xK

xK (chat kit) is an IRC software suite consisting of a terminal client, daemon, and bot. It’s all you’re ever going to need for chatting, so long as you can make do with slightly minimalist software.

They come with these potentially interesting properties:

• supporting IRCv3, SOCKS, IPv6, TLS (including client certificates)

• lean on dependencies

• compact and arguably easy to hack on

• maximally permissive license

xC

The IRC client, and the core of xK. It is largely defined by being built on top of GNU Readline that has been hacked to death. Its interface should feel somewhat familiar for weechat or irssi users.

It has most of the stuff you’d expect of an IRC client, such as being multiserver, a powerful configuration system, integrated help, text formatting, automatic splitting of overlong messages, multiline editing, bracketed paste support, decent word wrapping, autocomplete, logging, CTCP queries, auto-away, command aliases, and basic support for Lua scripting. As a unique bonus, you can launch a full text editor from within.

xD

The IRC daemon. It is designed to be used as a regular user application rather than a system-wide daemon. If all you want is a decent, minimal IRCd for testing purposes or a small network of respectful users (or bots), this one will do it just fine.

Notable features:

• TLS autodetection (I’m still wondering why everyone doesn’t have this)

• IRCop authentication via TLS client certificates

• partial IRCv3 support

Not supported:

• server linking (which also means no services); I consider existing protocols for this purpose ugly and tricky to implement correctly; I’ve also found no use for this feature yet

• online changes to configuration; the configuration system from xC could be used to implement this feature if needed

• limits of almost any kind, just connections and mode +l

This program has been ported to Go, and development continues over there.

xB

The IRC bot. While originally intended to be a simple rewrite of my old GNU AWK bot in C, it fairly quickly became a playground, and it eventually got me into writing the rest of this package.

Its main characteristic is that it runs plugins as coprocesses, allowing for enhanced reliability and programming language freedom. Moreover, it recovers from any crashes, and offers native SOCKS support (even though socksify can add that easily to any program).

Packages

Regular releases are sporadic. git master should be stable enough. You can get a package with the latest development version from Archlinux’s AUR.

Building

Build dependencies: CMake, pkg-config, asciidoctor or asciidoc, awk, liberty (included)
Runtime dependencies: openssl
Additionally for xC: curses, libffi, lua >= 5.3 (optional), readline >= 6.0 or libedit >= 2013-07-12

Avoid libedit if you can, in general it works but at the moment history is acting up and I have no clue about fixing it.

$ git clone --recursive https://git.janouch.name/p/xK.git
$ mkdir xK/build
$ cd xK/build
$ cmake .. -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=RelWithDebInfo \
           -DWANT_READLINE=ON -DWANT_LIBEDIT=OFF -DWANT_LUA=ON
$ make

To install the application, you can do either the usual:

# make install

Or you can try telling CMake to make a package for you:

$ cpack -G DEB  # also supported: RPM, FreeBSD
# dpkg -i xK-*.deb

Usage

xC has in-program configuration. Just run it and read the instructions. Consult its man page for details about the interface.

For the rest you might want to generate a configuration file:

$ xB --write-default-config
$ xD --write-default-config

After making any necessary edits to the file (there are comments to aid you in doing that), simply run the appropriate program with no arguments:

$ xB
$ xD

xB stays running in the foreground, therefore I recommend launching it inside a Screen or tmux session.

xD, on the other hand, immediately forks into the background. Use the PID file or something like killall if you want to terminate it. You can run it as a forking type systemd user service.

Client Certificates

xC will use the SASL EXTERNAL method to authenticate using the TLS client certificate specified by the respective server’s tls_cert option if you add sasl to the capabilities option and the server supports this.

xD uses SHA-1 fingerprints of TLS client certificates to authenticate users. To get the fingerprint from a certificate file in the required form, use:

$ openssl x509 -in public.pem -outform DER | sha1sum

Custom Key Bindings in xC

The default and preferred frontend used in xC is GNU Readline. This means that you can change your bindings by editing ~/.inputrc. For example:

# Preload with system-wide settings
$include /etc/inputrc

# Make M-left and M-right reorder buffers
$if xC
"\e\e[C": move-buffer-right
"\e\e[D": move-buffer-left
$endif

Consult the source code and the GNU Readline manual for a list of available functions. Also refer to the latter for the exact syntax of this file. Beware that you can easily break the program if you’re not careful.

How do I make xC look like the screenshot?

With the defaults, xC doesn’t look too fancy because I don’t want to have a hard dependency on either Lua for the bundled script that provides an easily adjustable enhanced prompt, or on 256-colour terminals. Moreover, it’s nearly impossible to come up with a colour theme that would work well with both black-on-white and white-on-black terminals, or anything wild in between.

Assuming that your build supports Lua plugins, and that you have a decent, properly set-up terminal emulator, it suffices to run:

/set behaviour.backlog_helper = Press Tab here and change +Gb to +Gb1d
/set behaviour.date_change_line = "%a %e %b %Y"
/set behaviour.plugin_autoload += "fancy-prompt.lua"
/set attributes.userhost = "\x1b[38;5;109m"
/set attributes.join = "\x1b[38;5;108m"
/set attributes.part = "\x1b[38;5;138m"
/set attributes.external = "\x1b[38;5;248m"
/set attributes.timestamp = "\x1b[48;5;255m\x1b[38;5;250m"
/set attributes.read_marker = "\x1b[38;5;202m"

Configuration profiles

Even though the applications don’t directly support configuration profiles, they conform to the XDG standard, and thus you can change the location they load configuration from via XDG_CONFIG_HOME (normally ~/.config) and the location where store their data via XDG_DATA_HOME (normally ~/.local/share).

It would be relatively easy to make the applications assume whatever name you run them under (for example by using symbolic links), and load different configurations accordingly, but I consider it rather messy and unnecessary.

Contributing and Support

Use https://git.janouch.name/p/xK to report any bugs, request features, or submit pull requests. git send-email is tolerated. If you want to discuss the project, feel free to join me at ircs://irc.janouch.name, channel #dev.

Bitcoin donations are accepted at: 12r5uEWEgcHC46xd64tt3hHt9EUvYYDHe9

License

This software is released under the terms of the 0BSD license, the text of which is included within the package along with the list of authors.

Note that xC becomes GPL-licensed when you link it against GNU Readline, but that is not a concern of this source package. The licenses are compatible.