IPC interface (interprocess communication)
==========================================
-Michael Stapelberg <michael+i3@stapelberg.de>
-December 2011
+Michael Stapelberg <michael@i3wm.org>
+October 2012
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. You can get the socketpath from i3 by calling +i3 --get-socketpath+.
+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
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 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_LOG_MARKERS (7)::
- Gets the SHM log markers for the current position, the last wrap, the
- SHM segment name and segment size. This is necessary for tools like
- i3-dump-log which want to display the SHM log.
+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:
Reply to the GET_MARKS message.
BAR_CONFIG (6)::
Reply to the GET_BAR_CONFIG message.
-LOG_MARKERS (7)::
- Reply to the GET_LOG_MARKERS message.
+VERSION (7)::
+ Reply to the GET_VERSION message.
=== COMMAND reply
{ "success": true }
-------------------
-=== GET_OUTPUTS reply
+=== OUTPUTS reply
The reply consists of a serialized list of outputs. Each output has the
following properties:
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. The order of that array is undefined. If more than one container has the
-same mark, it will be represented multiple times in the reply (the array
-contents are not unique).
+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 [].
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)::
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.
"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",
}
--------------
-=== LOG_MARKERS reply
-
-Gets the SHM log markers for the current position, the last wrap, the
-SHM segment name and segment size. This is necessary for tools like
-i3-dump-log which want to display the SHM log.
-
-The reply is a JSON map with the following entries:
-
-shmname (string)::
- The name of the SHM segment, will be of the format +/i3-log-<pid>+.
-size (integer)::
- The size (in bytes) of the SHM segment. If this is 0, SHM logging is
- disabled.
-offset_next_write (integer)::
- The offset in the SHM segment at which the next write will happen.
- Tools should start printing lines from here, since the bytes following
- this offset are the oldest log lines. However, the first line might be
- garbled, so it makes sense to skip all bytes until the first \0.
-offset_last_wrap (integer)::
- The offset in the SHM segment at which the last wrap occured. i3 only
- stores entire messages in the SHM log, so it might waste a few bytes at
- the end to be more efficient. Tools should not print content after the
- offset_last_wrap.
-
-*Example*:
------------------------------
+=== 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:*
+-------------------
{
- "offset_next_write":132839,
- "offset_last_wrap":26214400,
- "shmname":"/i3-log-3392",
- "size":26214400
+ "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).
+barconfig_update (4)::
+ Sent when the hidden_state or mode field in the barconfig of any bar
+ instance was updated.
*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":4,
+ ...
+ }
+ "old": {
+ "id": 28489715,
+ "type": 4,
+ ...
+ }
+}
---------------------
=== 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 currently can indicate only that a new window
+has been successfully reparented (the value will be "new").
+
+Additionally a +container (object)+ field will be present, which consists
+of the window's parent container. Be aware that 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": 2,
+ ...
+ }
+}
+---------------------------
+
+=== 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. The map always
+consists of a property +id (string)+, which specifies to which bar instance the
+sent config update belongs, a property +hidden_state (string)+, which indicates
+the hidden_state of an i3bar instance, and a property +mode (string)+, which
+corresponds to the current mode.
+
+*Example:*
+---------------------------
+{
+ "id": "bar-0",
+ "hidden_state": "hide"
+ "mode": "hide"
+}
+---------------------------
+
+== 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
Ruby::
http://github.com/badboy/i3-ipc
Perl::
- http://search.cpan.org/search?query=AnyEvent::I3
+ https://metacpan.org/module/AnyEvent::I3
Python::
- http://github.com/thepub/i3ipc
+ * https://github.com/whitelynx/i3ipc
+ * https://github.com/ziberna/i3-py (includes higher-level features)
+Go::
+ * https://github.com/proxypoke/i3ipc
projects / i3 / i3 / blobdiff