1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
"""ISO 8601 date time string parsing
Basic usage:
>>> import iso8601
>>> iso8601.parse_date("2007-01-25T12:00:00Z")
datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.iso8601.Utc ...>)
>>>
"""
from datetime import (
datetime,
timedelta,
tzinfo
)
from decimal import Decimal
import logging
import sys
import re
__all__ = ["parse_date", "ParseError"]
LOG = logging.getLogger(__name__)
if sys.version_info >= (3, 0, 0):
_basestring = str
else:
_basestring = basestring
# Adapted from http://delete.me.uk/2005/03/iso8601.html
ISO8601_REGEX = re.compile(
r"""
(?P<year>[0-9]{4})
((-(?P<monthdash>[0-9]{1,2}))|(?P<month>[0-9]{2}))
((-(?P<daydash>[0-9]{1,2}))|(?P<day>[0-9]{2}))
(
(
(?P<separator>[ T])
(?P<hour>[0-9]{2})
(:{0,1}(?P<minute>[0-9]{2})){0,1}
(
:{0,1}(?P<second>[0-9]{1,2})
(\.(?P<second_fraction>[0-9]+)){0,1}
){0,1}
(?P<timezone>
Z
|
(
(?P<tz_sign>[-+])
(?P<tz_hour>[0-9]{2})
:{0,1}
(?P<tz_minute>[0-9]{2}){0,1}
)
){0,1}
){0,1}
)
$
""",
re.VERBOSE
)
class ParseError(Exception):
"""Raised when there is a problem parsing a date string"""
# Yoinked from python docs
ZERO = timedelta(0)
class Utc(tzinfo):
"""UTC
"""
def utcoffset(self, dt):
return ZERO
def tzname(self, dt):
return "UTC"
def dst(self, dt):
return ZERO
UTC = Utc()
class FixedOffset(tzinfo):
"""Fixed offset in hours and minutes from UTC
"""
def __init__(self, offset_hours, offset_minutes, name):
self.__offset_hours = offset_hours # Keep for later __getinitargs__
self.__offset_minutes = offset_minutes # Keep for later __getinitargs__
self.__offset = timedelta(hours=offset_hours, minutes=offset_minutes)
self.__name = name
def __eq__(self, other):
if isinstance(other, FixedOffset):
return (
(other.__offset == self.__offset)
and
(other.__name == self.__name)
)
if isinstance(other, tzinfo):
return other == self
return False
def __getinitargs__(self):
return (self.__offset_hours, self.__offset_minutes, self.__name)
def utcoffset(self, dt):
return self.__offset
def tzname(self, dt):
return self.__name
def dst(self, dt):
return ZERO
def __repr__(self):
return "<FixedOffset %r %r>" % (self.__name, self.__offset)
def to_int(d, key, default_to_zero=False, default=None, required=True):
"""Pull a value from the dict and convert to int
:param default_to_zero: If the value is None or empty, treat it as zero
:param default: If the value is missing in the dict use this default
"""
value = d.get(key) or default
LOG.debug("Got %r for %r with default %r", value, key, default)
if (value in ["", None]) and default_to_zero:
return 0
if value is None:
if required:
raise ParseError("Unable to read %s from %s" % (key, d))
else:
return int(value)
def parse_timezone(matches, default_timezone=UTC):
"""Parses ISO 8601 time zone specs into tzinfo offsets
"""
if matches["timezone"] == "Z":
return UTC
# This isn't strictly correct, but it's common to encounter dates without
# timezones so I'll assume the default (which defaults to UTC).
# Addresses issue 4.
if matches["timezone"] is None:
return default_timezone
sign = matches["tz_sign"]
hours = to_int(matches, "tz_hour")
minutes = to_int(matches, "tz_minute", default_to_zero=True)
description = "%s%02d:%02d" % (sign, hours, minutes)
if sign == "-":
hours = -hours
minutes = -minutes
return FixedOffset(hours, minutes, description)
def parse_date(datestring, default_timezone=UTC):
"""Parses ISO 8601 dates into datetime objects
The timezone is parsed from the date string. However it is quite common to
have dates without a timezone (not strictly correct). In this case the
default timezone specified in default_timezone is used. This is UTC by
default.
"""
if not isinstance(datestring, _basestring):
raise ParseError("Expecting a string %r" % datestring)
m = ISO8601_REGEX.match(datestring)
if not m:
raise ParseError("Unable to parse date string %r" % datestring)
groups = m.groupdict()
LOG.debug("Parsed %s into %s with default timezone %s", datestring, groups, default_timezone)
tz = parse_timezone(groups, default_timezone=default_timezone)
groups["second_fraction"] = int(Decimal("0.%s" % (groups["second_fraction"] or 0)) * Decimal("1000000.0"))
try:
return datetime(
year=to_int(groups, "year"),
month=to_int(groups, "month", default=to_int(groups, "monthdash", required=False)),
day=to_int(groups, "day", default=to_int(groups, "daydash", required=False)),
hour=to_int(groups, "hour", default_to_zero=True),
minute=to_int(groups, "minute", default_to_zero=True),
second=to_int(groups, "second", default_to_zero=True),
microsecond=groups["second_fraction"],
tzinfo=tz,
)
except Exception as e:
raise ParseError(e)
|
