private async Task HandleNotificationsAsync(NotificationPayload notifications, CancellationToken cancellationToken)
{
// A single webhook might get notifications from different users.
List <WebhookTriggerData> resources = new List <WebhookTriggerData>();
foreach (Notification notification in notifications.Value)
{
var subId = notification.SubscriptionId;
var entry = await _subscriptionStore.GetSubscriptionEntryAsync(subId);
if (entry == null)
{
_log.LogError($"No subscription exists in our store for subscription id: {subId}");
// mapping of subscription ID to principal ID does not exist in file system
continue;
}
if (entry.Subscription.ClientState != notification.ClientState)
{
_log.LogTrace($"The subscription store's client state: {entry.Subscription.ClientState} did not match the notifications's client state: {notification.ClientState}");
// Stored client state does not match client state we just received
continue;
}
// call onto Graph to fetch the resource
var userId = entry.UserId;
var graphClient = await _clientManager.GetMSGraphClientFromUserIdAsync(userId, cancellationToken);
_log.LogTrace($"A graph client was obtained for subscription id: {subId}");
// Prepend with / if necessary
if (notification.Resource[0] != '/')
{
notification.Resource = '/' + notification.Resource;
}
var url = graphClient.BaseUrl + notification.Resource;
HttpRequestMessage request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri(url),
};
_log.LogTrace($"Making a GET request to {url} on behalf of subId: {subId}");
await graphClient.AuthenticationProvider.AuthenticateRequestAsync(request); // Add authentication header
var response = await graphClient.HttpProvider.SendAsync(request);
string responseContent = await response.Content.ReadAsStringAsync();
_log.LogTrace($"Recieved {responseContent} from request to {url}");
var actualPayload = JObject.Parse(responseContent);
// Superimpose some common properties onto the JObject for easy access.
actualPayload["ClientState"] = entry.Subscription.ClientState;
// Drive items only payload without resource data
string odataType = null;
if (notification.ResourceData != null)
{
odataType = notification.ResourceData.ODataType;
}
else if (notification.Resource.StartsWith("/me/drive"))
{
odataType = "#Microsoft.Graph.DriveItem";
}
actualPayload["@odata.type"] = odataType;
var data = new WebhookTriggerData
{
client = graphClient,
Payload = actualPayload,
odataType = odataType,
};
resources.Add(data);
}
_log.LogTrace($"Triggering {resources.Count} GraphWebhookTriggers");
Task[] webhookReceipts = resources.Select(item => _bindingProvider.PushDataAsync(item)).ToArray();
Task.WaitAll(webhookReceipts);
_log.LogTrace($"Finished responding to notifications.");
}
