rrules

RRules

A blazing fast and memory efficient library to manage recurrence rules inspired by the standards from RFC-5547. It provides the ability to define recurrence rules for events, and then iterate over them to get the dates that match the recurrence rules.

How to use it

The easiest way to use this library is to start by loading a Recurrence instance from a string following the standards:

Loading from string

Required attributes:

FREQ
- Defines the type of frequency (E.g. DAILY, WEEKLY, MONTHLY, etc)
INTERVAL
- Defines the interval of the frequency (E.g. every 2 days, every 3 months, etc)
DTSTART
- Defines the start date of the recurrence

Examples:

```rust // Daily recurrence example:

use std::str::FromStr; use chrono::{DateTime, Utc}; use rrules::Recurrence;

let recurrence = Recurrence::from_str("FREQ=DAILY;INTERVAL=1;DTSTART=2023-01-01T12:00:00Z").unwrap();

// You can then use the Recurrence as an iterator by looping over it or collecting the results into a Vec

for event in recurrence.clone().take(100) { // cloning to avoid moving the iterator // ... } // or let events: Vec> = recurrence.take(100).collect();

```

The Recurrence struct is an iterator that will yield all the dates that match the recurrence rules defined.

How to use it with structs definition

To define a recurrence rule, start by creating the desired frequency rule definition:

```rust use chrono::{Duration, Utc}; use rrules::Frequency; use rrules::Recurrence;

let daily = Frequency::Daily { interval: 1, by_time: vec![], };

// Then, create a Recurrence with the frequency defined:

let recurrence = Recurrence::new( daily, Utc::now(), // start date Some(Utc::now() + Duration::days(1)), // end date Some(Duration::hours(1)), // duration (optional ); ```

The end attribute of a Recurrence is optional, and if not specified, it will yield events until the MAX_DATE.

The MAX_DATE is defined as 9999-12-31T23:59:59Z

The duration attribute of a Recurrence is optional, and if not specified, it will use the default as 0 seconds Duration::seconds(0).

Attribute standards

| Attribute | Description | Example | |------------|----------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------| | FREQ | Defines the type of frequency (E.g. DAILY, WEEKLY, MONTHLY, etc) | FREQ=DAILY | | INTERVAL | Defines the interval of the frequency (E.g. every 2 days, every 3 months, etc) | INTERVAL=2 | | DTSTART | Defines the start date of the recurrence | DTSTART=2023-01-01T12:00:00Z | | DTEND | Defines the end date of the recurrence | DTEND=2023-01-01T12:00:00Z | | DURATION | Defines the duration of the recurrence | DURATION=PT1H | | BYDAY | Defines the days of the week that the recurrence will happen | BYDAY=MO,TU -> When FREQ=WEEKLY; BYDAY=1MO,3WE -> When FREQ=MONTHLY | | BYMONTHDAY | Defines the days of the month that the recurrence will happen | BYMONTHDAY=1,2,3,4, etc | | BYMONTH | Defines the months of the year that the recurrence will happen | BYMONTH=1,2,3,4,5,6,7,8,9,10,11,12 |

Supported recurrence rule types + examples

Current supporting recurrence rules:

Secondly
minutely
hourly
Daily
Weekly
Monthly
- By month day
- By nth weekday
Yearly
- By day
- By month day