oslo.utils/oslo_utils/encodeutils.py
Victor Stinner ac308341f6 Fix exception_to_unicode() for oslo_i18n Message
Message instances created by oslo_i18n are subclasses of the Unicode
type (unicode on Python 2, str on Python 3) and have no __unicode__()
method. exception_to_unicode() raises an AttributeError when trying to
convert it to Unicode.

This change fixes this issue and adds an unit test.

Change-Id: Ica67429ac64f74e5c636b6d74d71910a26511378
2015-07-02 23:53:41 +02:00

162 lines
6.2 KiB
Python

# Copyright 2014 Red Hat, Inc.
# All Rights Reserved.
#
# 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 sys
import six
def safe_decode(text, incoming=None, errors='strict'):
"""Decodes incoming text/bytes string using `incoming` if they're not
already unicode.
:param incoming: Text's current encoding
:param errors: Errors handling policy. See here for valid
values http://docs.python.org/2/library/codecs.html
:returns: text or a unicode `incoming` encoded
representation of it.
:raises TypeError: If text is not an instance of str
"""
if not isinstance(text, (six.string_types, six.binary_type)):
raise TypeError("%s can't be decoded" % type(text))
if isinstance(text, six.text_type):
return text
if not incoming:
incoming = (sys.stdin.encoding or
sys.getdefaultencoding())
try:
return text.decode(incoming, errors)
except UnicodeDecodeError:
# Note(flaper87) If we get here, it means that
# sys.stdin.encoding / sys.getdefaultencoding
# didn't return a suitable encoding to decode
# text. This happens mostly when global LANG
# var is not set correctly and there's no
# default encoding. In this case, most likely
# python will use ASCII or ANSI encoders as
# default encodings but they won't be capable
# of decoding non-ASCII characters.
#
# Also, UTF-8 is being used since it's an ASCII
# extension.
return text.decode('utf-8', errors)
def safe_encode(text, incoming=None,
encoding='utf-8', errors='strict'):
"""Encodes incoming text/bytes string using `encoding`.
If incoming is not specified, text is expected to be encoded with
current python's default encoding. (`sys.getdefaultencoding`)
:param incoming: Text's current encoding
:param encoding: Expected encoding for text (Default UTF-8)
:param errors: Errors handling policy. See here for valid
values http://docs.python.org/2/library/codecs.html
:returns: text or a bytestring `encoding` encoded
representation of it.
:raises TypeError: If text is not an instance of str
"""
if not isinstance(text, (six.string_types, six.binary_type)):
raise TypeError("%s can't be encoded" % type(text))
if not incoming:
incoming = (sys.stdin.encoding or
sys.getdefaultencoding())
# Avoid case issues in comparisons
if hasattr(incoming, 'lower'):
incoming = incoming.lower()
if hasattr(encoding, 'lower'):
encoding = encoding.lower()
if isinstance(text, six.text_type):
return text.encode(encoding, errors)
elif text and encoding != incoming:
# Decode text before encoding it with `encoding`
text = safe_decode(text, incoming, errors)
return text.encode(encoding, errors)
else:
return text
def exception_to_unicode(exc):
"""Get the message of an exception as a Unicode string.
On Python 3, the exception message is always a Unicode string. On
Python 2, the exception message is a bytes string *most* of the time.
If the exception message is a bytes strings, try to decode it from UTF-8
(superset of ASCII), from the locale encoding, or fallback to decoding it
from ISO-8859-1 (which never fails).
"""
msg = None
if six.PY2:
# First try by calling the unicode type constructor. We should try
# unicode() before exc.__unicode__() because subclasses of unicode can
# be easily casted to unicode, whereas they have no __unicode__()
# method.
try:
msg = unicode(exc)
except UnicodeError:
# unicode(exc) fail with UnicodeDecodeError on Python 2 if
# exc.__unicode__() or exc.__str__() returns a bytes string not
# decodable from the default encoding (ASCII)
if hasattr(exc, '__unicode__'):
# Call directly the __unicode__() method to avoid
# the implicit decoding from the default encoding
try:
msg = exc.__unicode__()
except UnicodeError:
pass
if msg is None:
# Don't call directly str(exc), because it fails with
# UnicodeEncodeError on Python 2 if exc.__str__() returns a Unicode
# string not encodable to the default encoding (ASCII)
msg = exc.__str__()
if isinstance(msg, six.text_type):
# This should be the default path on Python 3 and an *optional* path
# on Python 2 (if for some reason the exception message was already
# in unicode instead of the more typical bytes string); so avoid
# further converting to unicode in both of these cases.
return msg
try:
# Try to decode from UTF-8 (superset of ASCII). The decoder fails
# if the string is not a valid UTF-8 string: the UTF-8 codec includes
# a validation algorithm to ensure the consistency of the codec.
return msg.decode('utf-8')
except UnicodeDecodeError:
pass
# Try the locale encoding, most error messages are encoded to this encoding
# (ex: os.strerror(errno))
encoding = sys.getfilesystemencoding()
try:
return msg.decode(encoding)
except UnicodeDecodeError:
pass
# The encoding is not ASCII, not UTF-8, nor the locale encoding. Fallback
# to the ISO-8859-1 encoding which never fails. It will produce mojibake
# if the message is not encoded to ISO-8859-1, but we don't want a super
# complex heuristic to get the encoding of an exception message.
return msg.decode('latin1')