Mediator Integration

Rag.NET.Mediator wires the three core pipeline operations — ingest, retrieve, and delete — into ZeroAlloc.Mediator request/handler pairs. This lets you dispatch pipeline calls through IMediator from any layer of your application without taking a direct dependency on IRagPipeline.

Installation

dotnet add package Rag.NET.Mediator

Rag.NET.Mediator depends on both Rag.NET (for the pipeline interfaces and models) and ZeroAlloc.Mediator 1.1.7.

Registration

using Rag.NET.DependencyInjection;
using Rag.NET.Mediator.DependencyInjection;

services.AddRagNet(rag => rag
    .UsePgVector(connectionString, vectorDimensions: 1536)
    .AddPdfParser()
    .UseMediator());

.UseMediator() registers IMediator (ZeroAlloc.Mediator) together with the three built-in handlers, inline with the rest of the pipeline configuration.

Request types

IngestCommand

public sealed record IngestCommand(
    Stream Content,
    DocumentMetadata Metadata,
    IngestionOptions? Options = null,
    IProgress<IngestionProgress>? Progress = null)
    : IRequest<Result<IngestionResult, RagError>>;

using var stream = File.OpenRead("report.pdf");
var metadata = new DocumentMetadata
{
    DocumentId  = new DocumentId("report-2024-q4"),
    FileName    = "report.pdf",
    ContentType = "application/pdf",
};

var result = await mediator.Send(new IngestCommand(stream, metadata));
if (result.IsSuccess)
    Console.WriteLine($"Stored {result.Value.ChunksStored} chunks");

RetrieveQuery

public sealed record RetrieveQuery(string Query, RetrievalOptions? Options = null)
    : IRequest<Result<IReadOnlyList<SearchResult>, RagError>>;

var result = await mediator.Send(new RetrieveQuery("key findings", new RetrievalOptions { TopK = 5 }));
if (result.IsSuccess)
    foreach (var r in result.Value)
        Console.WriteLine($"[{r.Score:F2}] {r.Chunk.Text}");

DeleteCommand

public sealed record DeleteCommand(DocumentId DocumentId)
    : IRequest<Result<Unit, RagError>>;

var result = await mediator.Send(new DeleteCommand(new DocumentId("report-2024-q4")));
if (!result.IsSuccess)
    Console.WriteLine($"Delete failed: {result.Error}");

When to use

The mediator integration is useful when:

• You want to keep application layers decoupled from IRagPipeline directly.
• You are already using ZeroAlloc.Mediator for CQRS-style dispatch in your application.
• You want to attach cross-cutting behaviors (logging, validation, authorization) via mediator pipeline behaviors.

For simple applications where IRagPipeline is injected directly, adding the mediator layer is unnecessary overhead.

Note: AskAsync and AskStreamingAsync are not exposed as mediator requests. They are available directly on IRagPipeline because streaming responses (IAsyncEnumerable) do not fit the request/response mediator model well.