libervia-backend/libervia/backend/tools/trigger.py
Goffi ba1475962e core (tools/trigger): new add_with_check method:
this method add a wrapper which will skip the trigger is the plugin is not available in
the session (e.g. a component which doesn't use the plugin).
2023-12-09 19:19:26 +01:00

185 lines
7.1 KiB
Python

#!/usr/bin/env python3
# SAT: a jabber client
# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Misc usefull classes"""
import inspect
from typing import Callable
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger
from libervia.backend.core.core_types import SatXMPPEntity
log = getLogger(__name__)
class TriggerException(Exception):
pass
class SkipOtherTriggers(Exception):
""" Exception to raise if normal behaviour must be followed instead of following triggers list """
pass
class TriggerManager(object):
"""This class manage triggers: code which interact to change the behaviour of SàT"""
try: # FIXME: to be removed when a better solution is found
MIN_PRIORITY = float("-inf")
MAX_PRIORITY = float("+inf")
except: # XXX: Pyjamas will bug if you specify ValueError here
# Pyjamas uses the JS Float class
MIN_PRIORITY = Number.NEGATIVE_INFINITY
MAX_PRIORITY = Number.POSITIVE_INFINITY
def __init__(self):
self.__triggers = {}
def is_available(self, args: list):
"""Check if plugin used in a client context, and if it's available"""
if not args or not isinstance(args[0], SatXMPPEntity):
# we are not in the context of a client
return True
client = args[0]
if not client.is_component:
# plugins are always avaialble for normal clients
return True
def add(self, point_name, callback: Callable, priority=0):
"""Add a trigger to a point
@param point_name: name of the point when the trigger should be run
@param callback: method to call at the trigger point
@param priority: callback will be called in priority order, biggest
first
"""
if point_name not in self.__triggers:
self.__triggers[point_name] = []
if priority != 0 and priority in [
trigger_tuple[0] for trigger_tuple in self.__triggers[point_name]
]:
if priority in (self.MIN_PRIORITY, self.MAX_PRIORITY):
log.warning(_("There is already a bound priority [%s]") % point_name)
else:
log.debug(
_("There is already a trigger with the same priority [%s]")
% point_name
)
self.__triggers[point_name].append((priority, callback))
self.__triggers[point_name].sort(
key=lambda trigger_tuple: trigger_tuple[0], reverse=True
)
def add_with_check(
self,
point_name: str,
plugin,
callback: Callable,
priority: int=0
) -> None:
"""Like [Add], but check session before running the trigger
This method is to be used for triggers which can run in components and are
expecting a ``client``: as all plugins are not run for component, a check will be
added before running the trigger, if the plugin is not valid for this component,
the trigger is ignored. ``client`` must be the first positional argument.
@param point_name: name of the trigger point
@param plugin: instance of the plugin using this trigger. This is necessary to
check if the plugin is available in the session.
@param callback: method to call at the trigger point
@param priority: callback will be called in priority order, biggest first
"""
if inspect.iscoroutinefunction(callback):
async def async_wrapper(client: SatXMPPEntity, *args, **kwargs):
if client.is_component and plugin not in client.plugins:
log.debug(f"Ignoring {callback} as parent plugin is not available")
return True
else:
return await callback(client, *args, **kwargs)
self.add(point_name, async_wrapper, priority)
else:
def sync_wrapper(client: SatXMPPEntity, *args, **kwargs):
if client.is_component and plugin not in client.plugins:
log.debug(f"Ignoring {callback} as parent plugin is not available")
return True
else:
return callback(client, *args, **kwargs)
self.add(point_name, sync_wrapper, priority)
def remove(self, point_name, callback):
"""Remove a trigger from a point
@param point_name: name of the point when the trigger should be run
@param callback: method to remove, must exists in the trigger point
"""
for trigger_tuple in self.__triggers[point_name]:
if trigger_tuple[1] == callback:
self.__triggers[point_name].remove(trigger_tuple)
return
raise TriggerException("Trying to remove an unexisting trigger")
def point(self, point_name, *args, **kwargs):
"""This put a trigger point
All the triggers for that point will be run
@param point_name: name of the trigger point
@param *args: args to transmit to trigger
@param *kwargs: kwargs to transmit to trigger
if "triggers_no_cancel" is present, it will be popup out
when set to True, this argument don't let triggers stop
the workflow
@return: True if the action must be continued, False else
"""
if point_name not in self.__triggers:
return True
can_cancel = not kwargs.pop('triggers_no_cancel', False)
for priority, trigger in self.__triggers[point_name]:
try:
if not trigger(*args, **kwargs) and can_cancel:
return False
except SkipOtherTriggers:
break
return True
def return_point(self, point_name, *args, **kwargs):
"""Like point but trigger must return (continue, return_value)
All triggers for that point must return a tuple with 2 values:
- continue, same as for point, if False action must be finished
- return_value: value to return ONLY IF CONTINUE IS FALSE
@param point_name: name of the trigger point
@return: True if the action must be continued, False else
"""
if point_name not in self.__triggers:
return True
for priority, trigger in self.__triggers[point_name]:
try:
cont, ret_value = trigger(*args, **kwargs)
if not cont:
return False, ret_value
except SkipOtherTriggers:
break
return True, None