Invalid Message Channel

Invalid Message Channel routes messages that fail validation into a dedicated MessageChannel<InvalidMessage<TPayload>> with the original message, reason, headers, and routing timestamp preserved.

Fluent

var invalids = MessageChannel<InvalidMessage<OrderImportCommand>>
    .Create("invalid-order-imports")
    .Build();

var channel = InvalidMessageChannel<OrderImportCommand>.Create("order-import-invalids")
    .To(invalids)
    .When(message => string.IsNullOrWhiteSpace(message.Payload.Sku))
    .Because(_ => "SKU is required.")
    .Build();

var result = channel.Route(message);

Messages that do not match the invalid predicate are left unrouted. Invalid messages are wrapped with the reason and original headers before being sent to the invalid channel.

Source Generator

Use [GenerateInvalidMessageChannel] when the invalid-channel factory should be owned by generated code and completed by application validation rules:

[GenerateInvalidMessageChannel(typeof(OrderImportCommand), ChannelName = "order-import-invalids")]
public static partial class GeneratedOrderInvalidMessageChannel;

The generated Create(MessageChannel<InvalidMessage<TPayload>> invalidChannel) method returns an InvalidMessageChannel<TPayload>.Builder already connected to the target invalid channel.