Call Custom Service from Event Receiver as Current User

Question

Hello,
i bang my head on this problem for days now:
My custom web service hosted in Sharepoint 2013 needs to know the logged on user name. I used to have a self-written impersonation in my service client before, but with switching to claims authentication this should be obsolete.
So within my service i decode the user from
IClaimsPrincipal icp = Thread.CurrentPrincipal as IClaimsPrincipal;
IClaimsIdentity ci = (IClaimsIdentity)icp.Identity;
String User = ci.ToString();
This works well when i call the service from a custom aspx page.
It utterly fails when i call the service from a List Item Event Receiver. The User always is the Application Pool Account.
This is the Client code to open the Channel:
private void SetChannelFactory(
MyServiceApplicationProxy proxy,
Uri address)
if (null == proxy)
throw new ArgumentNullException("proxy");
if (null == address)
throw new ArgumentNullException("address");
// Check for a cached channel factory
string endpointConfigurationName = GetEndpointConfigurationName(address);// Get the endpoint configuration name
if ((null == s_ChannelFactory) || (endpointConfigurationName != m_EndpointConfigurationName))
lock (s_ChannelFactoryLock)
if ((null == s_ChannelFactory) || (endpointConfigurationName != m_EndpointConfigurationName))
// Create a channel factory without specifying an endpoint address
// so it can be cached and used for multiple endpoint addresses
s_ChannelFactory = new ConfigurationChannelFactory<IMyServiceContract>(
endpointConfigurationName, proxy.Configuration, null);
// Configure the channel factory for claims-based authentication
s_ChannelFactory.ConfigureCredentials(SPServiceAuthenticationMode.Claims);
foreach (var operation in s_ChannelFactory.Endpoint.Contract.Operations)
DataContractSerializerOperationBehavior behavior = operation.Behaviors.Find<DataContractSerializerOperationBehavior>() as DataContractSerializerOperationBehavior;
if (behavior != null)
behavior.MaxItemsInObjectGraph = 2147483647;
// Store the current endpoint configuration name.
m_EndpointConfigurationName = endpointConfigurationName;
private IMyServiceContract GetChannel(
MyServiceApplicationProxy proxy,
Uri address)
//Create Channelfactory
SetChannelFactory(proxy, address);
// Create a channel from the channel factory.
return s_ChannelFactory.CreateChannelActingAsLoggedOnUser(new EndpointAddress(address));
All research pointed out that "CreateChannelActingAsLoggedOnUser" would pass the current user (which is correctly identified within the event receiver!) to the service, but it doesn't work for my event receiver...
Any advice on this would be great!
With kind regards,
Joachim

Answer 1

You should be able to get the current user id from the SPListItemEventProperties object. From here you should be able to create a Claim. For example get the user by using
user = SPWeb.Users.GetByID(properties.CurrentUserId)
SPClaim claim = SPClaimProviderManager.CreateUserClaim(user.email, SPOriginalIssuerType.TrustedProvider, issuerIdentifier);
https://msdn.microsoft.com/en-us/library/microsoft.sharepoint.administration.claims.spclaimprovidermanager.createuserclaim(v=office.14).aspx
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