Jmail Server v1.0

Jmail is a simple socket-based mail server that allows clients to send and receive messages between users. The server handles multiple client connections and stores the messages persistently using JSON files.

Features

• Socket-Based Server: Listens for client connections and facilitates communication over a specified port.
• User Authentication: Clients must provide a username and password to log in.
• Messaging System: Allows users to send and receive messages, which are stored on the server.
• Multi-threaded: The server can handle multiple clients simultaneously using threading.
• Persistent Storage: User information and messages are stored in JSON files.

File Structure

• userdat.txt: Stores user login information (usernames and passwords).
• jmail.txt: Stores messages sent between users.

How It Works

1. Server Setup:
2. The server opens a socket and listens for incoming connections on a specified port.

3. It supports up to 100 simultaneous connections using threading.

4. Client Connection:

5. Once connected, the client sends its version number for compatibility checks.

6. If the client version is compatible with the server, it proceeds to the login process.

7. Login Process:

8. Clients must provide a username and password, which are verified against the userdat.txt file.
9. If the credentials are incorrect or the user does not exist, the client receives a login failure message.

10. On successful login, the user can access their mailbox and send messages.

11. Messaging:

12. Users can refresh their inbox to view new messages.

13. They can send a message to another user by typing the recipient's username and the message. Messages are stored in jmail.txt.

14. Error Handling:

15. The server can handle crashes and displays an error message when it fails.

How to Use

1. Running the Server:
2. Ensure Python 3.x is installed.
3. Run the server using the following command: bash python jmail_server.py

4. You will be prompted to enter a custom port number (e.g., 90).

5. Connecting a Client:

6. The client sends its version number and logs in using their username and password.

7. Once authenticated, they can send and receive messages.

8. Sending a Message:

9. To send a message, the user should input the recipient’s username followed by the message in the following format: plaintext (username) message
10. The server will store the message and send it to the recipient when they refresh their inbox.