python-telegram-bot/telegram/ext/conversationhandler.py
Jacob Bom 1b7f83625c Update copyright notice to include 2017
Not strictly needed, but it helps show that the project is being actively
developed which I find important.
2017-05-15 00:36:49 +03:00

270 lines
11 KiB
Python

#!/usr/bin/env python
#
# A library that provides a Python interface to the Telegram Bot API
# Copyright (C) 2015-2017
# Leandro Toledo de Souza <devs@python-telegram-bot.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser 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 Lesser Public License for more details.
#
# You should have received a copy of the GNU Lesser Public License
# along with this program. If not, see [http://www.gnu.org/licenses/].
""" This module contains the ConversationHandler """
import logging
from telegram import Update
from telegram.ext import (Handler, CallbackQueryHandler, InlineQueryHandler,
ChosenInlineResultHandler)
from telegram.utils.promise import Promise
class ConversationHandler(Handler):
"""
A handler to hold a conversation with a single user by managing four collections of other
handlers. Note that neither posts in Telegram Channels, nor group interactions with multiple
users are managed by instances of this class.
The first collection, a ``list`` named ``entry_points``, is used to initiate the conversation,
for example with a ``CommandHandler`` or ``RegexHandler``.
The second collection, a ``dict`` named ``states``, contains the different conversation steps
and one or more associated handlers that should be used if the user sends a message when the
conversation with them is currently in that state. You will probably use mostly
``MessageHandler`` and ``RegexHandler`` here.
The third collection, a ``list`` named ``fallbacks``, is used if the user is currently in a
conversation but the state has either no associated handler or the handler that is associated
to the state is inappropriate for the update, for example if the update contains a command, but
a regular text message is expected. You could use this for a ``/cancel`` command or to let the
user know their message was not recognized.
The fourth, optional collection of handlers, a ``list`` named ``timed_out_behavior`` is used if
the wait for ``run_async`` takes longer than defined in ``run_async_timeout``. For example,
you can let the user know that they should wait for a bit before they can continue.
To change the state of conversation, the callback function of a handler must return the new
state after responding to the user. If it does not return anything (returning ``None`` by
default), the state will not change. To end the conversation, the callback function must
return ``CallbackHandler.END`` or ``-1``.
Args:
entry_points (list): A list of ``Handler`` objects that can trigger the start of the
conversation. The first handler which ``check_update`` method returns ``True`` will be
used. If all return ``False``, the update is not handled.
states (dict): A ``dict[object: list[Handler]]`` that defines the different states of
conversation a user can be in and one or more associated ``Handler`` objects that
should be used in that state. The first handler which ``check_update`` method returns
``True`` will be used.
fallbacks (list): A list of handlers that might be used if the user is in a conversation,
but every handler for their current state returned ``False`` on ``check_update``.
The first handler which ``check_update`` method returns ``True`` will be used. If all
return ``False``, the update is not handled.
allow_reentry (Optional[bool]): If set to ``True``, a user that is currently in a
conversation can restart the conversation by triggering one of the entry points.
run_async_timeout (Optional[float]): If the previous handler for this user was running
asynchronously using the ``run_async`` decorator, it might not be finished when the
next message arrives. This timeout defines how long the conversation handler should
wait for the next state to be computed. The default is ``None`` which means it will
wait indefinitely.
timed_out_behavior (Optional[list]): A list of handlers that might be used if
the wait for ``run_async`` timed out. The first handler which ``check_update`` method
returns ``True`` will be used. If all return ``False``, the update is not handled.
