Task 043: .ASX File Format
Task 043: .ASX File Format
The Advanced Stream Redirector (ASX) file format is an XML-based playlist format developed by Microsoft, primarily used to store references to Windows Media files (such as ASF, WMA, or WMV) for multimedia presentations. It facilitates streaming or local playback by referencing media files via URLs, supporting protocols like HTTP, RTSP, and MMS. Below, I address the task requirements by listing the intrinsic properties of the ASX file format and providing classes in Python, Java, JavaScript, and C to handle ASX files.
1. Properties of the ASX File Format Intrinsic to Its File System
Based on the available information, the ASX file format is a text-based XML metafile with the following intrinsic properties relevant to its structure and function within the file system:
- File Extension:
.asx - Format Type: XML-based playlist format
- MIME Type:
video/x-ms-asf(also used by ASF files) - Encoding: Supports ANSI and Unicode UTF-8
- Structure: Text-based, hierarchical XML with elements and attributes
- Primary Function: Stores a playlist of references to multimedia files (e.g., ASF, WMA, WMV) for sequential playback
- Supported Protocols: HTTP, RTSP, MMS
- File Reference Types: References local or remote multimedia files via URLs
- Supported Media Types: Audio and video
- Editability: High, as it is a text-based format editable with any text editor
- Security Risk: Low to medium (may reference malicious URLs, but the file itself is typically safe)
- Key XML Elements:
<ASX>: Root element with aVERSIONattribute (commonly 3.0)<ENTRY>: Defines individual media entries<REF>: Specifies the URL (HREF) of a media file<TITLE>: Optional title of the playlist or media entry<AUTHOR>: Optional author information<COPYRIGHT>: Optional copyright information<ABSTRACT>: Optional description of the content<DURATION>: Optional duration for media playback<BANNER>: Optional banner image or advertisement<MOREINFO>: Optional additional information or URLs- Case Sensitivity: Element names and attributes are not case-sensitive
- Compatibility: Primarily associated with Windows Media Player, but supported by other players like VLC, Winamp, and MediaMonkey
- Additional Features:
- Supports alternative URLs for fallback if a primary URL is unreachable
- Allows embedding of advertisements, banners, or logos
- Can include metadata for describing content
- Supports playlist creation for sequential playback of multiple media files
These properties are derived from the XML structure and the functional role of ASX files in referencing media for streaming or playback, as described in sources like Microsoft’s documentation and related references.
2. Python Class for ASX File Handling
Below is a Python class that can open, read, decode, write, and print the properties of an ASX file using the xml.etree.ElementTree module for XML parsing.
import xml.etree.ElementTree as ET
import os
class ASXFileHandler:
def __init__(self, filename):
self.filename = filename
self.properties = {
"file_extension": ".asx",
"format_type": "XML-based playlist",
"mime_type": "video/x-ms-asf",
"encoding": "UTF-8 or ANSI",
"structure": "Text-based, hierarchical XML",
"primary_function": "Stores playlist of media file references",
"supported_protocols": ["HTTP", "RTSP", "MMS"],
"file_reference_types": ["Local", "Remote"],
"supported_media_types": ["Audio", "Video"],
"editability": "High",
"security_risk": "Low to Medium",
"xml_elements": [],
"alternative_urls": [],
"metadata": {}
}
def read_asx(self):
"""Read and decode the ASX file."""
try:
tree = ET.parse(self.filename)
root = tree.getroot()
# Extract XML elements and attributes
self.properties["xml_elements"] = []
for elem in root.iter():
elem_info = {"tag": elem.tag, "attributes": elem.attrib, "text": elem.text}
self.properties["xml_elements"].append(elem_info)
# Check for alternative URLs in <REF> elements
if elem.tag.upper() == "REF" and "HREF" in elem.attrib:
self.properties["alternative_urls"].append(elem.attrib["HREF"])
# Extract metadata (e.g., TITLE, AUTHOR, COPYRIGHT, ABSTRACT)
if elem.tag.upper() in ["TITLE", "AUTHOR", "COPYRIGHT", "ABSTRACT"]:
self.properties["metadata"][elem.tag.lower()] = elem.text or ""
return True
except ET.ParseError:
print(f"Error: Failed to parse {self.filename}. Invalid XML format.")
return False
except FileNotFoundError:
print(f"Error: File {self.filename} not found.")
return False
def write_asx(self, output_filename):
"""Write the ASX properties to a new ASX file."""
