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How to configure handlers in RedMQ from events raised in my domain

Just dipping around message queues and Redis MQ , great infrastructure.

I understand that you must use .RegisterHandler (...) to determine which handler will process the type of message / event in the message queue.

So, if I have EventA, EventB, etc., I should have one service that processes each of these events, for example:

public class DomainService : Service { public object Any(EventA eventA) {...} public object Any(EventB eventA) {...} }

So, this should only be a queue / redis list created?

Also, what if I want a chain of events to occur, for example, a message like EventA also has a handler that sends email handlers earlier in the chain, successfully?

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ServiceStack makes no difference between the services created for MQ, REST, HTML or SOAP services, they are the same. that is, each of them receives a DTO request and, possibly, returns a DTO of the response, and the same service can process calls from any endpoint or format, such as HTML, REST, SOAP or MQ.

Refer to the ServiceStack Architecture diagram for how MQ fits.

Limitations

The only thing you need to keep in mind:

  • Like SOAP, MQ only supports 1 verb, so your methods should be named Publish or Any
  • Only Action Filters are executed (i.e. not global or attribute filters)
  • Instead of IHttpRequest , IHttpResponse you get the MqRequest and MqResponse stubs. You can still use .Items to transfer data through the request pipeline, but any HTTP actions, such as setting cookies or HTTP headers, are benign

Redis MQ host setup

The MQ host itself is completely separate from the rest of the ServiceStack infrastructure, which does not know that MQ exists until you pass the message to ServiceStack yourself, which is usually done inside your registered handler, for example:

 var redisFactory = new PooledRedisClientManager("localhost:6379"); var mqHost = new RedisMqServer(redisFactory, retryCount:2); mqHost.RegisterHandler<Hello>(m => { return this.ServiceController.ExecuteMessage(m); }); //shorter version: //mqHost.RegisterHandler<Hello>(ServiceController.ExecuteMessage); mqHost.Start(); //Starts listening for messages

In RegisterHandler<T> you specify the type of request you want to listen to.

By default, you can register only one handler for each message, and in ServiceStack the request is tied to the well-known implementation of Service, in the case of MQ it looks for the first signature of the method: Post(Hello) , and if it is not, t it looks for a backup Any(Hello) .

Can add multiple handlers to a message on its own

If you want to call several handlers, then you just save your own List<Handler> and just execute and execute them all when prompted.

Call various services

If you want to call another service, just translate it into another DTO request and pass it instead of ServiceController.

When an MQ request is sent by someone, for example:

 mqClient.Publish(new Hello { Name = "Client" });

Your handler is called with an instance of IMessage type, where the DTO request is contained in the Body property. At this point, you can reject the message, confirm it or change it.

MQ requests are the same as any other service requests

In most cases, you usually just send a message to the ServiceController for processing , the implementation of which:

 public object ExecuteMessage<T>(IMessage<T> mqMsg) { return Execute(mqMsg.Body, new MqRequestContext(this.Resolver, mqMsg)); }

The implementation simply retrieves the DTO request from mqMsg.Body and treats this message as a normal service sent from the C # request DTO from now on, with the MqRequestContext that contains the MQ IHttpRequest, IHttpResponse Holes.

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