Microsoft Teams App - pass team's culture to oauth backend provider in Tabs - microsoft-teams

Question

I have build a Teams application on Asp.net core and connected the oauth backend provider. At startup.cs, I dont know the Team's culture yet. Then I ask user to login and get the culture in my cshtml page. But I am not able to find a way to pass Team's cultutre to my oauth backend.The settings goes like this in statup.cs:
services.AddAuthentication(options =>
{
options.DefaultScheme = CookieScheme;
options.DefaultChallengeScheme = OAuthScheme;
options.DefaultAuthenticateScheme = CookieScheme;
options.DefaultSignInScheme = CookieScheme;
options.DefaultSignOutScheme = CookieScheme;
})
.AddCookie(CookieScheme, options =>
{
options.Cookie.SecurePolicy = CookieSecurePolicy.Always;
options.Cookie.SameSite = SameSiteMode.None;
options.ExpireTimeSpan = TimeSpan.FromMinutes(120);
options.SlidingExpiration = false;
options.Events = new CookieAuthenticationEvents
{
OnValidatePrincipal = RefreshTokenIfRequired
};
})
.AddOAuth(OAuthScheme, options =>
{
var settings = JsonConvert.DeserializeObject<OnlineApiSettings>(Configuration["settings"]);
options.ClientId = settings.ClientId;
options.ClientSecret = settings.ClientSecret;
options.AuthorizationEndpoint = settings.AuthEndpoint;
options.TokenEndpoint = settings.TokenEndpoint;
options.CallbackPath = new PathString("/oauth/callback");
options.SaveTokens = true;
});
This is how login page constructed:
<script type="text/javascript">
function loginV1() {
microsoftTeams.app.initialize().then(() => {
microsoftTeams.app.getContext().then((context) => {
login(window.location.origin + "/LoginPopup?culture=" + context.app.locale);
});
});
}
function login(url) {
const urlParams = new URLSearchParams(window.location.search);
const redirectUrl = urlParams.get('redirectPath');
microsoftTeams.authentication.authenticate({
url: url,
width: 600,
height: 535,
successCallback: function (result) {
console.log("Login succeeded: " + result);
window.location.href = "/" + redirectUrl;
},
failureCallback: function (reason) {
console.log("Login failed: " + reason);
window.location.href = "/" + redirectUrl;
}
});
}
</script>
and LoginPopup page is like below:
[Authorize]
public class LoginPopupModel : PageModel
{
private readonly IHttpContextAccessor _httpContext;
public LoginPopupModel(IHttpContextAccessor httpContextAccessor)
{
_httpContext = httpContextAccessor;
}
public async Task<IActionResult> OnGetAsync()
{
if (_httpContext.HttpContext.User.Identity.IsAuthenticated)
{
return RedirectToPage("LoginSuccess");
}
return null;
}
}