RasaHQ/rasa_core

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rasa/core/channels/slack.py

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import re
import json
import logging
from sanic import Blueprint, response
from sanic.request import Request
from slackclient import SlackClient
from typing import Text, Optional, List

from rasa.core.channels import InputChannel
from rasa.core.channels.channel import UserMessage, OutputChannel

logger = logging.getLogger(__name__)


class SlackBot(SlackClient, OutputChannel):
    """A Slack communication channel"""

    @classmethod
    def name(cls):
        return "slack"

    def __init__(self,
                 token: Text,
                 slack_channel: Optional[Text] = None) -> None:

        self.slack_channel = slack_channel
        super(SlackBot, self).__init__(token)

    async def send_text_message(self, recipient_id, message):
        recipient = self.slack_channel or recipient_id
        for message_part in message.split("\n\n"):
            super(SlackBot, self).api_call("chat.postMessage",
                                           channel=recipient,
                                           as_user=True, text=message_part)

    async def send_image_url(self, recipient_id, image_url, message=""):
        image_attachment = [{"image_url": image_url,
                             "text": message}]
        recipient = self.slack_channel or recipient_id
        return super(SlackBot, self).api_call("chat.postMessage",
                                              channel=recipient,
                                              as_user=True,
                                              attachments=image_attachment)

    async def send_attachment(self, recipient_id, attachment, message=""):
        recipient = self.slack_channel or recipient_id
        return super(SlackBot, self).api_call("chat.postMessage",
                                              channel=recipient,
                                              as_user=True,
                                              text=message,
                                              attachments=attachment)

    @staticmethod
    def _convert_to_slack_buttons(buttons):
        return [{"text": b['title'],
                 "name": b['payload'],
                 "value": b['payload'],
                 "type": "button"} for b in buttons]

    @staticmethod
    def _get_text_from_slack_buttons(buttons):
        return "".join([b.get("title", "") for b in buttons])

    async def send_text_with_buttons(self, recipient_id, message, buttons,
                                     **kwargs):
        recipient = self.slack_channel or recipient_id

        if len(buttons) > 5:
            logger.warning("Slack API currently allows only up to 5 buttons. "
                           "If you add more, all will be ignored.")
            return await self.send_text_message(recipient, message)

        if message:
            callback_string = message.replace(' ', '_')[:20]
        else:
            callback_string = self._get_text_from_slack_buttons(buttons)
            callback_string = callback_string.replace(' ', '_')[:20]

        button_attachment = [{"fallback": message,
                              "callback_id": callback_string,
                              "actions":
                              self._convert_to_slack_buttons(buttons)}]

        super(SlackBot, self).api_call("chat.postMessage",
                                       channel=recipient,
                                       as_user=True,
                                       text=message,
                                       attachments=button_attachment)


class SlackInput(InputChannel):
    """Slack input channel implementation. Based on the HTTPInputChannel."""

    @classmethod
    def name(cls):
        return "slack"

    @classmethod
    def from_credentials(cls, credentials):
        if not credentials:
            cls.raise_missing_credentials_exception()

        return cls(credentials.get("slack_token"),
                   credentials.get("slack_channel"))

    def __init__(self,
                 slack_token: Text,
                 slack_channel: Optional[Text] = None,
                 errors_ignore_retry: Optional[List[Text]] = None) -> None:
        """Create a Slack input channel.

        Needs a couple of settings to properly authenticate and validate
        messages. Details to setup:

        https://github.com/slackapi/python-slackclient

        Args:
            slack_token: Your Slack Authentication token. You can find or
                generate a test token
                `here <https://api.slack.com/docs/oauth-test-tokens>`_.
            slack_channel: the string identifier for a channel to which
                the bot posts, or channel name (e.g. 'C1234ABC', 'bot-test'
                or '#bot-test') If unset, messages will be sent back
                to the user they came from.
            errors_ignore_retry: If error code given by slack
                included in this list then it will ignore the event.
                The code is listed here:
                https://api.slack.com/events-api#errors
        """
        self.slack_token = slack_token
        self.slack_channel = slack_channel
        self.errors_ignore_retry = errors_ignore_retry or ('http_timeout',)

