Convience method for converting from DateTime<FixedOffset> to UTC

[glennpierce]

Hi

Currently I am doing something like

let dt : DateTime = DateTime::parse_from_rfc3339("1970-01-01T00:00:00+00:00")?;
let dt_utc : DateTime = DateTime::::from_utc(dt.naive_utc(), UTC);

Is there any more convenient way todo this and vice versa ?

Thanks

[quodlibetor]

The fact that Utc is a type (and therefore can't depend on anything at run-time) means that it's impossible for methods on DateTime<FixedOffset> (which is where the parse_from_rfc3339 is implemented) to parse to a DateTime<Utc>.

However, we could probably implement either a DateTime<Utc>::parse_from_rfc3339() (or probably nicer a Utc::parse_from_rfc3339()) that does the parsing and auto-timezone conversion.

Doing that depends a bit on the philosophical outlook of this trait: whether we want to implement a whole bunch of kind-of-trivial ergonomic methods or if we want to keep the API surface small. We're currently thinking about the tradeoffs of the two philosophies.

[glennpierce]

Thanks

I can understand wanting to keep the api simple I guess. However, speaking from my experience from Python I would expect other crates that wrap chrono to popup eventually and I am not sure that is desirable.

The Python datetime library was difficult to work with and that lead to the "dateutil", "arrow", and "simple-date" wrapper libraries and probably more I don't know about.

[lilith]

I've spent about 30 minutes trying to figure out how to correctly convert between DateTime<Utc> and DateTime<FixedOffset>. I read the entire API documentation without enlightenment.

I support making that conversion obvious.

.with_timezone(&FixedOffset::east(0)) (UTC->Fixed) wasn't obvious. FixedOffset::zero() or ::utc() would have helped.

[Walther]

If a convenience method (e.g. FixedOffset::now()) would not be feasible, maybe the documentation could be improved? On a quick reading, the Readme seems to warmly suggest using FixedOffset as "it stores the most information and does not depend on the system environment". However, there's no instruction / example on how to properly use it.

EDIT: oops, misread the original issue, sorry. This comment is kind of tangential / unrelated.

[epipheus]

I also have to google around a long time and lucked upon finding this issue.

[djc]

I'm going to close this issue. The original request has been addressed with #806 in that you can now call parse_from_rfc3339() on DateTime<Utc>. Additionally, an impl From<DateTime<FixedOffset>> for DateTime<Utc> already exists.

However, I'm definitely open to the idea that ergonomic issues still exist here! In order to address those, please open a new issue with some example code of where you're running into trouble/a conversion that seems to require more complex code than what you feel is necessary.