# rrule-go
Go library for working with recurrence rules for calendar dates.
[![Build Status](http://img.shields.io/travis/teambition/rrule-go.svg?style=flat-square)](https://travis-ci.org/teambition/rrule-go)
[![Coverage Status](http://img.shields.io/coveralls/teambition/rrule-go.svg?style=flat-square)](https://coveralls.io/r/teambition/rrule-go)
[![License](http://img.shields.io/badge/license-mit-blue.svg?style=flat-square)](https://raw.githubusercontent.com/teambition/rrule-go/master/LICENSE)
[![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](http://godoc.org/github.com/teambition/rrule-go)
The rrule module offers a complete implementation of the recurrence rules documented in the [iCalendar
RFC](http://www.ietf.org/rfc/rfc2445.txt). It is a partial port of the rrule module from the excellent [python-dateutil](http://labix.org/python-dateutil/) library.
## Demo
### rrule.RRule
```go
package main
import (
"fmt"
"time"
"github.com/teambition/rrule-go"
)
func printTimeSlice(ts []time.Time) {
for _, t := range ts {
fmt.Println(t)
}
}
func main() {
// 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.String())
// DTSTART:19970902T090000Z
// RRULE:FREQ=DAILY;COUNT=10
printTimeSlice(r.All())
// 1997-09-02 09:00:00 +0000 UTC
// 1997-09-03 09:00:00 +0000 UTC
// ...
// 1997-09-07 09:00:00 +0000 UTC
printTimeSlice(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]
// Every 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.String())
// DTSTART:19961105T090000Z
// RRULE:FREQ=YEARLY;INTERVAL=4;COUNT=3;BYMONTH=11;BYMONTHDAY=2,3,4,5,6,7,8;BYDAY=TU
printTimeSlice(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
```go
func ExampleSet() {
// Daily, 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.String())
// DTSTART:19970902T090000Z
// RRULE:FREQ=DAILY;COUNT=7
printTimeSlice(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
// Weekly, 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.String())
// DTSTART:19970902T090000Z
// RRULE:FREQ=WEEKLY;COUNT=4
// RDATE:19970907T090000Z
// EXDATE:19970916T090000Z
printTimeSlice(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
```go
func ExampleStrToRRule() {
// Compatible with old DTSTART
r, _ := rrule.StrToRRule("FREQ=DAILY;DTSTART=20060101T150405Z;COUNT=5")
fmt.Println(r.OrigOptions.RRuleString())
// FREQ=DAILY;COUNT=5
fmt.Println(r.OrigOptions.String())
// DTSTART:20060101T150405Z
// RRULE:FREQ=DAILY;COUNT=5
fmt.Println(r.String())
// DTSTART:20060101T150405Z
// RRULE:FREQ=DAILY;COUNT=5
printTimeSlice(r.All())
// 2006-01-01 15:04:05 +0000 UTC
// 2006-01-02 15:04:05 +0000 UTC
// 2006-01-03 15:04:05 +0000 UTC
// 2006-01-04 15:04:05 +0000 UTC
// 2006-01-05 15:04:05 +0000 UTC
}
```
### rrule.StrToRRuleSet
```go
func ExampleStrToRRuleSet() {
s, _ := rrule.StrToRRuleSet("DTSTART:20060101T150405Z\nRRULE:FREQ=DAILY;COUNT=5\nEXDATE:20060102T150405Z")
fmt.Println(s.String())
// DTSTART:20060101T150405Z
// RRULE:FREQ=DAILY;COUNT=5
// EXDATE:20060102T150405Z
printTimeSlice(s.All())
// 2006-01-01 15:04:05 +0000 UTC
// 2006-01-03 15:04:05 +0000 UTC
// 2006-01-04 15:04:05 +0000 UTC
// 2006-01-05 15:04:05 +0000 UTC
}
```
For more examples see [python-dateutil](http://labix.org/python-dateutil/) documentation.
## License
Gear is licensed under the [MIT](https://github.com/teambition/gear/blob/master/LICENSE) license.
Copyright © 2017-2022 [Teambition](https://www.teambition.com).