C#: Subscribe to channel

Subscribe to realtime changes in your database.

• Realtime is disabled by default for new Projects for better database performance and security. You can turn it on by managing replication.
• If you want to receive the "previous" data for updates and deletes, you will need to set REPLICA IDENTITY to FULL, like this: ALTER TABLE your_table REPLICA IDENTITY FULL;

Examples

Listen to broadcast messages

class CursorBroadcast : BaseBroadcast
{
    [JsonProperty("cursorX")]
    public int CursorX {get; set;}

    [JsonProperty("cursorY")]
    public int CursorY {get; set;}
}

var channel = supabase.Realtime.Channel("any");
var broadcast = channel.Register<CursorBroadcast>();
broadcast.AddBroadcastEventHandler((sender, baseBroadcast) =>
{
    var response = broadcast.Current();
});

await channel.Subscribe();

// Send a broadcast
await broadcast.Send("cursor", new CursorBroadcast { CursorX = 123, CursorY = 456 });

Listen to presence sync

  class UserPresence : BasePresence
  {
      [JsonProperty("cursorX")]
      public bool IsTyping {get; set;}

      [JsonProperty("onlineAt")]
      public DateTime OnlineAt {get; set;}
  }

  var channel = supabase.Realtime.Channel("any");
  var presenceKey = Guid.NewGuid().ToString();
  var presence = channel.Register<UserPresence>(presenceKey);
  presence.AddPresenceEventHandler(EventType.Sync, (sender, type) =>
  {
      Debug.WriteLine($"The Event Type: {type}");
      var state = presence.CurrentState;
  });

  await channel.Subscribe();

  // Send a presence update
  await presence.Track(new UserPresence { IsTyping = false, OnlineAt = DateTime.Now });

Listening to a specific table

await supabase.From<City>().On(ListenType.All, (sender, change) =>
{
    Debug.WriteLine(change.Payload.Data);
});

Listen to all database changes

var channel = supabase.Realtime.Channel("realtime", "public", "*");

channel.AddPostgresChangeHandler(ListenType.All, (sender, change) =>
{
    // The event type
    Debug.WriteLine(change.Event);
    // The changed record
    Debug.WriteLine(change.Payload);
});

await channel.Subscribe();

Listening to inserts

await supabase.From<City>().On(ListenType.Inserts, (sender, change) =>
{
    Debug.WriteLine(change.Payload.Data);
});

Listening to updates

await supabase.From<City>().On(ListenType.Updates, (sender, change) =>
{
    Debug.WriteLine(change.Payload.Data);
});

Listening to deletes

await supabase.From<City>().On(ListenType.Deletes, (sender, change) =>
{
    Debug.WriteLine(change.Payload.Data);
});

Listening to row level changes

var channel = supabase.Realtime.Channel("realtime", "public", "countries", "id", "id=eq.200");

channel.AddPostgresChangeHandler(ListenType.All, (sender, change) =>
{
    // The event type
    Debug.WriteLine(change.Event);
    // The changed record
    Debug.WriteLine(change.Payload);
});

await channel.Subscribe();