dart_nats_streaming 0.0.7

A client for NATS Streaming Server.

Dart-NATS-Streaming

A null-safety Dart client for the NATS Streaming messaging system. Design to use with Dart and flutter.

This project is still in pre-release and not all features are yet implemented..

Publisher Example:

Run the example/publisher.dart:

dart example/publisher.dart

import 'dart:async';

import 'package:dart_nats_streaming/dart_nats_streaming.dart';

void main() async {
  final stan = Client();

  stan.onConnect(function: () {
    print('Stan connected..');
  });

  stan.onDisconnect(function: () {
    print('Stan disconnected..');
  });

  await stan.connect(host: 'localhost', clusterID: 'my-cluster-id');

  var counter = 0;
  Timer.periodic(Duration(seconds: 1), (timer) {
    counter++;
    print('Publishing: this is an event (#$counter) on topic: test');
    stan.pubString(subject: 'test', string: 'this is an event (#$counter}) on topic: test');
  });
}

Subscriber Example:

Run the example/publisher.dart:

dart example/publisher.dart

import 'package:dart_nats_streaming/dart_nats_streaming.dart';

void main() async {
  final stan = Client();

  stan.onConnect(function: () {
    print('Stan connected..');
  });

  stan.onDisconnect(function: () {
    print('Stan disconnected..');
  });

  await stan.connect(host: 'localhost', clusterID: 'my-cluster-id');
  final subscription = await stan.subscribe(subject: 'test', queueGroup: 'my-queue-group', durableName: 'my-dourable-name');
  await for (final dataMessage in subscription!.stream) {
    print(dataMessage.asString());
    stan.acknowledge(subscription, dataMessage);
  }
}

Flutter Examples:

Import and Declare object

import 'package:dart_nats_streaming/dart_nats_streaming.dart';

  final stan = Client();
  Subscription testSubscription;

Simply connect to server and subscribe to subject

  void connect() async {
    await stan.connect(host: 'localhost', clusterID: 'my-cluster-id');
    testSubscription = await stan.subscribe(subject: 'test', queueGroup: 'my-queue-group', durableName: 'my-dourable-name');
  }

Use as Stream in StreamBuilder

          StreamBuilder(
            stream: testSubscription.stream,
            builder: (context, AsyncSnapshot<DataMessage> snapshot) {
              stan.acknowledge(testSubscription, snapshot.data);
              return Text(snapshot.hasData ? '${snapshot.data.asString()}' : '');
            },
          ),

Publish Message

      stan.pubString(subject: 'subject', string: 'message string');

This project is built on top of dart_nats and was heavily inspired and copied from the stan_dart.

Contributors and PR are welcome.