Hands-On RESTful Web Services with ASP.NET Core 3

Injecting services into middleware

As discussed earlier, middleware can instantiate dependencies through a dependency injection container. We should take the life cycle of the middleware into consideration: they are initialized once per application lifetime. As a consequence, if we try to consume a scoped or transient instance into our middleware we shouldn't inject them through the constructor of the middleware, because this will cause some dependency resolution issues. A good way to avoid this is to use the parameter injection in the Invoke or InvokeAsync methods:

  namespace Middleware {     public class MyMiddleware     {         readonly RequestDelegate _next;          public MyMiddleware(RequestDelegate next)         {             _next = next;         }          public async Task