How to get identity values from google external provider in ASP.NET Core Web API - google-oauth

Question

[ApiController]
[Route("[controller]")]
public class AuthController : ControllerBase
{
private readonly SignInManager<IdentityUser> _signInManager;
public AuthController(SignInManager<IdentityUser> signInManager)
{
_signInManager = signInManager ?? throw new ArgumentNullException(nameof(signInManager));
}
[HttpGet("token")]
public ChallengeResult Token()
{
var properties = new GoogleChallengeProperties
{
RedirectUri = "/auth/retrieve",
AllowRefresh = true,
};
return Challenge(properties, "Google");
}
[HttpGet("[action]")]
public async Task Retrieve()
{
var token = await HttpContext.GetTokenAsync("access_token");
var externalLoginInfoAsync = await _signInManager.GetExternalLoginInfoAsync();
var identityName = User?.Identity?.Name;
var authenticateResult = await HttpContext.AuthenticateAsync();
}
}
I direct the user to /auth/token, where he is redirected to the Google Oauth Page, if successful, he is redirected to /auth/retrieve, where I expect the user data, but token, externalLoginInfoAsync, identityName, authenticateResult is null
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<ApplicationDbContext>(options =>
options.UseNpgsql(Configuration.GetConnectionString("Default")));
services.AddIdentity<IdentityUser, IdentityRole>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
services.AddAuthentication()
.AddCookie()
.AddGoogle(options =>
{
options.Scope.Add("https://www.googleapis.com/auth/gmail.settings.basic");
options.AccessType = "offline";
options.SaveTokens = true;
options.SignInScheme = IdentityConstants.ExternalScheme;
options.Events.OnCreatingTicket = ctx =>
{
var identityName = ctx.Identity.Name;
return Task.CompletedTask;
};
options.ClientId = "SMTH_VALUE";
options.ClientSecret = "SMTH_VALUE";
});
services.AddControllers();
}
I debug the google provider and found the user values in the Events - identityName is not null.
How i can get this value in the controller?

Answer 1

You could refer the following code to configure Google authentication in Startup.ConfigureServices method:
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(
Configuration.GetConnectionString("DefaultConnection")));
services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
.AddEntityFrameworkStores<ApplicationDbContext>();
services.AddAuthentication()
.AddGoogle(opt =>
{
opt.ClientId = "620831551062-rcvu44q4rhr5d8ossu3m0163jqbjdji0.apps.googleusercontent.com";
opt.ClientSecret = "GXFN0cHBbUlZ6nYLD7a7-cT8";
opt.SignInScheme = IdentityConstants.ExternalScheme;
});
services.AddControllersWithViews();
services.AddRazorPages();
}
Then, use the following sample to login using Google and get user information:
[Authorize]
public class AccountController : Controller
{
private UserManager<ApplicationUser> userManager;
private SignInManager<ApplicationUser> signInManager;
public AccountController(UserManager<ApplicationUser> userMgr, SignInManager<ApplicationUser> signinMgr)
{
userManager = userMgr;
signInManager = signinMgr;
}
// other methods
public IActionResult AccessDenied()
{
return View();
}
[AllowAnonymous]
public IActionResult GoogleLogin()
{
string redirectUrl = Url.Action("GoogleResponse", "Account");
var properties = signInManager.ConfigureExternalAuthenticationProperties("Google", redirectUrl);
return new ChallengeResult("Google", properties);
}
public IActionResult Login()
{
return View();
}
[AllowAnonymous]
public async Task<IActionResult> GoogleResponse()
{
ExternalLoginInfo info = await signInManager.GetExternalLoginInfoAsync();
if (info == null)
return RedirectToAction(nameof(Login));
var result = await signInManager.ExternalLoginSignInAsync(info.LoginProvider, info.ProviderKey, false);
string[] userInfo = { info.Principal.FindFirst(ClaimTypes.Name).Value, info.Principal.FindFirst(ClaimTypes.Email).Value };
if (result.Succeeded)
return View(userInfo);
else
{
ApplicationUser user = new ApplicationUser
{
Email = info.Principal.FindFirst(ClaimTypes.Email).Value,
UserName = info.Principal.FindFirst(ClaimTypes.Email).Value
};
IdentityResult identResult = await userManager.CreateAsync(user);
if (identResult.Succeeded)
{
identResult = await userManager.AddLoginAsync(user, info);
if (identResult.Succeeded)
{
await signInManager.SignInAsync(user, false);
return View(userInfo);
}
}
return AccessDenied();
}
}
}
The result like this:
More detail information, see How to integrate Google login feature in ASP.NET Core Identity and Google external login setup in ASP.NET Core