Seeking Guidance: Using iCal.net with a database / EF

[hardcodet]

I'm currently designing an API that will have to maintain a lot of resource allocations, and was thinking about leveraging standards like iCal to manage those (at the end of the day, I need to visualize everything in a calendar-like UI anyway).

iCal.net looks mature, but glancing at the API, it seems to be working mostly on top of files / streams, which implies that the calendar is loaded in full into memory? I'd rather have entries in a database, query them based on start/end times and then do further processing to determine the actual slots - reading the full calendar is not an option.

Is that something ICal is a good fit, or would that lead to hackery? To my surprise, I didn't find any discussions on that very topic. How are you dealing with big / complex calendars in your APIs?

Thanks for your advice :)
Philipp

[axunonb]

iCal.net looks mature

Yes, we think it is.

working mostly on top of files / streams, which implies that the calendar is loaded in full into memory

Correct.

query them based on start/end times

As long you're not working with recurrence this should be quite straightforward

dealing with big / complex calendars

Complex calendars are not necessarily the big ones. Complexity rather comes from recurrence, DST transitions, timezones, the number of iCalendar components et al.

ICal is a good fit

It depends. If in-memory processing is a show stopper, it's not, just because other ways are not what the current architecture supports.

[hardcodet]

Thanks for the quick reply (and sorry for putting the question in the wrong place)!

We will have recurrences and all that. But I guess if my calendar entries were serialized into a DB, i could still get all relevant entries for the current week (or whatever is in focus), which would be all entries where the start / end date somehow overlaps with the current week. That would probably be in the low thousands (absolutely worst case) that I could put into a calendar for further processing.

Does that sound like a feasible approach, or would I rather roll my own (which is feasible, as I'd only need a subset of the functionality offered here)?

[axunonb]

Not sure whether a calendar with 5,000 events comes close to what you have in mind:

// * Summary *

BenchmarkDotNet v0.14.0, Windows 11 (10.0.26100.3476)
13th Gen Intel Core i7-13700K, 1 CPU, 24 logical and 16 physical cores
.NET SDK 9.0.201
  [Host] : .NET 8.0.14 (8.0.1425.11118), X64 RyuJIT AVX2

Toolchain=InProcessNoEmitToolchain

| Method         | Mean     | Error    | StdDev   | Gen0      | Gen1      | Gen2      | Allocated |
|--------------- |---------:|---------:|---------:|----------:|----------:|----------:|----------:|
| CreateCalendar | 63.51 ms | 1.006 ms | 0.892 ms | 3666.6667 | 3555.5556 | 1111.1111 |  41.47 MB |
| GetOccurrences | 31.69 ms | 0.624 ms | 1.077 ms | 2125.0000 | 1312.5000 |  125.0000 |  30.61 MB |

[MemoryDiagnoser]
public class BigCalendarTests
{
    private Calendar? _calendar = null;

    [GlobalSetup]
    public void Setup()
    {
        CreateCalendar();
    }

    [Benchmark]
    public void CreateCalendar()
    {
        // Create a new calendar
        _calendar = new Calendar();

        // Add 5000 events to the calendar
        for (var i = 0; i < 5000; i++)
        {
            var calEvent = new CalendarEvent
            {
                Summary = $"Event {i + 1}",
                Description = $"Description for event {i + 1}",
                Start = CalDateTime.Now.AddDays(i),
                End = CalDateTime.Now.AddDays(i).AddHours(1),
                Location = $"Location {i + 1}",
                Uid = Guid.NewGuid().ToString()
            };
            _calendar.Events.Add(calEvent);
        }
    }

    [Benchmark]
    public void GetOccurrences()
    {
        _ = _calendar!.GetOccurrences<CalendarEvent>().ToList();
    }
}