Task 042: .ASPX File Format
Task 042: .ASPX File Format
The .ASPX file format is an Active Server Pages Extended format used for dynamic web pages in the Microsoft ASP.NET framework. It is a text-based format, not a binary one, and consists of HTML markup, server-side scripts (typically in C# or VB.NET), ASP.NET directives, and controls. Files are processed on the server to generate HTML output for browsers. There is no fixed binary structure or header; instead, the format relies on syntactic elements like directives (e.g., <%@ Page %>) that define configuration attributes.
The properties intrinsic to the .ASPX file format, as defined by its specifications (particularly the Page directive attributes used by the ASP.NET page parser and compiler), include the following. These are not file system metadata but format-specific attributes typically found in the <%@ Page %> directive at the start of the file:
- AutoEventWireup: Boolean value enabling or disabling automatic binding of page events to methods (e.g., Page_Load).
- Buffer: Boolean value enabling or disabling HTTP response buffering.
- ClassName: The class name for the page.
- ClientTarget: The target browser for rendering server controls.
- CodeFile: Name of the associated code-behind file.
- Debug: Boolean value enabling or disabling debug symbol compilation.
- Description: Textual description of the page (ignored by the parser).
- EnableSessionState: Enables, disables, or sets session state to read-only.
- EnableViewState: Boolean value enabling or disabling view state persistence across requests.
- ErrorPage: URL to redirect to on unhandled exceptions.
- Inherits: Name of the code-behind or base class.
- Language: Programming language for the code (e.g., C# or VB.NET).
- Src: File name of the code-behind class.
- Trace: Enables or disables tracing.
- TraceMode: Specifies how trace messages are displayed (e.g., sorted by time or category).
- Transaction: Indicates transaction support level.
- ValidateRequest: Boolean value enabling input validation against potentially dangerous values.
Two direct download links for .ASPX files (these are sample files from public repositories):
- https://raw.githubusercontent.com/anisrfd/asp.net-project/master/Sample.aspx
- https://gist.githubusercontent.com/spjeff/ca8e03e980669c36d383d8c9ba3a424e/raw/test.aspx
Below is the embedded HTML and JavaScript code for a Ghost blog (or any static site) that enables drag-and-drop of a .ASPX file. It reads the file content, parses the Page directive attributes using regular expressions, and displays the properties on the screen.
Drag and drop a .ASPX file here
Below is a Python class that can open, decode (parse), read, write (create a modified file), and print to console the properties from the list above.
import re
import os
class ASPXHandler:
def __init__(self, filename):
self.filename = filename
self.properties = {}
self.original_content = ''
def read(self):
if not os.path.exists(self.filename):
print(f"File {self.filename} does not exist.")
return
with open(self.filename, 'r', encoding='utf-8') as f:
self.original_content = f.read()
# Parse <%@ Page ... %>
directive_match = re.search(r'<%@\s*Page\s*(.*?)%>', self.original_content, re.IGNORECASE | re.DOTALL)
if directive_match:
attrs = directive_match.group(1)
# Parse key="value" or key=value
prop_matches = re.findall(r'(\w+)\s*=\s*(?:"([^"]*)"|\'([^\']*)\'|(\S+))', attrs)
for match in prop_matches:
key = match[0]
value = match[1] or match[2] or match[3]
self.properties[key] = value
else:
print("No Page directive found.")
def print_properties(self):
if not self.properties:
print("No properties extracted.")
return
print("Extracted Properties:")
for key, value in self.properties.items():
print(f"{key}: {value}")
def write(self, new_filename):
if not self.properties:
print("No properties to write.")
