dart_nats

Description:

dart nats

TLS, Token, User/Pass, NKey, JWT support NOW. #
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'));
client.connect(Uri.parse('wss://localhost:443'));
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Flutter Other Platform Support both TCP Socket and WebSocket #
client.connect(Uri.parse('nats://localhost:4222'));
client.connect(Uri.parse('tls://localhost:4222'));
client.connect(Uri.parse('ws://localhost:80'));
client.connect(Uri.parse('wss://localhost:443'));
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background retry #
// unawait
client.connect(Uri.parse('nats://localhost:4222'), retry: true, retryCount: -1);

// await for connect if need
await client.wait4Connected();

// listen to status stream
client.statusStream.lesten((status){
//
print(status);
});
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Turn off retry and catch exception #
try {
await client.connect(Uri.parse('nats://localhost:1234'), retry: false);
} on NatsException {
//Error handle
}
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Dart Examples: #
Run the example/main.dart:
dart example/main.dart
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import 'package:dart_nats/dart_nats.dart';

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

print(msg.string);
client.unSub(sub);
client.close();
}
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Flutter Examples: #
Import and Declare object
import 'package:dart_nats/dart_nats.dart' as nats;

nats.Client natsClient;
nats.Subscription fooSub, barSub;
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Simply connect to server and subscribe to subject
void connect() {
natsClient = nats.Client();
natsClient.connect(Uri.parse('nats://hostname');
fooSub = natsClient.sub('foo');
barSub = natsClient.sub('bar');
}
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Use as Stream in StreamBuilder
StreamBuilder(
stream: fooSub.stream,
builder: (context, AsyncSnapshot<nats.Message> snapshot) {
return Text(snapshot.hasData ? '${snapshot.data.string}' : '');
},
),
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Publish Message
await natsClient.pubString('subject','message string');
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Request
var client = Client();
client.inboxPrefix = '_INBOX.test_test';
await client.connect(Uri.parse('nats://localhost:4222'));
var receive = await client.request(
'service', Uint8List.fromList('request'.codeUnits));
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Structure Request
var client = Client();
await client.connect(Uri.parse('nats://localhost:4222'));
client.registerJsonDecoder<Student>(json2Student);
var receive = await client.requestString<Student>('service', '');
var student = receive.data;


Student json2Student(String json) {
return Student.fromJson(jsonDecode(json));
}
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Dispose
void dispose() {
natsClient.close();
super.dispose();
}
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Authentication #
Token Authtication
var client = Client();
client.connect(Uri.parse('nats://localhost'),
connectOption: ConnectOption(authToken: 'mytoken'));
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User/Passwore Authentication
var client = Client();
client.connect(Uri.parse('nats://localhost'),
connectOption: ConnectOption(user: 'foo', pass: 'bar'));
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NKEY Authentication
var client = Client();
client.seed =
'SUACSSL3UAHUDXKFSNVUZRF5UHPMWZ6BFDTJ7M6USDXIEDNPPQYYYCU3VY';
client.connect(
Uri.parse('nats://localhost'),
connectOption: ConnectOption(
nkey: 'UDXU4RCSJNZOIQHZNWXHXORDPRTGNJAHAHFRGZNEEJCPQTT2M7NLCNF4',
),
);
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JWT Authentication
var client = Client();
client.seed =
'SUAJGSBAKQHGYI7ZVKVR6WA7Z5U52URHKGGT6ZICUJXMG4LCTC2NTLQSF4';
client.connect(
Uri.parse('nats://localhost'),
connectOption: ConnectOption(
jwt:
'''eyJ0eXAiOiJKV1QiLCJhbGciOiJlZDI1NTE5LW5rZXkifQ.eyJqdGkiOiJBU1pFQVNGMzdKS0dPTFZLTFdKT1hOM0xZUkpHNURJUFczUEpVT0s0WUlDNFFENlAyVFlRIiwiaWF0IjoxNjY0NTI0OTU5LCJpc3MiOiJBQUdTSkVXUlFTWFRDRkUzRVE3RzVPQldSVUhaVVlDSFdSM0dRVERGRldaSlM1Q1JLTUhOTjY3SyIsIm5hbWUiOiJzaWdudXAiLCJzdWIiOiJVQzZCUVY1Tlo1V0pQRUVZTTU0UkZBNU1VMk5NM0tON09WR01DU1VaV1dORUdZQVBNWEM0V0xZUCIsIm5hdHMiOnsicHViIjp7fSwic3ViIjp7fSwic3VicyI6LTEsImRhdGEiOi0xLCJwYXlsb2FkIjotMSwidHlwZSI6InVzZXIiLCJ2ZXJzaW9uIjoyfX0.8Q0HiN0h2tBvgpF2cAaz2E3WLPReKEnSmUWT43NSlXFNRpsCWpmkikxGgFn86JskEN4yast1uSj306JdOhyJBA''',
),
);
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Full Flutter sample code example/flutter/main.dart
Features #
The following is a list of features currently supported:

✅

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


✅

TLS



Planned:

❌

Connect to list of servers