Table of Contents

Ploch.Common.AppServices

Abstractions for common cross-cutting application services, starting with user identity resolution.

Overview

Ploch.Common.AppServices defines the service contracts that application code depends on for platform-independent operations. The package intentionally contains only interfaces, keeping it free of any runtime dependency (no ASP.NET Core, no MAUI, no WPF). Concrete implementations live in separate companion packages such as Ploch.Common.AppServices.Web.

The current release exposes a single abstraction: IUserInfoProvider, which returns the current user as a ClaimsPrincipal. This allows business logic and use-case classes to resolve the acting user without coupling to HttpContext, IHttpContextAccessor, or any other host-specific type.

Additional cross-cutting service abstractions are expected to be added to this package over time, following the same pattern of interface-only definitions with implementations in companion packages.

Installation

dotnet add package Ploch.Common.AppServices

Key Types

Type Kind Description
IUserInfoProvider Interface GetCurrentUserInfo() — returns the current ClaimsPrincipal? or null if no user is authenticated. Located in the Ploch.Common.AppServices.Security namespace.

Usage Examples

Consuming the abstraction in a use case

public class CreateBlogPostUseCase(
    IReadWriteRepositoryAsync<BlogPost, int> repository,
    IUserInfoProvider userInfoProvider)
{
    public async Task<BlogPost> ExecuteAsync(CreateBlogPostRequest request, CancellationToken ct)
    {
        var user = userInfoProvider.GetCurrentUserInfo();
        var authorName = user?.Identity?.Name ?? "Anonymous";

        var post = new BlogPost
        {
            Title = request.Title,
            Contents = request.Contents,
            Author = authorName
        };

        return await repository.AddAsync(post, ct);
    }
}

Registering a custom implementation

For environments other than ASP.NET Core (e.g. a background service with a thread-local principal), provide your own implementation:

public class ThreadPrincipalUserInfoProvider : IUserInfoProvider
{
    public ClaimsPrincipal? GetCurrentUserInfo() => Thread.CurrentPrincipal as ClaimsPrincipal;
}

// Registration:
services.AddSingleton<IUserInfoProvider, ThreadPrincipalUserInfoProvider>();
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