docs » hs

Core Hammerspoon functionality

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API Overview

API Documentation

Constants

configdir
Signature hs.configdir
Type Constant
Description

A string containing Hammerspoon's configuration directory. Typically ~/.hammerspoon/

docstrings_json_file
Signature hs.docstrings_json_file
Type Constant
Description

A string containing the full path to the docs.json file inside Hammerspoon's app bundle. This contains the full Hammerspoon API documentation and can be accessed in the Console using help("someAPI"). It can also be loaded and processed by the hs.doc extension

processInfo
Signature hs.processInfo
Type Constant
Description

A table containing read-only information about the Hammerspoon application instance currently running.

Variables

accessibilityStateCallback
Signature hs.accessibilityStateCallback
Type Variable
Description

An optional function that will be called when the Accessibility State is changed.

Notes:

  • The function will not receive any arguments when called. To check what the accessibility state has been changed to, you should call hs.accessibilityState from within your function.
completionsForInputString
Signature hs.completionsForInputString(completionWord) -> table of strings
Type Variable
Description

Gathers tab completion options for the Console window

Parameters:

  • completionWord - A string from the Console window's input field that completions are needed for

Returns:

  • A table of strings, each of which will be shown as a possible completion option to the user

Notes:

  • Hammerspoon provides a default implementation of this function, which can complete against the global Lua namespace, the 'hs' (i.e. extension) namespace, and object metatables. You can assign a new function to the variable to replace it with your own variant.
dockIconClickCallback
Signature hs.dockIconClickCallback
Type Variable
Description

An optional function that will be called when the Hammerspoon Dock Icon is clicked while the app is running

Notes:

  • If set, this callback will be called regardless of whether or not Hammerspoon shows its console window in response to a click (which can be enabled/disabled via hs.openConsoleOnDockClick()
fileDroppedToDockIconCallback
Signature hs.fileDroppedToDockIconCallback
Type Variable
Description

An optional function that will be called when a files are dragged to the Hammerspoon Dock Icon or sent via the Services menu

Notes:

  • The function should accept a single parameter, which will be a string containing the full path to the file that was dragged to the dock icon
  • If multiple files are sent, this callback will be called once for each file
  • This callback will be triggered when ANY file type is dragged onto the Hammerspoon Dock Icon, however certain filetypes are also processed seperately by Hammerspoon. For example, hs.urlevent will be triggered when the following filetypes are dropped onto the Dock Icon: HTML Documents (.html, .htm, .shtml, .jhtml), Plain text documents (.txt, .text), Web site locations (.url), XHTML documents (.xhtml, .xht, .xhtm, .xht).
shutdownCallback
Signature hs.shutdownCallback
Type Variable
Description

An optional function that will be called when the Lua environment is being destroyed (either because Hammerspoon is exiting or reloading its config)

Notes:

  • This function should not perform any asynchronous tasks
  • You do not need to fastidiously destroy objects you have created, this callback exists purely for utility reasons (e.g. serialising state, destroying system resources that will not be released by normal Lua garbage collection processes, etc)
textDroppedToDockIconCallback
Signature hs.textDroppedToDockIconCallback
Type Variable
Description

An optional function that will be called when text is dragged to the Hammerspoon Dock Icon or sent via the Services menu

Notes:

  • The function should accept a single parameter, which will be a string containing the text that was dragged to the dock icon

Functions

accessibilityState
Signature hs.accessibilityState(shouldPrompt) -> isEnabled
Type Function
Description

Parameters:

  • shouldPrompt - an optional boolean value indicating if the dialog box asking if the System Preferences application should be opened should be presented when Accessibility is not currently enabled for Hammerspoon. Defaults to false.

Returns:

  • True or False indicating whether or not Accessibility is enabled for Hammerspoon.