try:
root = ET.Element("ASX", VERSION="3.0")
# Add metadata elements
for key, value in self.properties["metadata"].items():
if value:
elem = ET.SubElement(root, key.upper())
elem.text = value
# Add media entries from alternative_urls
for url in self.properties["alternative_urls"]:
entry = ET.SubElement(root, "ENTRY")
ref = ET.SubElement(entry, "REF", HREF=url)
# Write to file
tree = ET.ElementTree(root)
tree.write(output_filename, encoding="utf-8", xml_declaration=True)
print(f"Successfully wrote ASX file to {output_filename}")
return True
except Exception as e:
print(f"Error writing ASX file: {str(e)}")
return False
def print_properties(self):
"""Print all ASX file properties to console."""
print(f"ASX File Properties for {self.filename}:")
for key, value in self.properties.items():
if key == "xml_elements":
print(f"{key}:")
for elem in value:
print(f" Tag: {elem['tag']}, Attributes: {elem['attributes']}, Text: {elem['text']}")
elif key == "alternative_urls":
print(f"{key}: {', '.join(value)}")
elif key == "metadata":
print(f"{key}:")
for meta_key, meta_value in value.items():
print(f" {meta_key}: {meta_value}")
else:
print(f"{key}: {value}")
# Example usage
if __name__ == "__main__":
# Example ASX file content (for testing, save this as 'sample.asx')
"""
<?xml version="1.0" encoding="UTF-8"?>
<ASX VERSION="3.0">
<TITLE>Sample Playlist</TITLE>
<AUTHOR>John Doe</AUTHOR>
<COPYRIGHT>2025</COPYRIGHT>
<ABSTRACT>Sample multimedia playlist</ABSTRACT>
<ENTRY>
<REF HREF="http://example.com/media1.asf"/>
<TITLE>Media 1</TITLE>
</ENTRY>
<ENTRY>
<REF HREF="http://example.com/media2.asf"/>
<TITLE>Media 2</TITLE>
</ENTRY>
</ASX>
"""
handler = ASXFileHandler("sample.asx")
if handler.read_asx():
handler.print_properties()
handler.write_asx("output.asx")
Explanation:
- The class initializes with the intrinsic properties of the ASX format.
read_asx: Parses the XML file, extracts elements, attributes, alternative URLs, and metadata.write_asx: Creates a new ASX file using the stored properties.print_properties: Outputs all properties, including parsed XML elements and metadata, to the console.- Error handling ensures robustness for invalid files or XML.
- The example usage assumes a sample ASX file; you can create one with the provided content for testing.
3. Java Class for ASX File Handling
Below is a Java class using javax.xml.parsers to handle ASX files.
import org.w3c.dom.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.*;
import java.util.*;
public class ASXFileHandler {
private String filename;
private Map<String, Object> properties;
public ASXFileHandler(String filename) {
this.filename = filename;
this.properties = new HashMap<>();
initializeProperties();
}
private void initializeProperties() {
properties.put("file_extension", ".asx");
properties.put("format_type", "XML-based playlist");
properties.put("mime_type", "video/x-ms-asf");
properties.put("encoding", "UTF-8 or ANSI");
properties.put("structure", "Text-based, hierarchical XML");
properties.put("primary_function", "Stores playlist of media file references");
properties.put("supported_protocols", new String[]{"HTTP", "RTSP", "MMS"});
properties.put("file_reference_types", new String[]{"Local", "Remote"});
properties.put("supported_media_types", new String[]{"Audio", "Video"});
properties.put("editability", "High");
properties.put("security_risk", "Low to Medium");
properties.put("xml_elements", new ArrayList<Map<String, Object>>());
properties.put("alternative_urls", new ArrayList<String>());
properties.put("metadata", new HashMap<String, String>());
}
public boolean readASX() {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(new File(filename));
doc.getDocumentElement().normalize();
List<Map<String, Object>> xmlElements = new ArrayList<>();
List<String> alternativeUrls = new ArrayList<>();
Map<String, String> metadata = new HashMap<>();
NodeList nodeList = doc.getElementsByTagName("*");
