relativetimebuilder 3.0.2
A library for using the dateutil relativedeltas for calendar precision with aniso8601
Keywords: iso8601 dateutil aniso8601 datetime

RelativeTimeBuilder
===================

aniso8601 builder for dateutil relativedeltas
---------------------------------------------

Features
========
* Provides :code:`RelativeTimeBuilder` compatible with `aniso8601 <https://codeberg.org/nielsenb-jf/aniso8601>`_
* Returns `dateutil <https://dateutil.readthedocs.io/en/stable/relativedelta.html>`_ :code:`relativedelta` objects for durations

Installation
============

The recommended installation method is to use pip::

  $ pip install relativetimebuilder

Alternatively, you can download the source (git repository hosted at `Codeberg <https://codeberg.org/nielsenb-jf/relativetimebuilder>`_) and install directly::

  $ python setup.py install

Use
===

Parsing datetimes
-----------------

To parse a typical ISO 8601 datetime string::

  >>> import aniso8601
  >>> from relativetimebuilder import RelativeTimeBuilder
  >>> aniso8601.parse_datetime('1977-06-10T12:00:00', builder=RelativeTimeBuilder)
  datetime.datetime(1977, 6, 10, 12, 0)

Alternative delimiters can be specified, for example, a space::

  >>> aniso8601.parse_datetime('1977-06-10 12:00:00', delimiter=' ', builder=RelativeTimeBuilder)
  datetime.datetime(1977, 6, 10, 12, 0)

Both UTC (Z) and UTC offsets for timezones are supported::

  >>> aniso8601.parse_datetime('1977-06-10T12:00:00Z', builder=RelativeTimeBuilder)
  datetime.datetime(1977, 6, 10, 12, 0, tzinfo=+0:00:00 UTC)
  >>> aniso8601.parse_datetime('1979-06-05T08:00:00-08:00', builder=RelativeTimeBuilder)
  datetime.datetime(1979, 6, 5, 8, 0, tzinfo=-8:00:00 UTC)

Leap seconds are explicitly not supported::

  >>> aniso8601.parse_datetime('2018-03-06T23:59:60', builder=RelativeTimeBuilder)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/time.py", line 132, in parse_datetime
      return builder.build_datetime(datepart, timepart)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/python.py", line 181, in build_datetime
      cls._build_object(time))
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/__init__.py", line 64, in _build_object
      ss=parsetuple[2], tz=parsetuple[3])
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/python.py", line 141, in build_time
      raise LeapSecondError('Leap seconds are not supported.')
  aniso8601.exceptions.LeapSecondError: Leap seconds are not supported.

Parsing dates
-------------

To parse a date represented in an ISO 8601 string::

  >>> import aniso8601
  >>> from relativetimebuilder import RelativeTimeBuilder
  >>> aniso8601.parse_date('1984-04-23', builder=RelativeTimeBuilder)
  datetime.date(1984, 4, 23)

Basic format is supported as well::

  >>> aniso8601.parse_date('19840423', builder=RelativeTimeBuilder)
  datetime.date(1984, 4, 23)

To parse a date using the ISO 8601 week date format::

  >>> aniso8601.parse_date('1986-W38-1', builder=RelativeTimeBuilder)
  datetime.date(1986, 9, 15)

To parse an ISO 8601 ordinal date::

  >>> aniso8601.parse_date('1988-132', builder=RelativeTimeBuilder)
  datetime.date(1988, 5, 11)

Parsing times
-------------

To parse a time formatted as an ISO 8601 string::

  >>> import aniso8601
  >>> from relativetimebuilder import RelativeTimeBuilder
  >>> aniso8601.parse_time('11:31:14', builder=RelativeTimeBuilder)
  datetime.time(11, 31, 14)

As with all of the above, basic format is supported::

  >>> aniso8601.parse_time('113114', builder=RelativeTimeBuilder)
  datetime.time(11, 31, 14)

A UTC offset can be specified for times::

  >>> aniso8601.parse_time('17:18:19-02:30', builder=RelativeTimeBuilder)
  datetime.time(17, 18, 19, tzinfo=-2:30:00 UTC)
  >>> aniso8601.parse_time('171819Z', builder=RelativeTimeBuilder)
  datetime.time(17, 18, 19, tzinfo=+0:00:00 UTC)

Reduced accuracy is supported::

  >>> aniso8601.parse_time('21:42', builder=RelativeTimeBuilder)
  datetime.time(21, 42)
  >>> aniso8601.parse_time('22', builder=RelativeTimeBuilder)
  datetime.time(22, 0)

A decimal fraction is always allowed on the lowest order element of an ISO 8601 formatted time::

