dart_nats 0.4.0

A Dart client for the NATS messaging system. Design to use with Dart and flutter.

Dart-NATS

A Dart client for the NATS messaging system. Design to use with Dart and flutter.

Flutter Web Support by WebSocket

client.connect(Uri.parse('ws://localhost:80'));

Flutter Other Platform Support by TCP Socket and WebSocket

client.connect(Uri.parse('nats://localhost'));
client.connect(Uri.parse('ws://localhost:80'));

API Change from version 0.2.x

To support Flutter Web. We change default transport from TCP socket to WebSocket.

Dart Examples:

Run the example/main.dart:

dart example/main.dart

import 'package:dart_nats/dart_nats.dart';

void main() async {
  var client = Client();
  client.connect(Uri.parse('ws://localhost:80'));
  var sub = client.sub('subject1');
  client.pubString('subject1', 'message1');
  var msg = await sub.stream.first;

  print(msg.string);
  client.unSub(sub);
  client.close();
}

Flutter Examples:

Import and Declare object

import 'package:dart_nats/dart_nats.dart' as nats;

  nats.Client natsClient;
  nats.Subscription fooSub, barSub;

Simply connect to server and subscribe to subject

  void connect() {
    natsClient = nats.Client();
    natsClient.connect(Uri.parse('wss://demo.nats.io:443');
    fooSub = natsClient.sub('foo');
    barSub = natsClient.sub('bar');
  }

Use as Stream in StreamBuilder

          StreamBuilder(
            stream: fooSub.stream,
            builder: (context, AsyncSnapshot<nats.Message> snapshot) {
              return Text(snapshot.hasData ? '${snapshot.data.string}' : '');
            },
          ),

Publish Message

      natsClient.pubString('subject','message string');

Token Authtication

var client = Client();
client.connect(Uri.parse('ws://localhost:8084'),
          connectOption: ConnectOption(auth_token: 'mytoken'));

User/Passwore Authentication

var client = Client();
client.connect(Uri.parse('ws://localhost:8085'),
          connectOption: ConnectOption(user: 'foo', pass: 'bar'));

NKEY Authentication

var client = Client();
client.seed =
    'SUACSSL3UAHUDXKFSNVUZRF5UHPMWZ6BFDTJ7M6USDXIEDNPPQYYYCU3VY';
client.connect(
  Uri.parse('ws://localhost:8086'),
  retryInterval: 1,
  connectOption: ConnectOption(
    nkey: 'UDXU4RCSJNZOIQHZNWXHXORDPRTGNJAHAHFRGZNEEJCPQTT2M7NLCNF4',
  ),
);

JWT Authentication

var client = Client();
client.seed =
    'SUAJGSBAKQHGYI7ZVKVR6WA7Z5U52URHKGGT6ZICUJXMG4LCTC2NTLQSF4';
client.connect(
  Uri.parse('nats://localhost:4223'),
  retryInterval: 1,
  connectOption: ConnectOption(
    jwt:
        'eyJ0eXAiOiJKV1QiLCJhbGciOiJlZDI1NTE5LW5rZXkifQ.eyJqdGkiOiJBU1pFQVNGMzdKS0dPTFZLTFdKT1hOM0xZUkpHNURJUFczUEpVT0s0WUlDNFFENlAyVFlRIiwiaWF0IjoxNjY0NTI0OTU5LCJpc3MiOiJBQUdTSkVXUlFTWFRDRkUzRVE3RzVPQldSVUhaVVlDSFdSM0dRVERGRldaSlM1Q1JLTUhOTjY3SyIsIm5hbWUiOiJzaWdudXAiLCJzdWIiOiJVQzZCUVY1Tlo1V0pQRUVZTTU0UkZBNU1VMk5NM0tON09WR01DU1VaV1dORUdZQVBNWEM0V0xZUCIsIm5hdHMiOnsicHViIjp7fSwic3ViIjp7fSwic3VicyI6LTEsImRhdGEiOi0xLCJwYXlsb2FkIjotMSwidHlwZSI6InVzZXIiLCJ2ZXJzaW9uIjoyfX0.8Q0HiN0h2tBvgpF2cAaz2E3WLPReKEnSmUWT43NSlXFNRpsCWpmkikxGgFn86JskEN4yast1uSj306JdOhyJBA',
  ),
);

Dispose

  void dispose() {
    natsClient.close();
    super.dispose();
  }

Full Flutter sample code example/flutter/main.dart

Features

The following is a list of features currently supported and planned by this client:

• • Publish
• • Subscribe, unsubscribe
• • NUID, Inbox
• • Reconnect to single server when connection lost and resume subscription
• • Unsubscribe after N message
• • Request, Respond
• • Queue subscribe
• • Request timeout
• • Events/status
• • Buffering message during reconnect atempts
• • All authentication models, including NATS 2.0 JWT and nkey
• • NATS 2.x
• • Structured data
• • Connect to cluster
• • TLS