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# -*- coding: utf-8 -*-
# Copyright 2014 matrix.org
#
# 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.
"""This module contains classes for streaming from the event stream: /events.
"""
from twisted.internet import defer
from synapse.api.errors import EventStreamError
from synapse.api.events import SynapseEvent
from synapse.api.streams import PaginationStream, StreamData
import logging
logger = logging.getLogger(__name__)
class EventsStreamData(StreamData):
EVENT_TYPE = "EventsStream"
def __init__(self, hs, room_id=None, feedback=False):
super(EventsStreamData, self).__init__(hs)
self.room_id = room_id
self.with_feedback = feedback
@defer.inlineCallbacks
def get_rows(self, user_id, from_key, to_key, limit, direction):
data, latest_ver = yield self.store.get_room_events(
user_id=user_id,
from_key=from_key,
to_key=to_key,
limit=limit,
room_id=self.room_id,
with_feedback=self.with_feedback
)
defer.returnValue((data, latest_ver))
@defer.inlineCallbacks
def max_token(self):
val = yield self.store.get_room_events_max_id()
defer.returnValue(val)
class EventStream(PaginationStream):
SEPARATOR = '_'
def __init__(self, user_id, stream_data_list):
super(EventStream, self).__init__()
self.user_id = user_id
self.stream_data = stream_data_list
@defer.inlineCallbacks
def fix_tokens(self, pagination_config):
pagination_config.from_tok = yield self.fix_token(
pagination_config.from_tok)
pagination_config.to_tok = yield self.fix_token(
pagination_config.to_tok)
if (
not pagination_config.to_tok
and pagination_config.direction == 'f'
):
pagination_config.to_tok = yield self.get_current_max_token()
logger.debug("pagination_config: %s", pagination_config)
defer.returnValue(pagination_config)
@defer.inlineCallbacks
def fix_token(self, token):
"""Fixes unknown values in a token to known values.
Args:
token (str): The token to fix up.
Returns:
The fixed-up token, which may == token.
"""
if token == PaginationStream.TOK_END:
new_token = yield self.get_current_max_token()
logger.debug("fix_token: From %s to %s", token, new_token)
token = new_token
defer.returnValue(token)
@defer.inlineCallbacks
def get_current_max_token(self):
new_token_parts = []
for s in self.stream_data:
mx = yield s.max_token()
new_token_parts.append(str(mx))
new_token = EventStream.SEPARATOR.join(new_token_parts)
logger.debug("get_current_max_token: %s", new_token)
defer.returnValue(new_token)
@defer.inlineCallbacks
def get_chunk(self, config):
# no support for limit on >1 streams, makes no sense.
if config.limit and len(self.stream_data) > 1:
raise EventStreamError(
400, "Limit not supported on multiplexed streams."
)
chunk_data, next_tok = yield self._get_chunk_data(
config.from_tok,
config.to_tok,
config.limit,
config.direction,
)
defer.returnValue({
"chunk": chunk_data,
"start": config.from_tok,
"end": next_tok
})
@defer.inlineCallbacks
def _get_chunk_data(self, from_tok, to_tok, limit, direction):
""" Get event data between the two tokens.
Tokens are SEPARATOR separated values representing pkey values of
certain tables, and the position determines the StreamData invoked
according to the STREAM_DATA list.
The magic value '-1' can be used to get the latest value.
Args:
from_tok - The token to start from.
to_tok - The token to end at. Must have values > from_tok or be -1.
Returns:
A list of event data.
Raises:
EventStreamError if something went wrong.
"""
# sanity check
if to_tok is not None:
if (from_tok.count(EventStream.SEPARATOR) !=
to_tok.count(EventStream.SEPARATOR) or
(from_tok.count(EventStream.SEPARATOR) + 1) !=
len(self.stream_data)):
raise EventStreamError(400, "Token lengths don't match.")
chunk = []
next_ver = []
for i, (from_pkey, to_pkey) in enumerate(zip(
self._split_token(from_tok),
self._split_token(to_tok)
)):
if from_pkey == to_pkey:
# tokens are the same, we have nothing to do.
next_ver.append(str(to_pkey))
continue
(event_chunk, max_pkey) = yield self.stream_data[i].get_rows(
self.user_id, from_pkey, to_pkey, limit, direction,
)
chunk.extend([
e.get_dict() if isinstance(e, SynapseEvent) else e
for e in event_chunk
])
next_ver.append(str(max_pkey))
defer.returnValue((chunk, EventStream.SEPARATOR.join(next_ver)))
def _split_token(self, token):
"""Splits the given token into a list of pkeys.
Args:
token (str): The token with SEPARATOR values.
Returns:
A list of ints.
"""
if token:
segments = token.split(EventStream.SEPARATOR)
else:
segments = [None] * len(self.stream_data)
return segments
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