docs » hs.caffeinate

Control system power states (sleeping, preventing sleep, screen locking, etc)

NOTE: Any sleep preventions will be removed when hs.reload() is called. A future version of the module will save/restore state across reloads.

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API Overview

API Documentation

Functions

currentAssertions
Signature hs.caffeinate.currentAssertions()
Type Function
Description Fetches information about processes which are currently asserting display/power sleep restrictions
Parameters
  • None
Returns
  • A table containing information about current power assertions, with process IDs (PID) as the keys, each of which may contain multiple assertions
Source extensions/caffeinate/internal.m
declareUserActivity
Signature hs.caffeinate.declareUserActivity([id])
Type Function
Description Informs the OS that the user performed some activity
Parameters
  • id - An option number containing the assertion ID returned by a previous call of this function
Returns
  • A number containing the ID of the assertion generated by this function
Notes
  • This is intended to simulate user activity, for example to prevent displays from sleeping, or to wake them up
  • It is not mandatory to re-use assertion IDs if you are calling this function mulitple times, but it is recommended that you do so if the calls are related
Source extensions/caffeinate/internal.m
fastUserSwitch
Signature hs.caffeinate.fastUserSwitch()
Type Function
Description Show the Fast User Switch screen (ie a login screen without logging out first)
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/init.lua
get
Signature hs.caffeinate.get(sleepType) -> bool or nil
Type Function
Description Queries whether a particular sleep type is being prevented
Parameters
  • sleepType - A string containing the type of sleep to inspect (see hs.caffeinate.set() for information about the possible values)
Returns
  • True if the specified type of sleep is being prevented, false if not. nil if sleepType was an invalid value
Source extensions/caffeinate/init.lua
lockScreen
Signature hs.caffeinate.lockScreen()
Type Function
Description Locks the displays
Parameters
  • None
Returns
  • None
Notes
  • This function uses private Apple APIs and could therefore stop working in any given release of macOS without warning.
Source extensions/caffeinate/internal.m
logOut
Signature hs.caffeinate.logOut()
Type Function
Description Request the system log out the current user
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/init.lua
restartSystem
Signature hs.caffeinate.restartSystem()
Type Function
Description Request the system reboot
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/init.lua
sessionProperties
Signature hs.caffeinate.sessionProperties()
Type Function
Description Fetches information from the display server about the current session
Parameters
  • None
Returns
  • A table containing information about the current session, or nil if an error occurred
Notes
  • The keys in this dictionary will vary based on the current state of the system (e.g. local vs VNC login, screen locked vs unlocked).
Source extensions/caffeinate/internal.m
set
Signature hs.caffeinate.set(sleepType, aValue, acAndBattery)
Type Function
Description Configures the sleep prevention settings
Parameters
  • sleepType - A string containing the type of sleep to be configured. The value should be one of:
    • displayIdle - Controls whether the screen will be allowed to sleep (and also the system) if the user is idle.
    • systemIdle - Controls whether the system will be allowed to sleep if the user is idle (display may still sleep).
    • system - Controls whether the system will be allowed to sleep for any reason.
  • aValue - A boolean, true if the specified type of sleep should be prevented, false if it should be allowed
  • acAndBattery - A boolean, true if the sleep prevention should apply to both AC power and battery power, false if it should only apply to AC power.
Returns
  • None
Notes
  • These calls are not guaranteed to prevent the system sleep behaviours described above. The OS may override them if it feels it must (e.g. if your CPU temperature becomes dangerously high).
  • The acAndBattery argument only applies to the system sleep type.
  • You can toggle the acAndBattery state by calling hs.caffeinate.set() again and altering the acAndBattery value.
  • The acAndBattery option does not appear to work anymore - it is based on private API that is not allowed in macOS 10.15 when running with the Hardened Runtime (which Hammerspoon now uses).
Source extensions/caffeinate/init.lua
shutdownSystem
Signature hs.caffeinate.shutdownSystem()
Type Function
Description Request the system log out and power down
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/init.lua
startScreensaver
Signature hs.caffeinate.startScreensaver()
Type Function
Description Request the system start the screensaver (which may lock the screen if the OS is configured to do so)
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/init.lua
systemSleep
Signature hs.caffeinate.systemSleep()
Type Function
Description Requests the system to sleep immediately
Parameters
  • None
Returns
  • None
Source extensions/caffeinate/internal.m
toggle
Signature hs.caffeinate.toggle(sleepType) -> bool or nil
Type Function
Description Toggles the current state of the specified type of sleep
Parameters
  • sleepType - A string containing the type of sleep to toggle (see hs.caffeinate.set() for information about the possible values)
Returns
  • True if the specified type of sleep is being prevented, false if not. nil if sleepType was an invalid value
Notes
  • If systemIdle is toggled to on, it will apply to AC only
Source extensions/caffeinate/init.lua