ChatApp is a multi-threaded chat application built in C that supports real-time messaging, file transfers, and persistent user management using MongoDB. The project includes both server and client components, with the client featuring a modern terminal-based user interface powered by ncurses.
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User Registration & Login:
Users can register and log in with a unique user ID. -
Real-Time Messaging:
Supports broadcast messages and private messaging (both one-shot and continuous sessions). -
Chat History:
Retrieve previous chat history between users. -
Online User Listing:
List currently online users as well as all registered users. -
File Transfer:
Transfer files between users seamlessly. -
Cloud Data Persistence:
All user information and chat data are stored in a cloud MongoDB database. -
Offline Message Delivery:
When users are offline, incoming messages are saved in the cloud MongoDB and automatically delivered when they log in, ensuring no message is lost. -
Modular Design:
The codebase is organized into separate modules for the server (client handling, database interactions, user management, and timeout handling) and client (UI, message receiving, and file transfers).
cnn/
├── chat_server/
│ ├── include/
│ │ ├── client_handler.h // Function prototypes declared for client handling
│ │ │ void handle_client(int client_socket);
│ │ │ void create_client_thread(int *sockfd_ptr);
│ │ ├── db.h // Function prototypes for database operations
│ │ │ void init_mongo();
│ │ │ bool db_register_user(const char *username, const char *password, const char *ip_address, char *user_id_out, size_t user_id_size);
│ │ │ bool db_login_user(const char *username, const char *password, const char *ip_address, char *user_id_out, size_t user_id_size);
│ │ │ void db_set_user_offline(const char *user_id);
│ │ │ bool db_insert_chat(const char *sender_id, const char *recipient_id, const char *message, bool delivered, bool popped);
│ │ │ char* db_get_chat_history(const char *user_id, const char *other_id);
│ │ │ void deliver_offline_messages(const char *user_id, int sockfd);
│ │ ├── online_users.h // Prototypes for online user management
│ │ │ void add_online_user(const char *username);
│ │ │ void remove_online_user(const char *username);
│ │ │ int get_online_sockfd(const char *user_id);
│ │ │ void broadcast_message(const char *sender_username, const char *message);
│ │ │ void get_online_users_list(char *buffer, size_t buf_size);
│ │ └── timeout.h // Prototypes for timeout handling
│ │ void start_timeout_checker();
│ ├── src/
│ │ ├── client_handler.c // Function definitions for client handling
│ │ │ void *client_handler(void *arg) { … }
│ │ ├── db.c // Database operations definitions
│ │ ├── main.c // Main entry point for the chat server
│ │ ├── online_users.c // Online user management functions
│ │ └── timeout.c // Timeout checker functions
│ └── Makefile // Build configuration for the server
├── chat_client/
│ ├── include/
│ │ ├── client.h // Prototype for client connection
│ │ ├── file_transfer.h // Prototypes for file transfer functions
│ │ ├── receive_handler.h // Prototypes for the receive handler thread/function
│ │ └── ui.h // Prototypes for UI display/update routines
│ ├── src/
│ │ ├── client_main.c // Main entry point for the chat client
│ │ ├── file_transfer.c // File transfer definitions
│ │ ├── receive_handler.c // Receiving messages/files function
│ │ └── ui_ncurses.c // User interface display function
│ └── Makefile // Build configuration for the client
└── .vscode/
└── c_cpp_properties.json // VS Code configuration for C/C++
Client:
- Programming Language: C
- User Interface: ncurses (for a modern, terminal-based UI)
- Concurrency: POSIX threads (pthreads)
- Networking: POSIX sockets (TCP)
- Additional Libraries:
- Standard C libraries (stdio, stdlib, string, etc.)
- (Planned) OpenCV for future video call functionality
Server:
- Programming Language: C
- Concurrency: POSIX threads (pthreads)
- Networking: POSIX sockets (TCP)
- Database: MongoDB (using the MongoDB C Driver: mongoc and bson)
- Data Persistence: Cloud storage of user data, chat history, and offline messages
- Additional Libraries: Standard C libraries (stdio, stdlib, string, etc.)
Insert gif or link to demo
To run this project, you will need the following environment variables:
-
MONGO_URI
Your MongoDB connection string. For example:
mongodb+srv://<username>:<password>@cluster0.mongodb.net/?retryWrites=true&w=majority -
MONGO_DB
The name of the database to use. For example:
chat
Before building the project, make sure the following external dependencies are installed:
The application uses MongoDB to store user data and chat history. Install the MongoDB C Driver (which includes mongoc and bson). For example, on Ubuntu:
sudo apt-get update
sudo apt-get install libmongoc-1.0-dev libbson-1.0-devThe client’s terminal-based UI is built with ncurses. Install the ncurses development libraries. On Ubuntu, run:
sudo apt-get install libncurses5-dev libncursesw5-devTo deploy the project, you need to build and run both the server and client applications.
- Open a terminal and navigate to the
cnn/chat_serverdirectory:cd cnn/chat_server - Build the server using the provided Makefile:
make
- Run the server on your desired port (for example, 12345):
./chat_server 12345
- Open a new terminal and navigate to the cnn/chat_client directory:
cd cnn/chat_client - Build the client using the provided Makefile:
make
- Run the client by specifying the server's IP address and the port used by the server (for example, connecting to localhost on port 12345):
./chat_client 127.0.0.1 12345
Contributions are always welcome!
See contributing.md for ways to get started.
Please adhere to this project's code of conduct.