Channel Groups API for Dart SDK

Channel groups allow PubNub developers to bundle thousands of channels into a group that can be identified by a name. These channel groups can then be subscribed to, receiving data from the many back-end channels the channel group contains.

Channel group operations

You can't publish to a channel group. You can only subscribe to it. To publish within the channel group, you need to publish to each channel individually.

Add Channels

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

This function adds a channel to a channel group.

Methods

Adding Channels is accomplished by using the following method(s) in the Dart SDK:

Maximum number of channels

200 channels can be added to the channel group per API call.

pubnub.channelGroups.addChannels(
  String group,
  Set<String> channels,
  {Keyset? keyset,
  String? using}
) 

* required

Parameter	Description
group * Type: String	The channel group to add the channels to.
channels * Type: Set<String>	The channels to add to the channel group.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Basic Usage

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

import 'package:pubnub/pubnub.dart';

void main() async {
  // Create PubNub instance with default keyset.
  var pubnub = PubNub(
    defaultKeyset: Keyset(
      subscribeKey: 'demo',
      publishKey: 'demo',
      userId: UserId('myUniqueUserId')
    ),
  );

  // Define the channel group and channels to add.
  var group = 'cg1';
  var channels = {'ch1', 'ch2'};

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Response

The addChannels() method returns a ChannelGroupChangeChannelsResult.

{
  "service": "channel-registry",
  "status": "200",
  "error": false,
  "message": "OK"
}

List Channels

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

This function lists all the channels of the channel group.

Methods

Listing channels is accomplished by using the following method(s) in the Dart SDK:

pubnub.channelGroups.listChannels(
  String group,
  {Keyset? keyset,
  String? using}
) 

* required

Parameter	Description
group * Type: String	The channel group fetch the channels.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Basic Usage

var result = await pubnub.channelGroups.listChannels('cg1');

Returns

The listChannels() operation returns a ChannelGroupListChannelsResult which contains the following operations:

Method	Description
channels Type: Set<String>	List of channels of a channel group.
name Type: String	Channel group name.

Remove Channels

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

This function removes the channels from the channel group.

Method(s)

Removing Channels is accomplished by using the following method(s) in the Dart SDK:

pubnub.channelGroups.removeChannels(
  String group,
  Set<String> channels,
  {Keyset? keyset,
  String? using}
)

* required

Parameter	Description
group * Type: String	The channel group to remove the channels from.
channels * Type: Set<String>	The channels to remove from the channel group.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Basic Usage

var result = await pubnub.channelGroups.removeChannels('cg1', {'ch1'});

Returns

The removeChannels method returns a ChannelGroupChangeChannelsResult.

{
  "service": "channel-registry",
  "status": "200",
  "error": false,
  "message": "OK"
}

Delete Channel Group

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

This function removes all channels from the channel group.

Method(s)

Deleting Channel Group is accomplished by using the following method(s) in the Dart SDK:

pubnub.channelGroups.delete(
  String group,
  {Keyset? keyset,
  String? using}
) 

* required

Parameter	Description
group * Type: String	The channel group to remove all channels from.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Basic Usage

var result = await pubnub.channelGroups.delete('cg1');

Returns

The delete method returns a ChannelGroupDeleteResult.

{
"service": "channel-registry",
"status": "200",
"error": false,
"message": "OK"
}

Get Subscribed Channel Groups

Returns all the subscribed channel groups in a Set<String>.

Method(s)

Get Subscribed Channel Groups is accomplished by inspecting the following property in the Dart SDK:

// property of `Subscription` class
subscription.channelGroups

Basic Usage

var subscription = pubnub.subscribe(channelGroups: {'cg1', 'cg2'});
var subscribedChannelGroups = subscription.channelGroups;

print('subscribed channel groups are $subscribedChannelGroups');

Response

This property is of type Set<String>.

["channel1", "channel2"]