🧩 Implementing a Lightweight Query Handler in .NET using GMediator fully free for commerical use

In modern .NET applications, maintaining clean architecture is critical — and that’s where the Mediator pattern shines. It decouples the request/response flow and promotes separation of concerns.

While libraries like MediatR are popular, sometimes you want something even lighter — with zero dependencies.

Enter: GMediator, a custom lightweight mediator implementation.

🚀 What We’ll Build
In this blog, we’ll create a simple GET API using GMediator that returns a list of products stored in an in-memory store — no database, no ORM — just the core pattern in action.
🧱 Step 1: Define the Product Model

Code Snippet

public class Product { public Guid Id { get; set; } = Guid.NewGuid(); public string Name { get; set; } public decimal Price { get; set; } }

💾 Step 2: Create an In-Memory Store

Code Snippet

public static class ProductStore { public static List<Product> Products { get; set; } = new() { new Product { Name = "Laptop", Price = 1200 }, new Product { Name = "Mouse", Price = 20 }, new Product { Name = "Keyboard", Price = 45 } }; }

📬 Step 3: Create the Query Request

Code Snippet

using GMediator.Interfaces; public class GetAllProducts : IRequest<List<Pro>> { } public class Pro { public Guid Id { get; set; } = Guid.NewGuid(); public string Name { get; set; } public decimal Price { get; set; } } 🧠 Step 4: Implement the Query Handler using GMediator.Interfaces; public class GetAllProductsHandler : IRequestHandler<GetAllProducts, List<Pro>> { public Task<List<Pro>> Handle(GetAllProducts request, CancellationToken cancellationToken) { var products = ProductStore.Products .Select(x => new Pro { Id = x.Id, Name = x.Name, Price = x.Price }) .ToList(); // Important: convert to List<Pro> return Task.FromResult(products); } }

🎯 Step 5: Create the Controller

Code Snippet

[ApiController] [Route("api/[controller]")] public class ProductsController : ControllerBase { private readonly IMediator _mediator; public ProductsController(IMediator mediator) { _mediator = mediator; } [HttpGet] public async Task<IActionResult> Get() { var products = await _mediator.Send(new GetAllProducts()); return Ok(products); } }

🧪 Step 6: Register GMediator in Program.cs

Code Snippet

builder.Services.AddGMediator(); // Register your custom GMediator

💡 Final Thoughts
GMediator is a great option for internal projects, low-dependency APIs, or learning the Mediator pattern hands-on.
You can extend this by adding Create, Update, Delete, or integrating with a real database like SQLite or SQL Server.

Building a Scalable .NET Backend Using Clean Architecture (With Optional Layers) in just an second

If you're building a new .NET backend, Clean Architecture is the best way to keep your code organized, scalable, and future-proof.
🧱 What is Clean Architecture?
It's a way to structure your project into layers:
Domain – core business models
Application – commands, queries, interfaces
Infrastructure – external services (API, logging, etc.)
Persistence – database (EF Core, SQL)
API – controllers
Tests – optional unit/integration tests
⚙️ Script-Based Setup
You can auto-generate this structure using a simple CMD script.
✅ You choose what to include:
Want Infrastructure? Type y
Need Tests? Type n
Want to skip Persistence? Type n




Steps To use:

1. use notepad save below code as setup-architecture.cmd

Code Snippet

@echo off SETLOCAL ENABLEEXTENSIONS :: Prompt for solution name set /p SOLUTION_NAME=Enter your solution name (e.g., ResumeAI.Optimizer): :: Prompt for optional layers set /p ADD_TESTS=Do you want to add a Tests project? (y/n): set /p ADD_PERSISTENCE=Do you want to add a Persistence layer? (y/n): set /p ADD_INFRASTRUCTURE=Do you want to add an Infrastructure layer? (y/n): :: Create Solution echo Creating solution... dotnet new sln -n %SOLUTION_NAME% :: Create Base Projects dotnet new webapi -n %SOLUTION_NAME%.API dotnet new classlib -n %SOLUTION_NAME%.Application dotnet new classlib -n %SOLUTION_NAME%.Domain :: Optional Projects if /i "%ADD_INFRASTRUCTURE%"=="y" ( dotnet new classlib -n %SOLUTION_NAME%.Infrastructure ) if /i "%ADD_PERSISTENCE%"=="y" ( dotnet new classlib -n %SOLUTION_NAME%.Persistence ) if /i "%ADD_TESTS%"=="y" ( dotnet new xunit -n %SOLUTION_NAME%.Tests ) :: Add Projects to Solution echo Adding projects to solution... dotnet sln add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj dotnet sln add .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj dotnet sln add .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj if /i "%ADD_INFRASTRUCTURE%"=="y" ( dotnet sln add .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj ) if /i "%ADD_PERSISTENCE%"=="y" ( dotnet sln add .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj ) if /i "%ADD_TESTS%"=="y" ( dotnet sln add .\%SOLUTION_NAME%.Tests\%SOLUTION_NAME%.Tests.csproj ) :: Add Project References echo Adding project references... :: API references dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference ^ .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^ .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj if /i "%ADD_INFRASTRUCTURE%"=="y" ( dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj ) if /i "%ADD_PERSISTENCE%"=="y" ( dotnet add .\%SOLUTION_NAME%.API\%SOLUTION_NAME%.API.csproj reference .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj ) :: Application references Domain dotnet add .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj reference .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj :: Infrastructure and Persistence references if /i "%ADD_INFRASTRUCTURE%"=="y" ( dotnet add .\%SOLUTION_NAME%.Infrastructure\%SOLUTION_NAME%.Infrastructure.csproj reference ^ .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^ .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj ) if /i "%ADD_PERSISTENCE%"=="y" ( dotnet add .\%SOLUTION_NAME%.Persistence\%SOLUTION_NAME%.Persistence.csproj reference ^ .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ^ .\%SOLUTION_NAME%.Domain\%SOLUTION_NAME%.Domain.csproj ) :: Test references if /i "%ADD_TESTS%"=="y" ( dotnet add .\%SOLUTION_NAME%.Tests\%SOLUTION_NAME%.Tests.csproj reference ^ .\%SOLUTION_NAME%.Application\%SOLUTION_NAME%.Application.csproj ) echo. echo ✅ Clean Architecture setup completed for %SOLUTION_NAME%! echo. ENDLOCAL pause

2. save this file in respective folder where u want your project files
3. open cmd at this location and run this script by just type its name only that is setup-architecture.cmd