I'm trying to build a daemon in python and I want to get the name of the current active application.
For the daemon I'm using this nice code snipped from Sander Marechal
The following line works perfectly on OS X 10.7 when I DON'T run the application as a daemon, although the documentation says "activeApplication()" was deprecated on 10.6+
activeAppName = str(NSWorkspace.sharedWorkspace().activeApplication()['NSApplicationName'])
But as soon as I run the application as a daemon, the application crashes.
However, the daemon doesn't crash when I only do
workspace = str(NSWorkspace.sharedWorkspace())
which returns:
<NSWorkspace: 0x7ffe7cc013c0>
So my questions are:
I don't understand the error message, but maybe one of you does:
Process: Python [7920]
Path: /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
Identifier: Python
Version: ??? (???)
Code Type: X86-64 (Native)
Parent Process: ??? [1]
Date/Time: 2012-02-29 23:35:25.202 +0100
OS Version: Mac OS X 10.7.3 (11D50b)
Report Version: 9
Interval Since Last Report: 818421 sec
Crashes Since Last Report: 21
Per-App Crashes Since Last Report: 15
Anonymous UUID: 05B412BD-4629-472B-964D-BE4A88B06DD1
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000108
VM Regions Near 0x108:
-->
__TEXT 0000000102e90000-0000000102e91000 [ 4K] r-x/rwx SM=COW /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
Application Specific Information:
*** single-threaded process forked ***
objc[7918]: garbage collection is OFF
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libdispatch.dylib 0x00007fff8ceb7ce9 _dispatch_wakeup + 108
1 libdispatch.dylib 0x00007fff8ceba876 _dispatch_resume_slow + 20
2 com.apple.CoreServices.CarbonCore 0x00007fff8d34f919 _ZL22connectToCoreServicesDv + 269
3 com.apple.CoreServices.CarbonCore 0x00007fff8d34f7d5 _ZL9getStatusv + 24
4 com.apple.CoreServices.CarbonCore 0x00007fff8d34f74f scCreateSystemServiceVersion + 50
5 com.apple.LaunchServices 0x00007fff90b5ace1 _ZL45SetupCoreApplicationServicesCommunicationPortv + 147
6 com.apple.LaunchServices 0x00007fff90b5b37a getProcessDispatchTable() + 19
7 com.apple.LaunchServices 0x00007fff90b56de0 LSClientSideSharedMemory::GetClientSideSharedMemory(LSSessionID, bool) + 158
8 com.apple.LaunchServices 0x00007fff90b6b152 _LSCopyFrontApplication + 42
9 com.apple.AppKit 0x00007fff899adc5d -[NSWorkspace activeApplication] + 26
10 libffi.dylib 0x00007fff91df2e7c ffi_call_unix64 + 76
11 libffi.dylib 0x00007fff91df3ae9 ffi_call + 728
12 _objc.so 0x00000001031c7d60 PyObjCFFI_Caller + 2272
13 _objc.so 0x00000001031dd169 0x1031ae000 + 192873
14 org.python.python 0x0000000102ea0d32 PyObject_Call + 97
15 org.python.python 0x0000000102f20f63 PyEval_EvalFrameEx + 14353
16 org.python.python 0x0000000102f23df7 0x102e99000 + 568823
17 org.python.python 0x0000000102f20e0a PyEval_EvalFrameEx + 14008
18 org.python.python 0x0000000102f23df7 0x102e99000 + 568823
19 org.python.python 0x0000000102f20e0a PyEval_EvalFrameEx + 14008
20 org.python.python 0x0000000102f23cd8 PyEval_EvalCodeEx + 1996
21 org.python.python 0x0000000102f23d4d PyEval_EvalCode + 54
22 org.python.python 0x0000000102f3b08f 0x102e99000 + 663695
23 org.python.python 0x0000000102f3b14f PyRun_FileExFlags + 157
24 org.python.python 0x0000000102f3c2a2 PyRun_SimpleFileExFlags + 392
25 org.python.python 0x0000000102f4c2af Py_Main + 2715
26 org.python.python 0x0000000102e90e88 0x102e90000 + 3720
I did some tests with this, and I think your issue might be the way you are daemonizing this tool and then trying to make a call that requires windows services that may not be available. This link here hints at such a situation: http://grokbase.com/t/python/pythonmac-sig/08axst378p/appscript-and-launching-apps-from-background-only-python-processes
I had first tested this theory using your daemon script and making an osascript call to find the active application via AppleScript:
from subprocess import Popen, PIPE
cmd = """osascript \
-e 'tell application "System Events"' \
-e 'set app_name to name of the first process whose frontmost is true' \
-e 'end tell' """
v = Popen(cmd, shell=True, stdout=PIPE).stdout.read()
Popen is a way to launch a system command in a subprocess and be able to check its return code or read its output (or send input) http://docs.python.org/library/subprocess.html. . Osascript is a command line tool for calling apple scripts.
For me, this works because its starting a new subprocess that I think does have access to the window server?
I then created a launchd plist instead of using your daemon script. This works:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.company.test</string>
<key>Nice</key>
<integer>1</integer>
<key>OnDemand</key>
<false/>
<key>Program</key>
<string>/path/to/script.py</string>
</dict>
</plist>
Launchd is the OSX daemon process manager which does seem to launch programs in a way that they have complete access to the windowserver.
For script.py, I simply had it loop, writing the frontmost application name to a file and sleeping.
Update
Since you had mentioned that your pyobjc approach was deprecated, and you seemed to like the applescript approach, I thought I would tack on a pythonic way of doing that using appscript - the python bindings to apple script
from appscript import app, its
activeApp = app('System Events').processes[its.frontmost == True].first()
print activeApp
#result
app(u'/System/Library/CoreServices/System Events.app').application_processes[u'Terminal']
activeApp is an object representing the frontmost application, reported by the System Events app.