Task 176: .EMAIL File Format
Task 176: .EMAIL File Format
1. List of all the properties of this file format intrinsic to its file system
The .EMAIL file format appears to be a reference to the .EML (Electronic Mail) file format, as no distinct .EMAIL extension is documented in standard file format specifications; .EML is the standard extension for email message files adhering to RFC 5322 (Internet Message Format) and MIME standards (RFC 2045-2049). Properties "intrinsic to its file system" refer to the internal structural elements of the file format itself, such as header fields and body components, rather than external file metadata like size or timestamps. Based on RFC 5322 and MIME extensions, the key properties (header fields and structural elements) are:
Trace Fields:
- Return-Path
- Received (can occur multiple times)
Resent Fields (for forwarded messages, can occur in blocks):
- Resent-Date
- Resent-From
- Resent-Sender
- Resent-To
- Resent-Cc
- Resent-Bcc
- Resent-Message-ID
Origination Date Field:
- Date
Originator Fields:
- From
- Sender
- Reply-To
Destination Address Fields:
- To
- Cc
- Bcc
Identification Fields:
- Message-ID
- In-Reply-To
- References
Informational Fields:
- Subject
- Comments (can occur multiple times)
- Keywords (can occur multiple times)
MIME-Specific Fields (for handling content, encoding, and attachments):
- MIME-Version
- Content-Type
- Content-Transfer-Encoding
- Content-Disposition
- Content-ID
- Content-Description
Optional/Custom Fields:
- Any user-defined fields (e.g., X-Mailer, X-Priority)
Structural Components:
- Header Section: Sequence of the above fields, each as "Field-Name: Value" followed by CRLF, with possible line folding (continuation lines starting with whitespace).
- Separator: A blank line (CRLF only) dividing headers from body.
- Body: The message content, which can be plain text, HTML, or multipart (e.g., for attachments), encoded via methods like base64 or quoted-printable.
These properties define the format's structure; the file is typically ASCII text, with binary attachments encoded.
2. Two direct download links for files of format .EMAIL
- http://file.fyicenter.com/b/sample.eml
- https://www.phpclasses.org/browse/download/1/file/14672/name/test%2Fsample%2Fmessage.eml
3. Ghost blog embedded html javascript that allows a user to drag n drop a file of format .EMAIL and it will dump to screen all these properties
Here's an HTML snippet with embedded JavaScript suitable for embedding in a Ghost blog post (or any HTML-based blog). It creates a drag-and-drop area; when a .eml file is dropped, it reads the file, parses the headers (handling folding), extracts the properties (headers), and dumps them to the screen along with the body. It assumes .EMAIL is .eml.
Drag and drop a .eml file here
4. Python class that can open any file of format .EMAIL and decode read and write and print to console all the properties from the above list
This Python class uses the built-in email module to parse .eml files. It reads the file, prints the properties (headers), decodes the body (handling MIME), and can write modifications back to a new file.
import email
from email import policy
from email.parser import BytesParser
class EmailFileHandler:
def __init__(self, filepath):
self.filepath = filepath
self.message = None
def read_and_decode(self):
with open(self.filepath, 'rb') as f:
self.message = BytesParser(policy=policy.default).parse(f)
return self.message
def print_properties(self):
if not self.message:
self.read_and_decode()
print("Properties (Headers):")
for header, value in self.message.items():
print(f"{header}: {value}")
print("\nBody:")
body = self.message.get_body(preferencelist=('plain', 'html'))
if body:
print(body.get_content())
else:
print(self.message.get_payload(decode=True).decode(errors='ignore'))
def write(self, output_filepath, modifications=None):
if not self.message:
self.read_and_decode()
if modifications:
for key, value in modifications.items():
self.message.replace_header(key, value) if key in self.message else self.message.add_header(key, value)
with open(output_filepath, 'wb') as f:
f.write(self.message.as_bytes())
# Example usage:
# handler = EmailFileHandler('sample.eml')
# handler.print_properties()
# handler.write('modified.eml', {'Subject': 'New Subject'})
5. Java class that can open any file of format .EMAIL and decode read and write and print to console all the properties from the above list
This Java class manually parses the .eml file (no external libs needed). It reads headers, handles folding, prints properties and body, and can write back with modifications.
import java.io.*;
import java.util.*;
public class EmailFileHandler {
private String filepath;
private Map<String, String> headers = new LinkedHashMap<>();
private String body;
public EmailFileHandler(String filepath) {
this.filepath = filepath;
}
public void readAndDecode() throws IOException {
try (BufferedReader reader = new BufferedReader(new FileReader(filepath))) {
String line;
String currentKey = null;
StringBuilder valueBuilder = new StringBuilder();
boolean inHeaders = true;
StringBuilder bodyBuilder = new StringBuilder();
while ((line = reader.readLine()) != null) {
if (inHeaders) {
if (line.trim().isEmpty()) {
inHeaders = false;
if (currentKey != null) {
headers.put(currentKey, valueBuilder.toString().trim());
}
continue;
}
if (line.matches("^[a-zA-Z0-9-]+:.*")) {
if (currentKey != null) {
headers.put(currentKey, valueBuilder.toString().trim());
}
int colonIndex = line.indexOf(':');
currentKey = line.substring(0, colonIndex).trim();
valueBuilder = new StringBuilder(line.substring(colonIndex + 1).trim());
} else if (currentKey != null && line.startsWith(" ") || line.startsWith("\t")) {
valueBuilder.append(" ").append(line.trim());
}
} else {
bodyBuilder.append(line).append("\n");
}
}
if (currentKey != null) {
headers.put(currentKey, valueBuilder.toString().trim());
}
body = bodyBuilder.toString().trim();
// Basic decoding (e.g., for quoted-printable or base64 would require additional logic; omitted for simplicity)
}
}
public void printProperties() {
System.out.println("Properties (Headers):");
for (Map.Entry<String, String> entry : headers.entrySet()) {
System.out.println(entry.getKey() + ": " + entry.getValue());
}
System.out.println("\nBody:");
System.out.println(body);
}
public void write(String outputFilepath, Map<String, String> modifications) throws IOException {
if (headers.isEmpty()) {
readAndDecode();
}
if (modifications != null) {
headers.putAll(modifications);
}
try (BufferedWriter writer = new BufferedWriter(new FileWriter(outputFilepath))) {
for (Map.Entry<String, String> entry : headers.entrySet()) {
writer.write(entry.getKey() + ": " + entry.getValue() + "\n");
}
writer.write("\n");
writer.write(body);
}
}
// Example usage:
// public static void main(String[] args) throws IOException {
// EmailFileHandler handler = new EmailFileHandler("sample.eml");
// handler.readAndDecode();
// handler.printProperties();
// Map<String, String> mods = new HashMap<>();
// mods.put("Subject", "New Subject");
// handler.write("modified.eml", mods);
// }
}
6. Javascript class that can open any file of format .EMAIL and decode read and write and print to console all the properties from the above list
This JavaScript class uses Node.js (fs module) to read/write .eml files, parse headers, and print to console. Run with Node.js.
