ping
- Command
ping- Area
- basics
- Profile
- mandatory
- Response
{"pong":true}
Request and response#
{"v":1,"cmd":"ping"}
{"v":1,"ok":true,"result":{"pong":true}}
The request carries no further fields.
What it is for#
ping answers the one question that neither an identification file nor a
process entry can answer reliably: whether the display responds. A process
can be running and stuck all the same.
The display must answer ping even while it is busy – if need be before it
redraws the screen. A controlling program that receives no answer to ping
treats the display as absent and carries on without it.
Like every request, ping counts as activity: it ends the screen saver and
cancels an announced shutdown (see
lifecycle.shutdown).