IPC interface (interprocess communication)
==========================================
-Michael Stapelberg <michael+i3@stapelberg.de>
-March 2010
+Michael Stapelberg <michael@i3wm.org>
+February 2014
This document describes how to interface with i3 from a separate process. This
is useful for example to remote-control i3 (to write test cases for example) or
The method of choice for IPC in our case is a unix socket because it has very
little overhead on both sides and is usually available without headaches in
most languages. In the default configuration file, the ipc-socket gets created
-in +/tmp/i3-%u/ipc-socket.%p+ where +%u+ is your UNIX username and +%p+ is the
-PID of i3.
+in +/tmp/i3-%u.XXXXXX/ipc-socket.%p+ where +%u+ is your UNIX username, +%p+ is
+the PID of i3 and XXXXXX is a string of random characters from the portable
+filename character set (see mkdtemp(3)). You can get the socketpath from i3 by
+calling +i3 --get-socketpath+.
All i3 utilities, like +i3-msg+ and +i3-input+ will read the +I3_SOCKET_PATH+
X11 property, stored on the X11 root window.
+[WARNING]
+.Use an existing library!
+There are existing libraries for many languages. You can have a look at
+<<libraries>> or search the web if your language of choice is not mentioned.
+Usually, it is not necessary to implement low-level communication with i3
+directly.
+
== Establishing a connection
To establish a connection, simply open the IPC socket. The following code
-------------------------------------------------------------
use IO::Socket::UNIX;
-my $sock = IO::Socket::UNIX->new(Peer => '/tmp/i3-ipc.sock');
+chomp(my $path = qx(i3 --get-socketpath));
+my $sock = IO::Socket::UNIX->new(Peer => $path);
-------------------------------------------------------------
== Sending messages to i3
COMMAND (0)::
The payload of the message is a command for i3 (like the commands you
can bind to keys in the configuration file) and will be executed
- directly after receiving it. There is no reply to this message.
+ directly after receiving it.
GET_WORKSPACES (1)::
Gets the current workspaces. The reply will be a JSON-encoded list of
workspaces (see the reply section).
Gets the layout tree. i3 uses a tree as data structure which includes
every container. The reply will be the JSON-encoded tree (see the reply
section).
+GET_MARKS (5)::
+ Gets a list of marks (identifiers for containers to easily jump to them
+ later). The reply will be a JSON-encoded list of window marks (see
+ reply section).
+GET_BAR_CONFIG (6)::
+ Gets the configuration (as JSON map) of the workspace bar with the
+ given ID. If no ID is provided, an array with all configured bar IDs is
+ returned instead.
+GET_VERSION (7)::
+ Gets the version of i3. The reply will be a JSON-encoded dictionary
+ with the major, minor, patch and human-readable version.
So, a typical message could look like this:
--------------------------------------------------
Or, as a hexdump:
------------------------------------------------------------------------------
00000000 69 33 2d 69 70 63 04 00 00 00 00 00 00 00 65 78 |i3-ipc........ex|
-00000010 69 74 0a |it.|
+00000010 69 74 |it|
------------------------------------------------------------------------------
To generate and send such a message, you could use the following code in Perl:
COMMAND (0)::
Confirmation/Error code for the COMMAND message.
-GET_WORKSPACES (1)::
+WORKSPACES (1)::
Reply to the GET_WORKSPACES message.
SUBSCRIBE (2)::
Confirmation/Error code for the SUBSCRIBE message.
-GET_OUTPUTS (3)::
+OUTPUTS (3)::
Reply to the GET_OUTPUTS message.
-GET_TREE (4)::
+TREE (4)::
Reply to the GET_TREE message.
+MARKS (5)::
+ Reply to the GET_MARKS message.
+BAR_CONFIG (6)::
+ Reply to the GET_BAR_CONFIG message.
+VERSION (7)::
+ Reply to the GET_VERSION message.
=== COMMAND reply
-The reply consists of a single serialized map. At the moment, the only
-property is +success (bool)+, but this will be expanded in future versions.
+The reply consists of a list of serialized maps for each command that was
+parsed. Each has the property +success (bool)+ and may also include a
+human-readable error message in the property +error (string)+.
*Example:*
-------------------
-{ "success": true }
+[{ "success": true }]
-------------------
-=== GET_WORKSPACES reply
+=== WORKSPACES reply
The reply consists of a serialized list of workspaces. Each workspace has the
following properties:
{ "success": true }
-------------------
-=== GET_OUTPUTS reply
+=== OUTPUTS reply
The reply consists of a serialized list of outputs. Each output has the
following properties:
The name of this output (as seen in +xrandr(1)+). Encoded in UTF-8.
active (boolean)::
Whether this output is currently active (has a valid mode).
-current_workspace (integer)::
- The current workspace which is visible on this output. +null+ if the
- output is not active.
+current_workspace (string)::
+ The name of the current workspace that is visible on this output. +null+ if
+ the output is not active.
rect (map)::
The rectangle of this output (equals the rect of the output it
is on), consists of x, y, width, height.
