How to: Specify Client Credentials for a Data Service Request (WCF Data Services)

By default, the client library does not supply credentials when sending a request to an OData service. However, you can specify that credentials be sent to authenticate requests to the data service by supplying a NetworkCredential for the Credentials property of the DataServiceContext. For more information, see Securing WCF Data Services. The example in this topic shows how to explicitly provide credentials that are used by the WCF Data Services client when requesting data from the data service.

The example in this topic uses the Northwind sample data service and autogenerated client data service classes. This service and the client data classes are created when you complete the WCF Data Services quickstart. You can also use the Northwind sample data service that is published on the OData Web site; this sample data service is read-only and attempting to save changes returns an error. The sample data services on the OData Web site allow anonymous authentication.

Example

The following example is from the code-behind page for an Extensible Application Markup Language (XAML) file that is the main page of the Windows Presentation Framework application. This example displays a LoginWindow instance to collect authentication credentials from the user, and then uses these credentials when making a request to the data service.

using System;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Security;
using NorthwindClient.Northwind;
using System.Data.Services.Client;

namespace NorthwindClient
{
    public partial class ClientCredentials : Window
    {
        // Create the binding collections and the data service context.
        private DataServiceCollection<Customer> binding;
        NorthwindEntities context;
        CollectionViewSource customerAddressViewSource;

        // Instantiate the service URI and credentials.
        Uri serviceUri = new Uri("http://localhost:12345/Northwind.svc/");
        NetworkCredential credentials = new NetworkCredential();

        public ClientCredentials()
        {
            InitializeComponent();
        }

        private void ClientCredentials_Loaded(object sender, RoutedEventArgs e)
        {
            string userName = string.Empty;
            string domain = string.Empty;
            SecureString password = new SecureString();

            // Get credentials for authentication.
            LoginWindow login = new LoginWindow();
            login.ShowDialog();

            if (login.DialogResult == true 
                && login.userNameBox.Text != string.Empty
                && login.passwordBox.SecurePassword.Length != 0)
            { 
                // Instantiate the context.
                context =
                    new NorthwindEntities(serviceUri);

                // Get the user name and domain from the login.
                string[] qualifiedUserName = login.userNameBox.Text.Split(new char[] { '\\' });
                if (qualifiedUserName.Length == 2)
                {
                    domain = qualifiedUserName[0];
                    userName = qualifiedUserName[1];
                }
                else
                {
                    userName = login.userNameBox.Text;
                }
                password = login.passwordBox.SecurePassword;

                // Set the client authentication credentials.
                context.Credentials =
                    new NetworkCredential(userName, password, domain);


                // Define an anonymous LINQ query that returns a collection of Customer types.
                var query = from c in context.Customers
                            where c.Country == "Germany"
                            select c;

                try
                {
                    // Instantiate the binding collection, which executes the query.
                    binding = new DataServiceCollection<Customer>(query);

                    while (binding.Continuation != null)
                    {
                        // Continue to execute the query until all pages are loaded.
                        binding.Load(context.Execute<Customer>(binding.Continuation.NextLinkUri));
                    }

                    // Assign the binding collection to the CollectionViewSource.
                    customerAddressViewSource =
                        (CollectionViewSource)this.Resources["customerViewSource"];
                    customerAddressViewSource.Source = binding;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
            else if (login.DialogResult == false)
            {
                MessageBox.Show("Login cancelled.");
            }
        }
    }
}
Imports NorthwindClient.Northwind
Imports System.Data.Services.Client
Imports System.Windows.Data
Imports System.Net
Imports System.Windows
Imports System.Security

Partial Public Class ClientCredentials
    Inherits Window

    ' Create the binding collections and the data service context.
    Private binding As DataServiceCollection(Of Customer)
    Private context As NorthwindEntities
    Private customerAddressViewSource As CollectionViewSource

    ' Instantiate the service URI and credentials.
    Dim serviceUri As Uri = New Uri("http://localhost:54321/Northwind.svc/")
    Private credentials As NetworkCredential = New NetworkCredential()

    Public Sub Main()
        InitializeComponent()
    End Sub

    Private Sub ClientCredentials_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)

        Dim userName = String.Empty
        Dim domain = String.Empty
        Dim password = New SecureString()

