Develop Reference

Find the user based on the provider and provider Id in identity server 4.1.0

I am trying to register the login user from Facebook and Google, I am using latest Identity server 4.1.0.
Trying to find the user by provider and provider Id
private async Task<(ApplicationUser user, string provider, string providerUserId, IEnumerable<Claim> claims)> FindUserFromExternalProvider(AuthenticateResult result)
{
var externalUser = result.Principal;
var userIdClaim = externalUser.FindFirst(JwtClaimTypes.Subject) ??
externalUser.FindFirst(ClaimTypes.NameIdentifier) ??
throw new Exception("Unknown userid");
// remove the user id claim so we don't include it as an extra claim if/when we provision the user
var claims = externalUser.Claims.ToList();
claims.Remove(userIdClaim);
var provider = result.Properties.Items["scheme"];
var providerUserId = userIdClaim.Value;
// find external user
var user = await _userManager.FindByLoginAsync(provider, providerUserId);
//var user = _users.FindByExternalProvider(provider, providerUserId);
return (user, provider, providerUserId, claims);
}
I can't use the TestUser, how can I get the user info based on the provider and provider Id
// lookup our user and external provider info
var (user, provider, providerUserId, claims) = await FindUserFromExternalProvider(result);
if (user == null)
{
// SignUp user
}

What you use is one of the sample UIs as part of the quick starts. If you need to use custom userStore in the UI it's up to you to adjust and implement.
Here are a sample using for ASP.NET Identity:
https://github.com/IdentityServer/IdentityServer4/blob/main/samples/Quickstarts/6_AspNetIdentity/src/IdentityServerAspNetIdentity/Quickstart/Account/ExternalController.cs

Identity Server 4 Register Users from External Providers

I'm trying to store new users data from the claims return from an external login.
lets just say I have a model
public class User
{
Guid UniqueIdentifier;
string Username;
string Firstname;
string LastName;
string Email;
Date DateOfBirth;
}
and a method to add a user to the Database:
_userService.Add(new User());
This is the standard IdentityServer implementation for their eternal login call back.
[HttpGet]
public async Task<IActionResult> ExternalLoginCallback(string returnUrl)
{
// read external identity from the temporary cookie
var info = await HttpContext.Authentication.GetAuthenticateInfoAsync(IdentityServerConstants.ExternalCookieAuthenticationScheme);
var tempUser = info?.Principal;
if (tempUser == null)
{
throw new Exception("External authentication error");
}
// retrieve claims of the external user
var claims = tempUser.Claims.ToList();
// try to determine the unique id of the external user - the most common claim type for that are the sub claim and the NameIdentifier
// depending on the external provider, some other claim type might be used
var userIdClaim = claims.FirstOrDefault(x => x.Type == JwtClaimTypes.Subject);
if (userIdClaim == null)
{
userIdClaim = claims.FirstOrDefault(x => x.Type == ClaimTypes.NameIdentifier);
}
if (userIdClaim == null)
{
throw new Exception("Unknown userid");
}
// remove the user id claim from the claims collection and move to the userId property
// also set the name of the external authentication provider
claims.Remove(userIdClaim);
var provider = info.Properties.Items["scheme"];
var userId = userIdClaim.Value;
// check if the external user is already provisioned
var user = await _userManager.FindByLoginAsync(provider, userId);
if (user == null)
{
user = new IdentityUser { UserName = Guid.NewGuid().ToString()
};
await _userManager.CreateAsync(user);
await _userManager.AddLoginAsync(user, new UserLoginInfo(provider, userId, provider));
}
var additionalClaims = new List<Claim>();
// if the external system sent a session id claim, copy it over
var sid = claims.FirstOrDefault(x => x.Type == JwtClaimTypes.SessionId);
if (sid != null)
{
additionalClaims.Add(new Claim(JwtClaimTypes.SessionId, sid.Value));
}
// issue authentication cookie for user
await HttpContext.Authentication.SignInAsync(user.Id, user.UserName, provider, additionalClaims.ToArray());
// delete temporary cookie used during external authentication
await HttpContext.Authentication.SignOutAsync(IdentityServerConstants.ExternalCookieAuthenticationScheme);
// validate return URL and redirect back to authorization endpoint
if (_interaction.IsValidReturnUrl(returnUrl))
{
return Redirect(returnUrl);
}
return Redirect("~/");
}
My question is how can I retrieve a unique Identifier for each user that logs in? Say a user logs in via google, I Cannot use their email address as a unique id because they potentially could already have registered using that email from another provider?