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element elem = (Element) node;
Map<String, Object> elemInfo = new HashMap<>();
elemInfo.put("tag", elem.getTagName());
NamedNodeMap attrs = elem.getAttributes();
Map<String, String> attrMap = new HashMap<>();
for (int j = 0; j < attrs.getLength(); j++) {
attrMap.put(attrs.item(j).getNodeName(), attrs.item(j).getNodeValue());
}
elemInfo.put("attributes", attrMap);
elemInfo.put("text", elem.getTextContent().trim());
xmlElements.add(elemInfo);
if (elem.getTagName().equalsIgnoreCase("REF") && elem.hasAttribute("HREF")) {
alternativeUrls.add(elem.getAttribute("HREF"));
}
if (Arrays.asList("TITLE", "AUTHOR", "COPYRIGHT", "ABSTRACT")
.contains(elem.getTagName().toUpperCase())) {
metadata.put(elem.getTagName().toLowerCase(), elem.getTextContent().trim());
}
}
}
properties.put("xml_elements", xmlElements);
properties.put("alternative_urls", alternativeUrls);
properties.put("metadata", metadata);
return true;
} catch (Exception e) {
System.err.println("Error reading ASX file: " + e.getMessage());
return false;
}
}
public boolean writeASX(String outputFilename) {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.newDocument();
Element root = doc.createElement("ASX");
root.setAttribute("VERSION", "3.0");
doc.appendChild(root);
Map<String, String> metadata = (Map<String, String>) properties.get("metadata");
for (Map.Entry<String, String> entry : metadata.entrySet()) {
if (!entry.getValue().isEmpty()) {
Element elem = doc.createElement(entry.getKey().toUpperCase());
elem.setTextContent(entry.getValue());
root.appendChild(elem);
}
}
List<String> urls = (List<String>) properties.get("alternative_urls");
for (String url : urls) {
Element entry = doc.createElement("ENTRY");
Element ref = doc.createElement("REF");
ref.setAttribute("HREF", url);
entry.appendChild(ref);
root.appendChild(entry);
}
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(outputFilename));
transformer.transform(source, result);
System.out.println("Successfully wrote ASX file to " + outputFilename);
return true;
} catch (Exception e) {
System.err.println("Error writing ASX file: " + e.getMessage());
return false;
}
}
public void printProperties() {
System.out.println("ASX File Properties for " + filename + ":");
for (Map.Entry<String, Object> entry : properties.entrySet()) {
if (entry.getKey().equals("xml_elements")) {
System.out.println(entry.getKey() + ":");
List<Map<String, Object>> elements = (List<Map<String, Object>>) entry.getValue();
for (Map<String, Object> elem : elements) {
System.out.println(" Tag: " + elem.get("tag") + ", Attributes: " + elem.get("attributes") +
", Text: " + elem.get("text"));
}
} else if (entry.getKey().equals("alternative_urls")) {
System.out.println(entry.getKey() + ": " + String.join(", ", (List<String>) entry.getValue()));
} else if (entry.getKey().equals("metadata")) {
System.out.println(entry.getKey() + ":");
Map<String, String> metadata = (Map<String, String>) entry.getValue();
for (Map.Entry<String, String> meta : metadata.entrySet()) {
System.out.println(" " + meta.getKey() + ": " + meta.getValue());
}
} else {
System.out.println(entry.getKey() + ": " + entry.getValue());
}
}
}
public static void main(String[] args) {
ASXFileHandler handler = new ASXFileHandler("sample.asx");
if (handler.readASX()) {
handler.printProperties();
handler.writeASX("output.asx");
}
}
}
Explanation:
- The class uses
DocumentBuilderto parse the XML and extract elements, attributes, URLs, and metadata. writeASXcreates a new ASX file with the stored properties.printPropertiesdisplays all properties, handling lists and maps appropriately.- Error handling covers file and parsing issues.
- The main method demonstrates usage, assuming a sample ASX file exists.
4. JavaScript Class for ASX File Handling
Below is a JavaScript class using the fs module (Node.js) and xmldom for XML parsing.
