dbern
DateTimeParser - Parse DateTime, NaiveDateTime, Time, or Date from strings
I’m excited to announce that TaxJar has developed and open-sourced DateTimeParser. We developed it because we found a need to parse user input into DateTimes or NaiveDateTimes. I didn’t find any existing libraries that did this not without knowing the format of the string in advance. Maybe it could help you out too?
Check out the repo:
Check it out at Hex:
https://hexdocs.pm/date_time_parser
Learn more about TaxJar: https://www.taxjar.com. Special thanks to them for investing in my time to develop this and allowing me to open-source it! Also thanks to nimble_parsec for making this much easier to develop.
Examples
iex> DateTimeParser.parse_datetime("19 September 2018 08:15:22 AM")
{:ok, ~N[2018-09-19 08:15:22]}
iex> DateTimeParser.parse_datetime("2034-01-13")
{:ok, ~N[2034-01-13 00:00:00]}
iex> DateTimeParser.parse_date("2034-01-13")
{:ok, ~D[2034-01-13]}
iex> DateTimeParser.parse_date("01/01/2017")
{:ok, ~D[2017-01-01]}
iex> DateTimeParser.parse_datetime("1/1/18 3:24 PM")
{:ok, ~N[2018-01-01T15:24:00]}
iex> DateTimeParser.parse_datetime("1/1/18 3:24 PM", assume_utc: true)
{:ok, ~U[2018-01-01T15:24:00Z]}
# the ~U is a DateTime sigil introduced in Elixir 1.9.0
iex> DateTimeParser.parse_datetime(~s|"Dec 1, 2018 7:39:53 AM PST"|)
{:ok, ~U[2018-12-01T14:39:53Z]}
# Notice that the date is converted to UTC by default
iex> {:ok, datetime} = DateTimeParser.parse_datetime(~s|"Dec 1, 2018 7:39:53 AM PST"|, to_utc: false)
iex> datetime
#DateTime<2018-12-01 07:39:53-07:00 PDT PST8PDT>
iex> DateTimeParser.parse_time("10:13pm")
{:ok, ~T[22:13:00]}
iex> DateTimeParser.parse_time("10:13:34")
{:ok, ~T[10:13:34]}
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dbern
The theme of this release is no information is better than assumed information. So the breaking changes are simply to undo some defaults that we had set in pre-1.x. The biggest one was assuming a 00:00:00 time when no time was found, another was converting to UTC automatically. This no longer happens by default, but you can still have these behaviors through an option.
This release was dogfooded for a while, and we found some bugs in it during the RC phase, so if you’re using the library pre-1.x I recommend that you upgrade as soon as you can.
Here’s the changelog:
Breaking
- Change
parse_datetimeto no longer assume time. Previously, it would assume00:00:00if time could not be parsed. This is replaced with an opt-in optionassume_time. See next point. If you relied on this, to upgrade add the option; eg:DateTimeParser.parse_datetime(string, assume_time: true) - Change
parse_datetimeto no longer convert DateTime to UTC timezone. If you relied on this, to upgrade add the option; eg:DateTimeParser.parse_datetime(string, to_utc: true) - Change
parse_dateto no longer assume a date. Previously, it would assume the current date, and replace the found information from the string. This is replaced with an opt-in option ofassume_date. If you relied on this, to upgrade add the option; eg:DateTimeParser.parse_date(string, assume_date: true)
Bugs
- Fix a UTC conversion bug between Daylight/Standard time (#20). If you’re using an earlier version and converting to UTC, please upgrade to >= 1.0.0-rc2 immediately.
- Fix an epoch subsecond parsing bug (#16) (thanks @tmr08c)
- Updated for compatibility with Elixir 1.10.0
Features
- Add
parse/2that will respond with the best match. This function accepts all options introduced below. - Add
parse_datetime/2to accept options:-
assume_time: true | %Time{} | falsewith the default of false.
-
- Add
parse_date/2to accept options:-
assume_date: true | %Date{} | falsewith the default of false.
-
- Add support for parsing negative epoch times. (#24) (thanks @tmr08c)
- Add bang variants,
parse!/2,parse_datetime!/2,parse_time!/2, andparse_date!/2 - Added
parsers: []option to add or disable parsers. This is helpful if you are don’t want to consider Serial or Epoch timestamps
dbern
1.0 is releasing soon! Yesterday, I published 1.0.rc-1 as a means to dogfood the recent changes. It’ll stay there for a bit to ensure no bugs pop up.
Changes since initial release:
- Unix epoch times are now parsed
- Serial (spreadsheet) times are now parsed
- Added
DateTimeParser.parse/2to give the best answer it can give. Previously, you’d have to useparse_datetime,parse_date, orparse_time. Now you can throw strings intoparseand get the most specific struct for what it could parse. For example,2019-01-01will give you a%Date{};something @ 9:30pmwill give you a%Time{}, etc. -
[Breaking] some defaults changed. Previously, the lib would assume too much for you by default. For example if you used
DateTimeParser.parse_datetime("2019-01-01")it would give you2019-01-01T00:00:00. Where did the time come from? It was assumed. Now in 1.x this will not be the default. Also, it would auto-convert timezone’d timestamps to UTC; now you have to opt-in to that behavior.
if you’re interested, give it a shot and let me know what you think. https://hex.pm/packages/date_time_parser
maz
Awesome parser, thank you.
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