Messaging API

Chat API with support for multiple users, multiple rooms, and real-time WebSocket communication.

Project Structure

.
├── cmd/server/main.go        # Entry point
├── internal/                 # Application core
│   ├── db/                   # Database connection
│   ├── handler/              # HTTP handlers
│   ├── model/                # Data models
│   ├── repository/           # Database access layer
│   ├── router/               # HTTP routes setup
│   └── service/              # Business logic layer

API Routes

/user

Method	Route	Description
GET	/user	List all users
GET	/user/:id	Get user by ID
POST	/user	Create new user
PUT	/user/:id	Update user
DELETE	/user/:id	Delete user
GET	/user/username/:username	Find user by username
GET	/user/chat/:chat_id	Find users by chat ID

/chat

Method	Route	Description
GET	/chat	List all chats
GET	/chat/:id	Get chat by ID
POST	/chat	Create new chat
PUT	/chat/:id	Update chat
DELETE	/chat/:id	Delete chat
GET	/chat/user/:user_id	Add user to chat
DELETE	/chat/user/:user_id	Remove user from chat
GET	/chat/user/:user_id/chat/:chat_id/access	Check if user has access to a chat

/ws

Method	Route	Description
GET	/ws	WebSocket connection endpoint

WebSocket Message Types

Connect to chat

{
  "type": "connect-chat",
  "content": {
    "customerd": 1,
    "chatId": 1,
    "username": "name"
  }
}

Send message

{
  "type": "send-message",
  "content": {
    "chatId": 1,
    "customerId": 1,
    "content": "Hi world."
  }
}

Update message

{
  "type": "update-message",
  "content": {
    "chatId": 1,
    "customerId": 1,
    "content": "Hello world!"
  }
}

Delete message

{
  "type": "delete-message",
  "content": 10
}

WebSocket Handler

• Each chat has its own Hub.

• clients is a map of active WebSocket connections per chat.

• Messages are processed based on their type:

  • join and leave messages are automatically broadcasted.
  • send-message, update-message, and delete-message are broadcasted and persisted.

• Connection starts with a connect-chat message.

Connection Flow

1. Client sends a message with "type": "connect-chat".
2. Server creates or retrieves the Hub for the chat.
3. Client is registered in the Hub.
4. Server listens to incoming messages and forwards them to all clients in the same chat.

Setup

1. Create a .env file with necessary environment variables.
2. Run the SQL script to create and populate the database tables.
3. (Optional) Import the Postman collection for testing.
4. Start the application:

go run cmd/server/main.go