forked-synapse/synapse/util/stringutils.py
Richard van der Hoff 9ffac2bef1
Remote dependency on distutils (#9125)
`distutils` is pretty much deprecated these days, and replaced with
`setuptools`. It's also annoying because it's you can't `pip install` it, and
it's hard to figure out which debian package we should depend on to make sure
it's there.

Since we only use it for a tiny function anyway, let's just vendor said
function into our codebase.
2021-01-15 15:59:20 +00:00

97 lines
3.2 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2020 The Matrix.org Foundation C.I.C.
#
# 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 itertools
import random
import re
import string
from collections.abc import Iterable
from synapse.api.errors import Codes, SynapseError
_string_with_symbols = string.digits + string.ascii_letters + ".,;:^&*-_+=#~@"
# https://matrix.org/docs/spec/client_server/r0.6.0#post-matrix-client-r0-register-email-requesttoken
client_secret_regex = re.compile(r"^[0-9a-zA-Z\.\=\_\-]+$")
# random_string and random_string_with_symbols are used for a range of things,
# some cryptographically important, some less so. We use SystemRandom to make sure
# we get cryptographically-secure randoms.
rand = random.SystemRandom()
def random_string(length):
return "".join(rand.choice(string.ascii_letters) for _ in range(length))
def random_string_with_symbols(length):
return "".join(rand.choice(_string_with_symbols) for _ in range(length))
def is_ascii(s):
if isinstance(s, bytes):
try:
s.decode("ascii").encode("ascii")
except UnicodeDecodeError:
return False
except UnicodeEncodeError:
return False
return True
def assert_valid_client_secret(client_secret):
"""Validate that a given string matches the client_secret regex defined by the spec"""
if client_secret_regex.match(client_secret) is None:
raise SynapseError(
400, "Invalid client_secret parameter", errcode=Codes.INVALID_PARAM
)
def shortstr(iterable: Iterable, maxitems: int = 5) -> str:
"""If iterable has maxitems or fewer, return the stringification of a list
containing those items.
Otherwise, return the stringification of a a list with the first maxitems items,
followed by "...".
Args:
iterable: iterable to truncate
maxitems: number of items to return before truncating
"""
items = list(itertools.islice(iterable, maxitems + 1))
if len(items) <= maxitems:
return str(items)
return "[" + ", ".join(repr(r) for r in items[:maxitems]) + ", ...]"
def strtobool(val: str) -> bool:
"""Convert a string representation of truth to True or False
True values are 'y', 'yes', 't', 'true', 'on', and '1'; false values
are 'n', 'no', 'f', 'false', 'off', and '0'. Raises ValueError if
'val' is anything else.
This is lifted from distutils.util.strtobool, with the exception that it actually
returns a bool, rather than an int.
"""
val = val.lower()
if val in ("y", "yes", "t", "true", "on", "1"):
return True
elif val in ("n", "no", "f", "false", "off", "0"):
return False
else:
raise ValueError("invalid truth value %r" % (val,))