112 lines
3.1 KiB
Python
112 lines
3.1 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import random
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import string
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import six
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from six import PY2, PY3
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from six.moves import range
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_string_with_symbols = string.digits + string.ascii_letters + ".,;:^&*-_+=#~@"
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# random_string and random_string_with_symbols are used for a range of things,
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# some cryptographically important, some less so. We use SystemRandom to make sure
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# we get cryptographically-secure randoms.
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rand = random.SystemRandom()
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def random_string(length):
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return "".join(rand.choice(string.ascii_letters) for _ in range(length))
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def random_string_with_symbols(length):
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return "".join(rand.choice(_string_with_symbols) for _ in range(length))
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def is_ascii(s):
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if PY3:
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if isinstance(s, bytes):
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try:
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s.decode("ascii").encode("ascii")
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except UnicodeDecodeError:
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return False
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except UnicodeEncodeError:
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return False
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return True
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try:
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s.encode("ascii")
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except UnicodeEncodeError:
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return False
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except UnicodeDecodeError:
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return False
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else:
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return True
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def to_ascii(s):
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"""Converts a string to ascii if it is ascii, otherwise leave it alone.
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If given None then will return None.
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"""
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if PY3:
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return s
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if s is None:
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return None
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try:
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return s.encode("ascii")
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except UnicodeEncodeError:
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return s
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def exception_to_unicode(e):
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"""Helper function to extract the text of an exception as a unicode string
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Args:
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e (Exception): exception to be stringified
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Returns:
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unicode
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"""
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# urgh, this is a mess. The basic problem here is that psycopg2 constructs its
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# exceptions with PyErr_SetString, with a (possibly non-ascii) argument. str() will
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# then produce the raw byte sequence. Under Python 2, this will then cause another
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# error if it gets mixed with a `unicode` object, as per
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# https://github.com/matrix-org/synapse/issues/4252
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# First of all, if we're under python3, everything is fine because it will sort this
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# nonsense out for us.
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if not PY2:
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return str(e)
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# otherwise let's have a stab at decoding the exception message. We'll circumvent
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# Exception.__str__(), which would explode if someone raised Exception(u'non-ascii')
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# and instead look at what is in the args member.
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if len(e.args) == 0:
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return ""
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elif len(e.args) > 1:
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return six.text_type(repr(e.args))
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msg = e.args[0]
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if isinstance(msg, bytes):
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return msg.decode("utf-8", errors="replace")
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else:
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return msg
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