Implement an asyncio-based chat server

Q: Implement an asyncio-based chat server

This question evaluates a candidate's skill in asynchronous network programming and concurrent connection handling, including protocol parsing, room management, message broadcasting, and graceful resource cleanup using Python's asyncio.

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Question

Async Chat Server (Python `asyncio`)

Implement a TCP chat server using Python asyncio.

Part 1 — Single global room

Your server listens on a given port and supports multiple concurrent clients.

Protocol (line-based text):

When a client connects, the server prompts for a username (single line).
After login, each line a client sends is treated as a chat message.
The server broadcasts each message to all other connected clients in the format:
- <username>: <message>

Behavior requirements:

A client should not receive its own message back.
Handle client disconnects gracefully (no crashes; cleanup resources).
The server should continue serving other clients if one client misbehaves (e.g., disconnects mid-line).

Part 2 — Basic chat commands

Extend the protocol to support:

/join <room> : join (and create if needed) a named room.
- Each user is in exactly one room at a time .
- After joining, broadcasts only go to users in the same room .
/who : return the list of usernames currently in the user’s room.
/quit : disconnect.

Constraints / assumptions:

Up to ~1,000 concurrent connections.
Use only standard library ( asyncio / socket / etc.).
Favor clear concurrency handling and correctness over advanced features (no persistence required).

Implement an asyncio-based chat server

Overview

Async Chat Server (Python asyncio)

Part 1 — Single global room

Part 2 — Basic chat commands

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Async Chat Server (Python `asyncio`)