Channel Groups API for Kotlin SDK

Breaking changes in v9.0.0

PubNub Kotlin SDK version 9.0.0 unifies the codebases for Kotlin and Java SDKs, introduces a new way of instantiating the PubNub client, and changes asynchronous API callbacks and emitted status events. These changes can impact applications built with previous versions (< 9.0.0 ) of the Kotlin SDK.

For more details about what has changed, refer to Java/Kotlin SDK migration guide.

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.

Request execution

Most PubNub Kotlin SDK method invocations return an Endpoint object, which allows you to decide whether to perform the operation synchronously or asynchronously.

You must invoke the .sync() or .async() method on the Endpoint to execute the request, or the operation will not be performed.

val channel = pubnub.channel("channelName")

channel.publish("This SDK rules!").async { result ->
    result.onFailure { exception ->
        // Handle error
    }.onSuccess { value ->
        // Handle successful method result
    }
}

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 Kotlin SDK:

Maximum number of channels

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

pubnub.addChannelsToChannelGroup(
    channelGroup: String,
    channels: List<String>
).async { result -> }

* required

Parameter	Description
channelGroup * Type: String	The channel group to add the channels to.
channels * Type: List<String>	The channels to add to the channel group.

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 com.pubnub.api.PubNub
import com.pubnub.api.UserId

fun main() {
    // Configure PubNub with demo keys
    val config = com.pubnub.api.v2.PNConfiguration.builder(UserId("add-channels-demo"), "demo").apply {
        publishKey = "demo"
    }
    
    val pubnub = PubNub.create(config.build())
    
    // Set up channel names and channel group name
    val channelA = "demo-channel-a"
    val channelB = "demo-channel-b"
    val channelC = "demo-channel-c"

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Response

The addChannelsToChannelGroup() doesn't return actionable data, be sure to check the status object on the outcome of the operation by checking the status.error.

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 Kotlin SDK:

pubnub.listChannelsForChannelGroup(
    channelGroup: String
).async { result -> }

* required

Parameter	Description
channelGroup * Type: String	Channel group to fetch the belonging channels

Basic Usage

pubnub.listChannelsForChannelGroup(
    channelGroup = "cg1"
).async { result ->
    result.onFailure { exception ->
        // Handle error
    }.onSuccess { value ->
        // Handle successful method result
    }
}

Returns

The listChannelsForChannelGroup() operation returns a PNChannelGroupsAllChannelsResult which contains the following operations:

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

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 Kotlin SDK:

pubnub.removeChannelsFromChannelGroup(
    channels: List<String>,
    channelGroup: String
).async { result -> }

* required

Parameter	Description
channels * Type: List<String>	The channels to remove from the channel group
channelGroup * Type: String	The channel group to remove channels from

Basic Usage

pubnub.removeChannelsFromChannelGroup(
    channelGroup = "cg1"
).async { result -> }

Returns

The removeChannelsFromChannelGroup() doesn't return actionable data, be sure to check the status object on the outcome of the operation by checking the status.error.

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 the channel group.

Method(s)

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

pubnub.deleteChannelGroup(
    channelGroup: String
).async { result -> }

* required

Parameter	Description
channelGroup * Type: String	The channel group to remove

Basic Usage

pubnub.deleteChannelGroup(
    channelGroup = "cg1"
).async { result -> }

Returns

The deleteChannelGroup() doesn't return actionable data, be sure to check the status object on the outcome of the operation by checking the status.error.