• Language: en

Source code for django.utils.dateparse

"""Functions to parse datetime objects."""

# We're using regular expressions rather than time.strptime because:
# - They provide both validation and parsing.
# - They're more flexible for datetimes.
# - The date/datetime/time constructors produce friendlier error messages.

import datetime
import re

from django.utils.timezone import get_fixed_timezone, utc

date_re = re.compile(
    r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})$'
)

time_re = re.compile(
    r'(?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
    r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
)

datetime_re = re.compile(
    r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})'
    r'[T ](?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
    r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
    r'(?P<tzinfo>Z|[+-]\d{2}(?::?\d{2})?)?$'
)

standard_duration_re = re.compile(
    r'^'
    r'(?:(?P<days>-?\d+) (days?, )?)?'
    r'((?:(?P<hours>-?\d+):)(?=\d+:\d+))?'
    r'(?:(?P<minutes>-?\d+):)?'
    r'(?P<seconds>-?\d+)'
    r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
    r'$'
)

# Support the sections of ISO 8601 date representation that are accepted by
# timedelta
iso8601_duration_re = re.compile(
    r'^(?P<sign>[-+]?)'
    r'P'
    r'(?:(?P<days>\d+(.\d+)?)D)?'
    r'(?:T'
    r'(?:(?P<hours>\d+(.\d+)?)H)?'
    r'(?:(?P<minutes>\d+(.\d+)?)M)?'
    r'(?:(?P<seconds>\d+(.\d+)?)S)?'
    r')?'
    r'$'
)

# Support PostgreSQL's day-time interval format, e.g. "3 days 04:05:06". The
# year-month and mixed intervals cannot be converted to a timedelta and thus
# aren't accepted.
postgres_interval_re = re.compile(
    r'^'
    r'(?:(?P<days>-?\d+) (days? ?))?'
    r'(?:(?P<sign>[-+])?'
    r'(?P<hours>\d+):'
    r'(?P<minutes>\d\d):'
    r'(?P<seconds>\d\d)'
    r'(?:\.(?P<microseconds>\d{1,6}))?'
    r')?$'
)


[docs]def parse_date(value): """Parse a string and return a datetime.date. Raise ValueError if the input is well formatted but not a valid date. Return None if the input isn't well formatted. """ match = date_re.match(value) if match: kw = {k: int(v) for k, v in match.groupdict().items()} return datetime.date(**kw)
[docs]def parse_time(value): """Parse a string and return a datetime.time. This function doesn't support time zone offsets. Raise ValueError if the input is well formatted but not a valid time. Return None if the input isn't well formatted, in particular if it contains an offset. """ match = time_re.match(value) if match: kw = match.groupdict() if kw['microsecond']: kw['microsecond'] = kw['microsecond'].ljust(6, '0') kw = {k: int(v) for k, v in kw.items() if v is not None} return datetime.time(**kw)
[docs]def parse_datetime(value): """Parse a string and return a datetime.datetime. This function supports time zone offsets. When the input contains one, the output uses a timezone with a fixed offset from UTC. Raise ValueError if the input is well formatted but not a valid datetime. Return None if the input isn't well formatted. """ match = datetime_re.match(value) if match: kw = match.groupdict() if kw['microsecond']: kw['microsecond'] = kw['microsecond'].ljust(6, '0') tzinfo = kw.pop('tzinfo') if tzinfo == 'Z': tzinfo = utc elif tzinfo is not None: offset_mins = int(tzinfo[-2:]) if len(tzinfo) > 3 else 0 offset = 60 * int(tzinfo[1:3]) + offset_mins if tzinfo[0] == '-': offset = -offset tzinfo = get_fixed_timezone(offset) kw = {k: int(v) for k, v in kw.items() if v is not None} kw['tzinfo'] = tzinfo return datetime.datetime(**kw)
[docs]def parse_duration(value): """Parse a duration string and return a datetime.timedelta. The preferred format for durations in Django is '%d %H:%M:%S.%f'. Also supports ISO 8601 representation and PostgreSQL's day-time interval format. """ match = ( standard_duration_re.match(value) or iso8601_duration_re.match(value) or postgres_interval_re.match(value) ) if match: kw = match.groupdict() days = datetime.timedelta(float(kw.pop('days', 0) or 0)) sign = -1 if kw.pop('sign', '+') == '-' else 1 if kw.get('microseconds'): kw['microseconds'] = kw['microseconds'].ljust(6, '0') if kw.get('seconds') and kw.get('microseconds') and kw['seconds'].startswith('-'): kw['microseconds'] = '-' + kw['microseconds'] kw = {k: float(v) for k, v in kw.items() if v is not None} return days + sign * datetime.timedelta(**kw)
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