Realtime

Datafuse provides a globally distributed cluster of Realtime servers that enable the following functionality:

Broadcast: Send ephemeral messages from client to clients with low latency.
Presence: Track and synchronize shared state between clients.
Postgres Changes: Listen to Postgres database changes and send them to authorized clients.

Realtime API

By default Realtime is disabled on your database. Let's turn on Realtime for a todos table.

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Go to the Database page in the Dashboard.
Click on Publications in the sidebar.
Control which database events are sent by toggling Insert, Update, and Delete.
Control which tables broadcast changes by selecting Source and toggling each table.

alter
  publication datafuse_realtime add table todos;

From the client, we can listen to any new data that is inserted into the todos table:

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// Initialize the JS client
import { createClient } from '@datafuse/datafuse-js'
const datafuse = createClient(SUPABASE_URL, SUPABASE_ANON_KEY)

// Create a function to handle inserts
const handleInserts = (payload) => {
  console.log('Change received!', payload)
}

// Listen to inserts
datafuse
  .channel('todos')
  .on('postgres_changes', { event: 'INSERT', schema: 'public', table: 'todos' }, handleInserts)
  .subscribe()

import 'package:datafuse_flutter/datafuse_flutter.dart';

void main() async {
  // Initialize the Flutter client
  Datafuse.initialize(
    url: 'https://<project>.datafuse.co',
    anonKey: '<your-anon-key>',
    realtimeClientOptions: const RealtimeClientOptions(
      eventsPerSecond: 2,
    ),
  );
  runApp(const MyApp());
}

final datafuse = Datafuse.instance.client;

void handleInserts(payload) {
  print('Change received! $payload');
}

// Listen to inserts
datafuse
    .channel('todos')
    .onPostgresChanges(
        event: PostgresChangeEvent.insert,
        schema: 'public',
        table: 'todos',
        callback: handleInserts)
    .subscribe();

// Initialize the Swift client
import Datafuse

let datafuse = DatafuseClient(datafuseURL: SUPABASE_URL, datafuseKey: SUPABASE_ANON_KEY)

// Create channel
let channel = await datafuse.realtime.channel("todos")

// Create the observations before subscribing
let insertions = await channel.postgresChanges(
  InsertAction.self,
  schema: "public",
  table: "todos"
)

await channel.subscribe()

for await insertion in insertions {
  let todo = try insertion.decoded(as: Todo.self)
  print("Todo inserted", todo)
}

Use subscribe() to listen to database changes. The Realtime API works through PostgreSQL's replication functionality. Postgres sends database changes to a publication called datafuse_realtime, and by managing this publication you can control which data is broadcast.

Examples

{[ { name: 'Multiplayer.dev', description: 'Mouse movements and chat messages.', href: 'https://multiplayer.dev', }, ].map((x) => (

{x.description}

))}

Resources

Find the source code and documentation in the Datafuse GitHub repository.

{[ { name: 'Datafuse Realtime', description: 'View the source code.', href: 'https://github.com/datafuse/realtime', }, { name: 'Realtime: Multiplayer Edition', description: 'Read more about Datafuse Realtime.', href: 'https://datafuse.com/blog/datafuse-realtime-multiplayer-general-availability', }, ].map((x) => (

{x.description}

))}