3 Michael Stapelberg <michael@i3wm.org>
6 This document explains the protocol in which i3bar expects its input. It
7 provides support for colors, urgency, shortening and easy manipulation.
9 == Rationale for chosing JSON
11 Before describing the protocol, let’s cover why JSON is a building block of
14 1. Other bar display programs such as dzen2 or xmobar are using in-band
15 signaling: they recognize certain sequences (like ^fg(#330000) in your input
16 text). We would like to avoid that and separate information from
17 meta-information. By information, we mean the actual output, like the IP
18 address of your ethernet adapter and by meta-information, we mean in which
19 color it should be displayed right now.
20 2. It is easy to write a simple script which manipulates part(s) of the input.
21 Each block of information (like a block for the disk space indicator, a block
22 for the current IP address, etc.) can be identified specifically and modified
23 in whichever way you like.
24 3. It remains easy to write a simple script which just suffixes (or prefixes) a
25 status line input, because tools like i3status will output their JSON in
26 such a way that each line array will be terminated by a newline. Therefore,
27 you are not required to use a streaming JSON parser, but you can use any
28 JSON parser and write your script in any programming language. In fact, you
29 can decide to not bother with the JSON parsing at all and just inject your
30 output at a specific position (beginning or end).
31 4. Relying on JSON does not introduce any new dependencies. In fact, the IPC
32 interface of i3 also uses JSON, therefore i3bar already depends on JSON.
34 The only point against using JSON is computational complexity. If that really
35 bothers you, just use the plain text input format (which i3bar will continue to
40 The first message of the protocol is a header block, which contains (at least)
41 the version of the protocol to be used. In case there are significant changes
42 (not only additions), the version will be incremented. i3bar will still
43 understand the old protocol version, but in order to use the new one, you need
44 to provide the correct version. The header block is terminated by a newline and
45 consists of a single JSON hash:
52 *All features example*:
54 { "version": 1, "stop_signal": 10, "cont_signal": 12 }
57 (Note that before i3 v4.3 the precise format had to be +{"version":1}+,
60 What follows is an infinite array (so it should be parsed by a streaming JSON
61 parser, but as described above you can go for a simpler solution), whose
62 elements are one array per status line. A status line is one unit of
63 information which should be displayed at a time. i3bar will not display any
64 input until the status line is complete. In each status line, every block will
65 be represented by a JSON hash:
73 "full_text": "E: 10.0.0.1 (1000 Mbit/s)",
77 "full_text": "2012-01-05 20:00:01"
83 "full_text": "E: 10.0.0.1 (1000 Mbit/s)",
87 "full_text": "2012-01-05 20:00:02"
93 Please note that this example was pretty printed for human consumption.
94 i3status and others will output single statuslines in one line, separated by
97 You can find an example of a shell script which can be used as your
98 +status_command+ in the bar configuration at
99 http://code.stapelberg.de/git/i3/tree/contrib/trivial-bar-script.sh?h=next
104 The version number (as an integer) of the i3bar protocol you will use.
106 Specify to i3bar the signal (as an integer) to send to stop your
108 The default value (if none is specified) is SIGSTOP.
110 Specify to i3bar the signal (as an integer)to send to continue your
112 The default value (if none is specified) is SIGCONT.
117 The most simple block you can think of is one which just includes the
118 only required key, the +full_text+ key. i3bar will display the string
121 Where appropriate, the +short_text+ (string) entry should also be
122 provided. It will be used in case the status line needs to be shortened
123 because it uses more space than your screen provides. For example, when
124 displaying an IPv6 address, the prefix is usually (!) more relevant
125 than the suffix, because the latter stays constant when using autoconf,
126 while the prefix changes. When displaying the date, the time is more
127 important than the date (it is more likely that you know which day it
128 is than what time it is).
130 To make the current state of the information easy to spot, colors can
131 be used. For example, the wireless block could be displayed in red
132 (using the +color+ (string) entry) if the card is not associated with
133 any network and in green or yellow (depending on the signal strength)
134 when it is associated.
135 Colors are specified in hex (like in HTML), starting with a leading
136 hash sign. For example, +#ff0000+ means red.
138 Every block should have a unique +name+ (string) entry so that it can
139 be easily identified in scripts which process the output. i3bar
140 completely ignores the name and instance fields. Make sure to also
141 specify an +instance+ (string) entry where appropriate. For example,
142 the user can have multiple disk space blocks for multiple mount points.
144 A boolean which specifies whether the current value is urgent. Examples
145 are battery charge values below 1 percent or no more available disk
146 space (for non-root users). The presentation of urgency is up to i3bar.
148 If you want to put in your own entries into a block, prefix the key with an
149 underscore (_). i3bar will ignore all keys it doesn’t understand, and prefixing
150 them with an underscore makes it clear in every script that they are not part
151 of the i3bar protocol.
154 ------------------------------------------
156 "full_text": "E: 10.0.0.1 (1000 Mbit/s)",
157 "_ethernet_vendor": "Intel"
159 ------------------------------------------
161 An example of a block which uses all possible entries follows:
164 ------------------------------------------
166 "full_text": "E: 10.0.0.1 (1000 Mbit/s)",
167 "short_text": "10.0.0.1",
173 ------------------------------------------