dart_nats_client 0.1.12

A Dart client for the NATS messaging system. Design to use with Dart and flutter. Forked from https://github.com/chartchuo/dart-nats

Dart NATS Client

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

Dart Examples

All examples can be found in example folder.

Simple poll example

Run with:

dart example/simple_sub_pub.dart

import 'package:dart_nats_client/dart_nats_client.dart';

void main() async {
  // Create client instance
  var client = Client();
  // Connect to server
  await client.connect('localhost');
  // Subscribe on topic
  var sub = client.sub('subject1');
  // Publish string to topic
  client.pubString('subject1', 'message1');
  // Wait message from topic
  var msg = await sub.poll();
  // Print received message
  print(msg.string);
  // Unsubscribe from topic
  sub.unSub();
  // Close client connection
  client.close();
}

Listener example

Run with:

dart example/simple_listener.dart

import 'package:dart_nats_client/dart_nats_client.dart';

void main() async {
  // Create client instance
  var client = Client();
  // Connect to server
  await client.connect('localhost');
  // Subscribe on topic
  var sub = client.sub('subject1');
  // Subscribe on topic
  var subListener = sub.getStream().listen((msg) {
    print(msg.string);
  });
  // Publish string to topic
  client.pubString('subject1', 'message1');
  // Some delay for receiving
  await Future.delayed(Duration(milliseconds: 100));
  // Cancel listener
  await subListener.cancel();
  // Unsubscribe from topic
  sub.unSub();
  // Close client connection
  client.close();
}

Flutter Example

You can find it in example/simple_listener.dart.flutter

For run you need to init Flutter project in your folder with flutter create . and copy text from example file to lib/main.dart

App permissions

Android permissions

For android you need to add to android/app/src/profile/AndroidManifest file lines:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

For activiy in backgroud:

<!-- Allows run app in background -->
<uses-permission android:name="android.permission.REQUEST_COMPANION_RUN_IN_BACKGROUND"/>
<!-- Allows app use data in background -->
<uses-permission android:name="android.permission.REQUEST_COMPANION_USE_DATA_IN_BACKGROUND"/>

iOS permissions

For iOS you don't need any specific permissions for NATS client.

But for background activity you need to add to file ios/Runner/Info.plist lines:

<key>UIBackgroundModes</key>
<array>
  <string>audio</string>
  <string>external-accessory</string>
  <string>fetch</string>
  <string>processing</string>
  <string>remote-notification</string>
</array>

Testing

For running unit-tests use dart test in project root folder.

NOTE. For testing you need run NATS in docker. Instruction

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
• • Respond, Request example
• • Queue subscribe
• • caches, flush, drain
• • Request timeout
• • structured data
• • Connection option (cluster, timeout,ping interval, max ping, echo,... )
• • Random automatic reconnection, disable reconnect, number of attempts, pausing
• • Connect to cluster,randomize, Automatic reconnect upon connection failure base server info
• • Events/status disconnect handler, reconnect handler
• • Buffering message during reconnect atempts
• • All authentication models, including NATS 2.0 JWT and seed keys
• • TLS support