@pubnub/mcp

# PubNub Dart SDK 5.2.1 – Quick Start This condensed guide shows the minimum you need to: 1. Obtain keys 2. Install the SDK 3. Initialize PubNub 4. Subscribe / listen 5. Publish 6. Run & test All code blocks are unchanged from the original documentation. --- ## Prerequisites • Dart or Flutter SDK installed • PubNub account with publish & subscribe keys --- ## 1 Get PubNub keys Create an app in the Admin Portal and copy the generated **publish** and **subscribe** keys. --- ## 2 Install the SDK ### Flutter Add to `pubspec.yaml`: ``` `dependencies: pubnub: 5.2.1 flutter: sdk: flutter ` ``` Then: ``` `flutter pub get ` ``` Android requires: ``` `uses-permission android:name="android.permission.INTERNET" /> ` ``` ### Non-Flutter (pure Dart) Add to `pubspec.yaml`: ``` `dependencies: pubnub: 5.2.1 ` ``` Then: ``` `dart pub get ` ``` Source: <https://github.com/pubnub/dart> --- ## 3 Initialize PubNub ### Flutter (excerpt) ``` `// Import required packages import 'package:flutter/material.dart'; import 'package:pubnub/pubnub.dart'; class PubNubApp extends StatefulWidget { @override _PubNubAppState createState() => _PubNubAppState(); } class _PubNubAppState extends StatePubNubApp> { // PubNub instance late PubNub pubnub; // Subscription for messages late Subscription subscription; // Channel name ` ``` ### Non-Flutter ``` `// Import required packages import 'package:pubnub/pubnub.dart'; // Create PubNub instance with default keyset var pubnub = PubNub( defaultKeyset: Keyset( subscribeKey: 'demo', // Replace with your subscribe key publishKey: 'demo', // Replace with your publish key userId: UserId('myUniqueUserId'), ), ); ` ``` --- ## 4 Subscribe & listen ### Flutter ``` `void setupPubNub() { // Create a subscription to the channel subscription = pubnub.subscribe(channels: {channel}); // Set up message listener subscription.messages.listen((message) { // Update UI with the received message setState(() { messages.add(message.content.toString()); }); print('Received message: ${message.content}'); }); // You can also listen for presence events ` ``` UI snippet: ``` `@override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text('PubNub Flutter Example'), ), body: Column( children: [ Expanded( child: ListView.builder( itemCount: messages.length, itemBuilder: (context, index) { return ListTile( title: Text(messages[index]), ); ` ``` Controller: ``` `final TextEditingController _messageController = TextEditingController(); ` ``` ### Non-Flutter ``` `// Define the channel final channel = "my_channel"; // Create a subscription to the channel final subscription = pubnub.subscribe(channels: {channel}); // Set up message listener subscription.messages.listen((message) { print('Received message: ${message.content}'); }); // You can also listen for presence events subscription.presence.listen((presence) { print('Presence event: ${presence.event}'); }); ` ``` --- ## 5 Publish messages (≤ 32 KiB JSON) ### Flutter ``` `Futurevoid> sendMessage(String text) async { if (text.isEmpty) return; try { // Publish the message to the channel final result = await pubnub.publish( channel, {'text': text, 'sender': 'flutter_user'}, ); print('Published message with timetoken: ${result.timetoken}'); } catch (e) { print('Failed to publish message: $e'); // Show error to user ` ``` ### Non-Flutter ``` `Futurevoid> publishMessage() async { try { // Message to publish final message = {'text': 'Hello, world!', 'sender': 'dart_user'}; print('Message to send: $message'); // Publish the message to the channel final result = await pubnub.publish(channel, message); print('Message "${result.description}" with timetoken: ${result.timetoken}'); } catch (e) { print('Error publishing message: $e'); } } ` ``` --- ## 6 Run Pure Dart: ``` `dart pubnub_example.dart ` ``` Sample output: ``` `Message to send: {text: Hello, world!, sender: dart_user} Received message: {text: Hello, world!, sender: dart_user} Message "Sent" with timetoken: 16967543908123456 ` ``` --- ## Complete examples ### Flutter (truncated for brevity) ``` `import 'package:flutter/material.dart'; import 'package:pubnub/pubnub.dart'; void main() { runApp(MaterialApp(home: PubNubApp())); } class PubNubApp extends StatefulWidget { @override _PubNubAppState createState() => _PubNubAppState(); } class _PubNubAppState extends StatePubNubApp> { // PubNub instance late PubNub pubnub; ` ``` ### Non-Flutter (truncated for brevity) ``` `import 'package:pubnub/pubnub.dart'; Futurevoid> main() async { // Step 1: Initialize PubNub with configuration final pubnub = PubNub( defaultKeyset: Keyset( subscribeKey: 'demo', // Replace with your subscribe key publishKey: 'demo', // Replace with your publish key userId: UserId('myUniqueUserId'), ), ); // Step 2: Define the channel final channel = "my_channel"; ` ``` Output: ``` `Message to send: {text: Hello, world!, sender: dart_user} Received message: {text: Hello, world!, sender: dart_user} Message "Sent" with timetoken: 16967543908123456 Cleanup complete. ` ``` --- ## Troubleshooting (quick list) • No connection → check keys, network, firewall • No message → verify channel name & publish result • Build errors → run `dart pub get` / `flutter pub get`, confirm imports --- ## Next steps • Presence, Storage, Access Manager • Sample apps: <https://github.com/pubnub/flutter-ref-app-simple-chat> • API reference: links throughout this doc • Community & support: Discord, support portal, AI assistant _Last updated: May 7 2025_