  >>> aniso8601.parse_time('22:33.5', builder=RelativeTimeBuilder)
  datetime.time(22, 33, 30)
  >>> aniso8601.parse_time('23.75', builder=RelativeTimeBuilder)
  datetime.time(23, 45)

Leap seconds are explicitly not supported and attempting to parse one raises a :code:`LeapSecondError`::

  >>> aniso8601.parse_time('23:59:60', builder=RelativeTimeBuilder)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/time.py", line 117, in parse_time
      return _RESOLUTION_MAP[get_time_resolution(timestr)](timestr, tz, builder)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/time.py", line 166, in _parse_second_time
      return builder.build_time(hh=hourstr, mm=minutestr, ss=secondstr, tz=tz)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/python.py", line 141, in build_time
      raise LeapSecondError('Leap seconds are not supported.')
  aniso8601.exceptions.LeapSecondError: Leap seconds are not supported.

Parsing durations
-----------------

Parsing durations returns :code:`relativedelta` objects from `dateutil <https://dateutil.readthedocs.io/en/stable/relativedelta.html>`_ for calendar level accuracy.

To parse a duration formatted as an ISO 8601 string::

  >>> import aniso8601
  >>> from relativetimebuilder import RelativeTimeBuilder
  >>> aniso8601.parse_duration('P1Y2M3DT4H54M6S', builder=RelativeTimeBuilder)
  relativedelta(years=+1, months=+2, days=+3, hours=+4, minutes=+54, seconds=+6)

Reduced accuracy is supported::

  >>> aniso8601.parse_duration('P1Y', builder=RelativeTimeBuilder)
  relativedelta(years=+1)

A decimal fraction is allowed on the lowest order element::

  >>> aniso8601.parse_duration('P1YT3.5M', builder=RelativeTimeBuilder)
  relativedelta(years=+1, minutes=+3.5)

The decimal fraction can be specified with a comma instead of a full-stop::

  >>> aniso8601.parse_duration('P1YT3,5M', builder=RelativeTimeBuilder)
  relativedelta(years=+1, minutes=+3.5)

Decimal fractions are not supported for years or months as calendar level accuracy would not be guaranteed::

  >>> aniso8601.parse_duration('P1Y2.5M', builder=RelativeTimeBuilder)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 30, in parse_duration
      return _parse_duration_prescribed(isodurationstr, builder)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 75, in _parse_duration_prescribed
      return _parse_duration_prescribed_notime(durationstr, builder)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 119, in _parse_duration_prescribed_notime
      PnW=weekstr, PnD=daystr)
    File "relativetimebuilder/__init__.py", line 24, in build_duration
      raise RelativeValueError('Fractional months and years are not '
  relativetimebuilder.RelativeValueError: Fractional months and years are not defined for relative durations.
  >>> aniso8601.parse_duration('P1.5Y', builder=RelativeTimeBuilder)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 30, in parse_duration
      return _parse_duration_prescribed(isodurationstr, builder)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 75, in _parse_duration_prescribed
      return _parse_duration_prescribed_notime(durationstr, builder)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/duration.py", line 119, in _parse_duration_prescribed_notime
      PnW=weekstr, PnD=daystr)
    File "relativetimebuilder/__init__.py", line 24, in build_duration
      raise RelativeValueError('Fractional months and years are not '
  relativetimebuilder.RelativeValueError: Fractional months and years are not defined for relative durations.

Parsing a duration from a combined date and time is supported as well::

  >>> aniso8601.parse_duration('P0001-01-02T01:30:5', builder=RelativeTimeBuilder)
  relativedelta(years=+1, months=+1, days=+2, hours=+1, minutes=+30, seconds=+5)

Parsing intervals
-----------------

Intervals are built using :code:`relativedelta` objects from `dateutil <https://dateutil.readthedocs.io/en/stable/relativedelta.html>`_ for calendar level accuracy.

To parse an interval specified by a start and end::

  >>> import aniso8601
  >>> from relativetimebuilder import RelativeTimeBuilder
  >>> aniso8601.parse_interval('2007-03-01T13:00:00/2008-05-11T15:30:00', builder=RelativeTimeBuilder)
  (datetime.datetime(2007, 3, 1, 13, 0), datetime.datetime(2008, 5, 11, 15, 30))

Intervals specified by a start time and a duration are supported::

  >>> aniso8601.parse_interval('2007-03-01T13:00:00/P1Y2M10DT2H30M', builder=RelativeTimeBuilder)
  (datetime.datetime(2007, 3, 1, 13, 0), datetime.datetime(2008, 5, 11, 15, 30))

A duration can also be specified by a duration and end time::

  >>> aniso8601.parse_interval('P1M/1981-04-05', builder=RelativeTimeBuilder)
  (datetime.date(1981, 4, 5), datetime.date(1981, 3, 5))

