MatrixSynapse/synapse/handlers/appservice.py

# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from twisted.internet import defer

from synapse.api.constants import EventTypes, Membership
from synapse.api.errors import Codes, StoreError, SynapseError
from synapse.appservice import ApplicationService
from synapse.types import UserID
import synapse.util.stringutils as stringutils

import logging

logger = logging.getLogger(__name__)


def log_failure(failure):
    logger.error(
        "Application Services Failure",
        exc_info=(
            failure.type,
            failure.value,
            failure.getTracebackObject()
        )
    )


# NB: Purposefully not inheriting BaseHandler since that contains way too much
# setup code which this handler does not need or use. This makes testing a lot
# easier.
class ApplicationServicesHandler(object):

    def __init__(self, hs, appservice_api, appservice_scheduler):
        self.store = hs.get_datastore()
        self.hs = hs
        self.appservice_api = appservice_api
        self.scheduler = appservice_scheduler
        self.started_scheduler = False

    @defer.inlineCallbacks
    def register(self, app_service):
        logger.info("Register -> %s", app_service)
        # check the token is recognised
        try:
            stored_service = yield self.store.get_app_service_by_token(
                app_service.token
            )
            if not stored_service:
                raise StoreError(404, "Application service not found")
            app_service.id = stored_service.id
        except StoreError:
            raise SynapseError(
                403, "Unrecognised application services token. "
                "Consult the home server admin.",
                errcode=Codes.FORBIDDEN
            )
        app_service.hs_token = self._generate_hs_token()

        # create a sender for this application service which is used when
        # creating rooms, etc..
        account = yield self.hs.get_handlers().registration_handler.register()
        app_service.sender = account[0]

        yield self.store.update_app_service(app_service)
        defer.returnValue(app_service)

    @defer.inlineCallbacks
    def unregister(self, token):
        logger.info("Unregister as_token=%s", token)
        yield self.store.unregister_app_service(token)

    @defer.inlineCallbacks
    def notify_interested_services(self, event):
        """Notifies (pushes) all application services interested in this event.

        Pushing is done asynchronously, so this method won't block for any
        prolonged length of time.

        Args:
            event(Event): The event to push out to interested services.
        """
        # Gather interested services
        services = yield self._get_services_for_event(event)
        if len(services) == 0:
            return  # no services need notifying

        # Do we know this user exists? If not, poke the user query API for
        # all services which match that user regex. This needs to block as these
        # user queries need to be made BEFORE pushing the event.
        yield self._check_user_exists(event.sender)
        if event.type == EventTypes.Member:
            yield self._check_user_exists(event.state_key)

        if not self.started_scheduler:
            self.scheduler.start().addErrback(log_failure)
            self.started_scheduler = True

        # Fork off pushes to these services
        for service in services:
            self.scheduler.submit_event_for_as(service, event)

    @defer.inlineCallbacks
    def query_user_exists(self, user_id):
        """Check if any application service knows this user_id exists.

        Args:
            user_id(str): The user to query if they exist on any AS.
        Returns:
            True if this user exists on at least one application service.
        """
        user_query_services = yield self._get_services_for_user(
            user_id=user_id
        )
        for user_service in user_query_services:
            is_known_user = yield self.appservice_api.query_user(
                user_service, user_id
            )
            if is_known_user:
                defer.returnValue(True)
        defer.returnValue(False)

    @defer.inlineCallbacks
    def query_room_alias_exists(self, room_alias):
        """Check if an application service knows this room alias exists.

        Args:
            room_alias(RoomAlias): The room alias to query.
        Returns:
            namedtuple: with keys "room_id" and "servers" or None if no
            association can be found.
        """
        room_alias_str = room_alias.to_string()
        alias_query_services = yield self._get_services_for_event(
            event=None,
            restrict_to=ApplicationService.NS_ALIASES,
            alias_list=[room_alias_str]
        )
        for alias_service in alias_query_services:
            is_known_alias = yield self.appservice_api.query_alias(
                alias_service, room_alias_str
            )
            if is_known_alias:
                # the alias exists now so don't query more ASes.
                result = yield self.store.get_association_from_room_alias(
                    room_alias
                )
                defer.returnValue(result)

    @defer.inlineCallbacks
    def _get_services_for_event(self, event, restrict_to="", alias_list=None):
        """Retrieve a list of application services interested in this event.

        Args:
            event(Event): The event to check. Can be None if alias_list is not.
            restrict_to(str): The namespace to restrict regex tests to.
            alias_list: A list of aliases to get services for. If None, this
            list is obtained from the database.
        Returns:
            list<ApplicationService>: A list of services interested in this
            event based on the service regex.
        """
        member_list = None
        if hasattr(event, "room_id"):
            # We need to know the aliases associated with this event.room_id,
            # if any.
            if not alias_list:
                alias_list = yield self.store.get_aliases_for_room(
                    event.room_id
                )
            # We need to know the members associated with this event.room_id,
            # if any.
            member_list = yield self.store.get_room_members(
                room_id=event.room_id,
                membership=Membership.JOIN
            )

        services = yield self.store.get_app_services()
        interested_list = [
            s for s in services if (
                s.is_interested(event, restrict_to, alias_list, member_list)
            )
        ]
        defer.returnValue(interested_list)

    @defer.inlineCallbacks
    def _get_services_for_user(self, user_id):
        services = yield self.store.get_app_services()
        interested_list = [
            s for s in services if (
                s.is_interested_in_user(user_id)
            )
        ]
        defer.returnValue(interested_list)

    @defer.inlineCallbacks
    def _is_unknown_user(self, user_id):
        user = UserID.from_string(user_id)
        if not self.hs.is_mine(user):
            # we don't know if they are unknown or not since it isn't one of our
            # users. We can't poke ASes.
            defer.returnValue(False)
            return

        user_info = yield self.store.get_user_by_id(user_id)
        defer.returnValue(len(user_info) == 0)

    @defer.inlineCallbacks
    def _check_user_exists(self, user_id):
        unknown_user = yield self._is_unknown_user(user_id)
        if unknown_user:
            exists = yield self.query_user_exists(user_id)
            defer.returnValue(exists)
        defer.returnValue(True)

    def _generate_hs_token(self):
        return stringutils.random_string(24)