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# rfc3339.py -- Implementation of the majority of RFC 3339 for python. # Copyright (c) 2008, 2009, 2010 LShift Ltd. <query@lshift.net> # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in # all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN # THE SOFTWARE.
Implementation of the majority of http://www.ietf.org/rfc/rfc3339.txt.
Use datetime.datetime.isoformat() as an inverse of the various parsing routines in this module.
Limitations, with respect to RFC 3339:
- Section 4.3, "Unknown Local Offset Convention", is not implemented.
- Section 5.6, "Internet Date/Time Format", is the ONLY supported format implemented by the various parsers in this module. (Section 5.6 is reproduced in its entirety below.)
- Section 5.7, "Restrictions", is left to the datetime.datetime constructor to implement, with the exception of limits on timezone minutes-east-of-UTC magnitude. In particular, leap seconds are not addressed by this module. (And it appears that they are not supported by datetime, either.)
Potential Improvements:
- Support for leap seconds. (There's a table of them in RFC 3339 itself, and http://tf.nist.gov/pubs/bulletin/leapsecond.htm updates monthly.)
Here's an excerpt from RFC 3339 itself:
5.6. Internet Date/Time Format
The following profile of ISO 8601 [ISO8601] dates SHOULD be used in new protocols on the Internet. This is specified using the syntax description notation defined in [ABNF].
date-fullyear = 4DIGIT date-month = 2DIGIT ; 01-12 date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on ; month/year time-hour = 2DIGIT ; 00-23 time-minute = 2DIGIT ; 00-59 time-second = 2DIGIT ; 00-58, 00-59, 00-60 based on leap second ; rules time-secfrac = "." 1*DIGIT time-numoffset = ("+" / "-") time-hour ":" time-minute time-offset = "Z" / time-numoffset
partial-time = time-hour ":" time-minute ":" time-second [time-secfrac] full-date = date-fullyear "-" date-month "-" date-mday full-time = partial-time time-offset
date-time = full-date "T" full-time
NOTE: Per [ABNF] and ISO8601, the "T" and "Z" characters in this syntax may alternatively be lower case "t" or "z" respectively.
This date/time format may be used in some environments or contexts that distinguish between the upper- and lower-case letters 'A'-'Z' and 'a'-'z' (e.g. XML). Specifications that use this format in such environments MAY further limit the date/time syntax so that the letters 'T' and 'Z' used in the date/time syntax must always be upper case. Applications that generate this format SHOULD use upper case letters.
NOTE: ISO 8601 defines date and time separated by "T". Applications using this syntax may choose, for the sake of readability, to specify a full-date and full-time separated by (say) a space character. """
""" Implementation of a fixed-offset tzinfo. """ """ minutesEast -> number of minutes east of UTC that this tzinfo represents. name -> symbolic (but uninterpreted) name of this tzinfo. """
"""Returns minutesEast from the constructor, as a datetime.timedelta.""" return self.offset
"""This is a fixed offset tzinfo, so always returns a zero timedelta.""" return ZERO
"""Returns the name from the constructor.""" return self.name
def __repr__(self): """If minutesEast==0, prints specially as rfc3339.UTC_TZ.""" if self.minutesEast == 0: return "rfc3339.UTC_TZ" else: return "rfc3339.tzinfo(%s,%s)" % (self.minutesEast, repr(self.name))
""" Given a string matching the 'full-date' production above, returns a datetime.date instance. Any deviation from the allowed format will produce a raised ValueError.
>>> parse_date("2008-08-24") datetime.date(2008, 8, 24) >>> parse_date(" 2008-08-24 ") datetime.date(2008, 8, 24) >>> parse_date("2008-08-00") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 134, in parse_date return datetime.date(int(y), int(m), int(d)) ValueError: day is out of range for month >>> parse_date("2008-06-31") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 134, in parse_date return datetime.date(int(y), int(m), int(d)) ValueError: day is out of range for month >>> parse_date("2008-13-01") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 134, in parse_date return datetime.date(int(y), int(m), int(d)) ValueError: month must be in 1..12 >>> parse_date("22008-01-01") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 136, in parse_date raise ValueError('Invalid RFC 3339 date string', s) ValueError: ('Invalid RFC 3339 date string', '22008-01-01') >>> parse_date("2008-08-24").isoformat() '2008-08-24' """ m = date_re.match(s) if m: (y, m, d) = m.groups() return datetime.date(int(y), int(m), int(d)) else: raise ValueError('Invalid RFC 3339 date string', s)
""" Given a string matching the 'date-time' production above, returns a datetime.datetime instance. Any deviation from the allowed format will produce a raised ValueError.