const fs = require('fs');
const { DOMParser, XMLSerializer } = require('xmldom');
class ASXFileHandler {
constructor(filename) {
this.filename = filename;
this.properties = {
file_extension: '.asx',
format_type: 'XML-based playlist',
mime_type: 'video/x-ms-asf',
encoding: 'UTF-8 or ANSI',
structure: 'Text-based, hierarchical XML',
primary_function: 'Stores playlist of media file references',
supported_protocols: ['HTTP', 'RTSP', 'MMS'],
file_reference_types: ['Local', 'Remote'],
supported_media_types: ['Audio', 'Video'],
editability: 'High',
security_risk: 'Low to Medium',
xml_elements: [],
alternative_urls: [],
metadata: {}
};
}
readASX() {
try {
const data = fs.readFileSync(this.filename, 'utf-8');
const parser = new DOMParser();
const doc = parser.parseFromString(data, 'text/xml');
const elements = doc.getElementsByTagName('*');
this.properties.xml_elements = [];
this.properties.alternative_urls = [];
this.properties.metadata = {};
for (let i = 0; i < elements.length; i++) {
const elem = elements[i];
const elemInfo = {
tag: elem.tagName,
attributes: {},
text: elem.textContent.trim()
};
for (let j = 0; j < elem.attributes.length; j++) {
elemInfo.attributes[elem.attributes[j].name] = elem.attributes[j].value;
}
this.properties.xml_elements.push(elemInfo);
if (elem.tagName.toUpperCase() === 'REF' && elem.hasAttribute('HREF')) {
this.properties.alternative_urls.push(elem.getAttribute('HREF'));
}
if (['TITLE', 'AUTHOR', 'COPYRIGHT', 'ABSTRACT'].includes(elem.tagName.toUpperCase())) {
this.properties.metadata[elem.tagName.toLowerCase()] = elem.textContent.trim();
}
}
return true;
} catch (error) {
console.error(`Error reading ASX file: ${error.message}`);
return false;
}
}
writeASX(outputFilename) {
try {
const doc = new DOMParser().parseFromString('<ASX VERSION="3.0"></ASX>', 'text/xml');
const root = doc.documentElement;
for (const [key, value] of Object.entries(this.properties.metadata)) {
if (value) {
const elem = doc.createElement(key.toUpperCase());
elem.textContent = value;
root.appendChild(elem);
}
}
for (const url of this.properties.alternative_urls) {
const entry = doc.createElement('ENTRY');
const ref = doc.createElement('REF');
ref.setAttribute('HREF', url);
entry.appendChild(ref);
root.appendChild(entry);
}
const serializer = new XMLSerializer();
const xmlStr = serializer.serializeToString(doc);
fs.writeFileSync(outputFilename, xmlStr, 'utf-8');
console.log(`Successfully wrote ASX file to ${outputFilename}`);
return true;
} catch (error) {
console.error(`Error writing ASX file: ${error.message}`);
return false;
}
}
printProperties() {
console.log(`ASX File Properties for ${this.filename}:`);
for (const [key, value] of Object.entries(this.properties)) {
if (key === 'xml_elements') {
console.log(`${key}:`);
for (const elem of value) {
console.log(` Tag: ${elem.tag}, Attributes: ${JSON.stringify(elem.attributes)}, Text: ${elem.text}`);
}
} else if (key === 'alternative_urls') {
console.log(`${key}: ${value.join(', ')}`);
} else if (key === 'metadata') {
console.log(`${key}:`);
for (const [metaKey, metaValue] of Object.entries(value)) {
console.log(` ${metaKey}: ${metaValue}`);
}
} else {
console.log(`${key}: ${JSON.stringify(value)}`);
}
}
}
}
// Example usage
const handler = new ASXFileHandler('sample.asx');
if (handler.readASX()) {
handler.printProperties();
handler.writeASX('output.asx');
}
Explanation:
- Requires
xmldomfor XML parsing in Node.js (npm install xmldom). readASXparses the XML, extracting elements, URLs, and metadata.writeASXcreates a new ASX file using the stored properties.printPropertiesoutputs all properties to the console.- Error handling ensures robustness.
- Assumes a sample ASX file for testing.
