MatrixSynapse/synapse/http/__init__.py

# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2018 New Vector 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.
import re

from twisted.internet import task
from twisted.internet.defer import CancelledError
from twisted.python import failure
from twisted.web.client import FileBodyProducer

from synapse.api.errors import SynapseError


class RequestTimedOutError(SynapseError):
    """Exception representing timeout of an outbound request"""
    def __init__(self):
        super(RequestTimedOutError, self).__init__(504, "Timed out")


def cancelled_to_request_timed_out_error(value, timeout):
    """Turns CancelledErrors into RequestTimedOutErrors.

    For use with async.add_timeout_to_deferred
    """
    if isinstance(value, failure.Failure):
        value.trap(CancelledError)
        raise RequestTimedOutError()
    return value


ACCESS_TOKEN_RE = re.compile(r'(\?.*access(_|%5[Ff])token=)[^&]*(.*)$')


def redact_uri(uri):
    """Strips access tokens from the uri replaces with <redacted>"""
    return ACCESS_TOKEN_RE.sub(
        r'\1<redacted>\3',
        uri
    )


class QuieterFileBodyProducer(FileBodyProducer):
    """Wrapper for FileBodyProducer that avoids CRITICAL errors when the connection drops.

    Workaround for https://github.com/matrix-org/synapse/issues/4003 /
    https://twistedmatrix.com/trac/ticket/6528
    """
    def stopProducing(self):
        try:
            FileBodyProducer.stopProducing(self)
        except task.TaskStopped:
            pass