Notice that the result of the above parse is not in order from earliest to latest. If sorted intervals are required, simply use the :code:`sorted` keyword as shown below::

  >>> sorted(aniso8601.parse_interval('P1M/1981-04-05', builder=RelativeTimeBuilder))
  [datetime.date(1981, 3, 5), datetime.date(1981, 4, 5)]

The end of an interval is returned as a :code:`datetime` when required to maintain the resolution specified by a duration, even if the duration start is given as a date::

  >>> aniso8601.parse_interval('2014-11-12/PT4H54M6.5S', builder=RelativeTimeBuilder)
  (datetime.date(2014, 11, 12), datetime.datetime(2014, 11, 12, 4, 54, 6, 500000))
  >>> aniso8601.parse_interval('2007-03-01/P1.5D', builder=RelativeTimeBuilder)
  (datetime.date(2007, 3, 1), datetime.datetime(2007, 3, 2, 12, 0))

Repeating intervals are supported as well, and return a generator::

  >>> aniso8601.parse_repeating_interval('R3/1981-04-05/P1D', builder=RelativeTimeBuilder)
  <generator object _date_generator at 0x7f0862919fa0>
  >>> list(aniso8601.parse_repeating_interval('R3/1981-04-05/P1D', builder=RelativeTimeBuilder))
  [datetime.date(1981, 4, 5), datetime.date(1981, 4, 6), datetime.date(1981, 4, 7)]

Repeating intervals are allowed to go in the reverse direction::

  >>> list(aniso8601.parse_repeating_interval('R2/PT1H2M/1980-03-05T01:01:00', builder=RelativeTimeBuilder))
  [datetime.datetime(1980, 3, 5, 1, 1), datetime.datetime(1980, 3, 4, 23, 59)]

Unbounded intervals are also allowed (Python 2)::

  >>> result = aniso8601.parse_repeating_interval('R/PT1H2M/1980-03-05T01:01:00', builder=RelativeTimeBuilder)
  >>> result.next()
  datetime.datetime(1980, 3, 5, 1, 1)
  >>> result.next()
  datetime.datetime(1980, 3, 4, 23, 59)

or for Python 3::

  >>> result = aniso8601.parse_repeating_interval('R/PT1H2M/1980-03-05T01:01:00', builder=RelativeTimeBuilder)
  >>> next(result)
  datetime.datetime(1980, 3, 5, 1, 1)
  >>> next(result)
  datetime.datetime(1980, 3, 4, 23, 59)

Intervals are calculated with calendar level accuracy::

  >>> aniso8601.parse_interval('2003-01-27/P1M', builder=RelativeTimeBuilder)
  (datetime.date(2003, 1, 27), datetime.date(2003, 2, 27))
  >>> aniso8601.parse_interval('2003-01-31/P1M', builder=RelativeTimeBuilder)
  (datetime.date(2003, 1, 31), datetime.date(2003, 2, 28))
  >>> aniso8601.parse_interval('P1Y/2001-02-28', builder=RelativeTimeBuilder)
  (datetime.date(2001, 2, 28), datetime.date(2000, 2, 28))

Fractional years and months do not make sense for relative intervals::

  >>> aniso8601.parse_interval('P1.1Y/2001-02-28', builder=RelativeTimeBuilder)
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/interval.py", line 40, in parse_interval
      intervaldelimiter, datetimedelimiter)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/interval.py", line 98, in _parse_interval
      return builder.build_interval(end=enddate, duration=duration)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/python.py", line 311, in build_interval
      durationobject = cls._build_object(duration)
    File "/home/nielsenb/Jetfuse/aniso8601/aniso8601/aniso8601/builders/__init__.py", line 71, in _build_object
      TnS=parsetuple[6])
    File "relativetimebuilder/__init__.py", line 24, in build_duration
      raise RelativeValueError('Fractional months and years are not '
  relativetimebuilder.RelativeValueError: Fractional months and years are not defined for relative durations.

Development
===========

Setup
-----

It is recommended to develop using a `virtualenv <https://virtualenv.pypa.io/en/stable/>`_.

Inside a virtualenv, development dependencies can be installed automatically::

  $ pip install -e .[dev]

`pre-commit <https://pre-commit.com/>`_ is used for managing pre-commit hooks::

  $ pre-commit install

To run the pre-commit hooks manually::

  $ pre-commit run --all-files

Tests
-----

Tests can be run using the `unittest testing framework <https://docs.python.org/3/library/unittest.html>`_::

   $ python -m unittest discover relativetimebuilder

Contributing
============

RelativeTimeBuilder is an open source project hosted on `Codeberg <https://codeberg.org/nielsenb-jf/relativetimebuilder>`_.

Any and all bugs are welcome on our `issue tracker <https://codeberg.org/nielsenb-jf/relativetimebuilder/issues>`_.