# WebSocket Implementation

This document provides an overview of the WebSocket implementation in the Bedrock Server Manager, covering backend (server-side) components.

The backend WebSocket implementation is built using FastAPI and is divided into two main components: a WebSocket router and a connection manager.

### WebSocket Router

The WebSocket router is defined in `src/bedrock_server_manager/web/routers/websocket_router.py`. It is responsible for the following:

-   **Endpoint**: Creates a WebSocket endpoint at `/ws`.
-   **Authentication**: Uses a dependency to authenticate the user before establishing a connection.
-   **Message Handling**: Listens for incoming JSON messages from the client. These messages are expected to have an `action` (`subscribe` or `unsubscribe`) and a `topic`.
-   **Connection Management**: Hands off the connection and subscription management to the `ConnectionManager`.

### Connection Manager

The `ConnectionManager` is a class defined in `src/bedrock_server_manager/web/websocket_manager.py`. It is the core of the backend WebSocket implementation and is responsible for the following:

-   **Connection Tracking**: Keeps track of all active WebSocket connections.
-   **Topic-Based Subscriptions**: Manages which clients are subscribed to which topics.
-   **Message Broadcasting**: Provides methods for sending messages to a single client, all clients subscribed to a specific topic, or all clients for a specific user.

### Architecture

1.  A client connects to the `/ws` endpoint.
2.  The `websocket_router` authenticates the user.
3.  The `websocket_router` passes the connection to the `ConnectionManager`.
4.  The client sends a `subscribe` message to a topic.
5.  The `websocket_router` calls the `ConnectionManager` to subscribe the client to the topic.
6.  When an event occurs on the server (e.g., the server status changes), the `ConnectionManager` is used to broadcast a message to all clients subscribed to the relevant topic.

## Available Topics

The following WebSocket topics are available for subscription:

### Event Topics

Event topics broadcast a message when a specific event occurs on the server. The topic name is in the format `event:{event_name}`.

-   `event:before_addon_import`
-   `event:after_addon_import`
-   `event:before_backup`
-   `event:after_backup`
-   `event:before_restore`
-   `event:after_restore`
-   `event:before_prune_backups`
-   `event:after_prune_backups`
-   `event:before_players_add`
-   `event:after_players_add`
-   `event:before_player_db_scan`
-   `event:after_player_db_scan`
-   `event:before_server_start`
-   `event:after_server_start`
-   `event:before_server_stop`
-   `event:after_server_stop`
-   `event:before_command_send`
-   `event:after_command_send`
-   `event:before_allowlist_change`
-   `event:after_allowlist_change`
-   `event:before_server_install`
-   `event:after_server_install`
-   `event:before_server_update`
-   `event:after_server_update`
-   `event:before_autostart_change`
-   `event:after_autostart_change`
-   `event:after_server_statuses_updated`
-   `event:before_web_server_start`
-   `event:after_web_server_start`
-   `event:before_web_server_stop`
-   `event:after_web_server_stop`
-   `event:before_world_export`
-   `event:after_world_export`
-   `event:before_world_import`
-   `event:after_world_import`
-   `event:before_world_reset`
-   `event:after_world_reset`

### Resource Monitor Topics

Resource monitor topics broadcast resource usage information for a specific server. The topic name is in the format `resource-monitor:{server_name}`. Replace `{server_name}` with the name of the server you want to monitor.