Source code for dateutil.zoneinfo

# -*- coding: utf-8 -*-
import warnings
import json

from tarfile import TarFile
from pkgutil import get_data
from io import BytesIO

from import tzfile as _tzfile

__all__ = ["get_zonefile_instance", "gettz", "gettz_db_metadata"]

ZONEFILENAME = "dateutil-zoneinfo.tar.gz"

class tzfile(_tzfile):
    def __reduce__(self):
        return (gettz, (self._filename,))

def getzoneinfofile_stream():
        return BytesIO(get_data(__name__, ZONEFILENAME))
    except IOError as e:  # TODO  switch to FileNotFoundError?
        warnings.warn("I/O error({0}): {1}".format(e.errno, e.strerror))
        return None

class ZoneInfoFile(object):
    def __init__(self, zonefile_stream=None):
        if zonefile_stream is not None:
            with as tf:
                self.zones = { tzfile(tf.extractfile(zf),
                              for zf in tf.getmembers()
                              if zf.isfile() and != METADATA_FN}
                # deal with links: They'll point to their parent object. Less
                # waste of memory
                links = { self.zones[zl.linkname]
                         for zl in tf.getmembers() if
                         zl.islnk() or zl.issym()}
                    metadata_json = tf.extractfile(tf.getmember(METADATA_FN))
                    metadata_str ='UTF-8')
                    self.metadata = json.loads(metadata_str)
                except KeyError:
                    # no metadata in tar file
                    self.metadata = None
            self.zones = {}
            self.metadata = None

    def get(self, name, default=None):
        Wrapper for :func:`ZoneInfoFile.zones.get`. This is a convenience method
        for retrieving zones from the zone dictionary.

        :param name:
            The name of the zone to retrieve. (Generally IANA zone names)

        :param default:
            The value to return in the event of a missing key.

        .. versionadded:: 2.6.0

        return self.zones.get(name, default)

# The current API has gettz as a module function, although in fact it taps into
# a stateful class. So as a workaround for now, without changing the API, we
# will create a new "global" class instance the first time a user requests a
# timezone. Ugly, but adheres to the api.
# TODO: Remove after deprecation period.

[docs] def get_zonefile_instance(new_instance=False): """ This is a convenience function which provides a :class:`ZoneInfoFile` instance using the data provided by the ``dateutil`` package. By default, it caches a single instance of the ZoneInfoFile object and returns that. :param new_instance: If ``True``, a new instance of :class:`ZoneInfoFile` is instantiated and used as the cached instance for the next call. Otherwise, new instances are created only as necessary. :return: Returns a :class:`ZoneInfoFile` object. .. versionadded:: 2.6 """ if new_instance: zif = None else: zif = getattr(get_zonefile_instance, '_cached_instance', None) if zif is None: zif = ZoneInfoFile(getzoneinfofile_stream()) get_zonefile_instance._cached_instance = zif return zif
[docs] def gettz(name): """ This retrieves a time zone from the local zoneinfo tarball that is packaged with dateutil. :param name: An IANA-style time zone name, as found in the zoneinfo file. :return: Returns a :class:`` time zone object. .. warning:: It is generally inadvisable to use this function, and it is only provided for API compatibility with earlier versions. This is *not* equivalent to ````, which selects an appropriate time zone based on the inputs, favoring system zoneinfo. This is ONLY for accessing the dateutil-specific zoneinfo (which may be out of date compared to the system zoneinfo). .. deprecated:: 2.6 If you need to use a specific zoneinfofile over the system zoneinfo, instantiate a :class:`dateutil.zoneinfo.ZoneInfoFile` object and call :func:`dateutil.zoneinfo.ZoneInfoFile.get(name)` instead. Use :func:`get_zonefile_instance` to retrieve an instance of the dateutil-provided zoneinfo. """ warnings.warn("zoneinfo.gettz() will be removed in future versions, " "to use the dateutil-provided zoneinfo files, instantiate a " "ZoneInfoFile object and use ZoneInfoFile.zones.get() " "instead. See the documentation for details.", DeprecationWarning) if len(_CLASS_ZONE_INSTANCE) == 0: _CLASS_ZONE_INSTANCE.append(ZoneInfoFile(getzoneinfofile_stream())) return _CLASS_ZONE_INSTANCE[0].zones.get(name)
[docs] def gettz_db_metadata(): """ Get the zonefile metadata See `zonefile_metadata`_ :returns: A dictionary with the database metadata .. deprecated:: 2.6 See deprecation warning in :func:`zoneinfo.gettz`. To get metadata, query the attribute ``zoneinfo.ZoneInfoFile.metadata``. """ warnings.warn("zoneinfo.gettz_db_metadata() will be removed in future " "versions, to use the dateutil-provided zoneinfo files, " "ZoneInfoFile object and query the 'metadata' attribute " "instead. See the documentation for details.", DeprecationWarning) if len(_CLASS_ZONE_INSTANCE) == 0: _CLASS_ZONE_INSTANCE.append(ZoneInfoFile(getzoneinfofile_stream())) return _CLASS_ZONE_INSTANCE[0].metadata