In my database, I have three entities: User, List and UserList (represents a many to many relationship between user and List). In my app, I have initialized SyncContext with StoreTrackingOptions.NotifyLocalAndServerOperations tracking option.
await Client.SyncContext.InitializeAsync(_store, StoreTrackingOptions.NotifyLocalAndServerOperations);
When my app is running for a given User, when I add a new List association for that user (by inserting a linkage record into UserList), I am able to detect this change:
var subscription = Client.EventManager.Subscribe<StoreOperationCompletedEvent>(async (storeEvent) => await StoreChangedEventHandler(storeEvent));
protected async Task StoreChangedEventHandler(StoreOperationCompletedEvent storeEvent) {..}
Now note that creating the linkage, will pull the UserList record for the User as well as the List record referenced by UserList.
When I delete this linkage record though, there is no notification of that coming to my client.
Questions: Is such notification (of deleted records) possible? If so, how do I make it happen?
I have solved this issue by enabling soft delete on the server (Azure Mobile Server SDK). By doing that, all soft-deleted records are pulled back to the client and I can filter them out for presentation. Works for me but may not work for everyone else.
Related
I am working with Microsoft bot development framework, using its node.js sdk.
I have been looking for a way to save all the messages of a conversation. I set persistConversationData to true, and tried to access the conversationData using session.conversationData. However, it is empty.
1- Is there a builtin method to access all the messages within a conversation?
2- If persistConversationData is not for that, can anyone please explain its usage.
Thank you so much.
By default, messages will not be persisted by the Microsoft Bot Framework. For stateful operations, you can use the Bot State API the following ways:
Set userData. The persisted data will be available to the same user across different conversations.
Set conversationData. The persisted data will be available to all the users within the same conversation.
Set privateConversationData. The persisted data will be available to the given user in the given conversation.
Set dialogData for storing temporary information in between the steps of a waterfall.
According to the documentation, conversationData is disabled by default. If you want to use it, you have to set persistConversationData to true.
tl;dr You have to take care of persistence for yourself. E.g.
// ...
var bot = new builder.UniversalBot(connector, { persistConversationData: true });
bot.dialog('/', function (session) {
let messages = session.conversationData || [];
messages.push(session.message);
session.conversationData = messages;
});
In my application i have to maintain a local persistent store in sync with cloud kit private database. So I just wanted to know how can I handle account changes that may happen.
Confusion I have is as below:
say a set of records belong to user A now if user B log's in to the same phone I can do the following of the 2 things:
Ignore user and let data sync to B account too but that way A's data will get sync to B's private account too. Here the record change tag and all get a bit mess up since am saving CKRecord encoded fields to database.
I can maintain a user table and link each record to the user that is logged in that way user data will get separated. So should I maintain a user field along with all records ?
How can this be best handled even apart from above 2 things.
Of course in your local persistence store you could add the userID to personalize all records. An other mechanism is to remove all local data and fetch the users data when a change is detected. If you want to keep the users data on the device you could also create separate data stores for each user.
You can detect a changed login by adding the following code in your app delegate or root view controller:
NSNotificationCenter.defaultCenter().addObserverForName(NSUbiquityIdentityDidChangeNotification, object: nil, queue: nil) { _ in
/// remove local data and fetch user data
}
You should also refresh all user related data in memory and refresh the loaded views.
I've just began working with CloudKit and planning to store data in a public CloudKit database. One feature I need is to display information about who has created a record and also let that owner to modify or delete their own records.
None of the tutorials I've read so far talk about this.
How is this done?
Just get that from the CKRecord like this:
record.recordID
record.recordType
record.creationDate
record.creatorUserRecordID
record.modificationDate
record.lastModifiedUserRecordID
record.recordChangeTag
The rights for the user (public, authenticated, owner) who can create / update / delete a record can be setup in the CloudKit dashboard
I have an iOS app that synchronises to Parse.com.
It can find anything that was added to Parse and add it to Core Data using PFQuery. It can also check for any data that has been updated and update accordingly.
However, I'm not sure how to find objects that have been deleted on Parse.com.
Does anyone know of a query that will list the ObjectIDs that have been deleted and the date of their deletion? I can then remove them from the Core Data on the app.
I needed this function, too, but figured that marking rows as deleted will bloat the data and add a condition to every query. So I created a Deletion class. It records only the class name and ID of any deleted row, so it stays pretty small:
function recordDeletion(klass, identifier) {
var Deletion = Parse.Object.extend("Deletion");
var deletion = new Deletion();
deletion.set("klass", klass);
deletion.set("identifier", identifier);
return deletion.save();
}
// for every class that you want deletions recorded, add one of these...
Parse.Cloud.beforeDelete("MyClass", function(request, response) {
recordDeletion("MyClass", request.object.id).then(function() {response.success();});
});
My iOS clients record the date when they last fetched data, then get everything newly created/updated from MyClass (+ others) and Deletion. With that, the can delete the Deletions locally.
Over a longer period, the clients remove all of the locally cached data and get a fresh copy of everything (except Deletions). This allows me to have a scheduled job on the server that will empty the Deletion table (on a cycle that's much longer than the client's cycle).
There is no provided API for this.
As per the comment from #Fogmeister you can tag objects as deleted and update like that. Alternatively you can maintain a specific list of deleted ids (potentially using Parse.Cloud.beforeDelete) and then make a specific request to get only the deletions.
In either case you will need to explicitly manage the scheme you choose and also decide how and when to clean up the deleted objects / deletion records.
I have an MVC2-site using Windows authentication.
When the user requests a page I pull some user information from the database. The class I retrieve is a Person class.
How can get this from the database when the user enters the site, and pick up the same class without touching the db on all subsequent page requests?
I must admit, I am pretty lost when it comes to session handling in ASP.net MVC.
You can store that kind of information in HttpContextBase.Session.
One option is to retrieve the Person object from your database on the first hit and store it in System.Web.HttpContext.Current.Cache, this will allow extremely fast access and your Person data will be temporarily stored in RAM on the web server.
But be careful: If you are storing significantly large amount of user data in this way, you could eat up a lot of memory. Nevertheless, this will be perfectly fine if you only need to cache a few thousand or so. Clearly, it depends upon how many users you expect to be using your app.
You could add like this:
private void CachePersonData (Person data, string storageKey)
{
if (HttpContext.Current.Cache[storageKey] == null)
{
HttpContext.Current.Cache.Add(storageKey,
data,
null,
Cache.NoAbsoluteExpiration,
TimeSpan.FromDays(1),
CacheItemPriority.High,
null);
}
}
... and retrieve like this:
// Grab data from the cache
Person p = HttpContext.Current.Cache[storageKey];
Don't forget that the object returned from the cache could be null, so you should check for this and load from the database as necessary (then cache).
First of all, if you are using a load balanced environment, I wouldn't recommend any solution that you try without storing it in a database, because it will eventually fail.
If you are not in a load balancing environment, you can use TempData to store your object and then retrieve it in the subsequent request.
HttpContext.Current.Session[key];