UserToken throws exception

Question

When a user is created in SharePoint 2013 (using forms based authentication) the UserToken is not set for the user.

When the users token then is accessed programmatically a "OutOfMemoryException" is thrown. In our case it happens when we try to use SPWeb.GetUserEffectivePermissions(loginName).

This happens until the user visits the site and tp_ExternalToken etc. is set.

The question is, how can I force SharePoint to do this before the first logon?

Relevant part of stack trace:

Type : System.OutOfMemoryException, mscorlib, Version=4.0.0.0,   
Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : Server Out Of Memory.

There is no memory on the server to run your program. Please contact your administrator with this problem.
Source : 
Help link : 
Data : System.Collections.ListDictionaryInternal
TargetSite : Byte[] GetUserToken(System.String, System.String)
HResult : -2147024882
Stack Trace :
    at Microsoft.SharePoint.Library.SPRequestInternalClass.GetUserToken(String bstrUrl, String bstrLogin)
    at Microsoft.SharePoint.Library.SPRequest.GetUserToken(String bstrUrl, String bstrLogin)
    at Microsoft.SharePoint.Utilities.SPUtility.GetPermissions(String login, SPWeb web, SPSecurableObject securableObject, Boolean useCache)

Answer 1

After a lot of digging I found a way to get the token set. It is not pretty but it is the only way I found...

var spClaim = SPClaimProviderManager.Local.ConvertSPUserToClaim(user);
var identity = new ClaimsIdentity();
identity .Claims.Add(new Claim(ClaimTypes.Name, user.LoginName.Substring(user.LoginName.IndexOf(':') + 1), ClaimValueTypes.String));
identity .Claims.Add(new Claim(spClaim.ClaimType, spClaim.Value, spClaim.ValueType, spClaim.OriginalIssuer, spClaim.OriginalIssuer));
SPUserToken token = new SPUserToken(identity , new Uri(Web.Url));
using (SPSite impSite = new SPSite(Web.Site.ID, token))
using (impSite.OpenWeb(impSite.RootWeb.ID))
{
}