evennia/src/commands/cmdhandler.py

306 lines
12 KiB
Python

"""
Command handler
This module contains the infrastructure for accepting commands on the
command line. The process is as follows:
1) The calling object (caller) inputs a string and triggers the command parsing system.
2) The system checks the state of the caller - loggedin or not
3) If no command string was supplied, we search the merged cmdset for system command CMD_NOINPUT
and branches to execute that. --> Finished
4) Cmdsets are gathered from different sources (in order of dropping priority):
channels - all available channel names are auto-created into a cmdset, to allow
for giving the channel name and have the following immediately
sent to the channel. The sending is performed by the CMD_CHANNEL
system command.
object cmdsets - all objects at caller's location are scanned for non-empty
cmdsets. This includes cmdsets on exits.
caller - the caller is searched for its own currently active cmdset.
player - lastly the cmdsets defined on caller.player are added.
5) All the gathered cmdsets (if more than one) are merged into one using the cmdset priority rules.
6) If merged cmdset is empty, raise NoCmdSet exception (this should not happen, at least the
player should have a default cmdset available at all times). --> Finished
7) The raw input string is parsed using the parser defined by settings.COMMAND_PARSER. It
uses the available commands from the merged cmdset to know which commands to look for and
returns one or many matches.
8) If match list is empty, branch to system command CMD_NOMATCH --> Finished
9) If match list has more than one element, branch to system command CMD_MULTIMATCH --> Finished
10) A single match was found. If this is a channel-command (i.e. the command name is that of a channel),
branch to CMD_CHANNEL --> Finished
11) At this point we have found a normal command. We assign useful variables to it that
will be available to the command coder at run-time.
12) We have a unique cmdobject, primed for use. Call all hooks:
at_pre_cmd(), cmdobj.parse(), cmdobj.func() and finally at_post_cmd().
"""
from copy import copy
from traceback import format_exc
from twisted.internet.defer import inlineCallbacks, returnValue
from django.conf import settings
from src.comms.channelhandler import CHANNELHANDLER
from src.commands.cmdsethandler import import_cmdset
from src.utils import logger, utils
from src.commands.cmdparser import at_multimatch_cmd
#This switches the command parser to a user-defined one.
# You have to restart the server for this to take effect.
COMMAND_PARSER = utils.mod_import(*settings.COMMAND_PARSER.rsplit('.', 1))
# There are a few system-hardcoded command names. These
# allow for custom behaviour when the command handler hits
# special situations -- it then calls a normal Command
# that you can customize!
# Import these variables and use them rather than trying
# to remember the actual string constants.
CMD_NOINPUT = "__noinput_command"
CMD_NOMATCH = "__nomatch_command"
CMD_MULTIMATCH = "__multimatch_command"
CMD_CHANNEL = "__send_to_channel_command"
# this is the name of the command the engine calls when the player
# connects. It is expected to show the login screen.
CMD_LOGINSTART = "__unloggedin_look_command"
class NoCmdSets(Exception):
"No cmdsets found. Critical error."
pass
class ExecSystemCommand(Exception):
"Run a system command"
def __init__(self, syscmd, sysarg):
self.args = (syscmd, sysarg) # needed by exception error handling
self.syscmd = syscmd
self.sysarg = sysarg
@inlineCallbacks
def get_and_merge_cmdsets(caller):
"""
Gather all relevant cmdsets and merge them. Note
that this is only relevant for logged-in callers.
"""
# The calling object's cmdset
try:
yield caller.at_cmdset_get()
except Exception:
logger.log_trace()
try:
caller_cmdset = caller.cmdset.current
except AttributeError:
caller_cmdset = None
# Create cmdset for all player's available channels
channel_cmdset = None
if not caller_cmdset.no_channels:
channel_cmdset = yield CHANNELHANDLER.get_cmdset(caller)
# Gather cmdsets from location, objects in location or carried
local_objects_cmdsets = [None]
location = None
if hasattr(caller, "location"):
location = caller.location
if location and not caller_cmdset.no_objs:
# Gather all cmdsets stored on objects in the room and
# also in the caller's inventory and the location itself
local_objlist = yield location.contents_get(exclude=caller.dbobj) + caller.contents + [location]
for obj in local_objlist:
try:
# call hook in case we need to do dynamic changing to cmdset
yield obj.at_cmdset_get()
except Exception:
logger.log_trace()
local_objects_cmdsets = yield [obj.cmdset.current for obj in local_objlist
if (obj.cmdset.current and obj.locks.check(caller, 'call', no_superuser_bypass=True))]
for cset in local_objects_cmdsets:
#This is necessary for object sets, or we won't be able to separate
#the command sets from each other in a busy room.
