ASP.NET (OWIN)

Install-Package Microsoft.Owin.Security.OpenIdConnect

Install-Package Microsoft.Owin.Security.Cookies

// Startup.cs
using Microsoft.IdentityModel.Protocols.OpenIdConnect;
using Microsoft.IdentityModel.Tokens;
using Microsoft.Owin;
using Microsoft.Owin.Host.SystemWeb;
using Microsoft.Owin.Security;
using Microsoft.Owin.Security.Cookies;
using Microsoft.Owin.Security.OpenIdConnect;
using MvcApplication.Support;
using Owin;

public void Configuration(IAppBuilder app)
{
    // Configure Auth0 parameters
    string auth0Domain = ConfigurationManager.AppSettings["auth0:Domain"];
    string auth0ClientId = ConfigurationManager.AppSettings["auth0:ClientId"];
    string auth0RedirectUri = ConfigurationManager.AppSettings["auth0:RedirectUri"];
    string auth0PostLogoutRedirectUri = ConfigurationManager.AppSettings["auth0:PostLogoutRedirectUri"];

    // Set Cookies as default authentication type
    app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);
    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = CookieAuthenticationDefaults.AuthenticationType,
        LoginPath = new PathString("/Account/Login"),

        // Configure SameSite as needed for your app. Lax works well for most scenarios here but
        // you may want to set SameSiteMode.None for HTTPS
        CookieSameSite = SameSiteMode.Lax,

        // More information on why the CookieManager needs to be set can be found here: 
        // https://github.com/aspnet/AspNetKatana/wiki/System.Web-response-cookie-integration-issues
        CookieManager = new SameSiteCookieManager(new SystemWebCookieManager())
    });

    // Configure Auth0 authentication
    app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions
    {
        AuthenticationType = "Auth0",

        Authority = $"https://{auth0Domain}",

        ClientId = auth0ClientId,

        RedirectUri = auth0RedirectUri,
        PostLogoutRedirectUri = auth0PostLogoutRedirectUri,
        Scope = "openid profile email",
        TokenValidationParameters = new TokenValidationParameters
        {
            NameClaimType = "name"
        },

        // More information on why the CookieManager needs to be set can be found here: 
        // https://docs.microsoft.com/en-us/aspnet/samesite/owin-samesite
        CookieManager = new SameSiteCookieManager(new SystemWebCookieManager()),

        // Configure Auth0's Logout URL by hooking into the RedirectToIdentityProvider notification, 
        // which is getting triggered before any redirect to Auth0 happens.
        Notifications = new OpenIdConnectAuthenticationNotifications
        {
            RedirectToIdentityProvider = notification =>
            {
                // Only when the RequestType is OpenIdConnectRequestType.Logout should we configure the logout URL.
                // Any other RequestType means a different kind of interaction with Auth0 that isn't logging out.
                if (notification.ProtocolMessage.RequestType == OpenIdConnectRequestType.Logout)
                {
                    var logoutUri = $"https://{auth0Domain}/v2/logout?client_id={auth0ClientId}";

                    var postLogoutUri = notification.ProtocolMessage.PostLogoutRedirectUri;
                    if (!string.IsNullOrEmpty(postLogoutUri))
                    {
                        if (postLogoutUri.StartsWith("/"))
                        {
                            // transform to absolute
                            var request = notification.Request;
                            postLogoutUri = request.Scheme + "://" + request.Host + request.PathBase + postLogoutUri;
                        }
                        logoutUri += $"&returnTo={ Uri.EscapeDataString(postLogoutUri)}";
                    }

                    notification.Response.Redirect(logoutUri);
                    notification.HandleResponse();
                }
                return Task.FromResult(0);
            }
        }
    });
}

public class AccountController : Controller
{
    public ActionResult Login(string returnUrl)
    {
        HttpContext.GetOwinContext().Authentication.Challenge(new AuthenticationProperties
            {
                RedirectUri = returnUrl ?? Url.Action("Index", "Home")
            },
            "Auth0");
        return new HttpUnauthorizedResult();
    }
}

public class AccountController : Controller
{
    [Authorize]
    public void Logout()
    {
        HttpContext.GetOwinContext().Authentication.SignOut(CookieAuthenticationDefaults.AuthenticationType);
        HttpContext.GetOwinContext().Authentication.SignOut("Auth0");
    }
}

// Controllers/AccountController.cs

[Authorize]
public ActionResult UserProfile()
{
    var claimsIdentity = User.Identity as ClaimsIdentity;

    return View(new
    {
        Name = claimsIdentity?.FindFirst(c => c.Type == claimsIdentity.NameClaimType)?.Value,
        EmailAddress = claimsIdentity?.FindFirst(c => c.Type == ClaimTypes.Email)?.Value,
        ProfileImage = claimsIdentity?.FindFirst(c => c.Type == "picture")?.Value
    });
}