"""
END = -1
def __init__(self,
entry_points,
states,
fallbacks,
allow_reentry=False,
run_async_timeout=None,
timed_out_behavior=None,
per_chat=True,
per_user=True,
per_message=False):
self.entry_points = entry_points
""":type: list[telegram.ext.Handler]"""
self.states = states
""":type: dict[str: telegram.ext.Handler]"""
self.fallbacks = fallbacks
""":type: list[telegram.ext.Handler]"""
self.allow_reentry = allow_reentry
self.run_async_timeout = run_async_timeout
self.timed_out_behavior = timed_out_behavior
""":type: list[telegram.ext.Handler]"""
self.conversations = dict()
self.per_user = per_user
self.per_chat = per_chat
self.per_message = per_message
""":type: dict[tuple: object]"""
self.current_conversation = None
self.current_handler = None
self.logger = logging.getLogger(__name__)
if not any((self.per_user, self.per_chat, self.per_message)):
raise ValueError("'per_user', 'per_chat' and 'per_message' can't all be 'False'")
if self.per_message and not self.per_chat:
logging.warning("If 'per_message=True' is used, 'per_chat=True' should also be used, "
"since message IDs are not globally unique.")
all_handlers = list()
all_handlers.extend(entry_points)
all_handlers.extend(fallbacks)
for state_handlers in states.values():
all_handlers.extend(state_handlers)
if self.per_message:
for handler in all_handlers:
if not isinstance(handler, CallbackQueryHandler):
logging.warning("If 'per_message=True', all entry points and state handlers"
" must be 'CallbackQueryHandler', since no other handlers "
"have a message context.")
else:
for handler in all_handlers:
if isinstance(handler, CallbackQueryHandler):
logging.warning("If 'per_message=False', 'CallbackQueryHandler' will not be "
"tracked for every message.")
if self.per_chat:
for handler in all_handlers:
if isinstance(handler, (InlineQueryHandler, ChosenInlineResultHandler)):
logging.warning("If 'per_chat=True', 'InlineQueryHandler' can not be used, "
"since inline queries have no chat context.")
def _get_key(self, update):
chat = update.effective_chat
user = update.effective_user
key = list()
if self.per_chat:
key.append(chat.id)
if self.per_user:
key.append(user.id)
if self.per_message:
key.append(update.callback_query.inline_message_id
or update.callback_query.message.message_id)
return tuple(key)
def check_update(self, update):
# Ignore messages in channels
if (not isinstance(update, Update) or update.channel_post or self.per_chat
and (update.inline_query or update.chosen_inline_result) or self.per_message
and not update.callback_query or update.callback_query and self.per_chat
and not update.callback_query.message):
return False
key = self._get_key(update)
state = self.conversations.get(key)
# Resolve promises
if isinstance(state, tuple) and len(state) is 2 and isinstance(state[1], Promise):
self.logger.debug('waiting for promise...')
old_state, new_state = state
error = False
try:
res = new_state.result(timeout=self.run_async_timeout)
except Exception as exc:
self.logger.exception("Promise function raised exception")
self.logger.exception("{}".format(exc))
error = True
if not error and new_state.done.is_set():
self.update_state(res, key)
state = self.conversations.get(key)
else:
for candidate in (self.timed_out_behavior or []):
if candidate.check_update(update):
# Save the current user and the selected handler for handle_update
self.current_conversation = key
self.current_handler = candidate
return True
else:
return False
self.logger.debug('selecting conversation %s with state %s' % (str(key), str(state)))
handler = None
# Search entry points for a match
if state is None or self.allow_reentry:
for entry_point in self.entry_points:
if entry_point.check_update(update):
handler = entry_point
break
else:
if state is None:
return False
# Get the handler list for current state, if we didn't find one yet and we're still here
if state is not None and not handler:
handlers = self.states.get(state)
for candidate in (handlers or []):
if candidate.check_update(update):
handler = candidate
break
# Find a fallback handler if all other handlers fail
else:
for fallback in self.fallbacks:
if fallback.check_update(update):
handler = fallback
break
else:
return False
# Save the current user and the selected handler for handle_update
self.current_conversation = key
self.current_handler = handler
return True
def handle_update(self, update, dispatcher):
new_state = self.current_handler.handle_update(update, dispatcher)
self.update_state(new_state, self.current_conversation)
def update_state(self, new_state, key):
if new_state == self.END:
if key in self.conversations:
del self.conversations[key]
else:
pass
elif isinstance(new_state, Promise):
self.conversations[key] = (self.conversations.get(key), new_state)
elif new_state is not None:
self.conversations[key] = new_state