Injecting Service in Middleware in ASP.NET Core

Question

I want to inject a service based on the HTTP header value. So I have 2 classes - DbDataProvider and InMemDataProvider, both are implemented from IDataProvider. Whenever an API

Answer 1

You can achieve this in your DI config in Startup.cs.

They key is services.AddHttpContextAccessor() which allows you to get access to the HttpContext.

services.AddHttpContextAccessor();

services.AddScoped();
services.AddScoped();
services.AddScoped(ctx =>
{
    var contextAccessor = ctx.GetService();
    var httpContext = contextAccessor.HttpContext;

    // Whatever the header is that you are looking for
    if (httpContext.Request.Headers.TryGetValue("Synthetic", out var syth))
    {
        return ctx.GetService();
    }
    else
    {
        return ctx.GetService();
    }
});