Connect to the WCF Application Server from Non-XAF Applications (.NET Framework)

• Dec 28, 2023
• 3 minutes to read

This topic demonstrates the code that you can use in any non-XAF application to access data protected with the Middle Tier WCF Application Server.

Initialize Metadata for Persistent Classes

In the code below, metadata on Employee, Project and Task persistent classes is initialized.

C#

XPDictionary dictionary = new ReflectionDictionary();
Type[] types = { typeof(Employee), typeof(Project), typeof(Task) }
dictionary.CollectClassInfos(types);

VB.NET

Dim dictionary As XPDictionary = New ReflectionDictionary()
Dim types() As Type = { GetType(Employee), GetType(Project), GetType(Task) } dictionary.CollectClassInfos(types)

You can collect metadata for all persistent classes automatically when your data model is in a separate assembly. In the snippet below, metadata for all persistent classes in the assembly that contains the Employee class is collected:

C#

dictionary.CollectClassInfos(Assembly.GetAssembly(typeof(Employee)));

VB.NET

dictionary.CollectClassInfos(System.Reflection.Assembly.GetAssembly(GetType(Employee)))

Establish a Connection

Inherit the WcfSecuredClient class, override the GetLogonParameter method and declare the Logon method with the userName and password parameters:

C#

public class CustomWcfSecuredClient : WcfSecuredClient {
    private object logonParameters;
    public CustomWcfSecuredClient(Binding binding, EndpointAddress remoteAddress) : base(binding, remoteAddress) {
    }
    public void Logon(string userName, string password) {
        logonParameters = new AuthenticationStandardLogonParameters(userName, password);
        base.Logon();
    }
    protected override object GetLogonParameter() {
        return logonParameters;
    }
}

VB.NET

Public Class CustomWcfSecuredClient
    Inherits WcfSecuredClient
    Private logonParameters As Object
    Public Sub New(ByVal binding As Binding, ByVal remoteAddress As EndpointAddress)
        MyBase.New(binding, remoteAddress)
    End Sub
    Public Sub Logon(ByVal userName As String, ByVal password As String)
        logonParameters = New AuthenticationStandardLogonParameters(userName, password)
        MyBase.Logon()
    End Sub
    Protected Overrides Function GetLogonParameter() As Object
        Return logonParameters
    End Function
End Class

The code below demonstrates how to create a WCF Client Object and an Object Access Layer as a user named “User” with an empty string password.

C#

CustomWcfSecuredClient wcfSecuredClient = new CustomWcfSecuredClient(
    WcfDataServerHelper.CreateNetTcpBinding(), new EndpointAddress("net.tcp://localhost:1424/DataServer"));

VB.NET

Dim wcfSecuredClient As New CustomWcfSecuredClient( _
WcfDataServerHelper.CreateNetTcpBinding(), New EndpointAddress("net.tcp://localhost:1424/DataServer"))

Check if a Specific Permission is Granted

Before checking whether a specific permission is granted, call the CustomWcfSecuredClient.GetSecurityStrategyInfo method and pass the username and password to the CustomWcfSecuredClient.Logon method:

C#

wcfSecuredClient.GetSecurityStrategyInfo();
wcfSecuredClient.Logon("User", "");

VB.NET

wcfSecuredClient.GetSecurityStrategyInfo()
wcfSecuredClient.Logon("User", "")

When the WCF client is initialized, and the user is logged on, you can create a permission request and check whether a user has a specific permission via the client’s IsGranted method.

C#

SerializablePermissionRequest readRequest = new SerializablePermissionRequest(typeof(Employee), null, null, SecurityOperations.Read);
bool isReadGranted = wcfSecuredClient.IsGranted(readRequest);

SerializablePermissionRequest writeRequest = new SerializablePermissionRequest(typeof(Employee), null, null, SecurityOperations.Write);
bool isWriteGranted = wcfSecuredClient.IsGranted(writeRequest);

VB.NET

Dim readRequest As New SerializablePermissionRequest(GetType(Employee), Nothing, Nothing, SecurityOperations.Read)
Dim isReadGranted As Boolean = wcfSecuredClient.IsGranted(readRequest)

Dim writeRequest As New SerializablePermissionRequest(GetType(Employee), Nothing, Nothing, SecurityOperations.Write)
Dim isWriteGranted As Boolean = wcfSecuredClient.IsGranted(writeRequest)

Access Data

To access data via the secured Object Access Layer, create a UnitOfWork via the constructor that takes an object layer (see UnitOfWork). You can then create an XPCollection in this Unit of Work, or use UnitOfWork methods. Note that an exception is thrown when you access data that is restricted to the current user (the user that was previously specified when the WCF client was created).

C#

MiddleTierSerializableObjectLayerClient securedObjectLayerClient = new MiddleTierSerializableObjectLayerClient(wcfSecuredClient);
SerializableObjectLayerClient objectLayerClient = new SerializableObjectLayerClient(securedObjectLayerClient, dictionary);
UnitOfWork uow = new UnitOfWork(objectLayerClient);
foreach (Task task in new XPCollection<Task>(uow)) {
    Console.WriteLine(task.Subject);
}
try {
    var task = uow.FirstOrDefault<Task>(t => t.Subject == "Check Reports");
    task.Subject = "Review Reports";
    uow.CommitChanges();
}
catch(Exception e) {
    Console.WriteLine("Error: " + e.Message);
}

VB.NET

Dim securedObjectLayerClient As New MiddleTierSerializableObjectLayerClient(wcfSecuredClient)
Dim objectLayerClient As New SerializableObjectLayerClient(securedObjectLayerClient, dictionary)
Dim uow As New UnitOfWork(objectLayerClient)
For Each task As Task In New XPCollection(Of Task)(uow)
    Console.WriteLine(task.Subject)
Next task
Try
    Dim task = uow.FirstOrDefault(Function(t as Task) t.Subject = "Check Reports")
    task.Subject = "Review Reports"
    uow.CommitChanges()
Catch e As Exception
    Console.WriteLine("Error: " & e.Message)
End Try