Datetime

Support for reading, writing and converting date and time related objects.

See the datetime module, as well as the zope.interface.common.idatetime module for types of objects.

These are generally meant to be used as zope.interface adapters once this package has been configured, but they can be called manually as well.

class date_to_string(date)

Bases: object

Produce an IOS8601 string from a date.

Registered as an adapter from zope.interface.common.idatetime.IDate to IInternalObjectExternalizer.

>>> import datetime
>>> from nti.externalization.externalization import to_external_object
>>> from nti.externalization.datetime import date_to_string
>>> from zope import component
>>> component.provideAdapter(date_to_string)
>>> to_external_object(datetime.date(1982, 1, 31))
'1982-01-31'

date_from_string(string)

This adapter allows any field which comes in as a string in IOS8601 format to be transformed into a date. The schema field must be an zope.schema.Object field with a type of zope.interface.common.idatetime.IDate.

If you need a schema field that accepts human input, rather than programattic input, you probably want to use a custom field that uses zope.datetime.parse() in its fromUnicode method.

>>> from nti.externalization.datetime import date_from_string
>>> date_from_string('1982-01-31')
datetime.date(1982, 1, 31)

class datetime_to_string(date)

Bases: object

Produce an IOS8601 string from a datetime.

Registered as an adapter from zope.interface.common.idatetime.IDateTime to IInternalObjectExternalizer.

>>> from zope.component import provideAdapter
>>> import datetime
>>> from nti.externalization import to_external_object
>>> from nti.externalization.datetime import datetime_to_string
>>> provideAdapter(datetime_to_string)
>>> to_external_object(datetime.datetime(1982, 1, 31))
'1982-01-31T00:00:00Z'

datetime_from_string(string, assume_local=False, local_tzname=None)

This adapter allows any field which comes in as a string in IOS8601 format to be transformed into a datetime.datetime. The schema field should be an nti.schema.field.Object field with a type of zope.interface.common.idatetime.IDateTime or an instance of nti.schema.field.ValidDateTime. Wrap this with an nti.schema.fieldproperty.AdaptingFieldProperty.

Datetime values produced by this object will always be in GMT/UTC time, and they will always be datetime naive objects.

If you need a schema field that accepts human input, rather than programattic input, you probably want to use a custom field that uses zope.datetime.parse() in its fromUnicode method.

When used as an adapter, no parameters are accepted.

>>> from zope.interface.common.idatetime import IDateTime
>>> from zope.component import provideAdapter
>>> from nti.externalization.datetime import datetime_from_string
>>> provideAdapter(datetime_from_string)
>>> IDateTime('1982-01-31T00:00:00Z')
datetime.datetime(1982, 1, 31, 0, 0)

Parameters:

• assume_local (bool) – If False, the default, then when we parse a string that does not include timezone information, we will assume that it is already meant to be in UTC. Otherwise, if set to true, when we parse such a string we will assume that it is meant to be in the “local” timezone and adjust accordingly. If the local timezone experiences DST, then the time will be interpreted with the UTC offset as-of the DST rule in effect on the date parsed, not the current date, if possible. If not possible, the current rule will be used.
• local_tzname (str) – If given, either a string acceptable to pytz.timezone() to produce a tzinfo object, or a two-tuple as given from time.timezone. If not given, local timezone will be determined automatically.

datetime_from_timestamp(value)

Produce a datetime.datetime from a UTC timestamp.

This is a registered adapter for both integers and floats.

>>> from zope.interface.common.idatetime import IDateTime
>>> from zope.component import provideAdapter
>>> from nti.externalization.datetime import datetime_from_timestamp
>>> provideAdapter(datetime_from_timestamp, (int,))
>>> provideAdapter(datetime_from_timestamp, (float,))
>>> IDateTime(123456)
datetime.datetime(1970, 1, 2, 10, 17, 36)
>>> IDateTime(654321.0)
datetime.datetime(1970, 1, 8, 13, 45, 21)

class duration_to_string(date)

Bases: object

Produce an IOS8601 format duration from a datetime.timedelta object.

Timedelta objects do not represent years or months (the biggest duration they accept is weeks) and internally they normalize everything to days and smaller. Thus, the format produced by this transformation will never have a field larger than days.

Registered as an adapter from zope.interface.common.idatetime.ITimeDelta to IInternalObjectExternalizer.

>>> import datetime
>>> from zope.component import provideAdapter
>>> from nti.externalization import to_external_object
>>> from nti.externalization.datetime import duration_to_string
>>> provideAdapter(duration_to_string)
>>> to_external_object(datetime.timedelta(weeks=16))
'P112D'

duration_from_string(value)

Produce a datetime.timedelta from a ISO8601 format duration string.

>>> from zope.interface.common.idatetime import ITimeDelta
>>> from zope.component import provideAdapter
>>> from nti.externalization.datetime import duration_from_string
>>> provideAdapter(duration_from_string)
>>> ITimeDelta('P0D')
datetime.timedelta(0)