1.4AuthenticationOptions【AuthenticationOptions>AuthenticationSchemeBuilder>AuthenticationScheme】

AuthenticationOptions->AuthenticationSchemeBuilder->AuthenticationScheme

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Security.Claims;
using Microsoft.AspNetCore.Http;

namespace Microsoft.AspNetCore.Authentication
{
    /// <summary>
    /// Options to configure authentication.
    /// </summary>
    public class AuthenticationOptions
    {
        private readonly IList<AuthenticationSchemeBuilder> _schemes = new List<AuthenticationSchemeBuilder>();

        /// <summary>
        /// Returns the schemes in the order they were added (important for request handling priority)
        /// </summary>
        public IEnumerable<AuthenticationSchemeBuilder> Schemes => _schemes;

        /// <summary>
        /// Maps schemes by name.
        /// </summary>
        public IDictionary<string, AuthenticationSchemeBuilder> SchemeMap { get; } = new Dictionary<string, AuthenticationSchemeBuilder>(StringComparer.Ordinal);

        /// <summary>
        /// Adds an <see cref="AuthenticationScheme"/>.
        /// </summary>
        /// <param name="name">The name of the scheme being added.</param>
        /// <param name="configureBuilder">Configures the scheme.</param>
        public void AddScheme(string name, Action<AuthenticationSchemeBuilder> configureBuilder)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }
            if (configureBuilder == null)
            {
                throw new ArgumentNullException(nameof(configureBuilder));
            }
            if (SchemeMap.ContainsKey(name))
            {
                throw new InvalidOperationException("Scheme already exists: " + name);
            }

            var builder = new AuthenticationSchemeBuilder(name);
            configureBuilder(builder);
            _schemes.Add(builder);
            SchemeMap[name] = builder;
        }

        /// <summary>
        /// Adds an <see cref="AuthenticationScheme"/>.
        /// </summary>
        /// <typeparam name="THandler">The <see cref="IAuthenticationHandler"/> responsible for the scheme.</typeparam>
        /// <param name="name">The name of the scheme being added.</param>
        /// <param name="displayName">The display name for the scheme.</param>
        public void AddScheme<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)]THandler>(string name, string? displayName) where THandler : IAuthenticationHandler
            => AddScheme(name, b =>
            {
                b.DisplayName = displayName;
                b.HandlerType = typeof(THandler);
            });

        /// <summary>
        /// Used as the fallback default scheme for all the other defaults.
        /// </summary>
        public string? DefaultScheme { get; set; }

        /// <summary>
        /// Used as the default scheme by <see cref="IAuthenticationService.AuthenticateAsync(HttpContext, string)"/>.
        /// </summary>
        public string? DefaultAuthenticateScheme { get; set; }

        /// <summary>
        /// Used as the default scheme by <see cref="IAuthenticationService.SignInAsync(HttpContext, string, System.Security.Claims.ClaimsPrincipal, AuthenticationProperties)"/>.
        /// </summary>
        public string? DefaultSignInScheme { get; set; }

        /// <summary>
        /// Used as the default scheme by <see cref="IAuthenticationService.SignOutAsync(HttpContext, string, AuthenticationProperties)"/>.
        /// </summary>
        public string? DefaultSignOutScheme { get; set; }

        /// <summary>
        /// Used as the default scheme by <see cref="IAuthenticationService.ChallengeAsync(HttpContext, string, AuthenticationProperties)"/>.
        /// </summary>
        public string? DefaultChallengeScheme { get; set; }

        /// <summary>
        /// Used as the default scheme by <see cref="IAuthenticationService.ForbidAsync(HttpContext, string, AuthenticationProperties)"/>.
        /// </summary>
        public string? DefaultForbidScheme { get; set; }

        /// <summary>
        /// If true, SignIn should throw if attempted with a user is not authenticated.
        /// A user is considered authenticated if <see cref="ClaimsIdentity.IsAuthenticated"/> returns <see langword="true" /> for the <see cref="ClaimsPrincipal"/> associated with the HTTP request.
        /// </summary>
        public bool RequireAuthenticatedSignIn { get; set; } = true;
    }
}

using System;
using System.Diagnostics.CodeAnalysis;

namespace Microsoft.AspNetCore.Authentication
{
    /// <summary>
    /// Used to build <see cref="AuthenticationScheme"/>s.
    /// </summary>
    public class AuthenticationSchemeBuilder
    {
        /// <summary>
        /// Constructor.
        /// </summary>
        /// <param name="name">The name of the scheme being built.</param>
        public AuthenticationSchemeBuilder(string name)
        {
            Name = name;
        }

        /// <summary>
        /// Gets the name of the scheme being built.
        /// </summary>
        public string Name { get; }

        /// <summary>
        /// Gets or sets the display name for the scheme being built.
        /// </summary>
        public string? DisplayName { get; set; }

        /// <summary>
        /// Gets or sets the <see cref="IAuthenticationHandler"/> type responsible for this scheme.
        /// </summary>
        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)]
        public Type? HandlerType { get; set; }

        /// <summary>
        /// Builds the <see cref="AuthenticationScheme"/> instance.
        /// </summary>
        /// <returns>The <see cref="AuthenticationScheme"/>.</returns>
        public AuthenticationScheme Build()
        {
            if (HandlerType is null)
            {
                throw new InvalidOperationException($"{nameof(HandlerType)} must be configured to build an {nameof(AuthenticationScheme)}.");
            }

            return new AuthenticationScheme(Name, DisplayName, HandlerType);
        }
    }
}

using System;
using System.Diagnostics.CodeAnalysis;

namespace Microsoft.AspNetCore.Authentication
{
    /// <summary>
    /// AuthenticationSchemes assign a name to a specific <see cref="IAuthenticationHandler"/>
    /// handlerType.
    /// </summary>
    public class AuthenticationScheme
    {
        /// <summary>
        /// Initializes a new instance of <see cref="AuthenticationScheme"/>.
        /// </summary>
        /// <param name="name">The name for the authentication scheme.</param>
        /// <param name="displayName">The display name for the authentication scheme.</param>
        /// <param name="handlerType">The <see cref="IAuthenticationHandler"/> type that handles this scheme.</param>
        public AuthenticationScheme(string name, string? displayName, [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type handlerType)
        {
            if (name == null)
            {
                throw new ArgumentNullException(nameof(name));
            }
            if (handlerType == null)
            {
                throw new ArgumentNullException(nameof(handlerType));
            }
            if (!typeof(IAuthenticationHandler).IsAssignableFrom(handlerType))
            {
                throw new ArgumentException("handlerType must implement IAuthenticationHandler.");
            }

            Name = name;
            HandlerType = handlerType;
            DisplayName = displayName;
        }

        /// <summary>
        /// The name of the authentication scheme.
        /// </summary>
        public string Name { get; }

        /// <summary>
        /// The display name for the scheme. Null is valid and used for non user facing schemes.
        /// </summary>
        public string? DisplayName { get; }

        /// <summary>
        /// The <see cref="IAuthenticationHandler"/> type that handles this scheme.
        /// </summary>
        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)]
        public Type HandlerType { get; }
    }
}