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Diffstat (limited to 'python/dateutil/zoneinfo/__init__.py')
| -rw-r--r-- | python/dateutil/zoneinfo/__init__.py | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/python/dateutil/zoneinfo/__init__.py b/python/dateutil/zoneinfo/__init__.py new file mode 100644 index 0000000..a2ed4f9 --- /dev/null +++ b/python/dateutil/zoneinfo/__init__.py @@ -0,0 +1,183 @@ +# -*- coding: utf-8 -*- +import warnings +import json + +from tarfile import TarFile +from pkgutil import get_data +from io import BytesIO +from contextlib import closing + +from dateutil.tz import tzfile + +__all__ = ["get_zonefile_instance", "gettz", "gettz_db_metadata", "rebuild"] + +ZONEFILENAME = "dateutil-zoneinfo.tar.gz" +METADATA_FN = 'METADATA' + +# python2.6 compatability. Note that TarFile.__exit__ != TarFile.close, but +# it's close enough for python2.6 +tar_open = TarFile.open +if not hasattr(TarFile, '__exit__'): + def tar_open(*args, **kwargs): + return closing(TarFile.open(*args, **kwargs)) + + +class tzfile(tzfile): + def __reduce__(self): + return (gettz, (self._filename,)) + + +def getzoneinfofile_stream(): + try: + 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 tar_open(fileobj=zonefile_stream, mode='r') as tf: + # dict comprehension does not work on python2.6 + # TODO: get back to the nicer syntax when we ditch python2.6 + # self.zones = {zf.name: tzfile(tf.extractfile(zf), + # filename = zf.name) + # for zf in tf.getmembers() if zf.isfile()} + self.zones = dict((zf.name, tzfile(tf.extractfile(zf), + filename=zf.name)) + for zf in tf.getmembers() + if zf.isfile() and zf.name != METADATA_FN) + # deal with links: They'll point to their parent object. Less + # waste of memory + # links = {zl.name: self.zones[zl.linkname] + # for zl in tf.getmembers() if zl.islnk() or zl.issym()} + links = dict((zl.name, self.zones[zl.linkname]) + for zl in tf.getmembers() if + zl.islnk() or zl.issym()) + self.zones.update(links) + try: + metadata_json = tf.extractfile(tf.getmember(METADATA_FN)) + metadata_str = metadata_json.read().decode('UTF-8') + self.metadata = json.loads(metadata_str) + except KeyError: + # no metadata in tar file + self.metadata = None + else: + self.zones = dict() + 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. +_CLASS_ZONE_INSTANCE = list() + + +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 + + +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:`dateutil.tz.tzfile` 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 ``dateutil.tz.gettz()``, 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) + + +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 |