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Description:

pubnub

PubNub Dart SDK #

pubnub is a Flutter-friendly SDK written in Dart that allows you to connect to PubNub Data Streaming Network and add real-time features to your application.

Installation #
Using pub dependency management tool #
pubnub uses the standard pub tool for package management to distribute Dart code.
To add the package to your Dart or Flutter project, add pubnub as a dependency in your pubspec.yaml.
dependencies:
pubnub: ^4.3.4
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After adding the dependency to pubspec.yaml, run the dart pub get command in the root directory of your project (the same that the pubspec.yaml is in).
Using Git #
If you want to use the latest, unreleased version of pubnub, you can add it to pubspec.yaml as a Git package.
dependencies:
pubnub:
git: git://github.com/pubnub/dart.git
path: pubnub
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Using a local copy of the repository #
If you want to copy the Dart repository and modify it locally, clone it using git clone https://github.com/pubnub/dart and then import it into pubspec.yaml as follows:
dependencies:
pubnub:
path: ../path-to-cloned-pubnub-repo
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Importing #
After you install the pubnub package, import it in your application.
You can import it in one of two ways:
// Import all PubNub objects into your namespace
import 'package:pubnub/core.dart';

// Or import PubNub into a named namespace
import 'package:pubnub/pubnub.dart' as pn;
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Usage #
Keyset #
First, create a Keyset instance:
final myKeyset = Keyset(
subscribeKey: 'demo',
publishKey: 'demo',
uuid: UUID('demo'));
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Keyset contains all your configuration. You can use multiple Keysets (with different parameters) if you need.
If you have a PubNub account, replace demo with the key values from your PubNub dashboard. If you don't, you can use the highly rate-limited demo keys, but be aware that the keyset is public, so don't send any sensitive data.
PubNub instance #
Next, instantiate the PubNub class, passing myKeyset as a default keyset. This will be used any time a keyset is not passed into a method.
final pubnub = PubNub(defaultKeyset: myKeyset);
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Now you can use the pubnub instance to publish messages, subscribe to channels, and everything else!
Publishing messages #
To publish a message, use the publish method.
pubnub.publish('my_channel', { 'content': 'Hello world!' });
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Messages can be any JSON-serializable object.
If you are going to publish a lot of messages to one channel, you can use channel abstraction to obtain an instance of a Channel.
final myChannel = pubnub.channel('my_channel');

myChannel.publish(200);
myChannel.publish({ 'answer': 42 });
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Subscribing to channels #
To subscribe to a list of channels or channel groups, use the subscribe method.
You need to pass a Set of channels or channel groups.
var subscription = pubnub.subscribe(channels: {'ch1', 'ch2'});
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You can also use your Channel instance:
var subscription = myChannel.subscribe();
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Both of those methods return a Subscription.
A Subscription contains a Dart Stream messages from the channel(s) to which you are subscribed. You can transform that stream in the usual ways, or add a listener using listen:
subscription.messages.listen((envelope) {
print(`${envelope.uuid} sent a message: ${envelope.payload}`);
});

var envelope =
await sub.messages.firstWhere((envelope) => envelope.channel == 'ch2');
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Channel history #
You can retrieve past messages from a channel in two ways, as follows:
Using channel.history
Use this method if you want to fetch messages gradually. They are fetched in descending order (from newest to oldest) by default.
var history = myChannel.history(chunkSize: 50);

await history.more();
print(history.messages.length); // 50
await history.more();
print(history.messages.length); // 100
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Using channel.messages
Use this method to fetch many messages at once.
var history = myChannel.messages(from: Timetoken(1234567890));

var count = await history.count();
print(count);

var messages = await history.fetch();
print(messages.length);

await history.delete(); // Beware! This will delete all messages matched
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Multiple keysets #
There are two ways to use multiple keysets at the same time, as follows:
Using named keysets
You can add multiple keysets with a name to an instance of PubNub.
pubnub.keysets.add(myKeyset1, name: 'keyset1');
pubnub.keysets.add(myKeyset2, name: 'keyset2');
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To use a named keyset instead of the default, pass its name in a using: parameter into one of the pubnub instance methods:
pubnub.publish('channel', 42, using: 'keyset1');
var myChannel = pubnub.channel('channel', using: 'keyset2');
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Using a keyset instance
Instead of adding the keyset to pubnub.keysets, you can use the keyset: named parameter to pass a keyset instance directly to pubnub instance methods:
pubnub.subscribe(channels: {'channel'}, keyset: myKeyset1)
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Contributing #

Clone the repository.
git clone https://github.com/pubnub/dart.git
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Enter the directory and install dependencies.
cd dart
dart pub get
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Run the build_runner to generate necessary source files.
dart pub run build_runner build
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