MediatR 12.3.0

MediatR

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Simple mediator implementation in .NET

In-process messaging with no dependencies.

Supports request/response, commands, queries, notifications and events, synchronous and async with intelligent dispatching via C# generic variance.

Examples in the wiki.

Installing MediatR

You should install MediatR with NuGet:

Install-Package MediatR

Or via the .NET Core command line interface:

dotnet add package MediatR

Either commands, from Package Manager Console or .NET Core CLI, will download and install MediatR and all required dependencies.

Using Contracts-Only Package

To reference only the contracts for MediatR, which includes:

  • IRequest (including generic variants)
  • INotification
  • IStreamRequest

Add a package reference to MediatR.Contracts

This package is useful in scenarios where your MediatR contracts are in a separate assembly/project from handlers. Example scenarios include:

  • API contracts
  • GRPC contracts
  • Blazor

Registering with IServiceCollection

MediatR supports Microsoft.Extensions.DependencyInjection.Abstractions directly. To register various MediatR services and handlers:

services.AddMediatR(cfg => cfg.RegisterServicesFromAssemblyContaining<Startup>());

or with an assembly:

services.AddMediatR(cfg => cfg.RegisterServicesFromAssembly(typeof(Startup).Assembly));

This registers:

  • IMediator as transient
  • ISender as transient
  • IPublisher as transient
  • IRequestHandler<,> concrete implementations as transient
  • IRequestHandler<> concrete implementations as transient
  • INotificationHandler<> concrete implementations as transient
  • IStreamRequestHandler<> concrete implementations as transient
  • IRequestExceptionHandler<,,> concrete implementations as transient
  • IRequestExceptionAction<,>) concrete implementations as transient

This also registers open generic implementations for:

  • INotificationHandler<>
  • IRequestExceptionHandler<,,>
  • IRequestExceptionAction<,>

To register behaviors, stream behaviors, pre/post processors:

services.AddMediatR(cfg => {
    cfg.RegisterServicesFromAssembly(typeof(Startup).Assembly);
    cfg.AddBehavior<PingPongBehavior>();
    cfg.AddStreamBehavior<PingPongStreamBehavior>();
    cfg.AddRequestPreProcessor<PingPreProcessor>();
    cfg.AddRequestPostProcessor<PingPongPostProcessor>();
    cfg.AddOpenBehavior(typeof(GenericBehavior<,>));
    });

With additional methods for open generics and overloads for explicit service types.

Showing the top 20 packages that depend on MediatR.

Packages Downloads
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
16
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
17
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
18
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
19
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
20
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
21
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
23
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
24
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
25
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
28
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
32
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
33
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
1,984
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
10,686
MediatR.Extensions.Microsoft.DependencyInjection
MediatR extensions for ASP.NET Core
11,354

Version Downloads Last updated
12.3.0 3 06/09/2024
12.2.0 7 11/18/2023
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