internal static async Task <bool> InsertOrReplaceListWebHook(AzureTableSPWebHook listWebHookRow)
{
try
{
if (null == Table)
{
CloudTable table = await Utilities.GetCloudTableByName("SharePointWebHooks");
}
listWebHookRow.ETag = "*";
TableOperation insertOrReplace = TableOperation.InsertOrReplace(listWebHookRow);
await Table.ExecuteAsync(insertOrReplace);
return(true);
}
catch (Exception)
{
return(false);
}
}
public static async Task RunAsync([QueueTrigger("processchanges", Connection = "AzureWebJobsStorage")] WebhookNotification notificationModel, ILogger log)
{
log.LogInformation($"ProcesResourceChange queue trigger function process Site:{notificationModel.SiteUrl} Resource{notificationModel.Resource} ");
string tenant = System.Environment.GetEnvironmentVariable("Tenant", EnvironmentVariableTarget.Process);
string siteUrl = $"https://{tenant}.sharepoint.com{notificationModel.SiteUrl}";
log.LogInformation("Getting Azure SharePoint Token");
LoginEntity loginDetails = await LoginUtil.CertificateLoginDetails();
OfficeDevPnP.Core.AuthenticationManager authManager = new OfficeDevPnP.Core.AuthenticationManager();
log.LogInformation("Connecting to SharePoint");
using (ClientContext clientContext = authManager.GetAzureADAppOnlyAuthenticatedContext(siteUrl, loginDetails.ClientId, loginDetails.Tenant, loginDetails.Certificate))
{
log.LogInformation("Getting SharePoint List");
Guid listId = new Guid(notificationModel.Resource);
List list = clientContext.Web.Lists.GetById(listId);
// 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, false)
{
Item = true,
Add = true,
DeleteObject = false,
Update = true,
FetchLimit = 1000
};
ChangeToken lastChangeToken = null;
if (null == notificationModel.ClientState)
{
throw new ApplicationException("Webhook doesn't contain a Client State");
}
Guid id = new Guid(notificationModel.ClientState);
log.LogInformation("Checking Database for Change Token");
AzureTableSPWebHook listWebHookRow = await AzureTable.GetListWebHookByID(id, listId);
if (!string.IsNullOrEmpty(listWebHookRow.LastChangeToken))
{
log.LogInformation("Change Token found");
lastChangeToken = new ChangeToken
{
StringValue = listWebHookRow.LastChangeToken
};
}
//Start pulling down the changes
bool allChangesRead = false;
do
{
if (lastChangeToken == null)
{
log.LogInformation("Change Token not found grabbing the last 5 days of changes");
//If none found, grab only the last 5 day changes.
lastChangeToken = new ChangeToken
{
StringValue = string.Format("1;3;{0};{1};-1", notificationModel.Resource, DateTime.Now.AddDays(-5).ToUniversalTime().Ticks.ToString())
};
}
//Assing the change token to the query..this determins from what point in time we'll receive changes
changeQuery.ChangeTokenStart = lastChangeToken;
ChangeCollection changes = list.GetChanges(changeQuery);
clientContext.Load(list);
clientContext.Load(changes);
await clientContext.ExecuteQueryAsync();
if (changes.Count > 0)
{
log.LogInformation($"Found {changes.Count} changes");
foreach (Change change in changes)
{
lastChangeToken = change.ChangeToken;
if (change is ChangeItem item)
{
log.LogInformation($"Change {change.ChangeType} on Item:{item.ItemId} on List:{list.Title} Site:{notificationModel.SiteUrl}");
}
}
if (changes.Count < changeQuery.FetchLimit)
{
allChangesRead = true;
}
}
else
{
allChangesRead = true;
}
} while (allChangesRead == false);
if (!listWebHookRow.LastChangeToken.Equals(lastChangeToken.StringValue, StringComparison.InvariantCultureIgnoreCase))
{
listWebHookRow.LastChangeToken = lastChangeToken.StringValue;
log.LogInformation("Updating change token");
await AzureTable.InsertOrReplaceListWebHook(listWebHookRow);
}
if (notificationModel.ExpirationDateTime.AddDays(-30) < DateTime.Now)
{
bool updateResult = list.UpdateWebhookSubscription(new Guid(notificationModel.SubscriptionId), DateTime.Now.AddMonths(2));
if (!updateResult)
{
log.LogError($"The expiration date of web hook {notificationModel.SubscriptionId} with endpoint 'https://{Environment.GetEnvironmentVariable("WEBSITE_HOSTNAME")}/SharePointWebHook' could not be updated");
}
else
{
log.LogInformation($"The expiration date of web hook {notificationModel.SubscriptionId} with endpoint 'https://{Environment.GetEnvironmentVariable("WEBSITE_HOSTNAME")}/SharePointWebHook' successfully updated until {DateTime.Now.AddMonths(2).ToLongDateString()} ");
}
}
}
}
