151 lines
4.9 KiB
Python
151 lines
4.9 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 OpenStack Foundation.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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System-level utilities and helper functions.
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"""
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import sys
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from metadataclient.openstack.common.gettextutils import _
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TRUE_STRINGS = ('1', 't', 'true', 'on', 'y', 'yes')
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FALSE_STRINGS = ('0', 'f', 'false', 'off', 'n', 'no')
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def int_from_bool_as_string(subject):
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"""
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Interpret a string as a boolean and return either 1 or 0.
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Any string value in:
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('True', 'true', 'On', 'on', '1')
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is interpreted as a boolean True.
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Useful for JSON-decoded stuff and config file parsing
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"""
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return bool_from_string(subject) and 1 or 0
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def bool_from_string(subject, strict=False):
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"""
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Interpret a string as a boolean.
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A case-insensitive match is performed such that strings matching 't',
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'true', 'on', 'y', 'yes', or '1' are considered True and, when
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`strict=False`, anything else is considered False.
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Useful for JSON-decoded stuff and config file parsing.
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If `strict=True`, unrecognized values, including None, will raise a
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ValueError which is useful when parsing values passed in from an API call.
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Strings yielding False are 'f', 'false', 'off', 'n', 'no', or '0'.
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"""
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if not isinstance(subject, basestring):
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subject = str(subject)
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lowered = subject.strip().lower()
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if lowered in TRUE_STRINGS:
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return True
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elif lowered in FALSE_STRINGS:
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return False
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elif strict:
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acceptable = ', '.join(
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"'%s'" % s for s in sorted(TRUE_STRINGS + FALSE_STRINGS))
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msg = _("Unrecognized value '%(val)s', acceptable values are:"
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" %(acceptable)s") % {'val': subject,
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'acceptable': acceptable}
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raise ValueError(msg)
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else:
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return False
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def safe_decode(text, incoming=None, errors='strict'):
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"""
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Decodes incoming str using `incoming` if they're
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not already unicode.
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:param incoming: Text's current encoding
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:param errors: Errors handling policy. See here for valid
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values http://docs.python.org/2/library/codecs.html
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:returns: text or a unicode `incoming` encoded
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representation of it.
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:raises TypeError: If text is not an isntance of basestring
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"""
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if not isinstance(text, basestring):
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raise TypeError("%s can't be decoded" % type(text))
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if isinstance(text, unicode):
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return text
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if not incoming:
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incoming = (sys.stdin.encoding or
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sys.getdefaultencoding())
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try:
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return text.decode(incoming, errors)
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except UnicodeDecodeError:
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# Note(flaper87) If we get here, it means that
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# sys.stdin.encoding / sys.getdefaultencoding
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# didn't return a suitable encoding to decode
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# text. This happens mostly when global LANG
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# var is not set correctly and there's no
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# default encoding. In this case, most likely
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# python will use ASCII or ANSI encoders as
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# default encodings but they won't be capable
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# of decoding non-ASCII characters.
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#
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# Also, UTF-8 is being used since it's an ASCII
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# extension.
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return text.decode('utf-8', errors)
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def safe_encode(text, incoming=None,
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encoding='utf-8', errors='strict'):
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"""
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Encodes incoming str/unicode using `encoding`. If
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incoming is not specified, text is expected to
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be encoded with current python's default encoding.
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(`sys.getdefaultencoding`)
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:param incoming: Text's current encoding
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:param encoding: Expected encoding for text (Default UTF-8)
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:param errors: Errors handling policy. See here for valid
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values http://docs.python.org/2/library/codecs.html
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:returns: text or a bytestring `encoding` encoded
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representation of it.
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:raises TypeError: If text is not an isntance of basestring
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"""
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if not isinstance(text, basestring):
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raise TypeError("%s can't be encoded" % type(text))
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if not incoming:
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incoming = (sys.stdin.encoding or
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sys.getdefaultencoding())
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if isinstance(text, unicode):
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return text.encode(encoding, errors)
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elif text and encoding != incoming:
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# Decode text before encoding it with `encoding`
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text = safe_decode(text, incoming, errors)
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return text.encode(encoding, errors)
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return text
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