This code is old, largely untested and might not even support all features provided by the IPC protocol. I don't have the time to develop this further.

But there is another project that provides a great abstraction of all the IPC stuff: i3ipc-glib.

It's possible to use this library in ruby using gir_ffi and the following code:

require 'gir_ffi'

namespace = 'i3ipc'
GirFFI.setup namespace

i3 = I3ipc::Connection.new(nil)

i3.command 'focus left'

inter-process communication with i3, the improved tiling window manager.

RubyGem:

gem install i3-ipc

Old school (for the cli script only):

curl -s http://github.com/badboy/i3-ipc/raw/master/i3-ipc > i3-ipc &&
chmod 755 i3-ipc &&
mv i3-ipc /usr/local/bin/i3-ipc

If you're on Arch Linux, you can use the AUR package:

curl http://aur.archlinux.org/packages/i3-ipc/i3-ipc/PKGBUILD &&
makepkg -i

i3-ipc -t 1
i3-ipc -t 1 -p
i3-ipc -t 3 -j
i3-ipc "exec xterm"

Read the man-page for more information.

As of commit 3db4890 i3 added events. For now there's only two events: workspace and focus.

According to the documentation:

workspace Sent when the user switches to a different workspace, when a new workspace is initialized or when a workspace is removed (because the last client vanished). output Sent when RandR issues a change notification (of either screens, outputs, CRTCs or output properties).

i3-ipc uses EventMachine to receive and handle these events.

With i3-ipc's interface and EventMachine as its backend it's rather easy to subscribe to this event notifying:

I3::IPC.subscribe [:workspace] do |em, type, data|
  # ...
end

There are 3 arguments passed to the block:

• em is the instance of the EM::Connection class. To send data to the socket, you need to use em.send_data.
• type is the received message type. This could be one of
  • MESSAGE_TYPE_COMMAND
  • MESSAGE_TYPE_GET_WORKSPACES
  • MESSAGE_TYPE_SUBSCRIBE
  • MESSAGE_TYPE_GET_OUTPUTS
  • EVENT_WORKSPACE
• data is the received data, already parsed.

For example you can use the following code to get the actual focused screen:

I3::IPC.subscribe [:workspace] do |em, type, data|
  case type
  when I3::IPC.message_type_get_workspaces
    data.each do |e|
      if e["focused"]
        puts "focused: %s" % e["name"]
      else
        puts "unfocused: %s" % e["name"]
      end
    end
  when I3::IPC::EVENT_WORKSPACE
    em.send_data I3::IPC.format(I3::IPC.message_type_get_workspaces)
  end
end

A full example of how this can be used for the workspace bar can be found in the examples directory.

You can use EM.stop to stop the connection.

• cleanup the subscribtion frontend
• write tests
• …

Once you've made your great commits:

1. Fork the project.
2. Create a topic branch - git checkout -b my_branch
3. Push to your branch - git push origin my_branch
4. Create an Issue with a link to your branch
5. That's it!

Copyright (c) 2010 Jan-Erik Rediger. See LICENSE for details.