p2p-chat's Introduction

P2P Chat

It is a p2p chat application that uses centralized index approach. It consists of two parts a registry application and a chat application. Registry application keeps track of the peers, and chat application allows peers to communicate with each other.

Registry application can achieve following operations:
- Account Creation
  Accounts can be created on registry. Each user is identified by a unique username.
- Login and Logout
  When a user logs in, registry saves its ip address and port number into database and this entry stays in the database until the user logs out or disconnected.
  As long as user is online, a 'HELLO' message is sent to registry at every second to indicate that the user is still connected. If the registry hasn't received a 'HELLO' message from a user in 3 seconds, it considers user as disconnected and removes its entry from online peers.
- Search
  A user can search another online user using that user's username to retrieve the ip address and the port number of the user.
Chat application can achieve following operations:
- Communication with Registry
  Chat application sends messages to registry to achieve account creation, login, logout, and search operations.
- Chat
  When a user wants to chat with another user, a chat request is sent to the other user. User should send an 'OK' message to accept or a 'REJECT' message to reject. However, if user is already chatting with someone else, then a 'BUSY' message will be sent automatically.