Notes:

  • Since this check is done automatically when Hammerspoon loads, it is probably of limited use except for skipping things that are known to fail when Accessibility is not enabled. Evettaps which try to capture keyUp and keyDown events, for example, will fail until Accessibility is enabled and the Hammerspoon application is relaunched.
allowAppleScript
Signature hs.allowAppleScript([state]) -> bool
Type Function
Description

Set or display whether or not external Hammerspoon AppleScript commands are allowed

Parameters:

  • state - an optional boolean which will set whether or not external Hammerspoon's AppleScript commands are allowed

Returns:

  • A boolean, true if Hammerspoon's AppleScript commands are (or has just been) allowed otherwise false

Notes:

  • AppleScript access is disallowed by default
  • Due to the way AppleScript support works, Hammerspoon will always allow AppleScript commands that are part of the "Standard Suite", such as name,quit,version, etc. However, Hammerspoon will only allow commands from the "Hammerspoon Suite" ifhs.allowAppleScript()is set totrue`
  • For a full list of AppleScript Commands:
    • Open /Applications/Utilities/Script Editor.app
    • Click File > Open Dictionary...
    • Select Hammerspoon from the list of Applications
    • This will now open a Dictionary containing all of the availible Hammerspoon AppleScript commands.
  • Note that strings within the Lua code you pass from AppleScript can be delimited by [[ and ]] rather than normal quotes

Example:

tell application "Hammerspoon"
   execute lua code "hs.alert([[Hello from AppleScript]])"
 end tell
autoLaunch
Signature hs.autoLaunch([state]) -> bool
Type Function
Description

Set or display the "Launch on Login" status for Hammerspoon.

Parameters:

  • state - an optional boolean which will set whether or not Hammerspoon should be launched automatically when you log into your computer.

Returns:

  • True if Hammerspoon is currently (or has just been) set to launch on login or False if Hammerspoon is not.
automaticallyCheckForUpdates
Signature hs.automaticallyCheckForUpdates([setting]) -> bool
Type Function
Description

Gets and optionally sets the Hammerspoon option to automatically check for updates.

Parameters:

  • setting - an optional boolean variable indicating if Hammerspoon should (true) or should not (false) check for updates.

Returns:

  • The current (or newly set) value indicating whether or not automatic update checks should occur for Hammerspoon.

Notes:

  • If you are running a non-release or locally compiled version of Hammerspoon then the results of this function are unspecified.
canCheckForUpdates
Signature hs.canCheckForUpdates() -> boolean
Type Function
Description

Returns a boolean indicating whether or not the Sparkle framework is available to check for Hammerspoon updates.

Parameters:

  • None

Returns:

  • a boolean indicating whether or not the Sparkle framework is available to check for Hammerspoon updates

Notes:

  • The Sparkle framework is included in all regular releases of Hammerspoon but not included if you are running a non-release or locally compiled version of Hammerspoon, so this function can be used as a simple test to determine whether or not you are running a formal release Hammerspoon or not.
checkForUpdates
Signature hs.checkForUpdates([silent]) -> none
Type Function
Description

Check for an update now, and if one is available, prompt the user to continue the update process.

Parameters:

  • silent - An optional boolean. If true, no UI will be displayed if an update is available. Defaults to false.

Returns:

  • None

Notes:

  • If you are running a non-release or locally compiled version of Hammerspoon then the results of this function are unspecified.
cleanUTF8forConsole
Signature hs.cleanUTF8forConsole(inString) -> outString
Type Function
Description

Returns a copy of the incoming string that can be displayed in the Hammerspoon console. Invalid UTF8 sequences are converted to the Unicode Replacement Character and NULL (0x00) is converted to the Unicode Empty Set character.

Parameters:

  • inString - the string to be cleaned up

Returns:

  • outString - the cleaned up version of the input string.

Notes:

  • This function is applied automatically to all output which appears in the Hammerspoon console, but not to the output provided by the hs command line tool.
  • This function does not modify the original string - to actually replace it, assign the result of this function to the original string.
  • This function is a more specifically targeted version of the hs.utf8.fixUTF8(...) function.
consoleOnTop
Signature hs.consoleOnTop([state]) -> bool
Type Function
Description

Set or display whether or not the Hammerspoon console is always on top when visible.

Parameters:

  • state - an optional boolean which will set whether or not the Hammerspoon console is always on top when visible.

Returns:

  • True if the console is currently set (or has just been) to be always on top when visible or False if it is not.
dockIcon
Signature hs.dockIcon([state]) -> bool
Type Function
Description

Set or display whether or not the Hammerspoon dock icon is visible.

Parameters:

  • state - an optional boolean which will set whether or not the Hammerspoon dock icon should be visible.

