OData Client App Authentication with Azure App Service Example - odata

Question

Is there an example of a external OData client using AAD to access an Azure App Service acting as a OData server? The identity being provided is of the client app itself registered as a native app in AAD, not the user, so no user authentication interface is needed in the app.

Answer 1

Actually, it's same as regular Web API to set up AD for Odata service. So you can refer to this sample: https://github.com/azure-samples/active-directory-dotnet-daemon
The minor difference is on client side. As the client code is generated by "Odata Client Code Generator", it is not using HTTP Client class. You need to leverage DataServiceContext.SendingRequest Event to add authorization header.
Refer to the code below:
private static string aadInstance = ConfigurationManager.AppSettings["ida:AADInstance"];
private static string tenant = ConfigurationManager.AppSettings["ida:Tenant"];
private static string clientId = ConfigurationManager.AppSettings["ida:ClientId"];
private static string appKey = ConfigurationManager.AppSettings["ida:AppKey"];
private static string OdataServiceId = ConfigurationManager.AppSettings["OdataTestId"];
static string authority = String.Format(CultureInfo.InvariantCulture, aadInstance, tenant);
private static AuthenticationContext authContext = null;
private static ClientCredential clientCredential = null;
// Get an entire entity set.
static void ListAllProducts(Default.Container container)
{
foreach (var p in container.Products)
{
Console.WriteLine("{0} {1} {2}", p.Name, p.Price, p.Category);
}
}
static void AddProduct(Default.Container container, OdataTest.Models.Product product)
{
container.SendingRequest2 += Container_SendingRequest2;
container.AddToProducts(product);
var serviceResponse = container.SaveChanges();
foreach (var operationResponse in serviceResponse)
{
Console.WriteLine("Response: {0}", operationResponse.StatusCode);
}
}
private static void Container_SendingRequest2(object sender, Microsoft.OData.Client.SendingRequest2EventArgs e)
{
AuthenticationResult result= authContext.AcquireTokenAsync(OdataServiceId, clientCredential).Result;
e.RequestMessage.SetHeader("Authorization", "Bearer " + result.AccessToken);
}
static void Main(string[] args)
{
authContext = new AuthenticationContext(authority);
clientCredential = new ClientCredential(clientId, appKey);
// TODO: Replace with your local URI.
string serviceUri = "http://localhost:59837/";
var container = new Default.Container(new Uri(serviceUri));
var product = new OdataTest.Models.Product()
{
Name = "Yo-yo",
Category = "Toys",
Price = 4.95M
};
AddProduct(container, product);
ListAllProducts(container);
Console.ReadKey();
}
}