/// <summary>
/// Initializes the NextPageRequest property.
/// </summary>
public void InitializeNextPageRequest(IBaseClient client, string nextPageLinkString)
{
if (!string.IsNullOrEmpty(nextPageLinkString))
{
this.NextPageRequest = new UserDeltaRequest(
nextPageLinkString,
client,
null);
}
}
private static async Task <string> GetUsersWithDelta(IUserDeltaRequest request, ITargetBlock <User> target, CancellationToken token)
{
var page = await GraphHelper.ExecuteWithRetryAndRateLimit(async() => await request.GetAsync(token), token, 0);
foreach (User user in page.CurrentPage)
{
target.Post(user);
}
return(await GraphHelperUsers.GetUsersWithDelta(page, target, token));
}
/// <summary>
/// This is a "traditional" way of doing delta query. We download the currest state of the resource (Users collection) and then use delta links to pick up changes.
/// The problem with this approach is that it cannot be optimized as we need to page the initial state sequentially. If there are a lot of users, this will take a while.
/// </summary>
/// <param name="client"></param>
/// <returns></returns>
public static IEnumerable <User> UserDeltaQueryTraditional(GraphServiceClient client)
{
//Initialize the delta query
IUserDeltaRequest request = client.Users.Delta().Request().Top(999);
// Step 1: populate the current state of users by following the nextLink in the collection
IUserDeltaCollectionPage currentPage = ExecuteDeltaCycle(request);
// Step 2: Get the deltaLink from the last response
// Note: the Microsoft.Graph SDK doesn't fully implement delta, so we have to reach into the AdditionalData value bag
IUserDeltaRequest deltaRequest = GetNextDeltaRequest(currentPage, client);
// Step 3: After changes are made to users, execute the deltaRequest to pick them up
return(WaitForDeltaChanges(deltaRequest));
}
private static IEnumerable <User> WaitForDeltaChanges(IUserDeltaRequest deltaRequest)
{
Console.WriteLine("Make some changes to users and hit any key to proceed after making the changes");
Console.ReadKey();
IUserDeltaCollectionPage deltaChanges;
do
{
Console.WriteLine("Polling for changes");
Task.Delay(TimeSpan.FromSeconds(1));
deltaChanges = deltaRequest.GetAsync().Result;
} while (deltaChanges.Count < 1);
return(deltaChanges);
}
private static IUserDeltaCollectionPage ExecuteDeltaCycle(IUserDeltaRequest request)
{
IUserDeltaCollectionPage currentUserState = new UserDeltaCollectionPage();
IUserDeltaCollectionPage currentPage;
do
{
currentPage = request.GetAsync().Result;
foreach (var user in currentPage)
{
currentUserState.Add(user);
}
request = currentPage.NextPageRequest;
} while (request != null);
currentUserState.AdditionalData = currentPage.AdditionalData;
return(currentUserState);
}