Returns:

  • True if the icon is currently set (or has just been) to be visible or False if it is not.

Notes:

  • This function is a wrapper to functions found in the hs.dockicon module, but is provided here to provide an interface consistent with other selectable preference items.
execute
Signature hs.execute(command[, with_user_env]) -> output, status, type, rc
Type Function
Description

Runs a shell command, optionally loading the users shell environment first, and returns stdout as a string, followed by the same result codes as os.execute would return.

Parameters:

  • command - a string containing the shell command to execute
  • with_user_env - optional boolean argument which if provided and is true, executes the command in the users login shell as an "interactive" login shell causing the user's local profile (or other login scripts) to be loaded first.

Returns:

  • output -- the stdout of the command as a string. May contain an extra terminating new-line (\n).
  • status -- true if the command terminated successfully or nil otherwise.
  • type -- a string value of "exit" or "signal" indicating whether the command terminated of its own accord or if it was terminated by a signal (killed, segfault, etc.)
  • rc -- if the command exited of its own accord, then this number will represent the exit code (usually 0 for success, not 0 for an error, though this is very command specific, so check man pages when there is a question). If the command was killed by a signal, then this number corresponds to the signal type that caused the command to terminate.

Notes:

  • Setting with_user_env to true does incur noticeable overhead, so it should only be used if necessary (to set the path or other environment variables).
  • Because this function returns the stdout as it's first return value, it is not quite a drop-in replacement for os.execute. In most cases, it is probable that stdout will be the empty string when status is nil, but this is not guaranteed, so this trade off of shifting os.execute's results was deemed acceptable.
  • This particular function is most useful when you're more interested in the command's output then a simple check for completion and result codes. If you only require the result codes or verification of command completion, then os.execute will be slightly more efficient.
focus
Signature hs.focus()
Type Function
Description

Makes Hammerspoon the foreground app.

getObjectMetatable
Signature hs.getObjectMetatable(name) -> table or nil
Type Function
Description

Fetches the Lua metatable for objects produced by an extension

Parameters:

  • name - A string containing the name of a module to fetch object metadata for (e.g. "hs.screen")

Returns:

  • The extension's object metatable, or nil if an error occurred
help
Signature hs.help(identifier)
Type Function
Description

Prints the documentation for some part of Hammerspoon's API and Lua 5.3. This function is actually sourced from hs.doc.help.

Parameters:

  • identifier - A string containing the signature of some part of Hammerspoon's API (e.g. "hs.reload")

Returns:

  • None

Notes:

  • This function is mainly for runtime API help while using Hammerspoon's Console
  • You can also access the results of this function by the following methods from the console:
    • help("identifier") -- quotes are required, e.g. help("hs.reload")
    • help.identifier.path -- no quotes are required, e.g. help.hs.reload
  • Lua information can be accessed by using the lua prefix, rather than hs.
    • the identifier lua._man provides the table of contents for the Lua 5.3 manual. You can pull up a specific section of the lua manual by including the chapter (and subsection) like this: lua._man._3_4_8.
    • the identifier lua._C will provide information specifically about the Lua C API for use when developing modules which require external libraries.
hsdocs
Signature hs.hsdocs([identifier])
Type Function
Description

Display's Hammerspoon API documentation in a webview browser.

Parameters:

  • identifier - An optional string containing the signature of some part of Hammerspoon's API (e.g. "hs.reload"). If no string is provided, then the table of contents for the Hammerspoon documentation is displayed.

Returns:

  • None

Notes:

  • You can also access the results of this function by the following methods from the console:
    • hs.hsdocs.identifier.path -- no quotes are required, e.g. hs.hsdocs.hs.reload
  • See hs.doc.hsdocs for more information about the available settings for the documentation browser.
  • This function provides documentation for Hammerspoon modules, functions, and methods similar to the Hammerspoon Dash docset, but does not require any additional software.
  • This currently only provides documentation for the built in Hammerspoon modules, functions, and methods. The Lua documentation and third-party modules are not presently supported, but may be added in a future release.
loadSpoon
Signature hs.loadSpoon(name[, global]) -> Spoon object
Type Function
Description

Loads a Spoon

Parameters:

  • name - The name of a Spoon (without the trailing .spoon)
  • global - An optional boolean. If true, this function will insert the spoon into Lua's global namespace as spoon.NAME. Defaults to true.

