Convert UTC RFC3339 Timestamp to Local Time with the time crate

Question

I've been banging my head against the time crate for the last two days. I can't find, where in their documentation how to take a RFC3339 UTC 2022-12-28T02:11:46Z timestamp and convert that to local time for America/New_York (2022-12-27T21:11:46). I stepped away from using the chrono crate on advise that there is/was a vulnerability and it's not very well maintained as it once was. Chrono also depends on time but in the 0.1.x branch of it.

My cargo.toml includes the line time = { version = "0.3", features = ["macros", "parsing", "local-offset"] } so enable the features I think I need.

use time::{format_description::well_known::Rfc3339, PrimitiveDateTime};


/// The paramater zulu would be a RFC3339 formatted string.
///
/// ```
/// #use time::{format_description::well_known::Rfc3339, PrimitiveDateTime};
/// assert_eq!("2022-12-27T21:11:46", date_time_local("2022-12-28T02:11:46Z".to_string()));
/// ```
fn date_time_local(zulu: &String) -> String {
    match PrimitiveDateTime::parse(zulu, &Rfc3339) {
        Ok(local) => local.to_string(),
        Err(..) => zulu.to_owned(),
    }
}

I'm having no such luck here.

Answer 1

fn main() {
    assert_eq!("2022-12-27 21:11:46", date_time_local(&"2022-12-28T02:11:46Z".to_string()));
}

/// The parameter zulu should be a RFC3339 formatted string.
/// This converts that Zulu timestamp into a local timestamp.
/// ```
/// assert_eq!("2022-12-27 21:11:46", date_time_local("2022-12-28T02:11:46Z".to_string()));
/// ```
fn date_time_local(zulu: &String) -> String {
    use time::{format_description::well_known::Rfc3339, PrimitiveDateTime, UtcOffset};

    // Determine Local TimeZone
    let utc_offset = match UtcOffset::current_local_offset() {
        Ok(utc_offset) => utc_offset,
        Err(..) => return zulu.to_owned(),
    };

    // Parse the given zulu paramater.
    let zulu_parsed = match PrimitiveDateTime::parse(zulu, &Rfc3339) {
        Ok(zulu_parsed) => zulu_parsed.assume_utc(),
        Err(..) => return zulu.to_owned(),
    };

    // Convert zulu to local time offset.
    let parsed = zulu_parsed.to_offset(utc_offset);

    format!(
        "{:04}-{:02}-{:02} {:02}:{:02}:{:02}",
        parsed.year(),
        parsed.month() as u8,
        parsed.day(),
        parsed.hour(),
        parsed.minute(),
        parsed.second()
    )
}

With a slight change that I removed the T between the date and the time.