }

    private void printElement(Node node, int indent) {
        if (node.getNodeType() == Node.ELEMENT_NODE) {
            Element element = (Element) node;
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < indent; i++) sb.append("  ");
            System.out.println(sb + "Element: " + element.getTagName());
            if (element.hasAttributes()) {
                System.out.println(sb + "  Attributes: " + element.getAttributes().item(0)); // Simplified; iterate for all
                for (int i = 0; i < element.getAttributes().getLength(); i++) {
                    Node attr = element.getAttributes().item(i);
                    System.out.println(sb + "    " + attr.getNodeName() + ": " + attr.getNodeValue());
                }
            }
            if (element.getTextContent() != null && !element.getTextContent().trim().isEmpty()) {
                System.out.println(sb + "  Text: " + element.getTextContent().trim());
            }
            NodeList children = element.getChildNodes();
            for (int i = 0; i < children.getLength(); i++) {
                printElement(children.item(i), indent + 1);
            }
        }
    }

    public void printProperties() {
        System.out.println("XML Properties:");
        System.out.println("- XML Version: " + version);
        System.out.println("- Character Encoding: " + encoding);
        System.out.println("- Standalone Status: " + standalone);
        System.out.println("\nFull XML Structure:");
        if (document != null) {
            printElement(document.getDocumentElement(), 0);
        } else {
            System.out.println("No document element found.");
        }
    }

    public void writeFile(String outputFilepath, String newVersion, String newEncoding, String newStandalone) {
        if (newVersion != null) version = newVersion;
        if (newEncoding != null) encoding = newEncoding;
        if (newStandalone != null) standalone = newStandalone;
        try {
            document.setXmlVersion(version);
            document.setXmlStandalone("yes".equals(standalone));
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer transformer = transformerFactory.newTransformer();
            transformer.setOutputProperty("encoding", encoding);
            transformer.setOutputProperty("standalone", standalone);
            DOMSource source = new DOMSource(document);
            StreamResult result = new StreamResult(new File(outputFilepath));
            transformer.transform(source, result);
        } catch (Exception e) {
            System.err.println("Error writing XML: " + e.getMessage());
        }
    }

    // Example usage:
    // public static void main(String[] args) {
    //     XMLHandler handler = new XMLHandler("example.xml");
    //     handler.printProperties();
    //     handler.writeFile("output.xml", null, null, "yes");
    // }
}

6. Expanded JavaScript Class for Full XML Parsing

The class now includes a recursive function to traverse and print the DOM tree structure.

const fs = require('fs');
const { DOMParser, XMLSerializer } = require('xmldom');

class XMLHandler {
  constructor(filepath) {
    this.filepath = filepath;
    this.version = '1.0';
    this.encoding = 'UTF-8';
    this.standalone = 'no';
    this.document = null;
    this.readAndDecode();
  }

  readAndDecode() {
    const content = fs.readFileSync(this.filepath, 'utf-8');
    const parser = new DOMParser();
    this.document = parser.parseFromString(content, 'application/xml');
    if (this.document.xmlVersion) this.version = this.document.xmlVersion;
    if (this.document.xmlEncoding) this.encoding = this.document.xmlEncoding;
    this.standalone = this.document.xmlStandalone ? 'yes' : 'no';
  }

  _printElement(element, indent = 0) {
    const prefix = '  '.repeat(indent);
    console.log(`${prefix}Element: ${element.tagName}`);
    if (element.attributes.length > 0) {
      console.log(`${prefix}  Attributes:`);
      for (let i = 0; i < element.attributes.length; i++) {
        const attr = element.attributes[i];
        console.log(`${prefix}    ${attr.name}: ${attr.value}`);
      }
    }
    if (element.textContent && element.textContent.trim()) {
      console.log(`${prefix}  Text: ${element.textContent.trim()}`);
    }
    const children = element.childNodes;
    for (let i = 0; i < children.length; i++) {
      if (children[i].nodeType === 1) { // Element node
        this._printElement(children[i], indent + 1);
      }
    }
  }

  printProperties() {
    console.log('XML Properties:');
    console.log(`- XML Version: ${this.version}`);
    console.log(`- Character Encoding: ${this.encoding}`);
    console.log(`- Standalone Status: ${this.standalone}`);
    console.log('\nFull XML Structure:');
    if (this.document && this.document.documentElement) {
      this._printElement(this.document.documentElement);
    } else {
      console.log('No root element found.');
    }
  }

  writeFile(outputFilepath, newVersion, newEncoding, newStandalone) {
    if (newVersion) this.version = newVersion;
    if (newEncoding) this.encoding = newEncoding;
    if (newStandalone) this.standalone = newStandalone;
    this.document.xmlVersion = this.version;
    this.document.xmlEncoding = this.encoding;
    this.document.xmlStandalone = this.standalone === 'yes';
    const serializer = new XMLSerializer();
    const xmlString = serializer.serializeToString(this.document);
    fs.writeFileSync(outputFilepath, xmlString, { encoding: this.encoding });
  }
}

// Example usage:
// const handler = new XMLHandler('example.xml');
// handler.printProperties();
// handler.writeFile('output.xml', null, null, 'yes');

7. Expanded C++ Class for Full XML Parsing

For full parsing in C++, the class integrates pugixml (a lightweight, header-only XML library; include pugixml.hpp in your project). If unavailable, consider alternatives like TinyXML or RapidXML. The class now includes a recursive function to traverse and print the XML tree structure.

