第三方登陆认证功能该怎么做？

以微软官网的向web应用加入Microsoft账号登陆功能为例

向 ASP.NET Web 应用添加 Microsoft 登录功能

本人想做一个另外的第三方账号登陆功能，

我的Startup类：

public class Startup
    {
        // The Client ID is used by the application to uniquely identify itself to Azure AD.
        //已在webconfig文件替换
        string clientId =  System.Configuration.ConfigurationManager.AppSettings["ClientId"];//"d3c8b5dc-81db-48e7-b0ca-cd3c081c9287";//

        // RedirectUri is the URL where the user will be redirected to after they sign in.
        string redirectUri = System.Configuration.ConfigurationManager.AppSettings["RedirectUri"];

        // Tenant is the tenant ID (e.g. contoso.onmicrosoft.com, or 'common' for multi-tenant)
        //我不需要这个
        //static string tenant = System.Configuration.ConfigurationManager.AppSettings["Tenant"];

        // Authority is the URL for authority, composed by Microsoft identity platform endpoint and the tenant name (e.g. https://login.microsoftonline.com/contoso.onmicrosoft.com/v2.0)
        //微软官网登陆网址
        //string authority = String.Format(System.Globalization.CultureInfo.InvariantCulture, System.Configuration.ConfigurationManager.AppSettings["Authority"], tenant);//"https://auth-pre.landlog.info/connect/authorize";// 
        //我的第三方登陆网址
        string authority = "https://auth-pre.landlog.info/connect/authorize";
        /// <summary>
        /// Configure OWIN to use OpenIdConnect 
        /// </summary>
        /// <param name="app"></param>
        public void Configuration(IAppBuilder app)
        {
            app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);

            app.UseCookieAuthentication(new CookieAuthenticationOptions());
            app.UseOpenIdConnectAuthentication(
            new OpenIdConnectAuthenticationOptions
            {
                // Sets the ClientId, authority, RedirectUri as obtained from web.config
                ClientId = clientId,
                Authority = authority,
                RedirectUri = redirectUri,
                // PostLogoutRedirectUri is the page that users will be redirected to after sign-out. In this case, it is using the home page
                PostLogoutRedirectUri = redirectUri,
                Scope = OpenIdConnectScope.OpenIdProfile,
                // ResponseType is set to request the id_token - which contains basic information about the signed-in user
                ResponseType = OpenIdConnectResponseType.IdToken,
                // ValidateIssuer set to false to allow personal and work accounts from any organization to sign in to your application
                // To only allow users from a single organizations, set ValidateIssuer to true and 'tenant' setting in web.config to the tenant name
                // To allow users from only a list of specific organizations, set ValidateIssuer to true and use ValidIssuers parameter 
                TokenValidationParameters = new TokenValidationParameters()
                {
                    ValidateIssuer = false
                },
                // OpenIdConnectAuthenticationNotifications configures OWIN to send notification of failed authentications to OnAuthenticationFailed method
                Notifications = new OpenIdConnectAuthenticationNotifications
                {
                    AuthenticationFailed = OnAuthenticationFailed
                }
            }
        );
        }

        /// <summary>
        /// Handle failed authentication requests by redirecting the user to the home page with an error in the query string
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        private Task OnAuthenticationFailed(AuthenticationFailedNotification<OpenIdConnectMessage, OpenIdConnectAuthenticationOptions> context)
        {
            context.HandleResponse();
            context.Response.Redirect("/?errormessage=" + context.Exception.Message);
            return Task.FromResult(0);
        }
    }

在Home控制器加上 [Authorize] 后开始运行，但出现 TLS 证书错误问题。

然后我去掉控制器上的 [Authorize] 在 action 里面加入

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
            if (!Request.IsAuthenticated)
            {
                HttpContext.GetOwinContext().Authentication.Challenge(
                    new AuthenticationProperties { RedirectUri = "/" },
                    OpenIdConnectAuthenticationDefaults.AuthenticationType);
            }

运行后提示 404 的错误。本人想不通为什么会出现 404，请大佬帮解答。另外请教一下这个第三方登陆，我应该怎么做？

https://blog.csdn.net/csdn3436/article/details/67639181

https://www.cnblogs.com/powertoolsteam/p/PD_Thirdparty_login.html

https://github.com/netnr/Netnr.Login

这两个链接对楼主也许有帮助，尤其第二个，有代码，先调授权登录接口，获得code，再调接口获取用户信息，接下来楼主自己的项目如果想存用户信息也可以存，不想存直接显示也可以。然后如果存了用户信息，每次登录之后，判断用户是否在表中存在，若存在则更新，不存在则新增。再显示自己项目页面即可。