{
"name": "LVDS1",
"active": true,
- "current_workspace": 4,
+ "current_workspace": "4",
"rect": {
"x": 0,
"y": 0,
{
"name": "VGA1",
"active": true,
- "current_workspace": 1,
+ "current_workspace": "1",
"rect": {
"x": 1280,
"y": 0,
]
-------------------
-=== GET_TREE reply
+=== TREE reply
The reply consists of a serialized tree. Each node in the tree (representing
one container) has at least the properties listed below. While the nodes might
The internal name of this container. For all containers which are part
of the tree structure down to the workspace contents, this is set to a
nice human-readable name of the container.
+ For containers that have an X11 window, the content is the title
+ (_NET_WM_NAME property) of that window.
For all other containers, the content is not defined (yet).
+type (string)::
+ Type of this container. Can be one of "root", "output", "con",
+ "floating_con", "workspace" or "dockarea".
border (string)::
Can be either "normal", "none" or "1pixel", dependending on the
container’s border style.
+current_border_width (integer)::
+ Number of pixels of the border width.
layout (string)::
- Can be either "default", "stacked", "tabbed", "dockarea" or "output".
+ Can be either "splith", "splitv", "stacked", "tabbed", "dockarea" or
+ "output".
Other values might be possible in the future, should we add new
layouts.
orientation (string)::
Can be either "none" (for non-split containers), "horizontal" or
"vertical".
+ THIS FIELD IS OBSOLETE. It is still present, but your code should not
+ use it. Instead, rely on the layout field.
percent (float)::
The percentage which this container takes in its parent. A value of
+null+ means that the percent property does not make sense for this
geometry (map)::
The original geometry the window specified when i3 mapped it. Used when
switching a window to floating mode, for example.
+window (integer)::
+ The X11 window ID of the *actual client window* inside this container.
+ This field is set to null for split containers or otherwise empty
+ containers. This ID corresponds to what xwininfo(1) and other
+ X11-related tools display (usually in hex).
urgent (bool)::
Whether this container (window or workspace) has the urgency hint set.
focused (bool)::
}
------------------------
+=== MARKS reply
+
+The reply consists of a single array of strings for each container that has a
+mark. A mark can only be set on one container, so the array is unique.
+The order of that array is undefined.
+
+If no window has a mark the response will be the empty array [].
+
+=== BAR_CONFIG reply
+
+This can be used by third-party workspace bars (especially i3bar, but others
+are free to implement compatible alternatives) to get the +bar+ block
+configuration from i3.
+
+Depending on the input, the reply is either:
+
+empty input::
+ An array of configured bar IDs
+Bar ID::
+ A JSON map containing the configuration for the specified bar.
+
+Each bar configuration has the following properties:
+
+id (string)::
+ The ID for this bar. Included in case you request multiple
+ configurations and want to differentiate the different replies.
+mode (string)::
+ Either +dock+ (the bar sets the dock window type) or +hide+ (the bar
+ does not show unless a specific key is pressed).
+position (string)::
+ Either +bottom+ or +top+ at the moment.
+status_command (string)::
+ Command which will be run to generate a statusline. Each line on stdout
+ of this command will be displayed in the bar. At the moment, no
+ formatting is supported.
+font (string)::
+ The font to use for text on the bar.
+workspace_buttons (boolean)::
+ Display workspace buttons or not? Defaults to true.
+binding_mode_indicator (boolean)::
+ Display the mode indicator or not? Defaults to true.
+verbose (boolean)::
+ Should the bar enable verbose output for debugging? Defaults to false.
+colors (map)::
+ Contains key/value pairs of colors. Each value is a color code in hex,
+ formatted #rrggbb (like in HTML).
+
+The following colors can be configured at the moment:
+
+background::
+ Background color of the bar.
+statusline::
+ Text color to be used for the statusline.
+separator::
+ Text color to be used for the separator.
+focused_workspace_text/focused_workspace_bg::
+ Text color/background color for a workspace button when the workspace
+ has focus.
+active_workspace_text/active_workspace_bg::
+ Text color/background color for a workspace button when the workspace
+ is active (visible) on some output, but the focus is on another one.
+ You can only tell this apart from the focused workspace when you are
+ using multiple monitors.
+inactive_workspace_text/inactive_workspace_bg::
+ Text color/background color for a workspace button when the workspace
+ does not have focus and is not active (visible) on any output. This
+ will be the case for most workspaces.
+urgent_workspace_text/urgent_workspace_bar::
+ Text color/background color for workspaces which contain at least one
+ window with the urgency hint set.
