static void Main(string[] args)
{
var noSql = new MFlixNoSqlDbContext(
"mongodb+srv://######:########@freecluster-omk9a.mongodb.net/test?retryWrites=true&w=majority",
"sample_mflix"
);
FilterDefinition <ChangeStreamDocument <Movie> > filterBuilder =
Builders <ChangeStreamDocument <Movie> > .Filter
.In(x => x.OperationType, new[] { ChangeStreamOperationType.Insert }.ToList());
var options = new ChangeStreamOptions {
FullDocument = ChangeStreamFullDocumentOption.UpdateLookup
};
PipelineDefinition <ChangeStreamDocument <Movie>, ChangeStreamDocument <Movie> > pipeline =
new EmptyPipelineDefinition <ChangeStreamDocument <Movie> >()
.Match <ChangeStreamDocument <Movie>, ChangeStreamDocument <Movie> >(filterBuilder);
IChangeStreamCursor <ChangeStreamDocument <Movie> > cursor = noSql.GetCollection <Movie>("movies")
.Watch(pipeline, options);
using (IEnumerator <ChangeStreamDocument <Movie> > enumerator = cursor.ToEnumerable().GetEnumerator())
{
while (enumerator.MoveNext())
{
ChangeStreamDocument <Movie> doc = enumerator.Current;
Console.WriteLine(doc?.DocumentKey);
Console.WriteLine(doc?.FullDocument.Title);
}
}
Console.WriteLine("Done!");
}
void startListeningToNotification(CancellationToken cancellationToken)
{
try
{
using (IChangeStreamCursor <ChangeStreamDocument <Notification> > cursor = _collection.Watch(_userLogin, cancellationToken))
{
try
{
// might want to actually create an event inside the DAO
// that way we are not depending on IChangeStreamCursor in the service
// this might make unit tests much harder
// Could also return cursor.ToEnumerable(cancellationToken) inside the DAO that way it simply returns IEnumerable<ChangeStreamDocument<Notification>>
// ChangeStreamDocument<Notification> can easily be faked by creating a bson document
foreach (var notif in cursor.ToEnumerable(cancellationToken))
{
cancellationToken.ThrowIfCancellationRequested();
OnNewNotification?.Invoke(new NewNotificationEventArgs(
new NewNotificationDTO
{
Id = notif.FullDocument.Id,
Message = notif.FullDocument.Message,
DtgUtc = notif.FullDocument.EventDtgUtc,
Type = notif.FullDocument.Type
}
));
}
}
catch (OperationCanceledException ex)
{
Console.WriteLine("Operation was canceled");
throw ex;
}
catch (Exception ex)
{
notificationServiceErrorCount++;
if (notificationServiceErrorCount > 2)
{
throw ex;
}
}
}
}
catch (OperationCanceledException)
{
Console.WriteLine("Notification service cancellation requested");
}
catch (Exception ex)
{
Console.WriteLine("Notification service error:");
Console.WriteLine(ex);
}
}