core/email_server/EmailServer.py

import email
import os
import socket
import threading
import logging
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from queue import Queue

import pandas as pd

# Server configuration
SERVER_HOST = '0.0.0.0'
SERVER_PORT = 1234
saveMail_directory = os.getenv("SAVE_MAIL_DIRECTORY", "FlowSteering/ApplicationCode/EmailServer/EmailServerMailDatabase")  # Change this to the directory where you want to save the emails inbox for each user
if not saveMail_directory:
    raise ValueError("SAVE_MAIL_DIRECTORY environment variable is not set.")
message_queue = Queue()
default_image = 'FlowSteering/assets/PerturbatedImages/DjiPerturbClassForward.png'
# Server configuration

# Configure logging
logging.basicConfig(level=logging.ERROR, format='%(asctime)s - %(levelname)s - %(message)s')

def receive_complete_data(
        client_socket):  # This function is used to receive the complete data from the client, adjust the parameters as needed based on your network conditions
    received_data = b""
    count = 0
    client_socket.settimeout(3.0)
    try:
        while True:
            chunk = client_socket.recv(2 ** 16)  # Adjust the buffer size as needed
            if not chunk:
                count += 1
            else:
                count = 0
                received_data += chunk
            if count >= 50:
                break

    except socket.timeout as e:
        print('timeout')
        print(e)
    except Exception as e:
        print(f"Error receiving data: {e}")

    return received_data


def handle_messages():  # This function is used to handle the messages in the queue and process them accordingly based on the command received from the client (e.g., SEND_EMAIL, CHECK_INBOX)
    while True:
        if not message_queue.empty():

            print('______________________________________________________________')

            data, client_socket, client_address = message_queue.get()

            msg = email.message_from_bytes(data)

            Command, subject, sender, recipient = msg['Command'], msg["Subject"], msg["From"], msg["To"]

            if Command == "CHECK_INBOX":
                print("Checking Inbox")
                Check_Inbox(client_socket,
                            sender)  # This function is used to check the inbox of the user and send the email to the client
            elif Command == "SEND_EMAIL":  # This is the command to send the email to the recipient
                print("Sending Email")
                Save_Email_To_Recipient(client_socket, data, msg, Command, subject, sender,
                                        recipient)  # This function is used to save the email to the recipient's inbox
            print('______________________________________________________________')
            client_socket.close()


def Save_Email_To_Recipient(client_socket, data, msg, requests, subject, sender, recipient): # This function is used to save the email to the recipient's inbox
    try:
        recipient_directory = f"{saveMail_directory}/{recipient}" # This is the directory where the emails will be saved
        os.makedirs(recipient_directory, exist_ok=True) # Create the directory if it doesn't exist

        msg = email.message_from_bytes(data)

        try:
            if msg.is_multipart():
                for part in msg.get_payload():
                    if part.get_content_type() == "text/plain":
                        body = part.get_payload()
            else:
                body = msg.get_payload()
        except Exception as e:
            logging.error(f"Error processing email message: {e}")
            client_socket.sendall("Error processing email message".encode('utf-8'))
            return

        for part in msg.walk():
            if part.get_content_maintype() == "multipart":
                continue
            if part.get("Content-Disposition") is None:
                continue

            # Get the filename
            filename = part.get_filename()
            # split the filename by "\" and take the last part of it
            #filename = filename.split("\\")[-1]
            filename = filename.split("/")[-1]

            # Save the image file
            try:
                with open(os.path.join(recipient_directory, filename), "wb") as f:
                    f.write(part.get_payload(decode=True))
            except Exception as e:
                logging.error(f"Error saving email attachment: {e}")
                client_socket.sendall("Error saving email attachment".encode('utf-8'))
                return

        print(f"From: {sender}")
        print(f"To: {recipient}")
        print(f"Subject: {subject}")
        print(f"Attachment filename: {filename}")
        print(f' Text body: {body}')


        filepath = str(f"{recipient_directory}/{filename}")

        email_data = [[sender, recipient, subject, body, filepath]]

        MyColumns = ['Sender', 'Recipient', 'Subject', 'Body', 'FilePath']
        if not os.path.isfile(f"{recipient_directory}/{recipient}_received_emails.csv") or (
                os.stat(f"{recipient_directory}/{recipient}_received_emails.csv").st_size == 0): # If the file doesn't exist, then create the file and save the email to the file
            df = pd.DataFrame(email_data, columns=MyColumns)
            try:
                df.to_csv(f"{recipient_directory}/{recipient}_received_emails.csv", mode='w', header=True, index=False) # Save the email to the recipient's inbox
                df.to_csv(f"{recipient_directory}/{recipient}_received_emailsHistory.csv", mode='w', header=True, index=False) # Save the email to the recipient's inbox history
            except Exception as e:
                logging.error(f"Error saving email to CSV: {e}")
                client_socket.sendall("Error saving email to CSV".encode('utf-8'))
                return

