Skip to main content

CQRS: Building a pipeline using MediatR behaviors

I recently started a new project where we are using MediatR to simplify our CQRS infrastructure. This gives us our basic building blocks to create our queries, commands and the related handlers.

One of the things I wanted to add were some decorators to provide some extra functionality(like authorization, logging, transaction management,…) before and after a request. Turns out I’m lucky as with the release of MediatR 3.0 I can fall back to a built-in functionality called behaviors.

Similar to action filters in ASP.NET MVC, it gives me the opportunity to execute some arbitrary logic before and after a request(command/query). Usage is simple:

  • You have to implement the IPipelineBehavior<TRequest, TResponse> interface:
  • Don’t forget to register the pipeline behavior through your IoC container(StructureMap in the example below)!
Note: As I’m registering this as an Open Generic this behavior will apply to all my messages.













Labels:







































Popular posts from this blog



















.NET 8–Keyed/Named Services




























A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services.   This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy.   To support this feature a new interface IKeyedServiceProvider  got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance:      object? GetKeyedService(Type serviceType, object? serviceKey);     object GetRequiredKeyedService(Type serviceType, object? serviceKey);    To use it, we need to register our service using one of the new extension methods:    Resolving the service can be done either through the FromKeyedServices  attribute:    or by injecting the IKeyedServiceProvider  interface and calling the GetRequiredKeyedServic...

























Read more




























Azure DevOps/ GitHub emoji




























I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup:   All credits go to rcaviers  who created this list.   

























Read more






























Kubernetes–Limit your environmental impact




























Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green .     kube-green  is a simple Kubernetes operator that automatically  shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here  the calculation).   Reason enough to give it a try! Installing kube-green in your cluster   The easiest way to install the operator in your cluster is through kubectl.   We first need to install a cert-manager:   kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml   Remark:  Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster.   Now we can install the kube-green operator:   kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml   Now in the namespace where we want t...

























Read more