Add the InterruptCommand exception to cleanly interrupt commands

evennia/commands/cmdhandler.py

@@ -43,6 +43,7 @@ from twisted.internet import reactor
 from twisted.internet.task import deferLater
 from twisted.internet.defer import inlineCallbacks, returnValue
 from django.conf import settings
+from evennia.commands.command import InterruptCommand
 from evennia.comms.channelhandler import CHANNELHANDLER
 from evennia.utils import logger, utils
 from evennia.utils.utils import string_suggestions, to_unicode
@@ -51,7 +52,7 @@ from django.utils.translation import ugettext as _
 
 _IN_GAME_ERRORS = settings.IN_GAME_ERRORS
 
-__all__ = ("cmdhandler",)
+__all__ = ("cmdhandler", "InterruptCommand")
 _GA = object.__getattribute__
 _CMDSET_MERGE_CACHE = WeakValueDictionary()
 
@@ -601,6 +602,9 @@ def cmdhandler(called_by, raw_string, _testing=False, callertype="session", sess
             # return result to the deferred
             returnValue(ret)
 
+        except InterruptCommand:
+            # Do nothing, clean exit
+            pass
         except Exception:
             _msg_err(caller, _ERROR_UNTRAPPED)
             raise ErrorReported(raw_string)
@@ -748,4 +752,3 @@ def cmdhandler(called_by, raw_string, _testing=False, callertype="session", sess
     except Exception:
         # This catches exceptions in cmdhandler exceptions themselves
         _msg_err(error_to, _ERROR_CMDHANDLER)
-

evennia/commands/command.py

@@ -451,3 +451,10 @@ class Command(with_metaclass(CommandMeta, object)):
 
         """
         return self.__doc__
+
+
+class InterruptCommand(Exception):
+
+    """Cleanly interrupt a command."""
+
+    pass

evennia/commands/default/tests.py

@@ -20,6 +20,7 @@ from mock import Mock
 from evennia.commands.default.cmdset_character import CharacterCmdSet
 from evennia.utils.test_resources import EvenniaTest
 from evennia.commands.default import help, general, system, admin, player, building, batchprocess, comms
+from evennia.commands.command import Command, InterruptCommand
 from evennia.utils import ansi, utils
 from evennia.server.sessionhandler import SESSIONS
 
@@ -89,6 +90,8 @@ class CommandTest(EvenniaTest):
             else:
                 returned_msg = "\n".join(stored_msg)
                 returned_msg = ansi.parse_ansi(returned_msg, strip_ansi=noansi).strip()
+        except InterruptCommand:
+            pass
         finally:
             receiver.msg = old_msg
 
@@ -326,3 +329,19 @@ class TestBatchProcess(CommandTest):
         self.call(batchprocess.CmdBatchCommands(), "example_batch_cmds", "Running Batchcommand processor  Automatic mode for example_batch_cmds")
         # we make sure to delete the button again here to stop the running reactor
         self.call(building.CmdDestroy(), "button", "button was destroyed.")
+
+class CmdInterrupt(Command):
+
+    key = "interrupt"
+
+    def parse(self):
+        raise InterruptCommand
+
+    def func(self):
+        self.msg("in func")
+
+
+class TestInterruptCommand(CommandTest):
+    def test_interrupt_command(self):
+        ret = self.call(CmdInterrupt(), "")
+        self.assertEqual(ret, "")