xK/README.adoc

xK
==

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

They're all lean on dependencies, and offer a maximally permissive licence.

xC
--
The IRC client, and the core of 'xK'.  It is largely defined by building on top
of GNU Readline or BSD Editline that have been hacked to death.  Its interface
should feel somewhat familiar for weechat or irssi users.

image::xC.webp[align="center"]

It has most features you'd expect of an IRC client, such as being multiserver,
a powerful configuration system, integrated help, text formatting, automatic
message splitting, multiline editing, bracketed paste support, word wrapping
that doesn't break links, autocomplete, logging, CTCP queries, auto-away,
command aliases, SOCKS proxying, SASL EXTERNAL authentication using TLS client
certificates, a remote relay interface, or basic support for Lua scripting.
As a unique bonus, you can launch a full text editor from within.

xP
--
The web frontend for 'xC', making use of its networked relay interface.
It intentionally differs in that it uses a sans-serif font, and it shows
the list of all buffers in a side panel.  Otherwise it is a near replica,
including link:xC.adoc#_key_bindings[keyboard shortcuts].

image::xP.webp[align="center"]

xD
--
The IRC daemon.  It is designed for use as a regular user application rather
than a system-wide daemon, and follows the XDG Base Directory Specification.
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.

It autodetects TLS on incoming connections (I'm still wondering why everyone
doesn't have this), authenticates operators via TLS client certificate
fingerprints, and supports a number of IRCv3 capabilities.

What it notably doesn't support is online changes to configuration, any limits
besides the total number of connections and mode `+l`, or server linking
(which also means no services).

xS
--
The IRC daemon again, this time ported to Go, additionally supporting WEBIRC,
and thus ideal for pairing with, e.g.,
https://github.com/kiwiirc/webircgateway[].
Any further development, such as P10 or TS6 linking for IRC services,
or plugin support for arbitrary bridges, will happen here.

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 using Arch Linux's
https://aur.archlinux.org/packages/xk-git[AUR],
or as a https://git.janouch.name/p/nixexprs[Nix derivation].

Building
--------
Build-only dependencies: CMake, pkg-config, awk, liberty (included),
 asciidoctor or asciidoc (recommended but optional) +
Common runtime dependencies: openssl +
Additionally for 'xC': curses, libffi, readline >= 6.0 or libedit >= 2013-07-12,
 lua >= 5.3 (optional) +

 $ 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 -DWITH_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 link:xC.adoc[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.

xP
~~
The precondition for running 'xC' frontends is enabling its relay interface:

 /set general.relay_bind = "127.0.0.1:9000"

To build the web server, you'll need to install the Go compiler, and run `make`
from the _xP_ directory.  Then start it from the _public_ subdirectory,
and navigate to the adress you gave it as its first argument--in the following
example, that would be http://localhost:8080[]:

 $ ../xP 127.0.0.1:8080 127.0.0.1:9000

For remote use, it's recommended to put 'xP' behind a reverse proxy, with TLS,
and some form of HTTP authentication.  Pass the external URL of the WebSocket
endpoint as the third command line argument in this case.

xW
~~
The Win32 frontend is a separate CMake subproject that should be compiled
using MinGW-w64.  To avoid having to specify the relay address each time you
run it, create a shortcut for the executable and include the address in its
_Target_ field:

 C:\...\xW.exe 127.0.0.1 9000

It works reasonably well starting with Windows 7.

xM
~~
The Cocoa frontend is a separate CMake subproject that requires Xcode to build.
It is currently not that usable.  The relay address can either be passed on
the command line, or preset in the _defaults_ database:

 $ defaults write name.janouch.xM relayHost 127.0.0.1
 $ defaults write name.janouch.xM relayPort 9000

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' and 'xS' use SHA-256 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 | sha256sum

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 general.pager = Press Tab here and change +Gb to +Gb1d
 /set general.date_change_line = "%a %e %b %Y"
 /set general.plugin_autoload += "fancy-prompt.lua"
 /set theme.userhost = "109"
 /set theme.join = "108"
 /set theme.part = "138"
 /set theme.external = "248"
 /set theme.timestamp = "250 255"
 /set theme.read_marker = "202"

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.