Configuration 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.

Kotlin complete API reference for building real-time applications on PubNub, including basic usage and sample code.

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.

1val channel = pubnub.channel("channelName")
2

3channel.publish("This SDK rules!").async { result ->
4    result.onFailure { exception ->
5        // Handle error
6    }.onSuccess { value ->
7        // Handle successful method result
8    }
9}

Configuration

PNConfiguration instance is storage for user-provided information which describes further PubNub client behavior. The configuration instance contains additional set of properties which allow performing precise PubNub client configuration.

Immutable configuration

Once a configuration object has been passed to the PubNub constructor, you can't change its properties.

If you require changing values dynamically consider using value overrides.

Method(s)

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To create a pnConfiguration instance you can use the following properties in the Kotlin SDK:

* required

Parameter	Description
subscribeKey * Type: String Default: n/a	subscribeKey from the Admin Portal.
publishKey Type: String Default: n/a	publishKey from the Admin Portal (only required if publishing).
secretKey Type: String Default: n/a	secretKey (only required for access operations, keep away from Android).
userId * Type: UserId Default: n/a	userId to use. The UserId object takes String as an argument. You should set a unique identifier for the user or the device that connects to PubNub. It's a UTF-8 encoded string of up to 92 alphanumeric characters. If you don't set the userId, you won't be able to connect to PubNub.
customLoggers Type: List<CustomLogger> Default: n/a	Your custom logger implementations. See Logging.
cacheBusting Type: Boolean Default: false	If operating behind a misbehaving proxy, allow the client to shuffle the subdomains.
secure Type: Boolean Default: true	When true, TLS is enabled.
connectTimeout Type: Int Default: 5	Maximum time to establish a connection, in seconds.
subscribeTimeout Type: Int Default: 310	Subscribe request timeout, in seconds.
nonSubscribeRequestTimeout Type: Int Default: 10	Non-subscribe request timeout, in seconds.
filterExpression Type: String Default: n/a	Subscribe with a custom filter expression.
heartbeatNotificationOptions Type: PNHeartbeatNotificationOptions Default: PNHeartbeatNotificationOptions.FAILURES	Heartbeat notification options. By default, the SDK alerts on failed heartbeats (equivalent to PNHeartbeatNotificationOptions.FAILURES). Other options including all heartbeats (PNHeartbeatNotificationOptions.ALL) and no heartbeats (PNHeartbeatNotificationOptions.NONE).
origin Type: String Default: n/a	Custom origin if needed. To request a custom domain, contact support and follow the request process.
presenceTimeout Type: Int Default: 300	How long the server considers the client alive for presence. The client sends periodic heartbeats to stay active. If no heartbeat arrives within the timeout, the client is marked inactive and a "timeout" event is emitted on the presence channel. Minimum 20 seconds. Updates heartbeatInterval when set.
heartbeatInterval Type: Int Default: 0	How often the client sends heartbeats. To shorten presence timeout, set roughly to (presenceTimeout / 2) - 1. Minimum 3. Default 0 (disabled).
proxy Type: Proxy Default: n/a	Instructs the SDK to use a proxy configuration when communicating with PubNub servers. For more details refer to Oracle documentation.
proxySelector Type: ProxySelector Default: n/a	Sets Java ProxySelector. For more details, refer to Oracle documentation.
proxyAuthenticator Type: Authenticator Default: n/a	Sets Java Authenticator. For more details refer to Oracle documentation
googleAppEngineNetworking Type: Boolean Default: n/a	Enable Google App Engine networking.
suppressLeaveEvents Type: Boolean Default: false	When true the SDK doesn't send out the leave requests.
retryConfiguration Type: RetryConfiguration Default: RetryConfiguration.Exponential (subscribe only)	Custom reconnection configuration parameters. You can specify one or more endpoint groups for which the retry policy won't be applied. RetryConfiguration is the type of policy to be used. Available values: RetryConfiguration.None RetryConfiguration.Linear(delayInSec, maxRetryNumber, excludedOperations RetryConfiguration.Exponential(minDelayInSec, maxDelayInSec, maxRetryNumber, excludedOperations excludedOperations takes a list of RetryableEndpointGroup enums, for example, RetryableEndpointGroup.SUBSCRIBE. For more information, refer to SDK connection lifecycle.
maintainPresenceState Type: Boolean Default: true	Whether the custom presence state information set using pubnub.setPresenceState() should be sent every time the SDK sends a subscribe call.
cryptoModule Type: CryptoModule.createAesCbcCryptoModule(cipherKey) CryptoModule.createLegacyCryptoModule(cipherKey) Default: None	The cryptography module used for encryption and decryption of messages and files. Takes the cipherKey parameter as argument. For more information, refer to the cryptoModule section.
includeInstanceIdentifier Type: Boolean Default: false	Whether to include a PubNubCore.instanceId with every request.
includeRequestIdentifier Type: Boolean Default: true	Whether to include a PubNubCore.requestId with every request.
maximumConnections Type: Int? Default: n/a	Configures the maximum number of inbound concurrent connections that PubNub will handle.
certificatePinner Type: CertificatePinner Default: n/a	Manages SSL certificates for HTTPS requests. For more details, see OkHttp's CertificatePinner documentation.
sslSocketFactory Type: SSLSocketFactory Default: n/a	Custom SSLSocketFactory used for HTTPS connections.
x509ExtendedTrustManager Type: X509ExtendedTrustManager Default: n/a	Custom X509ExtendedTrust Manager to manage which X509 certificates may be used to authenticate the remote side of a secure socket.
connectionSpec Type: ConnectionSpec Default: n/a	Specifies which TLS versions and cipher suites are supported for HTTPS. See ConnectionSpec.
hostnameVerifier Type: HostnameVerifier Default: n/a	Hostname Verifier, checks whether the hostname is allowed within an SSL session.
fileMessagePublishRetryLimit Type: Int Default: 5	Defines how many times publishing of file messages should retry automatically before failure.
dedupOnSubscribe Type: Boolean Default: n/a	Indicates if message deduplication feature is enabled on subscription.
maximumMessagesCacheSize Type: Int Default: n/a	Specifies the maximum size of the messages cache.
pnsdkSuffixes Type: Map<String, String> Default: n/a	Maps custom suffixes for SDK identification headers.
managePresenceListManually Type: Boolean Default: n/a	Enables explicit manual management of presence list. Used with ACL on the server-side.
authKey Type: String Default: n/a	This parameter is deprecated. Refer to Manage Access to understand the permission authorization flow and to Kotlin Access Manager API for an overview of the API. If Access Manager v2 is utilized, client will use this authKey in all restricted requests.