const fs = require('fs');
class EmailFileHandler {
constructor(filepath) {
this.filepath = filepath;
this.headers = {};
this.body = '';
}
readAndDecode() {
const content = fs.readFileSync(this.filepath, 'utf8');
const lines = content.split(/\r?\n/);
let currentKey = '';
let inHeaders = true;
for (let line of lines) {
if (inHeaders) {
if (line.trim() === '') {
inHeaders = false;
continue;
}
if (/^[a-zA-Z0-9-]+:/.test(line)) {
const [key, value] = line.split(':', 2);
currentKey = key.trim();
this.headers[currentKey] = (value || '').trim();
} else if (currentKey && /^\s+/.test(line)) {
this.headers[currentKey] += ' ' + line.trim();
}
} else {
this.body += line + '\n';
}
}
this.body = this.body.trim();
// Basic decoding (advanced MIME would require libs like mime-js; omitted)
}
printProperties() {
console.log('Properties (Headers):');
for (let key in this.headers) {
console.log(`${key}: ${this.headers[key]}`);
}
console.log('\nBody:');
console.log(this.body);
}
write(outputFilepath, modifications) {
if (Object.keys(this.headers).length === 0) {
this.readAndDecode();
}
if (modifications) {
Object.assign(this.headers, modifications);
}
let content = '';
for (let key in this.headers) {
content += `${key}: ${this.headers[key]}\n`;
}
content += '\n' + this.body;
fs.writeFileSync(outputFilepath, content);
}
}
// Example usage:
// const handler = new EmailFileHandler('sample.eml');
// handler.readAndDecode();
// handler.printProperties();
// handler.write('modified.eml', { Subject: 'New Subject' });
7. C class that can open any file of format .EMAIL and decode read and write and print to console all the properties from the above list
This is a C++ class (since C doesn't have native classes; assuming "c class" means C++). It manually parses .eml, handles basic reading/writing, and prints to console.
#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <sstream>
class EmailFileHandler {
private:
std::string filepath;
std::map<std::string, std::string> headers;
std::string body;
public:
EmailFileHandler(const std::string& filepath) : filepath(filepath) {}
void readAndDecode() {
std::ifstream file(filepath);
if (!file.is_open()) {
std::cerr << "Error opening file" << std::endl;
return;
}
std::string line;
std::string currentKey;
bool inHeaders = true;
while (std::getline(file, line)) {
if (inHeaders) {
if (line.empty() || line == "\r") {
inHeaders = false;
continue;
}
size_t colonPos = line.find(':');
if (colonPos != std::string::npos && colonPos > 0) {
if (!currentKey.empty()) {
headers[currentKey] = trim(valueStream.str());
}
currentKey = trim(line.substr(0, colonPos));
valueStream.str(line.substr(colonPos + 1));
} else if (!currentKey.empty() && (line[0] == ' ' || line[0] == '\t')) {
valueStream << " " << trim(line);
}
} else {
body += line + "\n";
}
}
if (!currentKey.empty()) {
headers[currentKey] = trim(valueStream.str());
}
body = trim(body);
file.close();
// Basic decoding (no advanced MIME handling)
}
private:
std::string trim(const std::string& str) {
size_t first = str.find_first_not_of(" \t");
if (first == std::string::npos) return "";
size_t last = str.find_last_not_of(" \t");
return str.substr(first, (last - first + 1));
}
std::ostringstream valueStream;
public:
void printProperties() {
std::cout << "Properties (Headers):" << std::endl;
for (const auto& pair : headers) {
std::cout << pair.first << ": " << pair.second << std::endl;
}
std::cout << "\nBody:" << std::endl;
std::cout << body << std::endl;
}
void write(const std::string& outputFilepath, const std::map<std::string, std::string>& modifications) {
if (headers.empty()) {
readAndDecode();
}
for (const auto& mod : modifications) {
headers[mod.first] = mod.second;
}
std::ofstream file(outputFilepath);
if (!file.is_open()) {
std::cerr << "Error writing file" << std::endl;
return;
}
for (const auto& pair : headers) {
file << pair.first << ": " << pair.second << "\n";
}
file << "\n" << body;
file.close();
}
};
// Example usage:
// int main() {
// EmailFileHandler handler("sample.eml");
// handler.readAndDecode();
// handler.printProperties();
// std::map<std::string, std::string> mods = {{"Subject", "New Subject"}};
// handler.write("modified.eml", mods);
// return 0;
// }