CODEWITHSUNDEEP
timeelixirphoenix-framework
Incerteza
Incerteza

Reputation: 34884

Working with datetime in Elixir

I need to find a difference in minutes between the time from a database retrieved by Ecto and current time, in UTC. As far as I know, timing operating on Elixir aren't trivial without using third-party libraries such as Timex. I, however, want to avoid using third-party dependencies. So how can I find a time difference? I know I can get the current time by DateTime.utc_now(), but what's next, how to subtract a date-time from a database, which is in Ecto.DateTime format, from it?

Upvotes: 3

Views: 1908

Answers (1)

Harrison Lucas
Harrison Lucas

Reputation: 2961

I believe there are plans soon for Ecto to use the native Elixir Datetime format for the time being, I know your pain.

One solution is to convert the ecto date time to the erlang date time format:

{{YYYY, MM, DD}, {HH, MM, SS}}

And then compare that using the erlang calendar library. For example, say we had a Post model and we wanted to know how long ago it was updated:

Repo.Post.get!(%Post{}, 1).created_at
|> Ecto.DateTime.to_erl
|> :calendar.time_difference(:calendar.universal_time)

So let's say this post was created roughly 1 month ago (2016-10-25T10:24:23).

Running it through the above function would return:

{30, {17, 30, 53}}

Meaning 30 days, 17 hours, 30 minutes and 53 seconds ago.

You can easily from there destructure the tuple and take only the components you need (in your case the minutes).

E.g.

{_, {_h, minutes, _s}} = time_diff

Upvotes: 5

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