A cron expression parser. Works with stable Rust v1.28.0.
The project is based on zslayton/cron, thank him very much.
In addition to the regular expressions, you can also use the following shortcut expressions with Schedule::from_str, such as @yearly @monthly @weekly @daily @hourly @minutely @secondly, make cron- Expression Iterator.
If you need a periodicized task manager, you may need delay-timer (Time-manager of delayed tasks. Like crontab, but synchronous asynchronous tasks are possible, and dynamic add/cancel/remove is supported) .
```rust extern crate cron; extern crate chrono;
use cron::Schedule; use chrono::Utc; use std::str::FromStr;
fn main() { // sec min hour day of month month day of week year let expression = "0 30 9,12,15 1,15 May-Aug Mon,Wed,Fri 2018/2"; let schedule = Schedule::from_str(expression).unwrap(); println!("Upcoming fire times:"); for datetime in schedule.upcoming(Utc).take(10) { println!("-> {}", datetime); } }
/* Upcoming fire times: -> 2018-06-01 09:30:00 UTC -> 2018-06-01 12:30:00 UTC -> 2018-06-01 15:30:00 UTC -> 2018-06-15 09:30:00 UTC -> 2018-06-15 12:30:00 UTC -> 2018-06-15 15:30:00 UTC -> 2018-08-01 09:30:00 UTC -> 2018-08-01 12:30:00 UTC -> 2018-08-01 15:30:00 UTC -> 2018-08-15 09:30:00 UTC */ ```
shortcut expressions & ScheduleIteratorOwned``` rust extern crate chrono; extern crate cron_clock;
use cron_clock::Schedule; use chrono::Utc; use std::str::FromStr;
fn main() {
// shortcut expressions
let expression = "@hourly";
let schedule = Schedule::fromstr(expression).unwrap();
println!("Upcoming fire times:");
// upcoming_owned Get iterators with ownership, so you don't have lifetime to worry about.
for datetime in schedule.upcomingowned(Utc).take(10) {
println!("-> {}", datetime);
}
}
```