Python script to control the mediakeys on OS X. Used to emulate the mediakey on a keyboard with no such keys. Easiest used in combination with a launcher/trigger software such as Quicksilver.

mediakeys.py

#!/usr/bin/python

# CLI program to control the mediakeys on OS X. Used to emulate the mediakey on a keyboard with no such keys.
# Easiest used in combination with a launcher/trigger software such as Quicksilver.
# Main part taken from http://stackoverflow.com/questions/11045814/emulate-media-key-press-on-mac
# Glue to make it into cli program by Fredrik Wallner http://www.wallner.nu/fredrik/

import Quartz
import sys

# NSEvent.h
NSSystemDefined = 14

# hidsystem/ev_keymap.h
NX_KEYTYPE_SOUND_UP = 0
NX_KEYTYPE_SOUND_DOWN = 1
NX_KEYTYPE_PLAY = 16
NX_KEYTYPE_NEXT = 17
NX_KEYTYPE_PREVIOUS = 18
NX_KEYTYPE_FAST = 19
NX_KEYTYPE_REWIND = 20

supportedcmds = {'playpause': NX_KEYTYPE_PLAY, 'next': NX_KEYTYPE_NEXT, 'prev': NX_KEYTYPE_PREVIOUS, 'volup': NX_KEYTYPE_SOUND_UP, 'voldown': NX_KEYTYPE_SOUND_DOWN}

def HIDPostAuxKey(key):
	def doKey(down):
		ev = Quartz.NSEvent.otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
			NSSystemDefined, # type
			(0,0), # location
			0xa00 if down else 0xb00, # flags
			0, # timestamp
			0, # window
			0, # ctx
			8, # subtype
			(key << 16) | ((0xa if down else 0xb) << 8), # data1
			-1 # data2
			)
		cev = ev.CGEvent()
		Quartz.CGEventPost(0, cev)
	doKey(True)
	doKey(False)

if __name__ == "__main__":
	try:
		command = sys.argv[1]
		assert(command in supportedcmds)
		HIDPostAuxKey(supportedcmds[command])
	except (IndexError, AssertionError):
		print "Usage: %s command" % (sys.argv[0],)
		print "\tSupported commands are %s" % supportedcmds.keys()

Looks like you are correct but since 12.3 deprecated Python it is now installed in /usr/local/bin/python but when I run the command "/usr/local/bin/python -m pip install pyobjc-framework-Quartz" I got an error instead of saying already installed. I also tried: /Users/divincem/.pyenv/versions/2.7.18/bin/python2.7 -m pip install pyobjc-framework-Quartz" to the real path with the same error. Looks liek PIP does not support Python 2.7 if I am reading correctly.

DIVINCEM-mac:bin > /Users/divincem/.pyenv/versions/2.7.18/bin/python2.7 -m pip install pyobjc-framework-Quartz
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting pyobjc-framework-Quartz
Using cached https://files.pythonhosted.org/packages/ce/e3/be5dd50240fe90d597c2afabc3cd27304ba5bfc66354f5fa52b0fa5bfe09/pyobjc-framework-Quartz-5.3.tar.gz
ERROR: Command errored out with exit status 1:
command: /Users/divincem/.pyenv/versions/2.7.18/bin/python2.7 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/2d/pvf3w0y12p968b3vlv0dx_jc0000gp/T/pip-install-4TWtam/pyobjc-framework-Quartz/setup.py'"'"'; file='"'"'/private/var/folders/2d/pvf3w0y12p968b3vlv0dx_jc0000gp/T/pip-install-4TWtam/pyobjc-framework-Quartz/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(file);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, file, '"'"'exec'"'"'))' egg_info --egg-base pip-egg-info
cwd: /private/var/folders/2d/pvf3w0y12p968b3vlv0dx_jc0000gp/T/pip-install-4TWtam/pyobjc-framework-Quartz/
Complete output (7 lines):
Traceback (most recent call last):
File "", line 1, in
File "/private/var/folders/2d/pvf3w0y12p968b3vlv0dx_jc0000gp/T/pip-install-4TWtam/pyobjc-framework-Quartz/setup.py", line 61, in
[ 'Modules/_CVPixelBuffer.m' ]),
File "pyobjc_setup.py", line 408, in Extension
cflags.append("-DPyObjC_BUILD_RELEASE=%02d%02d"%(tuple(map(int, os.path.basename(data)[6:-4].split('.')))))
ValueError: invalid literal for int() with base 10: ''
----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
WARNING: You are using pip version 19.2.3, however version 20.3.4 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

So then probably change the first line to
#!/usr/local/bin/python
That should probably work looking at your result from /usr/local/bin/python -m pip install pyobjc-framework-Quartz
Python 2.7 should be avoided by now

I had tried that before expanding the command and got the same result. Someone on the Alfred Forum converted it to Swift for me 🙂

Hello there, I working on Mac OS Catalina 10.15.7, when I installed Quartz I got warning:

Cannot find reference 'CGEventPost' in '__init__.py | __init__.py'

How to solve them?

As I said above, this script is really dated so I don't remember and I don't use it any longer either. So I'm afraid I cannot help much. Did you really get the error when you installed Quartz?

I already installed quartz.However your code is working, despite the error.

And I want to ask you, where did you find Quartz documentation? I have seen the official Quartz documentation but have not found an explanation for it methods this framework.

I just copied the main thing from the StackOverflow answer that is linked in the top comment of the script. My only contribution was adding the CLI.

I've updated the script for python 3 and worked out the correct egg to install:
https://gist.github.com/aleksandersumowski/a296a910fd3c6722744a2c3b0a1b5bf5

the script assumes python 3 installed via homebrew on a M* computer