cset.old_duplicates = cset.duplicates
cset.duplicates = True
# Player object's commandsets
try:
player_cmdset = caller.player.cmdset.current
except AttributeError:
player_cmdset = None
cmdsets = [caller_cmdset] + [player_cmdset] + [channel_cmdset] + local_objects_cmdsets
# weed out all non-found sets
cmdsets = yield [cmdset for cmdset in cmdsets if cmdset]
# sort cmdsets after reverse priority (highest prio are merged in last)
cmdsets = yield sorted(cmdsets, key=lambda x: x.priority)
if cmdsets:
# Merge all command sets into one, beginning with the lowest-prio one
cmdset = cmdsets.pop(0)
for merging_cmdset in cmdsets:
#print "<%s(%s,%s)> onto <%s(%s,%s)>" % (merging_cmdset.key, merging_cmdset.priority, merging_cmdset.mergetype,
# cmdset.key, cmdset.priority, cmdset.mergetype)
cmdset = yield merging_cmdset + cmdset
else:
cmdset = None
for cset in (cset for cset in local_objects_cmdsets if cset):
cset.duplicates = cset.old_duplicates
returnValue(cmdset)
# Main command-handler function
@inlineCallbacks
def cmdhandler(caller, raw_string, testing=False):
"""
This is the main function to handle any string sent to the engine.
caller - calling object
raw_string - the command string given on the command line
testing - if we should actually execute the command or not.
if True, the command instance will be returned instead.
Note that this function returns a deferred!
"""
try: # catch bugs in cmdhandler itself
try: # catch special-type commands
cmdset = yield get_and_merge_cmdsets(caller)
if not cmdset:
# this is bad and shouldn't happen.
raise NoCmdSets
raw_string = raw_string.strip()
if not raw_string:
# Empty input. Test for system command instead.
syscmd = yield cmdset.get(CMD_NOINPUT)
sysarg = ""
raise ExecSystemCommand(syscmd, sysarg)
# Parse the input string and match to available cmdset.
# This also checks for permissions, so all commands in match
# are commands the caller is allowed to call.
matches = yield COMMAND_PARSER(raw_string, cmdset, caller)
# Deal with matches
if not matches:
# No commands match our entered command
syscmd = yield cmdset.get(CMD_NOMATCH)
if syscmd:
sysarg = raw_string
else:
sysarg = "Huh? (Type \"help\" for help)"
raise ExecSystemCommand(syscmd, sysarg)
if len(matches) > 1:
# We have a multiple-match
syscmd = yield cmdset.get(CMD_MULTIMATCH)
sysarg = "There where multiple matches."
if syscmd:
syscmd.matches = matches
else:
sysarg = yield at_multimatch_cmd(caller, matches)
raise ExecSystemCommand(syscmd, sysarg)
# At this point, we have a unique command match.
match = matches[0]
cmdname, args, cmd = match[0], match[1], match[2]
# Check if this is a Channel match.
if hasattr(cmd, 'is_channel') and cmd.is_channel:
# even if a user-defined syscmd is not defined, the
# found cmd is already a system command in its own right.
syscmd = yield cmdset.get(CMD_CHANNEL)
if syscmd:
# replace system command with custom version
cmd = syscmd
sysarg = "%s:%s" % (cmdname, args)
raise ExecSystemCommand(cmd, sysarg)
# A normal command.
# Assign useful variables to the instance
cmd.caller = caller
cmd.cmdstring = cmdname
cmd.args = args
cmd.cmdset = cmdset
if hasattr(cmd, 'obj') and hasattr(cmd.obj, 'scripts'):
# cmd.obj are automatically made available.
# we make sure to validate its scripts.
yield cmd.obj.scripts.validate()
if testing:
# only return the command instance
returnValue(cmd)
# pre-command hook
yield cmd.at_pre_cmd()
# Parse and execute
yield cmd.parse()
# (return value is normally None)
ret = yield cmd.func()
# post-command hook
yield cmd.at_post_cmd()
if cmd.save_for_next:
# store a reference to this command, possibly
# accessible by the next command.
caller.ndb.last_cmd = yield copy(cmd)
else:
caller.ndb.last_cmd = None
# Done! This returns a deferred. By default, Evennia does
# not use this at all.
returnValue(ret)
except ExecSystemCommand, exc:
# Not a normal command: run a system command, if available,
# or fall back to a return string.
syscmd = exc.syscmd
sysarg = exc.sysarg
if syscmd:
syscmd.caller = caller
syscmd.cmdstring = syscmd.key
syscmd.args = sysarg
syscmd.cmdset = cmdset
if hasattr(syscmd, 'obj') and hasattr(syscmd.obj, 'scripts'):
# cmd.obj is automatically made available.
# we make sure to validate its scripts.
yield syscmd.obj.scripts.validate()
if testing:
# only return the command instance
returnValue(syscmd)
# parse and run the command
yield syscmd.parse()
yield syscmd.func()
elif sysarg:
# return system arg
caller.msg(exc.sysarg)
except NoCmdSets:
# Critical error.
string = "No command sets found! This is a sign of a critical bug.\n"
string += "The error was logged.\n"
string += "If logging out/in doesn't solve the problem, try to "
string += "contact the server admin through some other means "
string += "for assistance."
caller.msg(string)
logger.log_errmsg("No cmdsets found: %s" % caller)
except Exception:
# We should not end up here. If we do, it's a programming bug.
string = "%s\nAbove traceback is from an untrapped error."
string += " Please file a bug report."
logger.log_trace(string)
caller.msg(string % format_exc())
except Exception:
# This catches exceptions in cmdhandler exceptions themselves
string = "%s\nAbove traceback is from a Command handler bug."
string += " Please contact an admin and/or file a bug report."
logger.log_trace(string)
caller.msg(string % format_exc())
#----------------------------------------------------- end cmdhandler