>>> parse_datetime("2008-08-24T00:00:00Z") datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) >>> parse_datetime(" 2008-08-24T00:00:00Z ") datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) >>> parse_datetime("2008-08-24T00:00:00") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 208, in parse_datetime raise ValueError('Invalid RFC 3339 datetime string', s) ValueError: ('Invalid RFC 3339 datetime string', '2008-08-24T00:00:00') >>> parse_datetime("2008-08-24T00:00:00+00:00") datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.UTC_TZ) >>> parse_datetime("2008-08-24T00:00:00+01:00") datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.tzinfo(60,'+01:00')) >>> parse_datetime("2008-08-24T00:00:00-01:00") datetime.datetime(2008, 8, 24, 0, 0, tzinfo=rfc3339.tzinfo(-60,'-01:00')) >>> parse_datetime("2008-08-24T24:00:00Z") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "rfc3339.py", line 206, in parse_datetime tz) ValueError: hour must be in 0..23 >>> midnightUTC = parse_datetime("2008-08-24T00:00:00Z") >>> oneamBST = parse_datetime("2008-08-24T01:00:00+01:00") >>> midnightUTC == oneamBST True >>> elevenpmUTC = parse_datetime("2008-08-23T23:00:00Z") >>> midnightBST = parse_datetime("2008-08-24T00:00:00+01:00") >>> midnightBST == elevenpmUTC True >>> elevenpmUTC.isoformat() '2008-08-23T23:00:00+00:00' >>> oneamBST.isoformat() '2008-08-24T01:00:00+01:00' >>> parse_datetime("2008-08-24T00:00:00.123Z").isoformat() '2008-08-24T00:00:00.123000+00:00' """ m = datetime_re.match(s) if m: (y, m, d, hour, min, sec, ignore1, frac_sec, wholetz, ignore2, tzsign, tzhour, tzmin) = \ m.groups()
if frac_sec: frac_sec = float("0." + frac_sec) else: frac_sec = 0 microsec = int((frac_sec * 1000000) + 0.5)
if wholetz == 'z' or wholetz == 'Z': tz = UTC_TZ else: tzhour = int(tzhour) tzmin = int(tzmin) offset = tzhour * 60 + tzmin if offset == 0: tz = UTC_TZ else: if tzhour > 24 or tzmin > 60 or offset > 1439: ## see tzinfo docs for the 1439 part raise ValueError('Invalid timezone offset', s, wholetz)
if tzsign == '-': offset = -offset tz = tzinfo(offset, wholetz)
return datetime.datetime(int(y), int(m), int(d), int(hour), int(min), int(sec), microsec, tz) else: raise ValueError('Invalid RFC 3339 datetime string', s)
"""Return a timezone-aware datetime.datetime object in rfc3339.UTC_TZ timezone, representing the current moment (time.time()). Useful as a replacement for the (timezone-unaware) datetime.datetime.now() method.""" return utcfromtimestamp(time.time())
"""Interprets its argument as a count of seconds elapsed since the Unix epoch, and returns a datetime.datetime in rfc3339.UTC_TZ timezone.""" (y, m, d, hour, min, sec) = time.gmtime(unix_epoch_timestamp)[:6] return datetime.datetime(y, m, d, hour, min, sec, 0, UTC_TZ)
"""Returns a count of the elapsed seconds between the Unix epoch and the passed-in datetime.datetime object.""" return calendar.timegm(dt.utctimetuple())
"""Return a RFC3339 date-time string corresponding to the given datetime object.""" if dt.utcoffset() is not None: return dt.isoformat() else: return "%sZ" % dt.isoformat()
"""Return a RFC3339 date-time string corresponding to the given Unix-epoch timestamp.""" return datetimetostr(utcfromtimestamp(ts))
"""Return the Unix-epoch timestamp corresponding to the given RFC3339 date-time string.""" return utctotimestamp(parse_datetime(s)) |