internal async Task <AccessTokenData> LoginAsync(string permissions, bool force, FacebookLoginBehavior loginBehavior)
{
if (this.LoginInProgress)
{
throw new InvalidOperationException("Login in progress.");
}
this.LoginInProgress = true;
try
{
var session = AccessTokenDataCacheProvider.Current.GetSessionData();
if (session == null)
{
#if WINDOWS
// Authenticate
var authResult = await PromptOAuthDialog(permissions, WebAuthenticationOptions.None, loginBehavior);
#else
var authResult = await PromptOAuthDialog(permissions, WebAuthenticationOptions.None, loginBehavior);
#endif
FacebookClient client = new FacebookClient(authResult.AccessToken);
var parameters = new Dictionary <string, object>();
parameters["fields"] = "id";
var result = await client.GetTaskAsync("me", parameters);
var dict = (IDictionary <string, object>)result;
session = new AccessTokenData
{
AccessToken = authResult.AccessToken,
Expires = authResult.Expires,
FacebookId = (string)dict["id"],
};
}
else
{
// Check if we are requesting new permissions
bool newPermissions = false;
if (!string.IsNullOrEmpty(permissions))
{
var p = permissions.Split(',');
newPermissions = session.CurrentPermissions.Join(p, s1 => s1, s2 => s2, (s1, s2) => s1).Count() != p.Length;
}
// Prompt OAuth dialog if force renew is true or
// if new permissions are requested or
// if the access token is expired.
if (force || newPermissions || session.Expires <= DateTime.UtcNow)
{
#if WINDOWS
// Authenticate
var authResult = await PromptOAuthDialog(permissions, WebAuthenticationOptions.None, loginBehavior);
#else
var authResult = await PromptOAuthDialog(permissions, WebAuthenticationOptions.None, loginBehavior);
#endif
if (authResult != null)
{
session.AccessToken = authResult.AccessToken;
session.Expires = authResult.Expires;
}
}
}
// Set the current known permissions
if (!string.IsNullOrEmpty(permissions))
{
var p = permissions.Split(',');
session.CurrentPermissions = session.CurrentPermissions.Union(p).ToList();
}
// Save session data
AccessTokenDataCacheProvider.Current.SaveSessionData(session);
CurrentAccessTokenData = session;
}
finally
{
this.LoginInProgress = false;
}
return(CurrentAccessTokenData);
}