return
# Generate directive
directive = '<%@ Page '
for key, value in self.properties.items():
directive += f'{key}="{value}" '
directive += '%>\n'
# Basic template
content = directive + '<!DOCTYPE html>\n<html>\n<body>\n<h1>Modified ASPX</h1>\n</body>\n</html>'
with open(new_filename, 'w', encoding='utf-8') as f:
f.write(content)
print(f"Written to {new_filename}")
# Example usage:
# handler = ASPXHandler('sample.aspx')
# handler.read()
# handler.print_properties()
# handler.write('modified.aspx')
Below is a Java class that can open, decode (parse), read, write (create a modified file), and print to console the properties from the list above.
import java.io.*;
import java.util.*;
import java.util.regex.*;
public class ASPXHandler {
private String filename;
private Map<String, String> properties = new HashMap<>();
private String originalContent = "";
public ASPXHandler(String filename) {
this.filename = filename;
}
public void read() {
File file = new File(filename);
if (!file.exists()) {
System.out.println("File " + filename + " does not exist.");
return;
}
try (BufferedReader br = new BufferedReader(new FileReader(file))) {
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line).append("\n");
}
originalContent = sb.toString();
} catch (IOException e) {
e.printStackTrace();
return;
}
// Parse <%@ Page ... %>
Pattern directivePattern = Pattern.compile("<%@\\s*Page\\s*(.*?)%>", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
Matcher directiveMatcher = directivePattern.matcher(originalContent);
if (directiveMatcher.find()) {
String attrs = directiveMatcher.group(1);
// Parse key="value" or key=value
Pattern propPattern = Pattern.compile("(\\w+)\\s*=\\s*(\"([^\"]*)\"|'([^']*)'|(\\S+))");
Matcher propMatcher = propPattern.matcher(attrs);
while (propMatcher.find()) {
String key = propMatcher.group(1);
String value = propMatcher.group(3) != null ? propMatcher.group(3) :
propMatcher.group(4) != null ? propMatcher.group(4) : propMatcher.group(5);
properties.put(key, value);
}
} else {
System.out.println("No Page directive found.");
}
}
public void printProperties() {
if (properties.isEmpty()) {
System.out.println("No properties extracted.");
return;
}
System.out.println("Extracted Properties:");
for (Map.Entry<String, String> entry : properties.entrySet()) {
System.out.println(entry.getKey() + ": " + entry.getValue());
}
}
public void write(String newFilename) {
if (properties.isEmpty()) {
System.out.println("No properties to write.");
return;
}
StringBuilder directive = new StringBuilder("<%@ Page ");
for (Map.Entry<String, String> entry : properties.entrySet()) {
directive.append(entry.getKey()).append("=\"").append(entry.getValue()).append("\" ");
}
directive.append("%>\n");
String content = directive.toString() + "<!DOCTYPE html>\n<html>\n<body>\n<h1>Modified ASPX</h1>\n</body>\n</html>";
try (BufferedWriter bw = new BufferedWriter(new FileWriter(newFilename))) {
bw.write(content);
System.out.println("Written to " + newFilename);
} catch (IOException e) {
e.printStackTrace();
}
}
// Example usage:
// public static void main(String[] args) {
// ASPXHandler handler = new ASPXHandler("sample.aspx");
// handler.read();
// handler.printProperties();
// handler.write("modified.aspx");
// }
}
Below is a JavaScript class (for Node.js) that can open, decode (parse), read, write (create a modified file), and print to console the properties from the list above. Requires Node.js with 'fs' module.
