MudEngine Part 6: Multiplayer

You just built a multiplayer MUD engine with real-time WebSocket communication!

What we achieved:

• Fullstack Dioxus — one codebase, two targets (server + WASM), all in Rust
• WebSocket endpoint — a #[get] server function that upgrades HTTP to a persistent bidirectional connection
• Authoritative server — movement validation prevents wall-walking; the server is the single source of truth
• Real-time broadcasting — tokio::sync::broadcast fans out every player action to all connected clients
• Reactive client UI — use_websocket + use_future react to incoming messages and update the grid/sidebar instantly
• Player lifecycle — join (name entry via Input component), move (D-pad via Button component), leave (disconnect detection)
• Part 5 components reused — RoomCell shows occupant names per grid cell, Card wraps the description, Button drives the D-pad, Input handles name registration

Architecture recap

┌──────────────┐     WebSocket     ┌──────────────────┐
│  Browser A   │ ◄──────────────► │  Axum Server      │
│  - Alice     │                   │  - #[get] handler │
│  - use_ws     │                   │  - PlayerManager  │
│  - grid+dpad  │                   │  - broadcast      │
└──────────────┘                   │  - room exits     │
                                   └──────────────────┘
┌──────────────┐     WebSocket            ▲
│  Browser B   │ ◄────────────────────────┘
│  - Bob       │
│  - use_ws     │
│  - grid+dpad  │
└──────────────┘

Every player action follows the same path: client → server → validate → broadcast → all clients update. No client trusts its own input for game state — the server decides and tells everyone.

What's next?

The dungeon keeps growing! Future parts could explore:

• Persistent world — store player positions and room state in a database (SQLite via sqlx)
• Chat — add a chat panel where players can send messages to each other
• Combat — monsters in rooms, attack commands, health tracking
• Inventory — items the player can pick up and carry between rooms
• Authentication — sessions and login so players keep their name across page reloads
• Room state — locks, doors, torches that can be lit or extinguished

The MUD lives! 🏰⚔️