83
80
seconds = td.seconds % 60,
87
def rfc3339_duration_to_delta(duration):
88
"""Parse an RFC 3339 "duration" and return a datetime.timedelta
90
>>> rfc3339_duration_to_delta("P7D")
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>>> rfc3339_duration_to_delta("PT60S")
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datetime.timedelta(0, 60)
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>>> rfc3339_duration_to_delta("PT60M")
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datetime.timedelta(0, 3600)
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>>> rfc3339_duration_to_delta("PT24H")
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>>> rfc3339_duration_to_delta("P1W")
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>>> rfc3339_duration_to_delta("PT5M30S")
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datetime.timedelta(0, 330)
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>>> rfc3339_duration_to_delta("P1DT3M20S")
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datetime.timedelta(1, 200)
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# Parsing an RFC 3339 duration with regular expressions is not
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# possible - there would have to be multiple places for the same
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# values, like seconds. The current code, while more esoteric, is
109
# cleaner without depending on a parsing library. If Python had a
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# built-in library for parsing we would use it, but we'd like to
111
# avoid excessive use of external libraries.
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# New type for defining tokens, syntax, and semantics all-in-one
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Token = collections.namedtuple("Token",
115
("regexp", # To match token; if
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# "value" is not None,
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# must have a "group"
119
"value", # datetime.timedelta or
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"followers")) # Tokens valid after
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# RFC 3339 "duration" tokens, syntax, and semantics; taken from
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# the "duration" ABNF definition in RFC 3339, Appendix A.
125
token_end = Token(re.compile(r"$"), None, frozenset())
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token_second = Token(re.compile(r"(\d+)S"),
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datetime.timedelta(seconds=1),
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frozenset((token_end,)))
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token_minute = Token(re.compile(r"(\d+)M"),
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datetime.timedelta(minutes=1),
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frozenset((token_second, token_end)))
132
token_hour = Token(re.compile(r"(\d+)H"),
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datetime.timedelta(hours=1),
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frozenset((token_minute, token_end)))
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token_time = Token(re.compile(r"T"),
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frozenset((token_hour, token_minute,
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token_day = Token(re.compile(r"(\d+)D"),
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datetime.timedelta(days=1),
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frozenset((token_time, token_end)))
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token_month = Token(re.compile(r"(\d+)M"),
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datetime.timedelta(weeks=4),
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frozenset((token_day, token_end)))
145
token_year = Token(re.compile(r"(\d+)Y"),
146
datetime.timedelta(weeks=52),
147
frozenset((token_month, token_end)))
148
token_week = Token(re.compile(r"(\d+)W"),
149
datetime.timedelta(weeks=1),
150
frozenset((token_end,)))
151
token_duration = Token(re.compile(r"P"), None,
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frozenset((token_year, token_month,
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token_day, token_time,
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# Define starting values
156
value = datetime.timedelta() # Value so far
158
followers = frozenset(token_duration,) # Following valid tokens
159
s = duration # String left to parse
160
# Loop until end token is found
161
while found_token is not token_end:
162
# Search for any currently valid tokens
163
for token in followers:
164
match = token.regexp.match(s)
165
if match is not None:
167
if token.value is not None:
168
# Value found, parse digits
169
factor = int(match.group(1), 10)
170
# Add to value so far
171
value += factor * token.value
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# Strip token from string
173
s = token.regexp.sub("", s, 1)
176
# Set valid next tokens
177
followers = found_token.followers
180
# No currently valid tokens were found
181
raise ValueError("Invalid RFC 3339 duration")
186
83
def string_to_delta(interval):
187
84
"""Parse a string and return a datetime.timedelta
added
removed
mandos-ctl
