Rust Chat Rooms (Tokio + TCP)

A small client/server chat written in Rust on top of raw TCP: newline-delimited JSON packets, a simple server hub with rooms, and a CLI client powered by rustyline (prompt + history).

This project is primarily a practical playground to learn:

• TCP stream framing (why “one packet == one line” matters)
• splitting a TcpStream into reader/writer halves
• coordinating async tasks via Tokio mpsc channels
• broadcasting to everyone in a room without storing sockets in the hub

Created without vibecoding

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Screenshots

Client

Server

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Features

Client (CLI)

• rustyline prompt: >> with history (arrow-up)
• Local command parsing + validation
• Background reader task → incoming packets channel → main tokio::select! loop
• Colored output + console clear (crossterm)
• “You:” echo with timestamp: [HH:MM:SS] You: ...

Server

• Tokio TCP listener (one task per connection)
• Per-connection:
  • reader loop (BufReader::lines()) → incoming channel
  • writer loop → outgoing channel → socket write
• ServerClientsHub:
  • users + rooms
  • join/create rooms with size limit
  • broadcast room messages to everyone except sender
  • auto-cleanup: remove user from rooms and delete empty rooms on disconnect

Protocol

• JSON Packet { command, args } (serde_json)
• One JSON packet per line (\n) → easy framing for both sides

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Quick start

Run server

cargo run --bin server

Run client

Open one (or multiple) terminals:

cargo run --bin client

Default address: 127.0.0.1:3000

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Config (config.json)

Both binaries read/create config.json in the current working directory.

Example:

{
  "user_name": "User",
  "address": "127.0.0.1:3000"
}

• Client uses user_name + address
• Server uses address

Tip: if you want different configs for server and client, run them from different folders (or separate build/run dirs).

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Client commands

Anything that is not a command is treated as a message (only when connected + in room).

• /help — show commands
• /connect [ip:port] or /cnt [ip:port] — connect
  (if omitted → uses config.json address)
• /disconnect — leave room or disconnect from server
• /change_name <name> — change local name (requires being disconnected)
• /get_rooms — request rooms list (table)
• /create_room <name> <size> — create room and auto-join
• /join_room <name> — join existing room
• /clear or /cls — clear console
• /quit or /q — quit

Examples:

>> /connect
>> /get_rooms
>> /create_room lobby 8
>> hello
>> /disconnect
>> /quit

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Packet format (newline-delimited JSON)

One packet:

{"command":"GetRooms","args":[]}

Writer always sends:

• packet_json + "\n"

Reader always does:

• BufReader::lines() → each line is one packet

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Project structure

• src/bin/client.rs — CLI entry point (select loop)
• src/bin/server.rs — server entry point (accept loop + per-client tasks)

Shared

• src/bin/shared_lib/c_command.rs — Packet (serde JSON)
• src/bin/shared_lib/c_commands_solver.rs — ECommand + parsing
• src/bin/shared_lib/c_config.rs — config load/save (config.json)
• src/bin/shared_lib/f_utils.rs — timestamp helper (chrono)

Client

• src/bin/client_lib/classes/c_client.rs — connect/disconnect, reader/writer loops, channels
• src/bin/client_lib/cli_utils/f_rusty_line_input.rs — rustyline + ExternalPrinter
• src/bin/client_lib/cli_utils/f_print_utils.rs — colored printing + clear console
• src/bin/client_lib/f_from_local_client_parse.rs — local commands handler
• src/bin/client_lib/f_from_server_parse.rs — server packets handler

Server

• src/bin/server_lib/c_hub.rs — users + rooms hub
• src/bin/server_lib/c_server_client.rs — user state + outgoing sender
• src/bin/server_lib/c_server_room.rs — room model + members
• src/bin/server_lib/f_server_logger.rs — colored server logs

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Notes / limitations

• Learning project: no auth, no persistence, no encryption.
• Packet framing is line-based: JSON must stay on one line.

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License

MIT (or pick any license you want).