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# Copyright 2014-2016 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.
import json
import logging
import re
import attr
from frozendict import frozendict
from twisted.internet import defer, task
from synapse.logging import context
logger = logging.getLogger(__name__)
def _reject_invalid_json(val):
"""Do not allow Infinity, -Infinity, or NaN values in JSON."""
raise ValueError("Invalid JSON value: '%s'" % val)
def _handle_frozendict(obj):
"""Helper for json_encoder. Makes frozendicts serializable by returning
the underlying dict
"""
if type(obj) is frozendict:
# fishing the protected dict out of the object is a bit nasty,
# but we don't really want the overhead of copying the dict.
return obj._dict
raise TypeError(
"Object of type %s is not JSON serializable" % obj.__class__.__name__
)
# A custom JSON encoder which:
# * handles frozendicts
# * produces valid JSON (no NaNs etc)
# * reduces redundant whitespace
json_encoder = json.JSONEncoder(
allow_nan=False, separators=(",", ":"), default=_handle_frozendict
)
# Create a custom decoder to reject Python extensions to JSON.
json_decoder = json.JSONDecoder(parse_constant=_reject_invalid_json)
def unwrapFirstError(failure):
# defer.gatherResults and DeferredLists wrap failures.
failure.trap(defer.FirstError)
return failure.value.subFailure
@attr.s(slots=True)
class Clock:
"""
A Clock wraps a Twisted reactor and provides utilities on top of it.
Args:
reactor: The Twisted reactor to use.
"""
_reactor = attr.ib()
@defer.inlineCallbacks
def sleep(self, seconds):
d = defer.Deferred()
with context.PreserveLoggingContext():
self._reactor.callLater(seconds, d.callback, seconds)
res = yield d
return res
def time(self):
"""Returns the current system time in seconds since epoch."""
return self._reactor.seconds()
def time_msec(self):
"""Returns the current system time in milliseconds since epoch."""
return int(self.time() * 1000)
def looping_call(self, f, msec, *args, **kwargs):
"""Call a function repeatedly.
Waits `msec` initially before calling `f` for the first time.
Note that the function will be called with no logcontext, so if it is anything
other than trivial, you probably want to wrap it in run_as_background_process.
Args:
f(function): The function to call repeatedly.
msec(float): How long to wait between calls in milliseconds.
*args: Postional arguments to pass to function.
**kwargs: Key arguments to pass to function.
"""
call = task.LoopingCall(f, *args, **kwargs)
call.clock = self._reactor
d = call.start(msec / 1000.0, now=False)
d.addErrback(log_failure, "Looping call died", consumeErrors=False)
return call
def call_later(self, delay, callback, *args, **kwargs):
"""Call something later
Note that the function will be called with no logcontext, so if it is anything
other than trivial, you probably want to wrap it in run_as_background_process.
Args:
delay(float): How long to wait in seconds.
callback(function): Function to call
*args: Postional arguments to pass to function.
**kwargs: Key arguments to pass to function.
"""
def wrapped_callback(*args, **kwargs):
with context.PreserveLoggingContext():
callback(*args, **kwargs)
with context.PreserveLoggingContext():
return self._reactor.callLater(delay, wrapped_callback, *args, **kwargs)
def cancel_call_later(self, timer, ignore_errs=False):
try:
timer.cancel()
except Exception:
if not ignore_errs:
raise
def log_failure(failure, msg, consumeErrors=True):
"""Creates a function suitable for passing to `Deferred.addErrback` that
logs any failures that occur.
Args:
msg (str): Message to log
consumeErrors (bool): If true consumes the failure, otherwise passes
on down the callback chain
Returns:
func(Failure)
"""
logger.error(
msg, exc_info=(failure.type, failure.value, failure.getTracebackObject())
)
if not consumeErrors:
return failure
def glob_to_regex(glob):
"""Converts a glob to a compiled regex object.
The regex is anchored at the beginning and end of the string.
Args:
glob (str)
Returns:
re.RegexObject
"""
res = ""
for c in glob:
if c == "*":
res = res + ".*"
elif c == "?":
res = res + "."
else:
res = res + re.escape(c)
# \A anchors at start of string, \Z at end of string
return re.compile(r"\A" + res + r"\Z", re.IGNORECASE)
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