        else: # If the file already exists, then append the email to the file

            try:
                df = pd.read_csv(f"{recipient_directory}/{recipient}_received_emails.csv") # Read the csv file of the recipient
                new_row_df = pd.DataFrame(email_data, columns=df.columns)
                df = pd.concat([df, new_row_df], ignore_index=True)
                df.to_csv(f"{recipient_directory}/{recipient}_received_emails.csv", mode='w', header=True, index=False)
                df = pd.read_csv(f"{recipient_directory}/{recipient}_received_emailsHistory.csv")
                df = pd.concat([df, new_row_df], ignore_index=True)
                df.to_csv(f"{recipient_directory}/{recipient}_received_emailsHistory.csv", mode='w', header=True, index=False)
            except Exception as e:
                logging.error(f"Error appending email to CSV: {e}")
                client_socket.sendall("Error appending email to CSV".encode('utf-8'))
                return

        # write back to the sender that the email was sent
        client_socket.sendall("Email Sent".encode('utf-8'))
    except Exception as e:
        logging.error(f"Unhandled exception in Save_Email_To_Recipient: {e}")
        client_socket.sendall("Unhandled exception in Save_Email_To_Recipient".encode('utf-8'))


def Check_Inbox(client_socket, sender): # This function is used to check the inbox of the user and send the email to the client
    try:
        print(f' A request ot check the inbox email from: {sender}')

        sender_directory = f"{saveMail_directory}/{sender}"
        os.makedirs(sender_directory, exist_ok=True)

        if (not os.path.isfile(f"{sender_directory}/{sender}_received_emails.csv")) or (
                os.stat(f"{sender_directory}/{sender}_received_emails.csv").st_size == 0):
            client_socket.sendall("No Emails".encode('utf-8'))
            return
        df = pd.read_csv(f"{sender_directory}/{sender}_received_emails.csv")
        rows = df.shape[0]
        print(f'found {rows} emails in the inbox of {sender}')
        if rows == 0: # If there are no emails in the inbox, then send "No Emails" to the client
            client_socket.sendall("No Emails".encode('utf-8'))
            return
        else: # If there are emails in the inbox, then send the email to the client
            # take the last row of the csv file
            header_columns = df.columns
            last_row = df.tail(1)
            msg = MIMEMultipart()
            msg["Command"] = "SEND_EMAIL"
            msg["From"] = last_row['Sender'].values[0]
            msg["To"] = last_row['Recipient'].values[0]
            msg["Subject"] = last_row['Subject'].values[0]
            msg.attach(MIMEText(last_row['Body'].values[0], "plain"))

            filename = last_row['FilePath'].values[0]
            with open(filename, "rb") as f:
                try:  #We faced some network errors resulting in images being sent partially black. To address this issue, we implemented a try-except block to handle such occurrences. Now, if an image fails to send correctly, a default image is sent for that experiment.
                    img = MIMEImage(f.read())
                    img.add_header("Content-Disposition", "attachment", filename=filename)
                    msg.attach(img)
                except Exception as e:
                    logging.error(f"Error sending image: {e}")
                    print('network error, sending default image instead of the original image')
                    with open(default_image,"rb") as f:
                        img = MIMEImage(f.read())
                        img.add_header("Content-Disposition", "attachment", filename=filename)
                        msg.attach(img)

            message = msg.as_bytes()
            # send the message to the client
            df.drop(df.tail(1).index, inplace=True)

            df.to_csv(f"{sender_directory}/{sender}_received_emails.csv", mode='w', header=True, index=False)
            client_socket.sendall(message)
            return
    except Exception as e:
        logging.error(f"Unhandled exception in Check_Inbox: {e}")
        client_socket.sendall("Unhandled exception in Check_Inbox".encode('utf-8'))

def prevent_deletion_of_exploits():
    print("Preventing deletion of exploits or resources/tools")
    # Add your preventive measures here

def start_server():
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind((SERVER_HOST, SERVER_PORT))
    server_socket.listen(1000)

    print(f"Server listening on {SERVER_HOST}:{SERVER_PORT}")

    threading.Thread(target=handle_messages, daemon=True).start()

    prevent_deletion_of_exploits()

    while True:
        client_socket, client_address = server_socket.accept()
        print(len(message_queue.queue))

        # Receive complete data from the client
        data = receive_complete_data(client_socket)

        if data:
            print(f"Received message from {client_address} put in queue")
            message_queue.put((data, client_socket, client_address))


if __name__ == '__main__':
    os.makedirs(saveMail_directory, exist_ok=True)
    start_server()