You might need to construct some form of identifier that comes from the token issued from the external provider. In OpenID Connect the subject claim is assumed to be locally unique to the provider. One way to construct a globally unique identifier is to make some sort of composite key (or constructed key) that uses both the issuer (iss) claim and the subject (sub) claim of the token, this identifier is generally guaranteed to be globally unique.

Implementing External Authentication for Mobile App in ASP.NET WebApi 2

I'm trying to build an API (using ASP.NET WebApi) that will be consumed by a native mobile app for a school project. (I'm not concerned about/developing the mobile app, this responsibility falls on a different member)
I'm at a point where I need to implement a token based Facebook login. There are a lot of tutorials available for how to implement this feature for browser based apps (this is pretty straight forward and most of it comes inbuilt), but I don't think I follow how this would work with native apps. What I don't understand is how the redirects would work?
According to this link, nothing needs to be handled specifically by my server. And I don't think I understand how this would work? How would the tokens from Facebook be handled?
Also, what part of token handling should I implement, I couldn't really find good documentation for WebApi external login authentication.
Anyway, if someone could point me to the exact flow of token exchanges that happen and what is implemented by default by ASP.NET, that would be super helpful.
Also, the biggest point of confusion for me is I don't understand how the token returned by Facebook will be handled.
I assume the token will be returned to the client (mobile app), how do I get access to it on my server?
How do I create a local token from facebook's token?
Is this all done internally/auto-magically by ASP.NET?
I'm sorry if this is something I should've been able to figure out. I did do quite a bit of research and I found myself drowning in (related & unrelated) information. I don't think I even know how to search for the information I need.
Some links I've read:
Claims And Token Based Authentication (ASP.NET Web API)
Token Based Authentication using ASP.NET Web API 2, Owin, and Identity
ASP.NET Web API 2 external logins with Facebook and Google in AngularJS app

I had to do pretty much the same thing for an application I was working on. I also had a lot of trouble finding information about it. It seemed like everything I found was close to what I needed, but not exactly the solution. I ended up taking bits and pieces from a bunch of different blog posts, articles, etc. and putting them all together to get it to work.
I remember two of the links you posted "Claims and Token Based Authentication" and "ASP.NET Web API 2 external logins with Facebook and Google in AngularJS app" as being ones that had useful information.
I can't give you a comprehensive answer since I don't remember everything I had to do, nor did I even understand everything I was doing at the time, but I can give you the general idea. You are on the right track.
Essentially I ended up using the token granted by Facebook to confirm that they were logged into their Facebook account, created a user based on their Facebook user ID, and granted them my own bearer token that they could use to access my API.
The flow looks something like this:
Client authenticates with Facebook via whatever method (we used oauth.io)
Facebook returns them a token
Client sends token information to the registration endpoint of my WebApi controller
The token is validated using Facebook's Graph API, which returns user info
A user is created in the database via ASP.NET Identity with their Facebook user ID as the key
Client sends token information to the authentication endpoint of my WebApi controller
The token is validated using Facebook's Graph API, which returns user info
The user info is used to look up the user in the database, confirm they have previously registered
ASP.NET Identity is used to generate a new token for that user
That token is returned to the client
Client includes an Authorization header in all future HTTP requests with the new token granted by my service (ex. "Authorization: Bearer TOKEN")
If the WebApi endpoint has the [Authorize] attribute, ASP.NET Identity will automatically validate the bearer token and refuse access if it is not valid
There ended up being a lot of custom code for implementing the OAuth stuff with ASP.NET Identity, and those links you included show you some of that. Hopefully this information will help you a little bit, sorry I couldn't help more.

