Blog

In this post I would like to discuss a frequently overlooked, though in some circumstances very important topic – concurrency handling in context of protection of the so-called Domain Invariants.

Each technology becomes obsolete after some time. It is no different with the .NET Framework - it can be safely said that after the appearance of the .NET Core platform, the old Framework is slowly disappearing. Few people write about this platform, at conferences it has not been heard for a long time in this topic. Nobody starts a project in this technology. Only the .NET Core everywhere... except for a beloved legacy systems.

Some time ago I wrote post about publishing and handling domain events. In addition, in one of the posts I described the Outbox Pattern, which provides us At-Least-Once delivery when integrating with external components / services without using the 2PC protocol. This time I wanted to present a combination of both approaches to complete previous posts. I will present a complete solution that enables reliable data processing in the system in a structured manner taking into account the transaction boundary.

Sometimes, when processing a business operation, you need to communicate with an external component in the Fire-and-forget mode. The question that arises is whether we are able to guarantee the atomicity of our business operation from a technical point of view?

In previous post I described how requests input data can be validated on Application Services Layer. I showed FluentValidation library usage in combination with Pipeline Pattern and Problem Details standard. In this post I would like to focus on the second type of validation which sits in the Domain Layer – Domain Model validation.

This time I would like to describe how we can protect our REST API applications from requests containing invalid data (data validation process). However, validation of our requests is not enough, unfortunately. In addition to validation, it is our responsibility to return the relevant messages and statuses to our API clients. I wanted to deal with these two things in this post.

Domain Model encapsulation implementation with Persistence Ignorance in mind using Entity Framework.

In this post I wanted to show you how you can quickly implement simple REST API application with CQRS using the .NET Core.

In previous post I described two popular ways to manage database changes - state versioning where you keep whole current design of your database and versioning of transitions to desired state. In this post I wanted to show implementation of these two approaches in .NET environment combined together – what I think is the best way to manage database changes.

In this post I would like to discuss places where we can store configuration of our application and warn against keeping sensitive configuration data in the code repository. Additionally, I will show example of configuration based on User Secrets and Environment Variables in .NET Core.

Often the time comes when we need to focus on optimizing the performance of our application. There are many ways to do this and one way is cache some data. In this post I will describe briefly the _Cache-Aside Pattern_ and its simple implementation in .NET Core.

From time to time I am asked to do code review of an application. I like doing this, because it is always learning experience. I can see how others program, what problems they have and how they solve them. Except that I can see code written in various conditions and by people with different skills and experience. I prepared a list of 10 popular _"clean code"_ broken rules which I often encounter during this code reviews and I would like to share this list with you.

Domain Event is one of the building blocks of Domain Driven Design. It is something that happened in particular domain and it captures memory of it. We create Domain Events to notify other parts of the same domain that something interesting happened and these other parts potentially can react to.

In previous post about processing multiple instance aggregates of the same type I suggested to consider using eventual consistency approach. In this post I would like to present one way to do this.