Returns:

  • The object provided by the Spoon (which can be ignored if you chose to make the Spoon global)

Notes:

  • Spoons are a way of distributing self-contained units of Lua functionality, for Hammerspoon. For more information, see https://github.com/Hammerspoon/hammerspoon/blob/master/SPOON.md
  • This function will load the Spoon and call its :init() method if it has one. If you do not wish this to happen, or wish to use a Spoon that somehow doesn't fit with the behaviours of this function, you can also simply require('name') to load the Spoon
  • If the Spoon provides documentation, it will be loaded by made available in hs.docs
  • To learn how to distribute your own code as a Spoon, see https://github.com/Hammerspoon/hammerspoon/blob/master/SPOON.md
openAbout
Signature hs.openAbout()
Type Function
Description

Displays the OS X About panel for Hammerspoon; implicitly focuses Hammerspoon.

openConsole
Signature hs.openConsole([bringToFront])
Type Function
Description

Opens the Hammerspoon Console window and optionally focuses it.

Parameters:

  • bringToFront - if true (default), the console will be focused as well as opened.
openConsoleOnDockClick
Signature hs.openConsoleOnDockClick([state]) -> bool
Type Function
Description

Set or display whether or not the Console window will open when the Hammerspoon dock icon is clicked

Parameters:

  • state - An optional boolean, true if the console window should open, false if not

Returns:

  • A boolean, true if the console window will open when the dock icon

Notes:

  • This only refers to dock icon clicks while Hammerspoon is already running. The console window is not opened by launching the app
openPreferences
Signature hs.openPreferences()
Type Function
Description

Displays the Hammerspoon Preferences panel; implicitly focuses Hammerspoon.

printf
Signature hs.printf(format, ...)
Type Function
Description

Prints formatted strings to the Console

Parameters:

  • format - A format string
  • ... - Zero or more arguments to fill the placeholders in the format string

Returns:

  • None

Notes:

  • This is a simple wrapper around the Lua code print(string.format(...)).
rawprint
Signature hs.rawprint(aString)
Type Function
Description

The original Lua print() function

Parameters:

  • aString - A string to be printed

Returns:

  • None

Notes:

  • Hammerspoon overrides Lua's print() function, but this is a reference we retain to is, should you need it for any reason
reload
Signature hs.reload()
Type Function
Description

Reloads your init-file in a fresh Lua environment.

showError
Signature hs.showError(err)
Type Function
Description

Shows an error to the user, using Hammerspoon's Console

Parameters:

  • err - A string containing an error message

Returns:

  • None

Notes:

  • This function is called whenever an (uncaught) error occurs or is thrown (via error())
  • The default implementation shows a notification, opens the Console, and prints the error message and stacktrace
  • You can override this function if you wish to route errors differently (e.g. for remote systems)
toggleConsole
Signature hs.toggleConsole()
Type Function
Description

Toggles the visibility of the console

Parameters:

  • None

Returns:

  • None

Notes:

  • If the console is not currently open, it will be opened. If it is open and not the focused window, it will be brought forward and focused.
  • If the console is focused, it will be closed.
updateAvailable
Signature hs.updateAvailable() -> string or false
Type Function
Description

Gets the version number of an available update

Parameters:

  • None

Returns:

  • A string containing the version number of the latest release, or a boolean false if no update is available

Notes:

  • This is not a live check, it is a cached result of whatever the previous update check found. By default Hammerspoon checks for updates every few hours, but you can also add your own timer to check for updates more frequently with hs.checkForUpdates()
uploadCrashData
Signature hs.uploadCrashData([state]) -> bool
Type Function
Description

Get or set the "Upload Crash Data" preference for Hammerspoon

Parameters:

  • state - An optional boolean, true to upload crash reports, false to not

Returns:

  • True if Hammerspoon is currently (or has just been) set to upload crash data or False otherwise

Notes:

  • If at all possible, please do allow Hammerspoon to upload crash reports to us, it helps a great deal in keeping Hammerspoon stable
  • Our Privacy Policy can be found here: http://www.hammerspoon.org/privacy.html