#include <iostream>
#include <fstream>
#include <string>
#include <regex>
#include "pugixml.hpp"  // Assume pugixml.hpp is included; download from https://pugixml.org/ if needed.

class XMLHandler {
private:
    std::string filepath;
    std::string version;
    std::string encoding;
    std::string standalone;
    std::string content;
    pugi::xml_document doc;

public:
    XMLHandler(const std::string& filepath) : filepath(filepath), version("1.0"), encoding("UTF-8"), standalone("no") {
        readAndDecode();
    }

    void readAndDecode() {
        std::ifstream file(filepath);
        if (!file.is_open()) {
            std::cerr << "Error opening file." << std::endl;
            return;
        }
        std::string line;
        while (std::getline(file, line)) {
            content += line + "\n";
        }
        file.close();

        // Extract using regex for declaration (pugixml doesn't expose declaration directly)
        std::regex declaration_regex(R"(<\?xml\s+(.*?)\?>)");
        std::smatch match;
        if (std::regex_search(content, match, declaration_regex)) {
            std::string attrs = match[1].str();
            std::regex version_regex(R"(version\s*=\s*["'](.*?)["'])");
            std::smatch vmatch;
            if (std::regex_search(attrs, vmatch, version_regex)) version = vmatch[1].str();

            std::regex encoding_regex(R"(encoding\s*=\s*["'](.*?)["'])");
            std::smatch ematch;
            if (std::regex_search(attrs, ematch, encoding_regex)) encoding = ematch[1].str();

            std::regex standalone_regex(R"(standalone\s*=\s*["'](.*?)["'])");
            std::smatch smatch;
            if (std::regex_search(attrs, smatch, standalone_regex)) standalone = smatch[1].str();
        }

        // Full parsing with pugixml
        pugi::xml_parse_result result = doc.load_string(content.c_str());
        if (!result) {
            std::cerr << "Error parsing XML: " << result.description() << std::endl;
        }
    }

    void printElement(const pugi::xml_node& node, int indent = 0) {
        std::string prefix(indent * 2, ' ');
        std::cout << prefix << "Element: " << node.name() << std::endl;
        for (pugi::xml_attribute attr = node.first_attribute(); attr; attr = attr.next_attribute()) {
            std::cout << prefix << "  Attribute: " << attr.name() << " = " << attr.value() << std::endl;
        }
        if (!std::string(node.text().get()).empty()) {
            std::cout << prefix << "  Text: " << node.text().get() << std::endl;
        }
        for (pugi::xml_node child = node.first_child(); child; child = child.next_sibling()) {
            if (child.type() == pugi::node_element) {
                printElement(child, indent + 1);
            }
        }
    }

    void printProperties() {
        std::cout << "XML Properties:" << std::endl;
        std::cout << "- XML Version: " << version << std::endl;
        std::cout << "- Character Encoding: " << encoding << std::endl;
        std::cout << "- Standalone Status: " << standalone << std::endl;
        std::cout << "\nFull XML Structure:" << std::endl;
        pugi::xml_node root = doc.root();
        if (root) {
            printElement(root);
        } else {
            std::cout << "No root element found." << std::endl;
        }
    }

    void writeFile(const std::string& outputFilepath, const std::string& newVersion = "", const std::string& newEncoding = "", const std::string& newStandalone = "") {
        if (!newVersion.empty()) version = newVersion;
        if (!newEncoding.empty()) encoding = newEncoding;
        if (!newStandalone.empty()) standalone = newStandalone;

        std::string newDeclaration = "<?xml version=\"" + version + "\" encoding=\"" + encoding + "\" standalone=\"" + standalone + "\" ?>\n";

        // Replace old declaration
        std::regex oldDecl_regex(R"(^<\?xml\s+.*?\?\>\s*)");
        std::string newContent = std::regex_replace(content, oldDecl_regex, newDeclaration);

        // To preserve full structure, save using pugixml
        doc.save_file(outputFilepath.c_str(), "  ", pugi::format_indent, pugi::encoding_utf8);
    }
};

// Example usage:
// int main() {
//     XMLHandler handler("example.xml");
//     handler.printProperties();
//     handler.writeFile("output.xml", "", "", "yes");
//     return 0;
// }