Migrating Authentication from dotnet core 1.1 to dotnet core 2.0

Question

We just migrated our authentication middleware from .net core 1.1 to .net core 2.0, following the example from this answer. Everything builds and runs, however, when I try to make a request (even when trying to get to the Swagger UI) I get the following exception on my custom AuthenticationHandler called UserAuthHandler : System.InvalidOperationException: A suitable constructor for type 'BrokerAPI.AuthMiddleware.UserAuthHandler' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.
The code from UserAuthHandler:

public class UserAuthHandler : AuthenticationHandler<UserAuthAuthenticationOptions>    
{
    protected UserAuthHandler(IOptionsMonitor<UserAuthAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock) : base(options, logger, encoder, clock)
    {
    }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        //handle authentication
        var ticket = new AuthenticationTicket(new ClaimsPrincipal(identity),
           new AuthenticationProperties(), "UserAuth");

        return Task.FromResult(AuthenticateResult.Success(ticket));
    }
}

The code from UserAuthExtensions:

public static class UserAuthExtensions
{
    public static AuthenticationBuilder AddCustomAuth(this AuthenticationBuilder builder, Action<UserAuthAuthenticationOptions> configureOptions)
    { 
        return builder.AddScheme<UserAuthAuthenticationOptions, UserAuthHandler>("UserAuth", "UserAuth", configureOptions);
    }
}

How I call everything in Startup.cs:

public void ConfigureServices(IServiceCollection services)
    {
        services.AddAuthentication(options =>
            {
                options.DefaultScheme = "UserAuth";
            }).AddCustomAuth(o => { });
    }
public void Configure()
    {
        app.UseAuthentication();
    }

I have scavenged Google for examples and people with similar issues, but to no avail.

Am I missing something related to my DI-container? Or is it something related to Authentication in .net core 2 in general?

Thanks in advance.

score 6 · Accepted Answer · answered Oct 24 '17 at 11:50

The exception message is actually really clear: your handler has a protected constructor that cannot be used by the dependency injection system. Make it public and it should work:

public class UserAuthHandler : AuthenticationHandler<UserAuthAuthenticationOptions>    
{
    public UserAuthHandler(IOptionsMonitor<UserAuthAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock) : base(options, logger, encoder, clock)
    {
    }
}

Migrating Authentication from dotnet core 1.1 to dotnet core 2.0

1 Answers1