Remora.Extensions.Options.Immutable

This package provides an extension to Microsoft.Extensions.Options, allowing the use of immutable types (such as records) in the options ecosystem.

The extension takes a simple and direct approach to integration with the existing Microsoft-provided extension, adding only the minimal API necessary to achieve feature parity.

Usage

Usage is simple - immutable option types may be configured in a practically identical manner to mutable types, provided one of the following conditions are true:

• The type defines a parameterless constructor
• The type defines a constructor where all arguments are optional
• The type is explicitly initialized with a root state

That is, given the following types,

public record ExplicitOptions(string Value, bool Flag);
public record ParameterlessOptions()
{
    public string? Value { get; init; }
}
public record AllOptionalOptions(string Value = "initial", bool Flag = true");

they may be utilized in the following manner:

var services = new ServiceCollection()
    .Configure(() => new ExplicitOptions("initial", true))
    .Configure<ExplicitOptions>(opt => opt with { Flag = false });

var services = new ServiceCollection()
    .Configure<ParameterlessOptions>(opt => opt with { Value = "configured" });

var services = new ServiceCollection()
    .Configure<AllOptionalOptions>(opt => opt with { Flag = false });

All the various normal configuration calls, such as Configure, PostConfigure, ConfigureAll, and PostConfigureAll (along with their named) variants are supported.

Installation

Get it on NuGet!