public async Task <ActionResult> Listen()
{
// Validate the new subscription by sending the token back to Microsoft Graph.
// This response is required for each subscription.
var query = QueryHelpers.ParseQuery(Request.QueryString.ToString());
if (query.ContainsKey("validationToken"))
{
return(Content(query["validationToken"], "plain/text"));
}
// Parse the received notifications.
else
{
try
{
Dictionary <string, Notification> notifications = new Dictionary <string, Notification>();
using (var inputStream = new System.IO.StreamReader(Request.Body))
{
JObject jsonObject = JObject.Parse(inputStream.ReadToEnd());
if (jsonObject != null)
{
// Notifications are sent in a 'value' array. The array might contain multiple notifications for events that are
// registered for the same notification endpoint, and that occur within a short timespan.
JArray value = JArray.Parse(jsonObject["value"].ToString());
foreach (var notification in value)
{
Notification current = JsonConvert.DeserializeObject <Notification>(notification.ToString());
SubscriptionStore subscription = subscriptionStore.GetSubscriptionInfo(current.SubscriptionId);
// Verify the current client state matches the one that was sent.
if (current.ClientState == subscription.ClientState)
{
// Just keep the latest notification for each resource. No point pulling data more than once.
notifications[current.Resource] = current;
}
}
if (notifications.Count > 0)
{
// Query for the changed messages.
await GetChangedMessagesAsync(notifications.Values);
}
}
}
}
catch (Exception ex)
{
logger.LogError($"ParsingNotification: { ex.Message }");
// TODO: Handle the exception.
// Still return a 202 so the service doesn't resend the notification.
}
return(new StatusCodeResult(202));
}
}
public async Task <IActionResult> Listen([FromQuery] string validationToken = null)
{
if (string.IsNullOrEmpty(validationToken))
{
try
{
// Parse the received notifications.
var plainNotifications = new Dictionary <string, ChangeNotification>();
var options = new JsonSerializerOptions
{
PropertyNameCaseInsensitive = true
};
options.Converters.Add(new JsonStringEnumConverter(JsonNamingPolicy.CamelCase));
var collection = await JsonSerializer.DeserializeAsync <ChangeNotificationCollection>(Request.Body, options);
foreach (var notification in collection.Value.Where(x => x.EncryptedContent == null))
{
SubscriptionStore subscription = subscriptionStore.GetSubscriptionInfo(notification.SubscriptionId.Value);
// Verify the current client state matches the one that was sent.
if (notification.ClientState == subscription.ClientState)
{
// Just keep the latest notification for each resource. No point pulling data more than once.
plainNotifications[notification.Resource] = notification;
}
}
if (plainNotifications.Count > 0)
{
// Query for the changed messages.
await GetChangedMessagesAsync(plainNotifications.Values);
}
if (collection.ValidationTokens != null && collection.ValidationTokens.Any())
{ // we're getting notifications with resource data and we should validate tokens and decrypt data
TokenValidator tokenValidator = new TokenValidator(identityOptions.Value.TenantId, new[] { identityOptions.Value.ClientId });
bool areValidationTokensValid = (await Task.WhenAll(
collection.ValidationTokens.Select(x => tokenValidator.ValidateToken(x))).ConfigureAwait(false))
.Aggregate((x, y) => x && y);
if (areValidationTokensValid)
{
List <NotificationViewModel> notificationsToDisplay = new List <NotificationViewModel>();
foreach (var notificationItem in collection.Value.Where(x => x.EncryptedContent != null))
{
string decryptedpublisherNotification =
Decryptor.Decrypt(
notificationItem.EncryptedContent.Data,
notificationItem.EncryptedContent.DataKey,
notificationItem.EncryptedContent.DataSignature,
await keyVaultManager.GetDecryptionCertificate().ConfigureAwait(false));
notificationsToDisplay.Add(new NotificationViewModel(decryptedpublisherNotification));
}
await notificationService.SendNotificationToClient(notificationHub, notificationsToDisplay);
return(Accepted());
}
else
{
return(Unauthorized("Token Validation failed"));
}
}
}
catch (Exception ex)
{
logger.LogError($"ParsingNotification: { ex.Message }");
// Still return a 202 so the service doesn't resend the notification.
}
return(Accepted());
}
else
{
// Validate the new subscription by sending the token back to Microsoft Graph.
// This response is required for each subscription.
return(Content(validationToken));
}
}