        ' Get credentials for authentication.
        Dim login As New LoginWindow()
        login.ShowDialog()

        If login.DialogResult = True _
            AndAlso Not login.userNameBox.Text Is String.Empty _
            AndAlso login.passwordBox.SecurePassword.Length <> 0 Then

            ' Instantiate the context.
            context = New NorthwindEntities(serviceUri)

            ' Get the user name and domain from the login.
            Dim qualifiedUserName As String() = login.userNameBox.Text.Split(New [Char]() {"\"c})
            If qualifiedUserName.Length = 2 Then
                domain = qualifiedUserName(0)
                userName = qualifiedUserName(1)
            Else
                userName = login.userNameBox.Text
            End If
            password = login.passwordBox.SecurePassword

            ' Set the client authentication credentials.
            context.Credentials = _
                New NetworkCredential(userName, password, domain)


            ' Define an anonymous LINQ query that returns a collection of Customer types.
            Dim query = From c In context.Customers
                        Where c.Country = "Germany"
                        Select c

            Try
                ' Instantiate the binding collection, which executes the query.
                binding = New DataServiceCollection(Of Customer)(query)

                ' Load result pages into the binding collection.
                While Not binding.Continuation Is Nothing
                    ' Continue to execute the query until all pages are loaded.
                    binding.Load(context.Execute(Of Customer)(binding.Continuation.NextLinkUri))
                End While

                ' Assign the binding collection to the CollectionViewSource.
                customerAddressViewSource = _
                    CType(Me.Resources("customerViewSource"), CollectionViewSource)
                customerAddressViewSource.Source = binding
            Catch ex As Exception
                MessageBox.Show(ex.Message)
            End Try
        ElseIf login.DialogResult = False Then
            MessageBox.Show("Login cancelled.")
        End If
    End Sub
End Class

Example

The following XAML defines the main page of the WPF application.

<Window x:Class="ClientCredentials"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="312" d:DesignWidth="577" 
             Loaded="ClientCredentials_Loaded">
    <Window.Resources>
        <CollectionViewSource x:Key="customerViewSource" />
    </Window.Resources>
    <Grid x:Name="LayoutRoot" Background="White" DataContext="" Height="312" Width="577"
          VerticalAlignment="Top" HorizontalAlignment="Left">
        <Grid.RowDefinitions>
            <RowDefinition Height="203*" />
            <RowDefinition Height="119*" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="336*" />
        </Grid.ColumnDefinitions>
        <DataGrid AutoGenerateColumns="False" Height="213" HorizontalAlignment="Left" 
                      ItemsSource="{Binding Source={StaticResource customerViewSource}}" 
                      Name="customerDataGrid" RowDetailsVisibilityMode="VisibleWhenSelected" 
                      VerticalAlignment="Top" Width="553" Margin="12,44,0,0" 
                      Grid.RowSpan="2" Grid.ColumnSpan="1">
            <DataGrid.Columns>
                <DataGridTextColumn x:Name="customerIDColumn" Binding="{Binding Path=CustomerID}" 
                                        Header="Customer" Width="80" />
                <DataGridTextColumn x:Name="addressColumn" Binding="{Binding Path=Address}" 
                                        Header="Address" Width="180" />
                <DataGridTextColumn x:Name="cityColumn" Binding="{Binding Path=City}" 
                                        Header="City" Width="120" />
                <DataGridTextColumn x:Name="countryColumn" Binding="{Binding Path=Country}" 
                                        Header="Country" Width="80" />
                <DataGridTextColumn x:Name="postalCodeColumn" Binding="{Binding Path=PostalCode}" 
                                        Header="Postal Code" Width="90" />
                <DataGridTextColumn Binding="{Binding Path=CompanyName}" Header="CompanyName" />
                <DataGridTextColumn Binding="{Binding Path=ContactName}" Header="ContactName" />
                <DataGridTextColumn Binding="{Binding Path=Phone}" Header="Phone" />
            </DataGrid.Columns>
        </DataGrid>
        <Label Grid.Row="0" Grid.Column="0" Height="26" HorizontalAlignment="Left" Margin="16,12,0,0" 
                   Name="serviceUriLabel" VerticalAlignment="Top" Width="550"  />
    </Grid>
</Window>

