rrule-go

Go library for working with recurrence rules for calendar dates.

The rrule module offers a complete implementation of the recurrence rules documented in the iCalendar RFC. It is a partial port of the rrule module from the excellent python-dateutil library.

Demo

rrule.RRule

package main

import (
  "fmt"
  "time"
  "github.com/teambition/rrule-go"
)
func exampleRRule() {
    fmt.Println("Daily, for 10 occurrences.")
    r, _ := rrule.NewRRule(rrule.ROption{
        Freq:    rrule.DAILY,
        Count:   10,
        Dtstart: time.Date(1997, 9, 2, 9, 0, 0, 0, time.UTC)})
    fmt.Println(r.All())
    // [1997-09-02 09:00:00 +0000 UTC
    //  1997-09-03 09:00:00 +0000 UTC
    //  1997-09-04 09:00:00 +0000 UTC
    //  ...
    //  1997-09-11 09:00:00 +0000 UTC]
fmt.Println(r.Between(
    time.Date(1997, 9, 6, 0, 0, 0, 0, time.UTC),
    time.Date(1997, 9, 8, 0, 0, 0, 0, time.UTC), true))
// [1997-09-06 09:00:00 +0000 UTC
//  1997-09-07 09:00:00 +0000 UTC]

fmt.Println(r)
// DTSTART:19970902T090000Z
// FREQ=DAILY;COUNT=10

fmt.Println("\nEvery four years, the first Tuesday after a Monday in November, 3 occurrences (U.S. Presidential Election day).")
r, _ = rrule.NewRRule(rrule.ROption{
    Freq:       rrule.YEARLY,
    Interval:   4,
    Count:      3,
    Bymonth:    []int{11},
    Byweekday:  []rrule.Weekday{rrule.TU},
    Bymonthday: []int{2, 3, 4, 5, 6, 7, 8},
    Dtstart:    time.Date(1996, 11, 5, 9, 0, 0, 0, time.UTC)})
fmt.Println(r.All())
// [1996-11-05 09:00:00 +0000 UTC
//  2000-11-07 09:00:00 +0000 UTC
//  2004-11-02 09:00:00 +0000 UTC]
}

rrule.Set

func exampleRRuleSet() {
    fmt.Println("\nDaily, for 7 days, jumping Saturday and Sunday occurrences.")
    set := rrule.Set{}
    r, _ := rrule.NewRRule(rrule.ROption{
        Freq:    rrule.DAILY,
        Count:   7,
        Dtstart: time.Date(1997, 9, 2, 9, 0, 0, 0, time.UTC)})
    set.RRule(r)
    fmt.Println(set.All())
    // [1997-09-02 09:00:00 +0000 UTC
    //  1997-09-03 09:00:00 +0000 UTC
    //  1997-09-04 09:00:00 +0000 UTC
    //  1997-09-05 09:00:00 +0000 UTC
    //  1997-09-06 09:00:00 +0000 UTC
    //  1997-09-07 09:00:00 +0000 UTC
    //  1997-09-08 09:00:00 +0000 UTC]

fmt.Println("\nWeekly, for 4 weeks, plus one time on day 7, and not on day 16.")
set = rrule.Set{}
r, _ = rrule.NewRRule(rrule.ROption{
    Freq:    rrule.WEEKLY,
    Count:   4,
    Dtstart: time.Date(1997, 9, 2, 9, 0, 0, 0, time.UTC)})
set.RRule(r)
set.RDate(time.Date(1997, 9, 7, 9, 0, 0, 0, time.UTC))
set.ExDate(time.Date(1997, 9, 16, 9, 0, 0, 0, time.UTC))
fmt.Println(set.All())
// [1997-09-02 09:00:00 +0000 UTC
//  1997-09-07 09:00:00 +0000 UTC
//  1997-09-09 09:00:00 +0000 UTC
//  1997-09-23 09:00:00 +0000 UTC]
}

rrule.StrToRRule

func exampleStrToRRule() {
    fmt.Println()
    r, _ := rrule.StrToRRule("FREQ=DAILY;INTERVAL=10;COUNT=5")
    fmt.Println(r.All())
    // [2020-10-12 02:26:35 +0000 UTC
    //  2020-10-22 02:26:35 +0000 UTC
    //  2020-11-01 02:26:35 +0000 UTC
    //  2020-11-11 02:26:35 +0000 UTC
    //  2020-11-21 02:26:35 +0000 UTC]
}

rrule.StrToRRuleSet

func exampleStrToRRuleSet() {
    s, _ := rrule.StrToRRuleSet(`RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5
RDATE:20060102T150405Z`)
    fmt.Println(s.All())
    // [2006-01-02 15:04:05 +0000 UTC
    //  2020-10-12 02:26:35 +0000 UTC
    //  2020-10-22 02:26:35 +0000 UTC
    //  2020-11-01 02:26:35 +0000 UTC
    //  2020-11-11 02:26:35 +0000 UTC
    //  2020-11-21 02:26:35 +0000 UTC]
}

For more examples see python-dateutil documentation.

License

Gear is licensed under the MIT license. Copyright © 2017-2020 Teambition.