properly check command arguments

fixes #6

agent.py

@@ -15,6 +15,7 @@ import tarfile
 from os.path import expanduser, join, exists
 from os.path import expanduser, join, exists
 from os import mkdir, environ
 from os import mkdir, environ
 from glob import glob
 from glob import glob
+from inspect import getargspec
 from StringIO import StringIO
 from StringIO import StringIO
 from base64 import decodestring
 from base64 import decodestring
 from shutil import rmtree, move
 from shutil import rmtree, move
@@ -346,24 +347,29 @@ class SerialLineReceiver(SerialLineReceiverBase):
         self.send_response(response='status',
         self.send_response(response='status',
                            args=args)
                            args=args)
 
 
-    def handle_command(self, command, args):
+    def _get_command(self, command, args):
         if not isinstance(command, basestring) or command.startswith('_'):
         if not isinstance(command, basestring) or command.startswith('_'):
-            raise Exception(u'Invalid command: %s' % command)
-
-        for k, v in args.iteritems():
-            if not (isinstance(v, int) or isinstance(v, float) or
-                    isinstance(v, basestring)):
-                raise Exception(u'Invalid argument: %s' % k)
-
+            raise AttributeError(u'Invalid command: %s' % command)
         try:
         try:
             func = getattr(Context, command)
             func = getattr(Context, command)
-            retval = func(**args)
-        except (AttributeError, TypeError) as e:
-            raise Exception(u'Command not found: %s (%s)' % (command, e))
-        else:
-            self.send_response(
-                response=func.__name__,
-                args={'retval': retval, 'uuid': args.get('uuid', None)})
+        except AttributeError as e:
+            raise AttributeError(u'Command not found: %s (%s)' % (command, e))
+
+        # check for unexpected keyword arguments
+        argspec = getargspec(func)
+        if argspec.keywords is None:  # _operation doesn't take ** args
+            unexpected_kwargs = set(args) - set(argspec.args)
+            if unexpected_kwargs:
+                raise TypeError("Command got unexpected keyword arguments: "
+                                "%s" % ", ".join(unexpected_kwargs))
+        return func
+
+    def handle_command(self, command, args):
+        func = self._get_command(command, args)
+        retval = func(**args)
+        self.send_response(
+            response=func.__name__,
+            args={'retval': retval, 'uuid': args.get('uuid', None)})
 
 
     def handle_response(self, response, args):
     def handle_response(self, response, args):
         pass
         pass