5. C Class for ASX File Handling
C does not have a native "class" construct, so we use a struct and functions to emulate class-like behavior. This implementation uses libxml2 for XML parsing.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#define MAX_STR 256
#define MAX_URLS 100
#define MAX_ELEMENTS 100
typedef struct {
char filename[MAX_STR];
char* file_extension;
char* format_type;
char* mime_type;
char* encoding;
char* structure;
char* primary_function;
char* supported_protocols[3];
char* file_reference_types[2];
char* supported_media_types[2];
char* editability;
char* security_risk;
struct {
char tag[MAX_STR];
char attributes[MAX_STR];
char text[MAX_STR];
} xml_elements[MAX_ELEMENTS];
int xml_element_count;
char* alternative_urls[MAX_URLS];
int url_count;
struct {
char title[MAX_STR];
char author[MAX_STR];
char copyright[MAX_STR];
char abstract[MAX_STR];
} metadata;
} ASXFileHandler;
void init_asx_handler(ASXFileHandler* handler, const char* filename) {
strncpy(handler->filename, filename, MAX_STR - 1);
handler->file_extension = ".asx";
handler->format_type = "XML-based playlist";
handler->mime_type = "video/x-ms-asf";
handler->encoding = "UTF-8 or ANSI";
handler->structure = "Text-based, hierarchical XML";
handler->primary_function = "Stores playlist of media file references";
handler->supported_protocols[0] = "HTTP";
handler->supported_protocols[1] = "RTSP";
handler->supported_protocols[2] = "MMS";
handler->file_reference_types[0] = "Local";
handler->file_reference_types[1] = "Remote";
handler->supported_media_types[0] = "Audio";
handler->supported_media_types[1] = "Video";
handler->editability = "High";
handler->security_risk = "Low to Medium";
handler->xml_element_count = 0;
handler->url_count = 0;
memset(handler->metadata.title, 0, MAX_STR);
memset(handler->metadata.author, 0, MAX_STR);
memset(handler->metadata.copyright, 0, MAX_STR);
memset(handler->metadata.abstract, 0, MAX_STR);
}
int read_asx(ASXFileHandler* handler) {
xmlDocPtr doc;
xmlNodePtr cur;
doc = xmlParseFile(handler->filename);
if (doc == NULL) {
fprintf(stderr, "Error: Failed to parse %s\n", handler->filename);
return 0;
}
cur = xmlDocGetRootElement(doc);
if (cur == NULL) {
fprintf(stderr, "Error: Empty document\n");
xmlFreeDoc(doc);
return 0;
}
handler->xml_element_count = 0;
handler->url_count = 0;
for (xmlNodePtr node = cur; node; node = node->next) {
if (node->type == XML_ELEMENT_NODE) {
if (handler->xml_element_count < MAX_ELEMENTS) {
strncpy(handler->xml_elements[handler->xml_element_count].tag, (char*)node->name, MAX_STR - 1);
xmlChar* content = xmlNodeGetContent(node);
strncpy(handler->xml_elements[handler->xml_element_count].text, (char*)content, MAX_STR - 1);
xmlFree(content);
char attr_str[MAX_STR] = "";
for (xmlAttrPtr attr = node->properties; attr; attr = attr->next) {
xmlChar* value = xmlGetProp(node, attr->name);
snprintf(attr_str + strlen(attr_str), MAX_STR - strlen(attr_str) - 1,
"%s=%s ", attr->name, value);
xmlFree(value);
}
strncpy(handler->xml_elements[handler->xml_element_count].attributes, attr_str, MAX_STR - 1);
handler->xml_element_count++;
if (strcasecmp((char*)node->name, "REF") == 0) {
xmlChar* href = xmlGetProp(node, (xmlChar*)"HREF");
if (href && handler->url_count < MAX_URLS) {
handler->alternative_urls[handler->url_count] = strdup((char*)href);
handler->url_count++;
}
xmlFree(href);
}
if (strcasecmp((char*)node->name, "TITLE") == 0) {
strncpy(handler->metadata.title, (char*)content, MAX_STR - 1);
} else if (strcasecmp((char*)node->name, "AUTHOR") == 0) {
strncpy(handler->metadata.author, (char*)content, MAX_STR - 1);
} else if (strcasecmp((char*)node->name, "COPYRIGHT") == 0) {
strncpy(handler->metadata.copyright, (char*)content, MAX_STR - 1);
} else if (strcasecmp((char*)node->name, "ABSTRACT") == 0) {
strncpy(handler->metadata.abstract, (char*)content, MAX_STR - 1);
}
}
}
for (xmlNodePtr child = node->children; child; child = child->next) {
// Recursive call to handle nested elements
xmlNodePtr temp = cur;
cur = child;
read_asx(handler); // Re-process for nested nodes
cur = temp;
}
}
xmlFreeDoc(doc);
return 1;
}
int write_asx(ASXFileHandler* handler, const char* output_filename) {
xmlDocPtr doc = xmlNewDoc((xmlChar*)"1.0");