    @staticmethod
    def _is_user_message(slack_event):
        return (slack_event.get('event') and
                (slack_event.get('event').get('type') == u'message' or
                 slack_event.get('event').get('type') == u'app_mention') and
                slack_event.get('event').get('text') and not
                slack_event.get('event').get('bot_id'))

    @staticmethod
    def _is_interactive_message(payload):
        return payload['type'] == "interactive_message"

    @staticmethod
    def _is_button(payload):
        return payload['actions'][0]['type'] == "button"

    @staticmethod
    def _is_button_reply(slack_event):
        payload = json.loads(slack_event['payload'])
        return (SlackInput._is_interactive_message(payload) and
                SlackInput._is_button(payload))

    @staticmethod
    def _get_button_reply(slack_event):
        return json.loads(slack_event['payload'])['actions'][0]['name']

    @staticmethod
    def _sanitize_user_message(text, uids_to_remove):
        """Remove superfluous/wrong/problematic tokens from a message.

        Probably a good starting point for pre-formatting of user-provided text
        to make NLU's life easier in case they go funky to the power of extreme

        In the current state will just drop self-mentions of bot itself

        Args:
            text: raw message as sent from slack
            uids_to_remove: a list of user ids to remove from the content

        Returns:
            str: parsed and cleaned version of the input text
        """
        for uid_to_remove in uids_to_remove:
            # heuristic to format majority cases OK
            # can be adjusted to taste later if needed,
            # but is a good first approximation
            for regex, replacement in [(r'<@{}>\s'.format(uid_to_remove), ''),
                                       (r'\s<@{}>'.format(uid_to_remove), ''),
                                       # a bit arbitrary but probably OK
                                       (r'<@{}>'.format(uid_to_remove), ' ')]:
                text = re.sub(regex, replacement, text)

        return text.rstrip().lstrip()  # drop extra spaces at beginning and end

    async def process_message(self, request: Request, on_new_message, text,
                              sender_id):
        """Slack retries to post messages up to 3 times based on
        failure conditions defined here:
        https://api.slack.com/events-api#failure_conditions
        """
        retry_reason = request.headers.get('HTTP_X_SLACK_RETRY_REASON')
        retry_count = request.headers.get('HTTP_X_SLACK_RETRY_NUM')
        if retry_count and retry_reason in self.errors_ignore_retry:
            logger.warning("Received retry #{} request from slack"
                           " due to {}".format(retry_count, retry_reason))

            return response.text(None,
                                 status=201,
                                 headers={'X-Slack-No-Retry': 1})

        try:
            out_channel = SlackBot(self.slack_token, self.slack_channel)
            user_msg = UserMessage(text, out_channel, sender_id,
                                   input_channel=self.name())

            await on_new_message(user_msg)
        except Exception as e:
            logger.error("Exception when trying to handle "
                         "message.{0}".format(e))
            logger.error(str(e), exc_info=True)

        return response.text("")

    def blueprint(self, on_new_message):
        slack_webhook = Blueprint('slack_webhook', __name__)

        @slack_webhook.route("/", methods=['GET'])
        async def health(request):
            return response.json({"status": "ok"})

        @slack_webhook.route("/webhook", methods=['GET', 'POST'])
        async def webhook(request: Request):
            if request.form:
                output = dict(request.form)
                if self._is_button_reply(output):
                    sender_id = json.loads(output['payload'])['user']['id']
                    return await self.process_message(
                        request,
                        on_new_message,
                        text=self._get_button_reply(output),
                        sender_id=sender_id)
            elif request.json:
                output = request.json
                if "challenge" in output:
                    return response.json(output.get("challenge"))

                elif self._is_user_message(output):
                    return await self.process_message(
                        request,
                        on_new_message,
                        text=self._sanitize_user_message(
                            output['event']['text'],
                            output['authed_users']),
                        sender_id=output.get('event').get('user'))

            return response.text("")

        return slack_webhook