MediatR.Extensions.RPC.AspNetCore 1.0.0

MediatR-RPC

Automatically expose your MediatR requests as Remote Procedure Call (RPC) like endpoints.

Introduction

MediatR is a simple, unambitious mediator implementation in .NET made by Jimmy Bogard. MediatR-RPC is an extension library aims to automatically expose endpoints to process the Requests using configuration.

When configurating MediatR-RPC all configurations needs to be explicitly set. This way it is more clear for the reader what is going and what the expected behaviors are. Altought there are no implicit defaults there are some predefined configurations helpers available ready to use.

Getting started in ASP.NET Core

In ASP.NET Core MediatR-RPC will configure itself as an EndpointMiddleware with a single templated route that only allows POST method, example: https://localhost:44393/rpc/{requestName}

Install package from Nuget:

Install-Package MediatR.Extensions.RPC.AspNetCore

First register MediatR-RPC when configurating the service by using the .AddMediatrRpc(...) extension method on the service collection:

public void ConfigureServices(IServiceCollection services)
{
  // Additional configuration
  var targetAssembly = this.GetType().Assembly;
  services.AddMediatR(targetAssembly);
  services.AddMediatrRpc(o =>
  {
      o.ScanRequests(targetAssembly);
      o.UseRequestNameMatchingConvention();
  });

  // Additional configuration
}

In ASP.NET Core MediatR-RPC configures an EndpointMiddleware by applying the .MapRpc(...) extension method on the endpoints configuration:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
  // Additional configuration
  app.UseEndpoints(endpoints =>
  {
      endpoints.MapControllers();
      endpoints.MapRpc(o =>
      {
          o.Path = "rpc";
          o.SerializeWithSystemJson(new System.Text.Json.JsonSerializerOptions
          {
              PropertyNameCaseInsensitive = true
          });
          o.ResponsesAs200Ok();
          o.UnmatchedRequestsAs404NotFound();
      });
  });
  // Additional configuration
}

Configuration

MediatR-RPC in its core is about matching a name with a corresponding request type that can be constructed and process by MediatR. This core feature is then applied on different hosting applications. In ASP.NET Core an EndpointMiddleware is configured so a name and properties can be extracted from HTTP request messages.

There are two parts of configurating MediatR-RCP. First configure which requests that are available and how they are mapped. This is done in .AddMediatrRpc(...) extenstion method and applying the RpcOptions. Second, depending on the host application, the endpoints are configured.

RpcOptions

RpcEndpointOptions in ASP.NET Core