xmlNodePtr root = xmlNewNode(NULL, (xmlChar*)"ASX");
xmlNewProp(root, (xmlChar*)"VERSION", (xmlChar*)"3.0");
xmlDocSetRootElement(doc, root);
if (strlen(handler->metadata.title) > 0) {
xmlNewChild(root, NULL, (xmlChar*)"TITLE", (xmlChar*)handler->metadata.title);
}
if (strlen(handler->metadata.author) > 0) {
xmlNewChild(root, NULL, (xmlChar*)"AUTHOR", (xmlChar*)handler->metadata.author);
}
if (strlen(handler->metadata.copyright) > 0) {
xmlNewChild(root, NULL, (xmlChar*)"COPYRIGHT", (xmlChar*)handler->metadata.copyright);
}
if (strlen(handler->metadata.abstract) > 0) {
xmlNewChild(root, NULL, (xmlChar*)"ABSTRACT", (xmlChar*)handler->metadata.abstract);
}
for (int i = 0; i < handler->url_count; i++) {
xmlNodePtr entry = xmlNewChild(root, NULL, (xmlChar*)"ENTRY", NULL);
xmlNodePtr ref = xmlNewChild(entry, NULL, (xmlChar*)"REF", NULL);
xmlNewProp(ref, (xmlChar*)"HREF", (xmlChar*)handler->alternative_urls[i]);
}
int result = xmlSaveFormatFileEnc(output_filename, doc, "UTF-8", 1);
xmlFreeDoc(doc);
if (result == -1) {
fprintf(stderr, "Error writing ASX file: %s\n", output_filename);
return 0;
}
printf("Successfully wrote ASX file to %s\n", output_filename);
return 1;
}
void print_properties(ASXFileHandler* handler) {
printf("ASX File Properties for %s:\n", handler->filename);
printf("file_extension: %s\n", handler->file_extension);
printf("format_type: %s\n", handler->format_type);
printf("mime_type: %s\n", handler->mime_type);
printf("encoding: %s\n", handler->encoding);
printf("structure: %s\n", handler->structure);
printf("primary_function: %s\n", handler->primary_function);
printf("supported_protocols: %s, %s, %s\n",
handler->supported_protocols[0], handler->supported_protocols[1], handler->supported_protocols[2]);
printf("file_reference_types: %s, %s\n",
handler->file_reference_types[0], handler->file_reference_types[1]);
printf("supported_media_types: %s, %s\n",
handler->supported_media_types[0], handler->supported_media_types[1]);
printf("editability: %s\n", handler->editability);
printf("security_risk: %s\n", handler->security_risk);
printf("xml_elements:\n");
for (int i = 0; i < handler->xml_element_count; i++) {
printf(" Tag: %s, Attributes: %s, Text: %s\n",
handler->xml_elements[i].tag, handler->xml_elements[i].attributes, handler->xml_elements[i].text);
}
printf("alternative_urls: ");
for (int i = 0; i < handler->url_count; i++) {
printf("%s%s", handler->alternative_urls[i], i < handler->url_count - 1 ? ", " : "");
}
printf("\n");
printf("metadata:\n");
if (strlen(handler->metadata.title) > 0) printf(" title: %s\n", handler->metadata.title);
if (strlen(handler->metadata.author) > 0) printf(" author: %s\n", handler->metadata.author);
if (strlen(handler->metadata.copyright) > 0) printf(" copyright: %s\n", handler->metadata.copyright);
if (strlen(handler->metadata.abstract) > 0) printf(" abstract: %s\n", handler->metadata.abstract);
}
void free_asx_handler(ASXFileHandler* handler) {
for (int i = 0; i < handler->url_count; i++) {
free(handler->alternative_urls[i]);
}
}
int main() {
ASXFileHandler handler;
init_asx_handler(&handler, "sample.asx");
if (read_asx(&handler)) {
print_properties(&handler);
write_asx(&handler, "output.asx");
}
free_asx_handler(&handler);
return 0;
}
Explanation:
- Uses
libxml2for XML parsing (apt-get install libxml2-devand compile with-lxml2). init_asx_handlersets up the properties.read_asxparses the XML, extracting elements, URLs, and metadata.write_asxcreates a new ASX file.print_propertiesoutputs all properties.- Memory management prevents leaks.
- Assumes a sample ASX file for testing.
Notes
- Testing: Create a
sample.asxfile with the example content provided in the Python section for testing each implementation. - Dependencies:
- Python: Requires
xml.etree.ElementTree(standard library). - Java: Uses standard
javax.xmllibraries. - JavaScript: Requires
xmldom(npm install xmldom) and Node.js. - C: Requires
libxml2(install and link appropriately). - Limitations: The implementations focus on core ASX elements (
ASX,ENTRY,REF,TITLE,AUTHOR,COPYRIGHT,ABSTRACT). Additional elements likeBANNERorDURATIONcan be added by extending the parsing logic. - Error Handling: Each class includes robust error handling for file access and XML parsing issues.
