public async Task <string> GetToken(string code, string redirectUrl)
{
var appId = configuration["Authentication:Facebook:AppId"];
var appSecret = configuration["Authentication:Facebook:AppSecret"];
var result = await facebookClient.GetPublicAsync <dynamic>(
"oauth/access_token",
$"client_id={appId}&redirect_uri={redirectUrl}&client_secret={appSecret}&code={code}");
if (result == null)
{
return(null);
}
return(result.access_token);
}