I followed this article. The flow is basically this
The server has the facebook keys just like with web login
The app asks for available social logins and displays buttons (you can hardcode this I guess)
When a button is pressed the app opens a browser and sets the URL to the one related to the specified social login. The ASP.NET then redirects the browser to facebook/google/whatever with the appropriate Challenge
The user might be logged in or not and might have given permission to your app or not. After he gives the permissions facebook redirects back to the provided callback URL
At that point you can get the external login info from the SignInManager and check if the user already exists and if you should create a new account
Finally a token is generated and the browser is redirected to a URL in which the token is placed. The app gets the token from the URL and closes the browser. Uses the token to proceed with API requests.
Honestly I have no idea if this approach is legit...
The code of the action buttons should redirect to:
public async Task<IEnumerable<ExternalLoginDto>> GetExternalLogins(string returnUrl, bool generateState = false)
{
IEnumerable<AuthenticationScheme> loginProviders = await SignInManager.GetExternalAuthenticationSchemesAsync();
var logins = new List<ExternalLoginDto>();
string state;
if (generateState)
{
const int strengthInBits = 256;
state = RandomOAuthStateGenerator.Generate(strengthInBits);
}
else
{
state = null;
}
foreach (AuthenticationScheme authenticationScheme in loginProviders)
{
var routeValues = new
{
provider = authenticationScheme.Name,
response_type = "token",
client_id = Configuration["Jwt:Issuer"],
redirect_uri = $"{Request.Scheme}//{Request.Host}{returnUrl}",
state = state
};
var login = new ExternalLoginDto
{
Name = authenticationScheme.DisplayName,
Url = Url.RouteUrl("ExternalLogin", routeValues),
State = state
};
logins.Add(login);
}
return logins;
}
The code for the callback action:
[Authorize(AuthenticationSchemes = "Identity.External")]
[Route("ExternalLogin", Name = "ExternalLogin")]
public async Task<IActionResult> GetExternalLogin(string provider, string state = null, string client_id = null, string error = null)
{
if (error != null)
{
ThrowBadRequest(error);
}
if (!User.Identity.IsAuthenticated)
{
return new ChallengeResult(provider);
}
string providerKey = User.FindFirstValue(ClaimTypes.NameIdentifier);
var externalLoginInfo = new ExternalLoginInfo(User, User.Identity.AuthenticationType, providerKey, User.Identity.AuthenticationType);
if (externalLoginInfo.LoginProvider != provider)
{
await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);
return new ChallengeResult(provider);
}
var userLoginInfo = new UserLoginInfo(externalLoginInfo.LoginProvider, externalLoginInfo.ProviderKey, externalLoginInfo.ProviderDisplayName);
User user = await UserManager.FindByLoginAsync(externalLoginInfo.LoginProvider, externalLoginInfo.ProviderKey);
if (client_id != Configuration["Jwt:Issuer"])
{
return Redirect($"/#error=invalid_client_id_{client_id}");
}
if (user != null)
{
return await LoginWithLocalUser(user, state);
}
else
{
string email = null;
string firstName = null;
string lastName = null;
IEnumerable<Claim> claims = externalLoginInfo.Principal.Claims;
if (externalLoginInfo.LoginProvider == "Google")
{
email = claims.FirstOrDefault(c => c.Type == ClaimTypes.Email)?.Value;
firstName = claims.FirstOrDefault(c => c.Type == ClaimTypes.GivenName)?.Value;
lastName = claims.FirstOrDefault(c => c.Type == ClaimTypes.Surname)?.Value;
}
else if (externalLoginInfo.LoginProvider == "Facebook")
{
email = claims.FirstOrDefault(c => c.Type == ClaimTypes.Email)?.Value;
string[] nameParts = claims.First(c => c.Type == ClaimTypes.Name)?.Value.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
firstName = nameParts?.First();
lastName = nameParts?.Last();
}
//some fallback just in case
firstName ??= externalLoginInfo.Principal.Identity.Name;
lastName ??= externalLoginInfo.Principal.Identity.Name;
user = new User
{
UserName = email,
Email = email,
FirstName = firstName,
LastName = lastName,
EmailConfirmed = true //if the user logs in with Facebook consider the e-mail confirmed
};
IdentityResult userCreationResult = await UserManager.CreateAsync(user);
if (userCreationResult.Succeeded)
{
userCreationResult = await UserManager.AddLoginAsync(user, userLoginInfo);
if (userCreationResult.Succeeded)
{
return await LoginWithLocalUser(user, state);
}
}
string identityErrrors = String.Join(" ", userCreationResult.Errors.Select(ie => ie.Description));
Logger.LogWarning($"Error registering user with external login. Email:{email}, Errors:" + Environment.NewLine + identityErrrors);
return Redirect($"/#error={identityErrrors}");
}
}
private async Task<RedirectResult> LoginWithLocalUser(User user, string state)
{
await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);
DateTime expirationDate = DateTime.UtcNow.AddDays(365);
string token = user.GenerateJwtToken(Configuration["Jwt:Key"], Configuration["Jwt:Issuer"], expirationDate);
return Redirect($"/#access_token={token}&token_type=bearer&expires_in={(int)(expirationDate - DateTime.UtcNow).TotalSeconds}&state={state}");
}

