Crontab Expression Parser and Driver

Overview

This library provides functionalities to calculate the next timestamp matching a given crontab pattern.

Usage

cargo add cronexpr

fn main() {
    // with jiff timestamp
    let timestamp = jiff::Timestamp::from_str("2024-01-01T00:00:00+08:00").unwrap();
    let driver = cronexpr::Driver::with_timestamp("0 0 1 1 * Asia/Shanghai", timestamp).unwrap();
    assert_eq!(driver.find_next_timestamp().unwrap().as_millisecond(), 1735660800000);

    // for compatibility, bridge by timestamp milliseconds (crontab support at most second level so it's fine)
    let driver = cronexpr::Driver::with_timestamp_millis("2 4 * * * Asia/Shanghai", 1704038400000).unwrap();
    assert_eq!(driver.find_next_timestamp_millis().unwrap(), 1704052920000);

    // can also be used as an iterator
    let mut driver = cronexpr::Driver::with_timestamp_millis("2 4 * * * Asia/Shanghai", 1704038400000).unwrap();
    assert_eq!(driver.next_timestamp_millis().unwrap(), 1704052920000);
    assert_eq!(driver.next_timestamp_millis().unwrap(), 1704139320000);
    assert_eq!(driver.next_timestamp_millis().unwrap(), 1704225720000);
}