const fs = require('fs');
class ASPXHandler {
constructor(filename) {
this.filename = filename;
this.properties = {};
this.originalContent = '';
}
read() {
if (!fs.existsSync(this.filename)) {
console.log(`File ${this.filename} does not exist.`);
return;
}
this.originalContent = fs.readFileSync(this.filename, 'utf-8');
// Parse <%@ Page ... %>
const directiveMatch = this.originalContent.match(/<%@\s*Page\s*(.*?)%>/i);
if (directiveMatch) {
const attrs = directiveMatch[1];
// Parse key="value" or key=value
const propMatches = attrs.matchAll(/(\w+)\s*=\s*(?:"([^"]*)"|'([^']*)'|(\S+))/g);
for (const match of propMatches) {
const key = match[1];
const value = match[2] || match[3] || match[4];
this.properties[key] = value;
}
} else {
console.log('No Page directive found.');
}
}
printProperties() {
if (Object.keys(this.properties).length === 0) {
console.log('No properties extracted.');
return;
}
console.log('Extracted Properties:');
for (const [key, value] of Object.entries(this.properties)) {
console.log(`${key}: ${value}`);
}
}
write(newFilename) {
if (Object.keys(this.properties).length === 0) {
console.log('No properties to write.');
return;
}
let directive = '<%@ Page ';
for (const [key, value] of Object.entries(this.properties)) {
directive += `${key}="${value}" `;
}
directive += '%>\n';
const content = directive + '<!DOCTYPE html>\n<html>\n<body>\n<h1>Modified ASPX</h1>\n</body>\n</html>';
fs.writeFileSync(newFilename, content, 'utf-8');
console.log(`Written to ${newFilename}`);
}
}
// Example usage:
// const handler = new ASPXHandler('sample.aspx');
// handler.read();
// handler.printProperties();
// handler.write('modified.aspx');
Below is a C++ class that can open, decode (parse), read, write (create a modified file), and print to console the properties from the list above. Uses standard libraries for file I/O and regex.
#include <iostream>
#include <fstream>
#include <string>
#include <regex>
#include <map>
class ASPXHandler {
private:
std::string filename;
std::map<std::string, std::string> properties;
std::string original_content;
public:
ASPXHandler(const std::string& fn) : filename(fn) {}
void read() {
std::ifstream file(filename);
if (!file.is_open()) {
std::cout << "File " << filename << " does not exist." << std::endl;
return;
}
std::string line;
while (std::getline(file, line)) {
original_content += line + "\n";
}
file.close();
// Parse <%@ Page ... %>
std::regex directive_regex(R"(<\%\@\s*Page\s*(.*?)\%\>)", std::regex::icase);
std::smatch directive_match;
if (std::regex_search(original_content, directive_match, directive_regex)) {
std::string attrs = directive_match[1].str();
// Parse key="value" or key=value
std::regex prop_regex(R"((\w+)\s*=\s*(?:"([^"]*)"|'([^']*)'|(\S+)))");
std::sregex_iterator iter(attrs.begin(), attrs.end(), prop_regex);
std::sregex_iterator end;
for (; iter != end; ++iter) {
std::string key = (*iter)[1].str();
std::string value = (*iter)[2].str().empty() ? ((*iter)[3].str().empty() ? (*iter)[4].str() : (*iter)[3].str()) : (*iter)[2].str();
properties[key] = value;
}
} else {
std::cout << "No Page directive found." << std::endl;
}
}
void print_properties() {
if (properties.empty()) {
std::cout << "No properties extracted." << std::endl;
return;
}
std::cout << "Extracted Properties:" << std::endl;
for (const auto& pair : properties) {
std::cout << pair.first << ": " << pair.second << std::endl;
}
}
void write(const std::string& new_filename) {
if (properties.empty()) {
std::cout << "No properties to write." << std::endl;
return;
}
std::string directive = "<%@ Page ";
for (const auto& pair : properties) {
directive += pair.first + "=\"" + pair.second + "\" ";
}
directive += "%>\n";
std::string content = directive + "<!DOCTYPE html>\n<html>\n<body>\n<h1>Modified ASPX</h1>\n</body>\n</html>";
std::ofstream out_file(new_filename);
if (out_file.is_open()) {
out_file << content;
out_file.close();
std::cout << "Written to " << new_filename << std::endl;
} else {
std::cout << "Failed to write file." << std::endl;
}
}
};
// Example usage:
// int main() {
// ASPXHandler handler("sample.aspx");
// handler.read();
// handler.print_properties();
// handler.write("modified.aspx");
// return 0;
// }