https://github.com/brunobord/ncat-chat
two dummy/minimalist bash scripts for client/server chatting using ncat/netcat
https://github.com/brunobord/ncat-chat
bash chat cli client-server ncat netcat
Last synced: about 1 year ago
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two dummy/minimalist bash scripts for client/server chatting using ncat/netcat
- Host: GitHub
- URL: https://github.com/brunobord/ncat-chat
- Owner: brunobord
- License: wtfpl
- Created: 2021-03-23T22:56:32.000Z (about 5 years ago)
- Default Branch: main
- Last Pushed: 2021-04-30T21:28:37.000Z (about 5 years ago)
- Last Synced: 2025-03-26T01:51:10.178Z (about 1 year ago)
- Topics: bash, chat, cli, client-server, ncat, netcat
- Language: Shell
- Homepage:
- Size: 16.6 KB
- Stars: 10
- Watchers: 3
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: Changelog.md
- License: COPYING
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README
# netcat-based chat
[](https://github.com/brunobord/ncat-chat/releases/)
Did you know that you could run a chat service using only `netcat`/`ncat`?
## BIG DISCLAIMER
**This solution is by no mean production-safe. It's a toy.**
* Anybody can usurp anybody's identity, there's no real control on the usernames.
* `ncat` is a hell of a tool, but even if it has a quite large `--max-conns` argument (set to 100 on \*Nix, 60 on Windows), there's no guarantee that it can handle the network traffic or the CPU load.
## Requirements
* `ncat` for servers & clients,
* `awk`,
* `mawk` (optional, only used in a "bare-bones" example below).
* `rlwrap` (optional, to use arrow keys in the client).
## License
Since this client/server toolkit is basically stolen from here and there examples found on the Internet, that wouldn't be fair to assign a privative license to it.
So this piece of software is published under the terms of the WTFPL (v2).
Copyright © 2021 Bruno Bord
This work is free. You can redistribute it and/or modify it under the
terms of the Do What The Fuck You Want To Public License, Version 2,
as published by Sam Hocevar. See the COPYING file for more details.
## Running the server
### "Bare bones" servers
A "Bare bones" server would run using:
```sh
ncat --ssl --broker --listen -p
```
You may assign any (available) port number for your server.
Another way is to use the `--chat` parameter of `ncat`. But it prefixes every message with an arbitrary identifier. It makes you sure that nobody is usurpating your identity, but it might not be readable to have ``, `` or `` talking to each other.
### Our ncat server
For your convenience, we're providing a `.sh` script. The following will run a server on port `12345`.
```sh
./ncat-server.sh
```
If you want to specify a dedicated port, you may use the following:
```sh
CHAT_PORT= ./ncat-server.sh
```
You can use the `Ctrl-C` key shortcut to stop the server.
## Running a client
### "Bare bones" clients
Run a chat client using:
```sh
ncat --ssl
```
*Tip*: you can even test this on your own PC, in two separate shell sessions, where the server hostname would be: `localhost`.
If you want to make sure that your username/nickname is sent each time you're sending a message, you may try to use `mawk` along:
```sh
mawk -W interactive '$0="Alice: "$0' | ncat --ssl
```
#### About the SSL option
By default, the `ncat-client.sh` and `ncat-server.sh` scripts we're providing use SSL encryption.
It's a bit safer for your privacy, because it prevents intruders to sniff your messages over the network. Although, as long as someone knows both your hostname and port, they can access your messaging service, so… things are not as safe as they seem.
Please note that, if your server uses SSL, your client must use it also, otherwise you won't be able to send and receive messages through it.
And, if you intend to *avoid* using SSL, the clients connected to it shouldn't use the `--ssl` option either, and you'll have to use the barebones clients & servers for that.
### Our client
For your convenience, there's even a `.sh` script. If you want to connect to the default server on your PC, run:
```sh
./ncat-client.sh
```
You'll then be connected to the server on `localhost` on port `12345`. But the discussion here will be limited, since you'll be the only person speaking. And if you open another shell and run the same command, and try to write messages, you'll see that all messages are prefixed by your `username@host` (extracted from the result of the `whoami` & `hostname` commands).
Similarly to the server port, you can also use environment variables to change your connection parameters. See the following example:
```sh
CHAT_HOST=alice-laptop CHAT_PORT=9999 CHAT_USER=Bob ./ncat-client.sh
```
You can use the `Ctrl-D` key shortcut to disconnect.
#### Colors
You may chose the color with which your messages will be received by the other users. By default, no specific colour will be sent along. If you want to change that, use the `CHAT_COLOR` environment variable, such as:
```sh
CHAT_COLOR=cyan ./ncat-client.sh
```
Available colors:
* `red`
* `green`
* `yellow`
* `blue`
* `magenta`
* `cyan`
* `white`
If you're providing an unknown color, the "no-color" will be used.
### User-friendly interface with `rlwrap`
You may notice that if you want to use arrows to move your cursor up/down or left/right, it inserts characters such as `^[[A^` or `[[D`. In order to enable arrow keys, you'd need to wrap launching the client script with the `rlwrap` tool, which wraps your program around GNU Readline.
Then you can edit your message before sending it using right/left keys, and browse your input history using up/down arrow keys.
Example usage:
```sh
rlwrap ./ncat-client.sh
```
Or, with environment variables:
```sh
CHAT_COLOR=blue CHAT_HOST=alice-laptop CHAT_PORT=9999 CHAT_USER=Bob rlwrap ./ncat-client.sh
```
Please note that the call to `rlwrap` should appear *after* the environment variable definitions, not before.