cryptoModule

cryptoModule encrypts and decrypts messages and files. From 7.6.0, you can configure the algorithms it uses. By default, encryption is disabled.

Each SDK includes two options: legacy 128‑bit encryption and recommended 256‑bit AES‑CBC. For background, see Message Encryption and File Encryption.

For configuration details, utilities, and examples, see Encryption.

Legacy encryption with 128-bit cipher key entropy

You don't have to change your encryption configuration if you want to keep using the legacy encryption. If you want to use the recommended 256-bit AES-CBC encryption, you must explicitly set that in PubNub config.

Sample code

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.

Required User ID

Always set the UserId to uniquely identify the user or device that connects to PubNub. This UserId should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the UserId, you won't be able to connect to PubNub.

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Value override

You can provide updated values for certain configuration options for a single request to any supported API with overrideConfiguration.

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The configuration options you can override include:

• subscribeKey
• publishKey
• secretKey
• retryConfiguration
• userId
• includeInstanceIdentifier
• includeRequestIdentifier
• cryptoModule
• connectTimeout
• nonSubscribeReadTimeout

Initialization

Add PubNub to your project using one of the procedures in Getting Started.

Description

Initialize the PubNub Client API before using any APIs. This sets account-level credentials such as publishKey and subscribeKey.

Methods

Initialize PubNub with:

1

* required

Parameter	Description
builder * Type: PNConfiguration	Refer to configuration for more details.

Sample code

Required User ID

Always set the userId to uniquely identify the user or device that connects to PubNub. This userId should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the userId, you won't be able to connect to PubNub.

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Returns

Returns the PubNub instance to call APIs such as publish(), subscribe(), history(), and hereNow().

Other examples

Initialize a non-secure client

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Initialization for a Read-Only client

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Initializing with SSL enabled

This example demonstrates how to enable PubNub Transport Layer Encryption with SSL. Just initialize the client with secure set to true. The hard work is done, now the PubNub API takes care of the rest. Just subscribe and publish as usual and you are good to go.

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Initializing with Access Manager

Requires Access Manager add-on

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

Secure your secretKey

Anyone with the secretKey can grant and revoke permissions to your app. Never let your secretKey be discovered, and to only exchange it / deliver it securely. Only use the secretKey on secure server-side platforms.

When you init with secretKey, you get root permissions for the Access Manager. With this feature you don't have to grant access to your servers to access channel data. The servers get all access on all channels.

For applications that will administer Access Manager permissions, the API is initialized with the secretKey as in the following example:

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Now that the pubnub object is instantiated the client will be able to access the Access Manager functions. The pubnub object will use the secretKey to sign all Access Manager messages to the PubNub Network.

How to set proxy

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Event listeners

PubNub SDKs provide several sources for real-time updates:

• The PubNub client can receive updates from all subscriptions: all channels, channel groups, channel metadata, and users metadata.
• The Subscription object can receive updates only for the particular object for which it was created: channel, channel group, channel metadata, or user.
• The SubscriptionsSet object can receive updates for all objects for which a list of subscription objects was created.

To work with these sources, the SDK provides local representations of server entities, so you can subscribe and add handlers per entity. For details, see Publish & Subscribe.

UserId

These functions are used to set/get a user ID on the fly.

Method(s)

To set/get userId you can use the following method(s) in the Kotlin SDK:

1// Getting the userId
2val userId = pubnub.configuration.userId.value

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* required

Parameter	Description
userId * Type: UserId Default: n/a	userId to be used as a device identifier. The UserId object takes String as an argument. If you don't set the userId, you won't be able to connect to PubNub.

Sample code

Required User ID

Always set the userId to uniquely identify the user or device that connects to PubNub. This userId should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the userId, you won't be able to connect to PubNub.

Set UserId

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Get UserId

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Filter expression

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.

Stream filtering allows a subscriber to apply a filter to only receive messages that satisfy the conditions of the filter. The message filter is set by the subscribing client(s) but it is applied on the server side thus preventing unwanted messages (those that do not meet the conditions of the filter) from reaching the subscriber.

To set or get message filters, you can use the following method. To learn more about filtering, refer to the Publish Messages documentation.

Method(s)

1

* required

Parameter	Description
filterExpression * Type: String	PSV2 feature to subscribe with a custom filter expression.

Sample code

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