Meridian

Meridian is a lightweight, framework-style toolset for .NET applications:

• Meridian.Mapping for high-performance object-to-object mapping
• Meridian.Mediator for CQRS-style in-process request/response, notifications, and streams

Simple Setup

The shortest useful mediator setup is:

using Meridian.Mediator.Extensions;
using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();

services.AddMeridianMediator(cfg =>
{
    cfg.RegisterServicesFromAssemblyContaining<Program>();
});

Use the focused abstractions from DI depending on what you need:

var sender = provider.GetRequiredService<ISender>();
var publisher = provider.GetRequiredService<IPublisher>();
var streamSender = provider.GetRequiredService<IStreamSender>();

For pipeline registration, prefer the explicit APIs:

services.AddMeridianMediator(cfg =>
{
    cfg.RegisterServicesFromAssemblyContaining<Program>();
    cfg.AddBehavior<MyClosedBehavior>();
    cfg.AddStreamBehavior<MyClosedStreamBehavior>();
    cfg.AddOpenBehavior(typeof(MyOpenBehavior<,>));
    cfg.AddOpenStreamBehavior(typeof(MyOpenStreamBehavior<,>));
});

AddBehavior(Type, Type, ...) and AddStreamBehavior(Type, Type) remain only as compatibility shims. Prefer the typed or explicit closed-registration APIs for new code.

Getting Started

Install from NuGet once published:

dotnet add package Meridian.Mapping
dotnet add package Meridian.Mediator

Samples

This repo includes architecture-focused samples to show different ways to structure a project with the same core primitives:

Sample	Architecture Style	Focus
samples/Meridian.QuickStart	Minimal Consumer	Smallest end-to-end setup for mediator + mapping
samples/Meridian.Showcase	Baseline	End-to-end mapping + mediator feature showcase
samples/Meridian.CleanArchitecture	Clean Architecture	Domain/use-case boundaries, repository abstraction, transactional command flow
samples/Meridian.ModularMonolith	Modular Monolith	Module-level service registration and cross-module notifications
samples/Meridian.VerticalSlice	Vertical Slice	Feature-first request grouping with per-slice handlers and validation
samples/Meridian.EventDrivenCqrs	Event-Driven CQRS	Write/read split using commands, notifications, and timeline stream

Run a sample:

dotnet run --project samples/Meridian.CleanArchitecture/Meridian.CleanArchitecture.csproj

Testing

From repository root:

dotnet restore Meridian.sln
dotnet build Meridian.sln -c Release
dotnet test Meridian.sln -c Release

Validate every sample:

dotnet run --project samples/Meridian.QuickStart/Meridian.QuickStart.csproj -c Release
dotnet run --project samples/Meridian.Showcase/Meridian.Showcase.csproj -c Release
dotnet run --project samples/Meridian.CleanArchitecture/Meridian.CleanArchitecture.csproj -c Release
dotnet run --project samples/Meridian.ModularMonolith/Meridian.ModularMonolith.csproj -c Release
dotnet run --project samples/Meridian.VerticalSlice/Meridian.VerticalSlice.csproj -c Release
dotnet run --project samples/Meridian.EventDrivenCqrs/Meridian.EventDrivenCqrs.csproj -c Release

Preparing NuGet Packages

dotnet pack src/Meridian.Mapping/Meridian.Mapping.csproj -c Release --output ./artifacts
dotnet pack src/Meridian.Mediator/Meridian.Mediator.csproj -c Release --output ./artifacts
dotnet nuget push ./artifacts/Meridian.Mapping.*.nupkg --source https://api.nuget.org/v3/index.json --api-key <API_KEY>
dotnet nuget push ./artifacts/Meridian.Mediator.*.nupkg --source https://api.nuget.org/v3/index.json --api-key <API_KEY>