Index: umc/python/setup/__init__.py
===================================================================
--- umc/python/setup/__init__.py	(Revision 33668)
+++ umc/python/setup/__init__.py	(Arbeitskopie)
@@ -55,6 +55,58 @@
 
 PATH_SYS_CLASS_NET = '/sys/class/net'
 
+def simple_response(function):
+	import inspect
+	from univention.management.console.protocol.message import InvalidArgumentsError
+	from univention.management.console.protocol.definitions import BAD_REQUEST_INVALID_ARGS
+	# argument names of the function, including 'self'
+	argspec = inspect.getargspec(function)
+	# remove self, use all the others
+	arguments = argspec.args[1:]
+	defaults = argspec.defaults
+	# use defaults as dict
+	if defaults:
+		defaults = dict(zip(arguments[-len(defaults):], defaults))
+	else:
+		defaults = {}
+	def _response(self, request):
+		try:
+			try:
+				# extract arguments from request, raise if not given and no default
+				# pass arguments as **kwargs, not *args to be more flexible with defaults
+				kwargs = {}
+				for arg in arguments:
+					if arg in request.options:
+						kwargs[arg] = request.options[arg]
+					else:
+						kwargs[arg] = defaults[arg]
+			except KeyError, e:
+				# raise InvalidArgs if a mandatory argument was not given
+				raise InvalidArgumentsError(BAD_REQUEST_INVALID_ARGS, 'Required argument "%s" not found' % e)
+			else:
+				try:
+					try:
+						ret = function(self, **kwargs)
+					except InvalidArgumentsError, e:
+						if int(e.args[0]) and e.args[1]:
+							# re-raise a valid InvalidArgumentsError
+							raise e
+					else:
+						self.finished(request.id, ret)
+				except InvalidArgumentsError, e:
+					# this is the re-raised: re-re-raise
+					raise e
+				except:
+					raise InvalidArgumentsError(BAD_REQUEST_INVALID_ARGS, 'The arguments caused the command to fail')
+					# better raise 40x
+					# codes like CLIENT_ERR_NONFATAL 301 are mapped to 500 for HTTP requests.
+					# raise InvalidArgumentsError(CLIENT_ERR_NONFATAL, 'The arguments caused the command to fail')
+		except InvalidArgumentsError, e:
+			self.finished(request.id, None, message=e.args[1], success=False, status=e.args[0])
+	# copy __doc__, otherwise it would not show up in api and such
+	_response.__doc__ = function.__doc__
+	return _response
+
 class TimeoutError(Exception):
 	pass
 
@@ -535,25 +587,18 @@
 
 		self.finished(request.id, locales)
 
-	def lang_default_timezone(self, request):
+	@simple_response
+	def lang_default_timezone(self, countrycode):
 		'''Returns default timezone for given locale.'''
-		countrycode = request.options.get('countrycode', '')
-		timezone = None
-		file = open('/lib/univention-installer/locale/countrycode2timezone')
+		with open('/lib/univention-installer/locale/countrycode2timezone') as file:
+			reader = csv.reader(file, delimiter=' ')
+			for row in reader:
+				if row[0].startswith("#"): continue
+				if len(row) > 1:
+					if countrycode.upper() == row[0].upper():
+						return row[1]
+			return 'Europe/Berlin'
 
-		reader = csv.reader(file, delimiter=' ')
-		for row in reader:
-			if row[0].startswith("#"): continue
-			if len(row) > 1:
-				if countrycode.upper() == row[0].upper():
-					timezone = row[1]
-					break
-		file.close()
-
-		if timezone is None:
-			timezone = 'Europe/Berlin'
-		self.finished(request.id, timezone)
-
 	def lang_timezones(self, request):
 		'''Return a list of all available time zones.'''
 		try:
@@ -567,26 +612,18 @@
 
 		self.finished(request.id, timezones)
 
-	def lang_default_keymap(self, request):
+	@simple_response
+	def lang_default_keymap(self, countrycode):
 		'''Returns default timezone for given locale.'''
-		# use "or ''" to be sure to not get None
-		countrycode = (request.options.get('countrycode') or  '').upper()
-		keymap = None
-		file = open('/lib/univention-installer/locale/default-kmaps')
+		with open('/lib/univention-installer/locale/default-kmaps') as file:
+			reader = csv.reader(file, delimiter=':')
+			for row in reader:
+				if row[0].startswith("#"): continue
+				if len(row) > 1:
+					if row[1].upper().startswith(countrycode.upper()):
+						return row[1]
+			return 'us'
 
-		reader = csv.reader(file, delimiter=':')
-		for row in reader:
-			if row[0].startswith("#"): continue
-			if len(row) > 1:
-				if row[1].upper().startswith(countrycode):
-					keymap = row[1]
-					break
-		file.close()
-
-		if keymap is None:
-			keymap = 'us'
-		self.finished(request.id, keymap)
-
 	def lang_keymaps(self, request):
 		'''Return a list of all available keyboard layouts.'''
 		try: