QueryInterceptorAttribute Class

Entity set-level authorization and validation is implemented by methods annotated with the QueryInterceptorAttribute. WCF Data Servicess do not implement security policies but instead provide the infrastructure required for service developers to write their own security rules and business validation.

Entity set access control and validation is enabled through query operations by using query composition. To control entity-based access, implement a method-per-entity set according to the following rules:

The method must have public scope and be annotated with the QueryInterceptorAttribute, taking the name of a entity set as a parameter.

The method must accept no parameters.

The method must return an expression of type Expression<Func<T, bool>> that is the filter to be composed for the entity set.

The following example controls access to the Customers entity set. Each Customer can only see Orders associated with that Customer.

[QueryInterceptor("Orders")]
public Expression<Func<Order, bool>> FilterOrders() 
{
    return o => o.Customer.Name == /* Current principal name. */;
} 
 
// Insures that the user accessing the customer(s) has the appropriate
// rights as defined in the QueryRules object to access the customer
// resource(s).
 
[QueryInterceptor ("Customers")]
public Expression<Func<Customer, bool>> FilterCustomers() 
{
  return c => c.Name == /* Current principal name. */ &&
              this.CurrentDataSource.QueryRules.Contains(
                rule => rule.Name == c.Name &&
                        rule.CustomerAllowedToQuery == true
              );
}

.NET Framework

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference