/// <summary>
/// Processes a received notification. This typically is triggered via an Azure Web Job that reads the Azure storage queue
/// </summary>
/// <param name="notification">Notification to process</param>
public void ProcessNotification(NotificationModel notification)
{
ClientContext cc = null;
try
{
#region Setup an app-only client context
var am = new AuthenticationManager();
var url = $"https://{CloudConfigurationManager.GetSetting("TenantName")}{notification.SiteUrl}";
var realm = TokenHelper.GetRealmFromTargetUrl(new Uri(url));
var clientId = CloudConfigurationManager.GetSetting("ClientId");
var clientSecret = CloudConfigurationManager.GetSetting("ClientSecret");
cc = new Uri(url).DnsSafeHost.Contains("spoppe.com")
? am.GetAppOnlyAuthenticatedContext(url, realm, clientId, clientSecret,
acsHostUrl: "windows-ppe.net", globalEndPointPrefix: "login")
: am.GetAppOnlyAuthenticatedContext(url, clientId, clientSecret);
cc.ExecutingWebRequest += Cc_ExecutingWebRequest;
#endregion
#region Grab the list for which the web hook was triggered
var lists = cc.Web.Lists;
var listId = new Guid(notification.Resource);
var results = cc.LoadQuery(lists.Where(lst => lst.Id == listId));
cc.ExecuteQueryRetry();
var changeList = results.FirstOrDefault();
if (changeList == null)
{
// list has been deleted in between the event being fired and the event being processed
return;
}
#endregion
#region Grab the list changes and do something with them
// grab the changes to the provided list using the GetChanges method
// on the list. Only request Item changes as that's what's supported via
// the list web hooks
var changeQuery = new ChangeQuery(false, true)
{
Item = true,
FetchLimit = 1000, // Max value is 2000, default = 1000
DeleteObject = false,
Add = true,
Update = true,
SystemUpdate = false
};
// grab last change token from database if possible
using (var dbContext = new SharePointWebHooks())
{
ChangeToken lastChangeToken = null;
var id = new Guid(notification.SubscriptionId);
var listWebHookRow = dbContext.ListWebHooks.Find(id);
if (listWebHookRow != null)
{
lastChangeToken = new ChangeToken
{
StringValue = listWebHookRow.LastChangeToken
};
}
// Start pulling down the changes
var allChangesRead = false;
do
{
// should not occur anymore now that we record the starting change token at
// subscription creation time, but it's a safety net
if (lastChangeToken == null)
{
lastChangeToken = new ChangeToken
{
StringValue =
$"1;3;{notification.Resource};{DateTime.Now.AddMinutes(-5).ToUniversalTime().Ticks.ToString()};-1"
};
// See https://blogs.technet.microsoft.com/stefan_gossner/2009/12/04/content-deployment-the-complete-guide-part-7-change-token-basics/
}
// Assign the change token to the query...this determines from what point in
// time we'll receive changes
changeQuery.ChangeTokenStart = lastChangeToken;
// Execute the change query
var changes = changeList.GetChanges(changeQuery);
cc.Load(changes);
cc.ExecuteQueryRetry();
// If item is changed more than once
var uniqueChanges = changes.Cast <ChangeItem>().AsEnumerable().DistinctBy(change => change.ItemId).ToList();
if (uniqueChanges.Any())
{
foreach (var change in uniqueChanges)
{
lastChangeToken = change.ChangeToken;
try
{
// do "work" with the found change
DoWork(cc, changeList, change);
}
catch (Exception)
{
// ignored
}
}
// We potentially can have a lot of changes so be prepared to repeat the
// change query in batches of 'FetchLimit' until we've received all changes
if (changes.Count < changeQuery.FetchLimit)
{
allChangesRead = true;
}
}
else
{
allChangesRead = true;
}
// Are we done?
} while (allChangesRead == false);
// Persist the last used change token as we'll start from that one
// when the next event hits our service
if (listWebHookRow != null)
{
// Only persist when there's a change in the change token
if (!listWebHookRow.LastChangeToken.Equals(lastChangeToken.StringValue, StringComparison.InvariantCultureIgnoreCase))
{
listWebHookRow.LastChangeToken = lastChangeToken.StringValue;
dbContext.SaveChanges();
}
}
else
{
// should not occur anymore now that we record the starting change token at
// subscription creation time, but it's a safety net
dbContext.ListWebHooks.Add(new ListWebHooks()
{
Id = id,
ListId = listId,
LastChangeToken = lastChangeToken.StringValue,
});
dbContext.SaveChanges();
}
}
#endregion
#region "Update" the web hook expiration date when needed
// Optionally add logic to "update" the expiration date time of the web hook
// If the web hook is about to expire within the coming 5 days then prolong it
if (notification.ExpirationDateTime.AddDays(-5) >= DateTime.Now)
{
return;
}
var webHookManager = new WebHookManager();
var updateResult = Task.WhenAny(
webHookManager.UpdateListWebHookAsync(
url,
listId.ToString(),
notification.SubscriptionId,
CloudConfigurationManager.GetSetting("WebHookEndPoint"),
DateTime.Now.AddMonths(3),
_accessToken)
).Result;
if (updateResult.Result == false)
{
throw new Exception(
$"The expiration date of web hook {notification.SubscriptionId} with endpoint {CloudConfigurationManager.GetSetting("WebHookEndPoint")} could not be updated");
}
#endregion
}
catch (Exception ex)
{
// Log error
Console.WriteLine(ex.ToString());
}
finally
{
// ReSharper disable once ConstantConditionalAccessQualifier
cc?.Dispose();
}
}
/// <summary>
/// Processes a received notification. This typically is triggered via an Azure Web Job that reads the Azure storage queue
/// </summary>
/// <param name="notification">Notification to process</param>
public void ProcessNotification(NotificationModel notification)
{
ClientContext cc = null;
try
{
string url = null;
Guid listId = new Guid(notification.Resource);
Guid id = new Guid(notification.SubscriptionId);
// grab last change token from database if possible
using (SharePointWebHooks dbContext = new SharePointWebHooks("pnpwebhooksdemoEntities"))
{
var listWebHookRow = dbContext.ListWebHooks.Find(id);
#region Setup an app-only client context
AuthenticationManager am = new AuthenticationManager();
string startingUrl = WebConfigurationManager.AppSettings["TenantName"];
url = String.Format("https://{0}{1}", startingUrl, notification.SiteUrl);
string realm = TokenHelper.GetRealmFromTargetUrl(new Uri(url));
if (listWebHookRow != null)
{
startingUrl = listWebHookRow.StartingUrl;
url = string.Format(startingUrl + notification.SiteUrl);
}
string clientId = WebConfigurationManager.AppSettings["ClientId"];
string clientSecret = WebConfigurationManager.AppSettings["ClientSecret"];
if (new Uri(url).DnsSafeHost.Contains("spoppe.com"))
{
cc = am.GetAppOnlyAuthenticatedContext(url, realm, clientId, clientSecret, acsHostUrl: "windows-ppe.net", globalEndPointPrefix: "login");
}
else
{
cc = am.GetAppOnlyAuthenticatedContext(url, clientId, clientSecret);
}
cc.ExecutingWebRequest += Cc_ExecutingWebRequest;
#endregion
#region Grab the list for which the web hook was triggered
ListCollection lists = cc.Web.Lists;
var changeList = cc.Web.Lists.GetById(listId);
var listItems = changeList.GetItems(new Microsoft.SharePoint.Client.CamlQuery());
cc.Load(changeList, lst => lst.Title, lst => lst.DefaultViewUrl);
cc.Load(listItems, i => i.Include(item => item.DisplayName,
item => item.Id));
cc.ExecuteQuery();
if (changeList == null)
{
// list has been deleted inbetween the event being fired and the event being processed
return;
}
#endregion
#region Grab the list used to write the web hook history
