"""Backports and compatible methods."""
# get_model(app_name, model_name)
# Retrieves Django model class given the app and model name
try:
# Django 1.8 and later
from django.apps import apps
get_model = apps.get_model
except ImportError: # pragma: nocover
from django.db.models.loading import get_model
assert get_model
# parse_duration(string)
# Parses a Django or ISO 8601 string into a datetime.timedelta
try:
# Django 1.8 and later
from django.utils.dateparse import parse_duration
except: # pragma: nocover
from datetime import timedelta
import re
from django.utils import six
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'$'
)
# Support the sections of ISO 8601 date representation that are accepted by
# timedelta
iso8601_duration_re = re.compile(
r'^P'
r'(?:(?P<days>\d+(.\d+)?)D)?'
r'(?:T'
r'(?:(?P<hours>\d+(.\d+)?)H)?'
r'(?:(?P<minutes>\d+(.\d+)?)M)?'
r'(?:(?P<seconds>\d+(.\d+)?)S)?'
r')?'
r'$'
)
def parse_duration(value):
"""Parse a duration string and returns a datetime.timedelta.
The preferred format for durations in Django is '%d %H:%M:%S.%f'.
Also supports ISO 8601 representation.
"""
match = standard_duration_re.match(value)
if not match:
match = iso8601_duration_re.match(value)
if match:
kw = match.groupdict()
if kw.get('microseconds'):
kw['microseconds'] = kw['microseconds'].ljust(6, '0')
kw = dict([
(k, float(v)) for k, v in six.iteritems(kw)
if v is not None])
return timedelta(**kw)
