Programmierprojekt/documents/docs/networking/commands/README.md

Commands

Commands are the primary extension point of the server. Every client-facing operation e.g. checking a username, sending a chat message, joining a lobby is implemented as a command. Each command consists of four classes: a Parser, a Request, a Handler, and a Response.

The infrastructure for routing and dispatching commands lives in the network/ layer and is intentionally kept generic. The concrete implementations for each command live in app/commands/ and are wired together at startup in ServerApp.

Contents

Guides

• Implementing a Command - Step-by-step walkthrough for adding a new command to the server, including registration and common pitfalls.

Reference

• Command Infrastructure - Technical deep-dive into the CommandParser, CommandParserDispatcher, CommandHandler, CommandRouter, Request, and the response hierarchy.

Key Concepts

Each command is self-contained. A command's Parser, Request, Handler, and Response all live in the same package under app/commands/<name>/. This keeps related code co-located and makes it easy to reason about a single command without navigating across multiple directories.

The network/ layer knows nothing about specific commands. CommandParser and CommandHandler are generic interfaces. The CommandParserDispatcher and CommandRouter operate on those interfaces. Adding a new command never requires modifying infrastructure code.

Registration happens at the composition root. All commands are wired in ServerApp by calling parserDispatcher.register(...) and commandRouter.register(...). This keeps the wiring explicit and compiler-checked.