Built on iCal.Net for RFC 5545 recurrence rules, RecurringThings adds a persistence layer with multi-tenant isolation and efficient date range queries.

Features

• Multi-tenant isolation - TenantId and resource path scoping
• Efficient date range queries - Query only the events you need
• Transaction support - ACID operations via Transactional library

Installation

# Core library (required)
dotnet add package RecurringThings

# Choose ONE persistence provider:
dotnet add package RecurringThings.MongoDB
dotnet add package RecurringThings.PostgreSQL

Setup

Register RecurringThings in your Program.cs or Startup.cs:

// Using MongoDB
services.AddRecurringThings(builder =>
    builder.UseMongoDb((provider, options) =>
    {
        options.ConnectionString = "mongodb://localhost:27017";
        options.DatabaseName = "myapp";
        options.CollectionName = "mycalendar";
    }));

// Or using PostgreSQL
services.AddRecurringThings(builder =>
    builder.UsePostgreSql((provider, options) =>
    {
        options.ConnectionString = "Host=localhost;Database=myapp;Username=user;Password=pass";
    }));

The IServiceProvider parameter allows you to resolve services registered before AddRecurringThings, such as IOptions<T> or IConfiguration.

Then inject IRecurrenceEngine wherever you need it.

Usage

Create an event:

var evt = new CalendarEvent
{
    Uid = "meeting-123",
    Summary = "Weekly Standup",
    Start = new CalDateTime(2025, 1, 6, 9, 0, 0, "America/New_York"),
    Duration = TimeSpan.FromMinutes(30),
    RecurrenceRules = [new RecurrencePattern(FrequencyType.Weekly)]
};

await engine.CreateEventAsync(evt, "tenant-1", "user-abc", cancellationToken);

Query events:

var filter = EventFilter.Create()
    .ForUser("user-abc")
    .From(DateTime.UtcNow)
    .To(DateTime.UtcNow.AddMonths(1))
    .Build();

await foreach (var evt in engine.GetEventsAsync("tenant-1", filter).WithCancellation(cancellationToken))
{
    Console.WriteLine(evt.Summary);
}

Supported Databases

Provider	Documentation
MongoDB	RecurringThings.MongoDB
PostgreSQL	RecurringThings.PostgreSQL

License

Apache 2.0 - see LICENSE