auto switch keyboard to english in specific applications

auto_switch_kb.py

#! /usr/bin/env python
# coding: utf-8

'''
auto switch keyboard between different applications

if you want to change the app list, modify the var 'ignore_list'
'''

from AppKit import NSWorkspace, NSWorkspaceDidActivateApplicationNotification, NSWorkspaceApplicationKey
from Foundation import NSObject
from PyObjCTools import AppHelper
import ctypes
import ctypes.util
import objc
import CoreFoundation

# add your custom apps here, check the bundle id in /Application/xx.app/Contents/info.plist

ignore_list = [
    "com.googlecode.iterm2",
    "com.runningwithcrayons.Alfred-2",
    "com.jetbrains.intellij.ce-EAP"
]


carbon = ctypes.cdll.LoadLibrary(ctypes.util.find_library('Carbon'))

_objc = ctypes.PyDLL(objc._objc.__file__)

# PyObject *PyObjCObject_New(id objc_object, int flags, int retain)
_objc.PyObjCObject_New.restype = ctypes.py_object
_objc.PyObjCObject_New.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_int]

def objc_object(id):
    return _objc.PyObjCObject_New(id, 0, 1)

# kTISPropertyLocalizedName
kTISPropertyUnicodeKeyLayoutData_p = ctypes.c_void_p.in_dll(carbon, 'kTISPropertyInputSourceIsEnabled')
kTISPropertyInputSourceLanguages_p = ctypes.c_void_p.in_dll(carbon, 'kTISPropertyInputSourceLanguages')
kTISPropertyInputSourceType_p = ctypes.c_void_p.in_dll(carbon, 'kTISPropertyInputSourceType')
kTISPropertyLocalizedName_p = ctypes.c_void_p.in_dll(carbon, 'kTISPropertyLocalizedName')
# kTISPropertyInputSourceLanguages_p = ctypes.c_void_p.in_dll(carbon, 'kTISPropertyInputSourceLanguages')

kTISPropertyInputSourceCategory = objc_object(ctypes.c_void_p.in_dll(carbon, 'kTISPropertyInputSourceCategory'))
kTISCategoryKeyboardInputSource = objc_object(ctypes.c_void_p.in_dll(carbon, 'kTISCategoryKeyboardInputSource'))


# TISCreateInputSourceList
carbon.TISCreateInputSourceList.restype = ctypes.c_void_p
carbon.TISCreateInputSourceList.argtypes = [ctypes.c_void_p, ctypes.c_bool]

carbon.TISSelectInputSource.restype = ctypes.c_void_p
carbon.TISSelectInputSource.argtypes = [ctypes.c_void_p]

carbon.TISGetInputSourceProperty.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
carbon.TISGetInputSourceProperty.restype = ctypes.c_void_p

# carbon.TISCopyCurrentKeyboardLayoutInputSource.argtypes = []
# carbon.TISCopyCurrentKeyboardLayoutInputSource.restype = ctypes.c_void_p

carbon.TISCopyInputSourceForLanguage.argtypes = [ctypes.c_void_p]
carbon.TISCopyInputSourceForLanguage.restype = ctypes.c_void_p


def get_avaliable_languages():
    single_langs = filter(lambda x: x.count() == 1, \
        map(lambda x: objc_object(carbon.TISGetInputSourceProperty(CoreFoundation.CFArrayGetValueAtIndex(objc_object(s), x).__c_void_p__(), kTISPropertyInputSourceLanguages_p)), \
            range(CoreFoundation.CFArrayGetCount(objc_object(carbon.TISCreateInputSourceList(None, 0))))))
    res = set()
    map(lambda y: res.add(y[0]), single_langs)
    return res

def select_kb(lang):
    cur = carbon.TISCopyInputSourceForLanguage(CoreFoundation.CFSTR(lang).__c_void_p__())
    carbon.TISSelectInputSource(cur)

class Observer(NSObject):
    def handle_(self, noti):
        info = noti.userInfo().objectForKey_(NSWorkspaceApplicationKey)
        bundleIdentifier = info.bundleIdentifier()
        if bundleIdentifier in ignore_list:
            print "found: %s active" % bundleIdentifier
            select_kb(u'en')


def main():
    nc = NSWorkspace.sharedWorkspace().notificationCenter()
    observer = Observer.new()
    nc.addObserver_selector_name_object_(
        observer,
        "handle:",
        NSWorkspaceDidActivateApplicationNotification,
        None
    )
    AppHelper.runConsoleEventLoop(installInterrupt=True)

main()