def bool_from_string(subject, strict=False):
"""
Interpret a string as a boolean.
A case-insensitive match is performed such that strings matching 't',
'true', 'on', 'y', 'yes', or '1' are considered True and, when
`strict=False`, anything else is considered False.
Useful for JSON-decoded stuff and config file parsing.
If `strict=True`, unrecognized values, including None, will raise a
ValueError which is useful when parsing values passed in from an API call.
Strings yielding False are 'f', 'false', 'off', 'n', 'no', or '0'.
"""
if not isinstance(subject, basestring):
subject = str(subject)
lowered = subject.strip().lower()
if lowered in TRUE_STRINGS:
return True
elif lowered in FALSE_STRINGS:
return False
elif strict:
acceptable = ", ".join("'%s'" % s for s in sorted(TRUE_STRINGS + FALSE_STRINGS))
msg = _("Unrecognized value '%(val)s', acceptable values are:" " %(acceptable)s") % {
"val": subject,
"acceptable": acceptable,
}
raise ValueError(msg)
else:
return False
def to_bytes(text, default=0):
"""Try to turn a string into a number of bytes. Looks at the last
characters of the text to determine what conversion is needed to
turn the input text into a byte number.
Supports: B/b, K/k, M/m, G/g, T/t (or the same with b/B on the end)
"""
# Take off everything not number 'like' (which should leave
# only the byte 'identifier' left)
mult_key_org = text.lstrip("-1234567890")
mult_key = mult_key_org.lower()
mult_key_len = len(mult_key)
if mult_key.endswith("b"):
mult_key = mult_key[0:-1]
try:
multiplier = BYTE_MULTIPLIERS[mult_key]
if mult_key_len:
# Empty cases shouldn't cause text[0:-0]
text = text[0:-mult_key_len]
return int(text) * multiplier
except KeyError:
msg = _("Unknown byte multiplier: %s") % mult_key_org
raise TypeError(msg)
except ValueError:
return default
