YB.ParseLiveQueryDotNet 1.0.0

Parse-Live-Query-Unofficial

• Added Support for .NET 9 and .NET MAUI.
• Replaced previous web client with System Net WebSockets Client as I believe is better.
• Should be FULLY compatible with .NET 9 and MAUI.

Here is a full YouTube video walking through what it is, and how to use it.

https://youtu.be/OlpHIJDvl7E

Here is the full ReadMe;

Since I Updated this based on my MAUI Projects, I had to update my fork of Parse SDK to have MAUI support, thus

THIS is DEPENDENT on my ParseSDK fork.

Will release a Nuget version later for both.

What are Live Queries?

Glad you asked! So to put it VERY SIMPLE : Live Queries lets you build a RealTime Chat App in less than idk 25 lines of code? (Excluding UI ofc).

In "Long" it essentially opens a Websocket/caller-listener tunnel where WHATEVER changes done to the subscribed class/table(for sql folks), will reflect to ALL listening clients in "real time" (very very minimal delay. Like and Eye blink's delay!)

Example: You Create a Class/Table (for SQL folks) then tell the server "Whatever is done here TELL EVERYONE WHO NEEDS TO BE INFORMED ASAP ", then the client apps (your developed app) will subscribe to the EVENTUAL POSSIBILITIES of any change happening to your class/table records.

As such.

1. Device A Subscribes to class/table "Comments" found in Server.
2. Device B subscribes to "Comments" too.
3. Device A → Server (A sends to server)
4. Device A ← Server → Device B (Server sends back data to both devices ASSUMING THEY ARE ALLOWED TO VIEW THE CHANGES, you can configure this with ACL!)

I hope it's a OVERexplanation now haha! But if you any more specific questions, please shoot!

How To Use In addition to the docs over from the folks at ; For now:

STEP 0 (VERY IMPORTANT): MAKE SURE YOUR ENABLE LIVE QUERY ON THE CLASSES NEEDED.

I used Back4Apps for dev/testing so the 2 classes I needed were checked! (see on main repo)

1. Download the project's source and add to your solution , your solution will look like this

(see on main repo)

2. You will have to initialize your ParseClient with your app's details

// Check for internet connection
if (Connectivity.NetworkAccess != NetworkAccess.Internet)
{
    Console.WriteLine("No Internet Connection: Unable to initialize ParseClient.");
    return false;
}

// Create ParseClient
ParseClient client = new ParseClient(new ServerConnectionData
{
    ApplicationID = APIKeys.ApplicationId, 
    ServerURI = APIKeys.ServerUri,
    Key = APIKeys.DotNetKEY, // Or use MASTERKEY

}
);
HostManifestData manifest = new HostManifestData() // Optional but I really recommend setting just to avoid potential crashes
{
    Version = "1.0.0",
    Identifier = "com.yvanbrunel.myMauiApp",
    Name = "myAppName",
};

client.Publicize(); // Best to use if you want to access ParseClient.Instance anywhere in the app.

3. Setup Live Queries

A subscription can be very easily handled as such;

ParseLiveQueryClient LiveClient = new ParseLiveQueryClient();
 async Task SetupLiveQuery()
 {
     try
     {
         var query = ParseClient.Instance.GetQuery("CLASS_TO_SUB_TO");
         //.WhereEqualTo("IsDeleted", false); Condition where App/Server will communicate

         var subscription = LiveClient.Subscribe(query); // You subscribe here
        
//optional
 LiveClient.RegisterListener(this); // This is important is you need to reach to Web Connection changes


         sub.HandleSubscribe(async query =>
         {
             await Shell.Current.DisplayAlert("Subscribed", "Subscribed to query", "OK");
             Debug.WriteLine($"Subscribed to query: {query.GetClassName()}"); 
         })
         .HandleEvents((query, objEvent, obj) =>
         {
             var object = obj  // will be the data returned by server. Could be new data, Same data or no data (After a Create, Read/Update/ Delete respectively)

             if (objEvent == Subscription.Event.Create) // if data was added to DAB online
             {

             }
             else if (objEvent == Subscription.Event.Update) //Data was updated
             {
                 var f = Messages.FirstOrDefault(newComment);
                 if (f is not null)
                 {

                 }
             }
             else if (objEvent == Subscription.Event.Delete) //Data Removed from DB online
             {
            
             }
             Debug.WriteLine($"Event {objEvent} occurred for object: {obj.ObjectId}");
         })
         .HandleError((query, exception) =>
         {
             Debug.WriteLine($"Error in query for class {query.GetClassName()}: {exception.Message}");
         })
         .HandleUnsubscribe(query =>
         {
             Debug.WriteLine($"Unsubscribed from query: {query.GetClassName()}");
         });

         // Connect asynchronously 
//OPTIONAL, but in real world scenarios, you'd better off calling it anyway.
         await Task.Run(() => LiveClient.ConnectIfNeeded());
     }
     catch (IOException ex)
     {
         Console.WriteLine($"Connection error: {ex.Message}");
     }
     catch (Exception ex)
     {
         Debug.WriteLine($"SetupLiveQuery encountered an error: {ex.Message}");
     }
 }

If you need a connection listener, you can set a class as

public class CLASS_NAME_FOR_LISTENERCLASS: ObservableObject, IParseLiveQueryClientCallbacks
{
//You will NEED to implement 
 public void OnLiveQueryClientConnected(ParseLiveQueryClient client)
 {
     Debug.WriteLine("Client Connected");
 }

 public void OnLiveQueryClientDisconnected(ParseLiveQueryClient client, bool userInitiated)
 {
     Debug.WriteLine("Client Disconnected");
 }

 public void OnLiveQueryError(ParseLiveQueryClient client, LiveQueryException reason)
 {
     Debug.WriteLine("Error " + reason.Message);
 }

 public void OnSocketError(ParseLiveQueryClient client, Exception reason)
 {
     Debug.WriteLine("Socket Error ");
 }
}

That's it! I'll be updating the SDK with any new features if any, The .NET SDK had no Equivalent but we do now ! This is a simple "Port" with no real fixes implemented Fixes from the Parse SDK itself, and some PRs from the forked repo (and except for unwanted crashes) and no security updates (if any, after Nov 27th 2024, when I prepared this release)either. PRs are welcomed!

• Many thanks to JohnMcPherson for Parse-Live-Query-Dotnet . I would absolutely NOT have done it without you!
• Parse Community