Message Routing

Once you have instantiated a message you need to get it to a specific endpoint. You can let Shuttle.Esb decide this for you implicitly by configuring a routing mechanism or you can even specify the endpoint explicitly.

Message routing only when sending any message. In most cases a message would be a "command", but any message can be sent. Messages are sent by calling the SendAsync method on the service bus instance:

Task<TransportMessage> SendAsync(object message, Action<TransportMessageBuilder>? builder = null);

Only messages that have no RecipientInboxWorkQueueUri set will be routed by the service bus; else the message will be sent to the RecipientInboxWorkQueueUri, e.g.:

await serviceBus.SendAsync(new RegisterMember
{
    UserName = userName
}, 
    builder =>
    {
        builder.WithRecipient("scheme://host/queue");
    });

The TransportMessage envelope will be returned should you need access to any of the metadata available for the message.

Shuttle.Esb uses an implementation of an IMessageRouteProvider to determine where messages are sent.

public interface IMessageRouteProvider
{
    IEnumerable<IMessageRoute> MessageRoutes { get; }
    Task AddAsync(IMessageRoute messageRoute);
    Task<IEnumerable<string>> GetRouteUrisAsync(string messageType);
}

Implementation

The MessageRouteProvider is registered if no IMessageRouteProvider has been registered and makes use of the message routing options to determine where to send messages:

Each implementation of IMessageRouteProvider can determine the routes however it needs to, from the given message type. A typical scenario, and the way the MessageRouteProvider works, is to use the full type name to determine the destination.

Please note: each message type may only be sent to one endpoint using SendAsync.