how to retrieve facebook user info ASP.NET WEB API 2 - asp.net

Question

I want to register a user, through an external provider (like facebook), in order to get the information I need, I configure FacebookProvider as follows
var options = new FacebookAuthenticationOptions {
AppId = "***",
AppSecret = "***",
Scope = { "email" },
Provider = new FacebookAuthenticationProvider {
OnAuthenticated = (context) => {
foreach (var x in context.User)
{
var claimType = string.Format("urn:facebook:{0}", x.Key);
string claimValue = x.Value.ToString();
if (!context.Identity.HasClaim(claimType, claimValue))
context.Identity.AddClaim(new System.Security.Claims.Claim(claimType, claimValue, XmlSchemaString, "Facebook"));
}
return Task.FromResult(0);
}
}
};
options.Fields.Add("id");
options.Fields.Add("name");
options.Fields.Add("email");
options.SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalBearer;
app.UseFacebookAuthentication(options);
in the OnAuthenticated while debugging I see all the requested fields but when I call RegisterExternal from postman as follow pic
RegisterExternal call postman
GetExternalLoginInfoAsync returns null
var info = await Authentication.GetExternalLoginInfoAsync();
if (info == null)
{
return InternalServerError();
}
so how to retrieve query fields such as email? I think all the necessary information is stored in the cookies, but how do I transfer them to the server and extract Identity instance?
all nuget packages have been updated to the latests versions
p.s. I plan to work with the API from the iOS app

Answer 1

I found solution.
Changed ExternalLoginData class as follows
private class ExternalLoginData
{
...
// here added new field
public IList<Claim> Claims { get; private set; }
public static ExternalLoginData FromIdentity(ClaimsIdentity identity)
{
...
return new ExternalLoginData
{
...
// here added claims setting
Claims = identity.Claims.ToList()
};
}
}
Changed ExternalLogin callback as follows
public async Task<IHttpActionResult> GetExternalLogin(string provider, string error = null)
{
...
if (hasRegistered)
{
...
}
else
{
// here replaced getting claims by Claims field
IEnumerable<Claim> claims = externalLogin.Claims;
//IEnumerable<Claim> claims = externalLogin.GetClaims();
ClaimsIdentity identity = new ClaimsIdentity(claims, OAuthDefaults.AuthenticationType);
Authentication.SignIn(identity);
}
return Ok();
}
As a result we receive a bearer token. Extracting Identity from it we receive earlier saved claims.