// Ensure reference to the history list, create when not available
List historyList = cc.Web.GetListByTitle("WebHookHistory");
if (historyList == null)
{
historyList = cc.Web.CreateList(ListTemplateType.GenericList, "WebHookHistory", false);
}
#endregion
#region Grab the list changes and do something with them
// grab the changes to the provided list using the GetChanges method
// on the list. Only request Item changes as that's what's supported via
// the list web hooks
ChangeQuery changeQuery = new ChangeQuery(false, true);
changeQuery.Item = true;
changeQuery.FetchLimit = 1000; // Max value is 2000, default = 1000
ChangeToken lastChangeToken = null;
if (listWebHookRow != null)
{
lastChangeToken = new ChangeToken();
lastChangeToken.StringValue = listWebHookRow.LastChangeToken;
}
// Start pulling down the changes
bool allChangesRead = false;
do
{
// should not occur anymore now that we record the starting change token at
// subscription creation time, but it's a safety net
if (lastChangeToken == null)
{
lastChangeToken = new ChangeToken();
// See https://blogs.technet.microsoft.com/stefan_gossner/2009/12/04/content-deployment-the-complete-guide-part-7-change-token-basics/
lastChangeToken.StringValue = string.Format("1;3;{0};{1};-1", notification.Resource, DateTime.Now.AddMinutes(-5).ToUniversalTime().Ticks.ToString());
}
// Assign the change token to the query...this determines from what point in
// time we'll receive changes
changeQuery.ChangeTokenStart = lastChangeToken;
// Execute the change query
var changes = changeList.GetChanges(changeQuery);
cc.Load(changes);
cc.ExecuteQueryRetry();
if (changes.Count > 0)
{
foreach (Change change in changes)
{
lastChangeToken = change.ChangeToken;
if (change is ChangeItem)
{
// do "work" with the found change
DoWork(cc, changeList, historyList, change);
}
}
// We potentially can have a lot of changes so be prepared to repeat the
// change query in batches of 'FetchLimit' untill we've received all changes
if (changes.Count < changeQuery.FetchLimit)
{
allChangesRead = true;
}
}
else
{
allChangesRead = true;
}
// Are we done?
} while (allChangesRead == false);
// Persist the last used changetoken as we'll start from that one
// when the next event hits our service
if (listWebHookRow != null)
{
// Only persist when there's a change in the change token
if (!listWebHookRow.LastChangeToken.Equals(lastChangeToken.StringValue, StringComparison.InvariantCultureIgnoreCase))
{
listWebHookRow.LastChangeToken = lastChangeToken.StringValue;
dbContext.SaveChanges();
}
}
else
{
// should not occur anymore now that we record the starting change token at
// subscription creation time, but it's a safety net
dbContext.ListWebHooks.Add(new ListWebHook()
{
Id = id,
ListId = listId,
LastChangeToken = lastChangeToken.StringValue,
});
dbContext.SaveChanges();
}
}
#endregion
#region "Update" the web hook expiration date when needed
// Optionally add logic to "update" the expirationdatetime of the web hook
// If the web hook is about to expire within the coming 5 days then prolong it
if (notification.ExpirationDateTime.AddDays(-5) < DateTime.Now)
{
WebHookManager webHookManager = new WebHookManager();
Task <bool> updateResult = Task.WhenAny(
webHookManager.UpdateListWebHookAsync(
url,
listId.ToString(),
notification.SubscriptionId,
WebConfigurationManager.AppSettings["WebHookEndPoint"],
DateTime.Now.AddMonths(3),
this.accessToken)
).Result;
if (updateResult.Result == false)
{
throw new Exception(String.Format("The expiration date of web hook {0} with endpoint {1} could not be updated",
notification.SubscriptionId,
WebConfigurationManager.AppSettings["WebHookEndPoint"]));
}
}
#endregion
}
catch (Exception ex)
{
// Log error
Console.WriteLine(ex.ToString());
}
finally
{
if (cc != null)
{
cc.Dispose();
}
}
}