Get Occurrences based on a RRULE FREQ=SECONDLY

[DaleyKD]

Does this library support getting occurrences if we use a secondly recurrence pattern?

Our project doesn't use this for calendar events, but more to help us determine when to run the next job (as part of our job scheduler). And SOME jobs need to run every 45 seconds or so.

I've been trying to get it to work, but have had no luck. It seems to work for FREQ=MINUTELY.

[axunonb]

@DaleyKD
We took over this project few days ago and are heavily working on all kinds of RRULEs. Please allow some time to get on top of things pending.
In the meantime maybe post the sample code that doesn't seem to work.

@minichma

Evaluator contains FREQ=SECONDLY

ical.net/Ical.Net/Evaluation/Evaluator.cs

Lines 62 to 64 in a0179f8

	case FrequencyType.Secondly:
	dt = old.AddSeconds(interval);
	break;

and RecurrencePattern contains comments for a fixed bug

ical.net/Ical.Net/DataTypes/RecurrencePattern.cs

Line 91 in a0179f8

// NOTE: Fixes bug #1924358 - Cannot evaluate Secondly patterns

Is RRULE FREQ=SECONDLY on our todo list?

[minichma]

I think, secondly should work, but it's disabled by default. There's a flag to control this.

ical.net/Ical.Net/Calendar.cs

Line 169 in a0179f8

public virtual RecurrenceRestrictionType RecurrenceRestriction

[axunonb]

[Test]
public void SecondlyRecurrence()
{
    var dateTime = DateTime.UtcNow;

    // Create a new calendar
    var calendar = new Calendar
    {
        RecurrenceRestriction = RecurrenceRestrictionType.NoRestriction
    };

    var calendarEvent = new CalendarEvent
    {
        Summary = "Recurring Event Every 45 Seconds",
        DtStart = new CalDateTime(dateTime),
        DtEnd = new CalDateTime(dateTime.AddHours(1)),
        RecurrenceRules = new List<RecurrencePattern>
        {
            new RecurrencePattern(FrequencyType.Secondly, 45)
        }
    };

    // Add the event to the calendar
    calendar.Events.Add(calendarEvent);

    // Serialize the calendar to an iCalendar string
    var serializer = new CalendarSerializer();
    var serializedCalendar = serializer.SerializeToString(calendar);

    // Evaluate the recurrences
    var occurrences = calendar.GetOccurrences(dateTime, dateTime.AddHours(1));
    // or
    // var occurrences = calendarEvent.GetOccurrences(dateTime, dateTime.AddHours(1));

    Assert.That(occurrences, Has.Count.EqualTo(80));
}

Serializes correctly:

BEGIN:VCALENDAR
PRODID:-//github.com/ical-org/ical.net//NONSGML ical.net 4.0//EN
VERSION:2.0
X-DDAY-ICAL-RECURRENCE-RESTRICTION:NoRestriction
BEGIN:VEVENT
DTEND:20241022T232551Z
DTSTAMP:20241022T222551Z
DTSTART:20241022T222551Z
RRULE:FREQ=SECONDLY;INTERVAL=45
SEQUENCE:0
SUMMARY:Recurring Event Every 45 Seconds
UID:888078c5-ff36-46cd-b16c-a6e1609e8c01
END:VEVENT
END:VCALENDAR

Fails here when calling GetOccurrences.

ical.net/Ical.Net/Evaluation/RecurrencePatternEvaluator.cs

Lines 181 to 191 in a0179f8

	case FrequencyType.Secondly:
	{
	switch (evaluationRestriction)
	{
	case RecurrenceRestrictionType.Default:
	case RecurrenceRestrictionType.RestrictSecondly:
	case RecurrenceRestrictionType.RestrictMinutely:
	case RecurrenceRestrictionType.RestrictHourly:
	throw new ArgumentException();
	}
	}

because variable evaluationRestriction is RecurrenceRestrictionType.Default although set with RecurrenceRestrictionType.NoRestriction.

[axunonb]

Closed in favor of #622