- Sources: Properties and structure are based on information from Microsoft’s ASX documentation and related sources.
If you need further clarification or additional features (e.g., handling specific ASX elements), please let me know!
- ASX properties (XML elements and attributes):
- ASX (root): VERSION (decimal, req), PREVIEWMODE (YES/NO, opt), BANNERBAR (AUTO/FIXED, opt)
- ABSTRACT: VALUE (text)
- AUTHOR: VALUE (text)
- BANNER: HREF (URL), ABSTRACT (text), MOREINFO (URL)
- BASE: HREF (URL)
- COPYRIGHT: VALUE (text)
- DURATION: VALUE (hh:mm:ss)
- ENDMARKER: NUMBER/NAME (marker)
- ENTRY: CLIENTSKIP (YES/NO), SKIPIFREF (YES/NO)
- ENTRYREF: HREF (URL), CLIENTBIND (YES/NO)
- EVENT: NAME (string), WHENDONE (RESUME/NEXT/EXIT)
- LOGURL: HREF (URL)
- MOREINFO: HREF (URL), TARGET (frame)
- PARAM: NAME (string), VALUE (string)
- PREVIEWDURATION: VALUE (seconds)
- REF: HREF (URL)
- REPEAT: COUNT (integer)
- STARTMARKER: NUMBER/NAME (marker)
- STARTTIME: VALUE (hh:mm:ss)
- TITLE: VALUE (text)
- Comments:
- Python class:
import xml.etree.ElementTree as ET
class ASXHandler:
def __init__(self):
self.tree = None
self.root = None
def open(self, filename):
self.tree = ET.parse(filename)
self.root = self.tree.getroot()
def read_properties(self):
props = {}
props['ASX'] = self.root.attrib
for elem in self.root.iter():
if elem.tag != 'ASX':
props[elem.tag] = {'attrib': elem.attrib, 'text': elem.text}
return props
def write_properties(self, filename, props):
root = ET.Element('ASX', props.get('ASX', {}))
for tag, data in props.items():
if tag != 'ASX':
sub = ET.SubElement(root, tag, data.get('attrib', {}))
sub.text = data.get('text')
tree = ET.ElementTree(root)
tree.write(filename, encoding='utf-8', xml_declaration=True)
- Java class:
import javax.xml.parsers.*;
import org.w3c.dom.*;
import java.io.*;
import java.util.HashMap;
import java.util.Map;
public class ASXHandler {
private Document doc;
public void open(String filename) throws Exception {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(new File(filename));
}
public Map<String, Object> readProperties() {
Map<String, Object> props = new HashMap<>();
Element root = doc.getDocumentElement();
NamedNodeMap attribs = root.getAttributes();
Map<String, String> rootAttrib = new HashMap<>();
for (int i = 0; i < attribs.getLength(); i++) {
Attr attr = (Attr) attribs.item(i);
rootAttrib.put(attr.getName(), attr.getValue());
}
props.put("ASX", rootAttrib);
NodeList nodes = root.getChildNodes();
for (int i = 0; i < nodes.getLength(); i++) {
if (nodes.item(i) instanceof Element) {
Element elem = (Element) nodes.item(i);
Map<String, Object> data = new HashMap<>();
NamedNodeMap elemAttrib = elem.getAttributes();
Map<String, String> attrMap = new HashMap<>();
for (int j = 0; j < elemAttrib.getLength(); j++) {
Attr attr = (Attr) elemAttrib.item(j);
attrMap.put(attr.getName(), attr.getValue());
}
data.put("attrib", attrMap);
data.put("text", elem.getTextContent());
props.put(elem.getTagName(), data);
}
}
return props;
}
public void writeProperties(String filename, Map<String, Object> props) throws Exception {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document newDoc = db.newDocument();
Element root = newDoc.createElement("ASX");
@SuppressWarnings("unchecked")
Map<String, String> rootAttrib = (Map<String, String>) props.get("ASX");
for (Map.Entry<String, String> entry : rootAttrib.entrySet()) {
root.setAttribute(entry.getKey(), entry.getValue());
}
newDoc.appendChild(root);
for (Map.Entry<String, Object> p : props.entrySet()) {
if (!p.getKey().equals("ASX")) {
Element sub = newDoc.createElement(p.getKey());
@SuppressWarnings("unchecked")
Map<String, Object> data = (Map<String, Object>) p.getValue();
@SuppressWarnings("unchecked")
Map<String, String> attrMap = (Map<String, String>) data.get("attrib");
