timezone-detect: Haskell bindings for the zone-detect C library; plus tz-aware utils.

[ data, foreign, gpl, library, time ] [ Propose Tags ]

Please see the README on GitHub at https://github.com/lfborjas/timezone-detect#readme


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Versions [RSS] [faq] 0.1.0.0, 0.2.0.0, 0.2.1.0, 0.2.2.0, 0.3.0.0, 0.3.0.1
Change log ChangeLog.md
Dependencies base (>=4.9 && <4.14), time (>=1.9.1 && <=1.10), timezone-olson (>=0.2.0 && <0.3), timezone-series (>=0.1.0 && <0.2) [details]
License GPL-2.0-only
Author Luis Borjas Reyes
Maintainer timezone-detect@lfborjas.com
Category Data, Foreign, Time
Home page https://github.com/lfborjas/timezone-detect#readme
Bug tracker https://github.com/lfborjas/timezone-detect/issues
Source repo head: git clone https://github.com/lfborjas/timezone-detect
Uploaded by lfborjas at 2020-08-30T20:58:47Z
Distributions NixOS:0.3.0.1
Downloads 445 total (17 in the last 30 days)
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2020-08-30 [all 1 reports]

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Readme for timezone-detect-0.2.2.0

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TimezoneDetect

build

Haskell bindings to the excellent ZoneDetect library, plus additional UNIX-aware facilities to determine the UTC time of a given local time in a latitude and longitude.

Usage

You'll need timezone database files to work with this library, see instructions in the original repository.

Once you have those files in hand, you'll be able to get a timezone from a given latitude and longitude:

>>> lookupTimeZoneName "./test/tz_db/timezone21.bin" 40.7831 (-73.9712) :: Maybe TimeZoneName
Just "America/New_York"

Additionally, we now depend on the timezone-series and timezone-olson packages to add awareness of tz database information.

With that, you can look up the UTC time at a point in time and space:

>>> import Data.Time
>>> localWinter <- parseTimeM True defaultTimeLocale "%Y-%-m-%-d %T" "2019-12-25 00:30:00"
>>> utcTime <- timeAtPointToUTC "./test/tz_db/timezone21.bin" 40.7831 (-73.9712) localWinter
2019-12-25 05:30:00 UTC

>>> localSummer <- parseTimeM True defaultTimeLocale "%Y-%-m-%-d %T" "2019-07-25 00:30:00"
>>> utcTime <- timeAtPointToUTC "./test/tz_db/timezone21.bin" 40.7831 (-73.9712) localWinter
2019-07-25 04:30:00 UTC

You can also opt to obtain the timezone name separately (if you wanted to isolate that as a failure scenario,) and, once in possession of it, use timeInTimeZoneToUTC:

>>> localSummer <- parseTimeM True defaultTimeLocale "%Y-%-m-%-d %T" "2019-07-25 00:30:00"
>>> utcTime <- timeInTimeZoneToUTC "America/New_York" localSummer
2019-07-25 04:30:00 UTC