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
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
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)::
}
--------------
-=== 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.
*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" }
+---------------------------
+
+== 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