Token-based Authorization in Existing ASP.NET MVC App

I have inherited an existing application. This application uses ASP.NET MVC 3. It has some APIs. Those APIs look like the following:
[AcceptVerbs(HttpVerbs.Post)]
[Endpoint]
public ActionResult AuthenticatePlayer(string username, string password)
{
// Ensure that the user entered valid credentials
if (Membership.ValidateUser(username, password) == false)
return Json(new { statusCode = StatusCodes.INVALID_CREDENTIALS, message = "You entered an invalid username or password. Please try again." });
// Get the profile of the person that just logged in.
ProfileCommon userProfile = (ProfileCommon)(ProfileCommon.Create(username));
if (userProfile != null)
{
string name = username;
if (String.IsNullOrEmpty(userProfile.FirstName) == false)
name = userProfile.FirstName;
return Json(new {
statusCode = StatusCodes.SUCCESS,
payload = name,
username = username.ToLower(),
});
}
}
[AcceptVerbs(HttpVerbs.Get)]
[Endpoint]
public ActionResult SomeUserAction(string q)
{
// TODO: Ensure the user is authorized to perform this action via a token
// Do something
return Json(new { original = q, response = DateTime.UtcNow.Millisecond }, JsonRequestBehavior.AllowGet);
}
I'm trying to figure out how to integrate a token-based authorization schema into this process. From my understanding, a token-based system would return a short-lived token and a refresh token to a user if they successfully login. Then, each method can check to see if a user is authorized to perform the action by looking at the token. I'm trying to learn if this is built-in to ASP.NET MVC or if there is a library I can use. I need to figure out the shortest way to get this done.
Thank you so much!

I've built a WebAPI Token Authentication library a year ago, providing Token based authentication:
WebAPI Token Auth Bootstrap is out of the box Token based User Auth for WebAPI applications, Provides ready to use 'TokenAuthorize'
Attribute and 'TokenAuthApiController' Controller.
Among its features - Token Based User Authentication User Property inside the
TokenAuthApiController (Id, Username, Role, LastAccess).
Token Based User Authorization TokenAuthorizeAttribute with Access
Level - Public, User, Admin or Anonymous.
Built-in Functionality Login(), Logoff(), Error(), Unauthorized()
Responses with various overloads.
You can read more about here and in its own wiki in GitHub.
Nowadays I am working on a Node.js application and I am using Json Web Tokens (JWT) using Node.js library and it is very easy and straightforward.. its Node.js after all ;)
I saw there is a .NET implementation of JWT explained on this article which I recommend you to look at.

You can use Owin ... i.e. Microsoft.owin.security
I haven't tried this implementation but this is just to give you an idea:
var identity = new ClaimsIdentity(Startup.OAuthBearerOptions.AuthenticationType);
var currentUtc = new SystemClock().UtcNow;
ticket.Properties.IssuedUtc = currentUtc;
ticket.Properties.ExpiresUtc = currentUtc.Add(TimeSpan.FromMinutes(30));
DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
return Json(new {
statusCode = StatusCodes.SUCCESS,
payload = name,
username = username.ToLower(),
accessToken = Startup.OAuthBearerOptions.AccessTokenFormat.Protect(ticket)
});

Retrieving information of validated user in WCF

I was following this tutorial at http://www.codeproject.com/Articles/380900/WCF-Authentication-and-Authorization-in-Enterprise
Now I have it logging in and everything, no problems infact it works just like it should. I've even added some cryptography to it using MD5 hashing. But I'm not sure how to get the users information. So when they call the Utility service, how would I query the database for that specific user?
[PrincipalPermission(SecurityAction.Demand, Role = "Read")]
public Data.UserProfiles ViewProfile()
{
using (var context = new DatabaseEntities())
{
var user = context.UserProfiles.SingleOrDefault(u => u.UserName == ???)
return user;
}
}

If you are using the WCF in web application you can store the user details in cookie as the CodeProject article does or you can follow WCF Authentication as here: msdn.microsoft.com/en-us/library/ff405740.aspx
Use below code to get user:
var currentUser = new WindowsPrincipal((WindowsIdentity) System.Threading.Thread.CurrentPrincipal.Identity);