identity server4身份验证中间件源码

通过下载ids4的源码来看，可以把相关的源码放到自己项目中，方便分析整个流程和进行一些个性化定制，下面贴一下身份验证中间件的源码

扩展方法：

 public static class MyAuthAppBuilderExtensions
    {
        public static IApplicationBuilder UseMyAuthentication(this IApplicationBuilder app)
        {
            if (app == null)
            {
                throw new ArgumentNullException(nameof(app));
            }

            return app.UseMiddleware<MyAuthenticationMiddleware>();
        }
    }

具体中间件的类：

public class MyAuthenticationMiddleware
    {
        private readonly RequestDelegate _next;

        public MyAuthenticationMiddleware(RequestDelegate next, IAuthenticationSchemeProvider schemes)
        {
            if (next == null)
            {
                throw new ArgumentNullException(nameof(next));
            }
            if (schemes == null)
            {
                throw new ArgumentNullException(nameof(schemes));
            }

            _next = next;
            Schemes = schemes;
        }

        public IAuthenticationSchemeProvider Schemes { get; set; }

        public async Task Invoke(HttpContext context)
        {
            context.Features.Set<IAuthenticationFeature>(new AuthenticationFeature
            {
                OriginalPath = context.Request.Path,
                OriginalPathBase = context.Request.PathBase
            });

            // Give any IAuthenticationRequestHandler schemes a chance to handle the request
            var handlers = context.RequestServices.GetRequiredService<IAuthenticationHandlerProvider>();
            foreach (var scheme in await Schemes.GetRequestHandlerSchemesAsync())
            {
                var handler = await handlers.GetHandlerAsync(context, scheme.Name) as IAuthenticationRequestHandler;
                bool issccuess = await handler.HandleRequestAsync();
                if (handler != null && issccuess)
                {
                    return;
                }
            }

            var defaultAuthenticate = await Schemes.GetDefaultAuthenticateSchemeAsync();
            if (defaultAuthenticate != null)
            {
                //这里边成功了才能拿到用户信息
                var result = await context.AuthenticateAsync(defaultAuthenticate.Name);
                if (result?.Principal != null)
                {
                    context.User = result.Principal;
                }
            }

            await _next(context);
        }
    }