MediatR.BackgroundService

This library extends MediatR to enable the mediator pattern for background services in .NET applications. It uses a queue-based background task system, as described in the Microsoft Docs.

Supported Versions

• .NET 9.0
• MediatR 12.5.0 (restricted due to licensing changes in later versions)
• Microsoft.Extensions.* 9.x

How it Works

• Background tasks are enqueued using an IBackgroundTaskQueue implementation.
• Tasks are processed by a hosted service running in the background.
• You can send MediatR requests to be handled asynchronously, offloading long-running or resource-intensive operations from the main request pipeline.
• The queue is implemented using System.Threading.Channels for efficient, thread-safe task management.

Usage

You can enqueue MediatR requests to be processed in the background from either a controller or another handler. Below are examples for both scenarios:

From a Controller

[ApiController] [Route("api/[controller]")] public class InitiateController : ControllerBase { private readonly IMediatRBackground _mediatorBackground; // ... constructor omitted for brevity ... [HttpPost("from-controller")] public async Task<ActionResult> InitiateCall() { var request = new LongOperationRequest(Source: "Controller"); await _mediatorBackground.Send(request, default); return Accepted("Action has been initiated. Check Logs for details..."); } }

From a Handler

public class InitiateOperationHandler : IRequestHandler<InitiateOperationRequest, InitiateOperationResponse> { private readonly IMediatRBackground _mediatorBackground; // ... constructor omitted for brevity ... public async Task<InitiateOperationResponse> Handle(InitiateOperationRequest request, CancellationToken cancellationToken) { var backgroundRequest = new LongOperationRequest("Handler"); await _mediatorBackground.Send(backgroundRequest, default); return new InitiateOperationResponse { Value = "Initiation from handler has been successful." }; } }