What exactly is 'UseAuthentication()' for?

Question

I have a question regarding authentication in ASP.NET Core 2: what exactly is the call app.UseAuthentication() for?

Is it a basic prerequisite so t

Answer 1

You do need to call it.

UseAuthentication() is documented as:

https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.builder.authappbuilderextensions.useauthentication?view=aspnetcore-2.0

Adds the AuthenticationMiddleware to the specified IApplicationBuilder, which enables authentication capabilities.

It basically does this:

IApplicationBuilder AddAuthentication(this IApplicationBuilder app) {

    return app.UseMiddleware();
}

...so it's just saving you some typing and possibly some extra using imports.

This adds an AuthenticationMiddleware instance into the process' request-handling pipeline, and this particular object adds the plumbing for authentication.