for (Map.Entry<String, String> attr : attrMap.entrySet()) {
sub.setAttribute(attr.getKey(), attr.getValue());
}
sub.setTextContent((String) data.get("text"));
root.appendChild(sub);
}
}
TransformerFactory tf = TransformerFactory.newInstance();
Transformer t = tf.newTransformer();
DOMSource source = new DOMSource(newDoc);
StreamResult result = new StreamResult(new File(filename));
t.transform(source, result);
}
}
- Javascript class:
const fs = require('fs');
const { DOMParser, XMLSerializer } = require('xmldom');
class ASXHandler {
constructor() {
this.doc = null;
}
open(filename) {
const xml = fs.readFileSync(filename, 'utf8');
this.doc = new DOMParser().parseFromString(xml);
}
readProperties() {
const props = {};
const root = this.doc.documentElement;
props['ASX'] = {};
for (let i = 0; i < root.attributes.length; i++) {
const attr = root.attributes[i];
props['ASX'][attr.name] = attr.value;
}
const children = root.childNodes;
for (let i = 0; i < children.length; i++) {
if (children[i].nodeType === 1) {
const elem = children[i];
const data = { attrib: {}, text: elem.textContent };
for (let j = 0; j < elem.attributes.length; j++) {
const attr = elem.attributes[j];
data.attrib[attr.name] = attr.value;
}
props[elem.tagName] = data;
}
}
return props;
}
writeProperties(filename, props) {
const newDoc = new DOMParser().parseFromString('<ASX/>');
const root = newDoc.documentElement;
const rootAttrib = props['ASX'] || {};
for (const key in rootAttrib) {
root.setAttribute(key, rootAttrib[key]);
}
for (const tag in props) {
if (tag !== 'ASX') {
const sub = newDoc.createElement(tag);
const data = props[tag];
const attrib = data.attrib || {};
for (const key in attrib) {
sub.setAttribute(key, attrib[key]);
}
sub.textContent = data.text || '';
root.appendChild(sub);
}
}
const serializer = new XMLSerializer();
const xmlStr = serializer.serializeToString(newDoc);
fs.writeFileSync(filename, xmlStr);
}
}
- C++ class (using TinyXML2, assume available):
#include <tinyxml2.h>
#include <string>
#include <map>
#include <fstream>
class ASXHandler {
private:
tinyxml2::XMLDocument doc;
public:
void open(const std::string& filename) {
doc.LoadFile(filename.c_str());
}
std::map<std::string, std::map<std::string, std::string>> readProperties() {
std::map<std::string, std::map<std::string, std::string>> props;
tinyxml2::XMLElement* root = doc.FirstChildElement("ASX");
if (root) {
std::map<std::string, std::string> rootAttrib;
for (const tinyxml2::XMLAttribute* attr = root->FirstAttribute(); attr; attr = attr->Next()) {
rootAttrib[attr->Name()] = attr->Value();
}
props["ASX"] = rootAttrib;
for (tinyxml2::XMLElement* elem = root->FirstChildElement(); elem; elem = elem->NextSiblingElement()) {
std::map<std::string, std::string> data;
data["text"] = elem->GetText() ? elem->GetText() : "";
for (const tinyxml2::XMLAttribute* attr = elem->FirstAttribute(); attr; attr = attr->Next()) {
data[attr->Name()] = attr->Value();
}
props[elem->Name()] = data;
}
}
return props;
}
void writeProperties(const std::string& filename, const std::map<std::string, std::map<std::string, std::string>>& props) {
tinyxml2::XMLDocument newDoc;
tinyxml2::XMLElement* root = newDoc.NewElement("ASX");
auto it = props.find("ASX");
if (it != props.end()) {
for (const auto& attr : it->second) {
root->SetAttribute(attr.first.c_str(), attr.second.c_str());
}
}
newDoc.InsertFirstChild(root);
for (const auto& p : props) {
if (p.first != "ASX") {
tinyxml2::XMLElement* sub = newDoc.NewElement(p.first.c_str());
const auto& data = p.second;
auto textIt = data.find("text");
if (textIt != data.end()) {
sub->SetText(textIt->second.c_str());
}
for (const auto& attr : data) {
if (attr.first != "text") {
sub->SetAttribute(attr.first.c_str(), attr.second.c_str());
}
}
root->InsertEndChild(sub);
}
}
newDoc.SaveFile(filename.c_str());
}
};