+
+
+*Example of configured bars:*
+--------------
+["bar-bxuqzf"]
+--------------
+
+*Example of bar configuration:*
+--------------
+{
+ "id": "bar-bxuqzf",
+ "mode": "dock",
+ "position": "bottom",
+ "status_command": "i3status",
+ "font": "-misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1",
+ "workspace_buttons": true,
+ "binding_mode_indicator": true,
+ "verbose": false,
+ "colors": {
+ "background": "#c0c0c0",
+ "statusline": "#00ff00",
+ "focused_workspace_text": "#ffffff",
+ "focused_workspace_bg": "#000000"
+ }
+}
+--------------
+
+=== VERSION reply
+
+The reply consists of a single JSON dictionary with the following keys:
+
+major (integer)::
+ The major version of i3, such as +4+.
+minor (integer)::
+ The minor version of i3, such as +2+. Changes in the IPC interface (new
+ features) will only occur with new minor (or major) releases. However,
+ bugfixes might be introduced in patch releases, too.
+patch (integer)::
+ The patch version of i3, such as +1+ (when the complete version is
+ +4.2.1+). For versions such as +4.2+, patch will be set to +0+.
+human_readable (string)::
+ A human-readable version of i3 containing the precise git version,
+ build date and branch name. When you need to display the i3 version to
+ your users, use the human-readable version whenever possible (since
+ this is what +i3 --version+ displays, too).
+
+*Example:*
+-------------------
+{
+ "human_readable" : "4.2-169-gf80b877 (2012-08-05, branch \"next\")",
+ "minor" : 2,
+ "patch" : 0,
+ "major" : 4
+}
+-------------------
== Events
output (1)::
Sent when RandR issues a change notification (of either screens,
outputs, CRTCs or output properties).
+mode (2)::
+ Sent whenever i3 changes its binding mode.
+window (3)::
+ Sent when a client's window is successfully reparented (that is when i3
+ has finished fitting it into a container), when a window received input
+ focus or when certain properties of the window have changed.
+barconfig_update (4)::
+ Sent when the hidden_state or mode field in the barconfig of any bar
+ instance was updated and when the config is reloaded.
*Example:*
--------------------------------------------------------------------
+change (string)+ which indicates the type of the change ("focus", "init",
"empty", "urgent").
+Moreover, when the change is "focus", an +old (object)+ and a +current
+(object)+ properties will be present with the previous and current
+workspace respectively. When the first switch occurs (when i3 focuses
+the workspace visible at the beginning) there is no previous
+workspace, and the +old+ property will be set to +null+. Also note
+that if the previous is empty it will get destroyed when switching,
+but will still be present in the "old" property.
+
*Example:*
---------------------
-{ "change": "focus" }
+{
+ "change": "focus",
+ "current": {
+ "id": 28489712,
+ "type": "workspace",
+ ...
+ }
+ "old": {
+ "id": 28489715,
+ "type": "workspace",
+ ...
+ }
+}
---------------------
=== output event
{ "change": "unspecified" }
---------------------------
-== See also
+=== mode event
+
+This event consists of a single serialized map containing a property
++change (string)+ which holds the name of current mode in use. The name
+is the same as specified in config when creating a mode. The default
+mode is simply named default.
+
+*Example:*
+---------------------------
+{ "change": "default" }
+---------------------------
+
+=== window event
+
+This event consists of a single serialized map containing a property
++change (string)+ which indicates the type of the change
+
+* +new+ - the window has become managed by i3
+* +focus+ - the window has received input focus
+* +title+ - the window's title has changed
+* +fullscreen_mode+ - the window has entered or exited fullscreen mode
+
+Additionally a +container (object)+ field will be present, which consists
+of the window's parent container. Be aware that for the "new" event, the
+container will hold the initial name of the newly reparented window (e.g.
+if you run urxvt with a shell that changes the title, you will still at
+this point get the window title as "urxvt").
+
+*Example:*
+---------------------------
+{
+ "change": "new",
+ "container": {
+ "id": 35569536,
+ "type": "con",
+ ...
+ }
+}
+---------------------------
+
+=== barconfig_update event
+
+This event consists of a single serialized map reporting on options from the
+barconfig of the specified bar_id that were updated in i3. This event is the
+same as a +GET_BAR_CONFIG+ reply for the bar with the given id.
+
+== See also (existing libraries)
+
+[[libraries]]
For some languages, libraries are available (so you don’t have to implement
all this on your own). This list names some (if you wrote one, please let me
C::
i3 includes a headerfile +i3/ipc.h+ which provides you all constants.
- However, there is no library yet.
-Ruby::
- http://github.com/badboy/i3-ipc
+
+ https://github.com/acrisci/i3ipc-glib
+Go::
+ * https://github.com/proxypoke/i3ipc
+JavaScript::
+ * https://github.com/acrisci/i3ipc-gjs
+Lua::
+ * https:/github.com/acrisci/i3ipc-lua
Perl::
- http://search.cpan.org/search?query=AnyEvent::I3
+ * https://metacpan.org/module/AnyEvent::I3
Python::
- http://github.com/thepub/i3ipc
+ * https://github.com/acrisci/i3ipc-python
+ * https://github.com/whitelynx/i3ipc (not maintained)
+ * https://github.com/ziberna/i3-py (not maintained)
+Ruby::
+ http://github.com/badboy/i3-ipc