Meziantou.Framework.Scheduling 4.0.2

Meziantou.Framework.Scheduling

This package supports 2 schedule formats:

• Recurrence rules (RRULE) as defined in RFC5545 and RFC2445
• Cron expressions

Recurrence rules (RRULE)

Parse recurrence rules:

var rrule = "FREQ=DAILY;UNTIL=20000131T140000Z;BYMONTH=1";
if (RecurrenceRule.TryParse(rrule, out var rule, out var error))
{
    var nextOccurrences = rule.GetNextOccurrences(DateTime.Now).Take(50).ToArray();
}

Convert a recurrence rule to human-readable text:

var culture = CultureInfo.GetCultureInfo("en-US");
RecurrenceRule.Parse("FREQ=DAILY").GetHumanText(culture); // every day
RecurrenceRule.Parse("FREQ=WEEKLY;INTERVAL=3;BYDAY=TU;UNTIL=20150101").GetHumanText(culture); // every 3 weeks on Tuesday until January 1, 2015

Supported languages for human-readable text:

• English (en, en-*, and invariant culture)
• French (fr, fr-*)

Cron expressions

The library also provides CronExpression to parse and evaluate cron schedules.

var cron = CronExpression.Parse("0 */15 * * * *");
var occurrences = cron.GetNextOccurrences(DateTime.Now).Take(10).ToArray();

Supported formats

• 5 fields: minute hour day-of-month month day-of-week
• 6 fields: second minute hour day-of-month month day-of-week
• 7 fields: second minute hour day-of-month month day-of-week year

When using the 5-field format, seconds are implicitly set to 0.

Field ranges

• second: 0-59
• minute: 0-59
• hour: 0-23
• day-of-month: 1-31
• month: 1-12 or JAN-DEC
• day-of-week: 0-6 or SUN-SAT (0 = Sunday)
• year (optional): 1970-2099

Operators and special values

For all fields:

• * or ?: any value
• a,b,c: list
• a-b: range
• */n: step from field minimum
• a-b/n: stepped range
• a/n: step starting at a

Day-of-month field additionally supports:

• L: last day of month
• L-n: nth day before end of month (for example L-2)
• LW: last weekday of month
• nW: nearest weekday to day n

Day-of-week field additionally supports:

• nL: last occurrence of weekday n in month
• n#m: m-th occurrence of weekday n in month (m in 1-5)

Predefined schedules

• @yearly / @annually
• @monthly
• @weekly
• @daily / @midnight
• @hourly

Notes

• Parsing is case-insensitive for month/day names and predefined schedules.
• day-of-month and day-of-week are combined with AND semantics. A date must satisfy both fields to match.