In software engineering, dependency injection is a technique whereby one object supplies the dependencies of another object. A “dependency” is an object that can be used, for example as a service. Instead of a client specifying which service it will use, something tells the client what service to use. The “injection” refers to the passing of a dependency (a service) into the object (a client) that would use it. The service is made part of the client’s state. Passing the service to the client, rather than allowing a client to build or find the service, is the fundamental requirement of the pattern.
Dependency Injection based on request headers
Dependency Injection (DI) helps us to change the behavior of parts of our program on the fly. This is especially neat when you want to test your domain services against a mocked data-store. But what if you need to change the behavior of your API based on a request header?
Yesterday I had a discussion with my colleague Robert Kranenburg about this. He showed an example of a console application changing its behavior based on an argument. I took the idea and converted it into .NET Core 3.1 code to change behavior based on a cookie.
Dictionary-style settings as IOptions
I love how we can use appsettings.json files to configure applications in the .NET Core platform. The JSON-format feels a lot less bloated than the old XML appSettings config I used to work with. In this blog I’ll explore how to load a dictionary-style settings class as an IOption. This can be very useful when working with dependency injection.
Setup multiple appsetting-files with a .NET Console Application
In ASP.NET Core we are used to have multiple appsettings.json files with settings that differ per environment. I want to do the same in a Console Application. This makes debugging the application easier.
Dependency injection (with IOptions) in Console Apps in .NET Core
When you are used to building web applications, you kind of get hooked to the ease of Dependency Injection (DI) and the way settings can be specified in a JSON file and accessed through DI (IOptions