Example

The following example is from the code-behind page for the window that is used to collect the authentication credentials from the user before making a request to the data service.

using System;
using System.Windows;
using System.Windows.Controls;
using System.ComponentModel;

namespace NorthwindClient
{
    public partial class LoginWindow : Window
    {
        public LoginWindow()
        {
            InitializeComponent();
        }

        private void OKButton_Click(object sender, RoutedEventArgs e)
        {
            this.DialogResult = true;
            e.Handled = true;
        }

        private void CancelButton_Click(object sender, RoutedEventArgs e)
        {
             this.DialogResult = false;
             e.Handled = true;
        }

        private void LoginWindow_Closing(object sender, CancelEventArgs e)
        {
            if (this.DialogResult == true &&
                    (this.userNameBox.Text == string.Empty || this.passwordBox.SecurePassword.Length == 0))
            {
                e.Cancel = true;
                MessageBox.Show("Please enter name and password or click Cancel.");
            }
        }
    }
}
Imports System.ComponentModel
Imports System.Windows
Imports System.Security

Partial Public Class LoginWindow
    Inherits Window

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub OKButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles OKButton.Click
        Me.DialogResult = True
        e.Handled = True
    End Sub

    Private Sub CancelButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles CancelButton.Click
        Me.DialogResult = False
        e.Handled = True
    End Sub

    Private Sub LoginWindow_Closing(ByVal sender As System.Object, ByVal e As CancelEventArgs)
        If Me.DialogResult = True AndAlso _
                    (Me.userNameBox.Text = String.Empty OrElse Me.passwordBox.SecurePassword.Length = 0) Then
            e.Cancel = True
            MessageBox.Show("Please enter name and password or click Cancel.")
        End If
    End Sub
End Class

Example

The following XAML defines the login of the WPF application.

<Window x:Class="LoginWindow"
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
           Width="400" Height="200" 
           Title="LoginWindow" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk" Closing="LoginWindow_Closing">
    <StackPanel Name="LayoutRoot" Orientation="Vertical" VerticalAlignment="Top">
        <StackPanel Orientation="Horizontal">
            <TextBlock Height="25" HorizontalAlignment="Left" Margin="10,20,0,0" Name="userNameLabel" VerticalAlignment="Top" 
                       Width="80" Text="User name:"/>
            <TextBox Height="23" HorizontalAlignment="Left" Margin="10,20,0,0"  Name="userNameBox" VerticalAlignment="Top" 
                     Width="150" Text="DOMAIN\login"/>
        </StackPanel>
        <StackPanel Orientation="Horizontal" VerticalAlignment="Top">
            <TextBlock Height="25" HorizontalAlignment="Left" Margin="10,20,0,0" Name="pwdLabel" Width="80" Text="Password:"/>
            <PasswordBox Height="23" HorizontalAlignment="Left" Margin="10,20,0,0" Name="passwordBox" Width="150" />
        </StackPanel>
        <StackPanel Orientation="Horizontal" HorizontalAlignment="Right" Height="80" VerticalAlignment="Top">
            <Button x:Name="CancelButton" Content="Cancel" Click="CancelButton_Click" Width="75" Height="23" 
                HorizontalAlignment="Right" Margin="8" IsCancel="True" />
            <Button x:Name="OKButton" Content="OK" Click="OKButton_Click" Width="75" Height="23" 
                HorizontalAlignment="Right" Margin="8" IsDefault="True" />
        </StackPanel>
    </StackPanel>
</Window>

.NET Framework Security

The following security considerations apply to the example in this topic:

  • To verify that the credentials supplied in this sample work, the Northwind data service must use an authentication scheme other than anonymous access. Otherwise, the Web site hosting the data service will not request credentials.

  • User credentials should only be requested during execution and should not be cached. Credentials must always be stored securely.

  • Data sent with Basic and Digest Authentication is not encrypted, so the data can be seen by an adversary. Additionally, basic authentication credentials (user name and password) are sent in cleartext and can be intercepted.

For more information, see Securing WCF Data Services.

See Also

Securing WCF Data Services
WCF Data Services Client Library