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.

val channel = pubnub.channel("channelName")

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

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)​


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

* required
ParameterDescription
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.
logVerbosity
Type: PNLogVerbosity
Default:
PNLogVerbosity.NONE
Set PNLogVerbosity.BODY to enable logging of network calls along with proper logging framework configuration (if any) that is described in the Logging document. To disable logging of network calls, use the PNLogVerbosity.NONE option.
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
How long before the client gives up trying to connect with the server. The unit is seconds.
subscribeTimeout
Type: Int
Default:
310
The subscribe request timeout. The unit is seconds.
nonSubscribeRequestTimeout
Type: Int
Default:
10
For non subscribe operations (publish, herenow, etc), this property relates to a read timeout that is applied from the moment the connection between a client and the server has been successfully established. It defines a maximum time of inactivity between two data packets when waiting for the server's response. The unit is seconds.
filterExpression
Type: String
Default:
n/a
Feature to 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.
presenceTimeout
Type: Int
Default:
300
Defines how long the server considers the client alive for presence. This property works similarly to the concept of long polling by sending periodic requests to the PubNub server every 300 seconds by default. These requests ensure the client remains active on subscribed channels.

If no heartbeat is received within the timeout period, the client is marked inactive, triggering a "timeout" event on the presence channel.

The value is in seconds, and the minimum value is 20 seconds. When set explicitly, also updates the heartbeatInterval.
heartbeatInterval
Type: Int
Default:
0
Specifies how often the client will send heartbeat signals to the server. This property offers more granular control over client activity tracking than presenceTimeout.

Configure this property to achieve a shorter presence timeout if needed, with the interval typically recommended to be (presenceTimeout / 2) - 1.

Heartbeats are disabled by default, hence the default value is 0 seconds.
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.
httpLoggingInterceptor
Type: HttpLoggingInterceptor
Default:
n/a
Provides HTTP request-response logging. See HttpLoggingInterceptor.
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 provides encrypt/decrypt functionality for messages and files. From the 7.6.0 release on, you can configure how the actual encryption/decryption algorithms work.

Each PubNub SDK is bundled with two ways of encryption: the legacy encryption with 128-bit cipher key entropy and the recommended 256-bit AES-CBC encryption. For more general information on how encryption works, refer to the Message Encryption and File Encryption sections.

If you do not explicitly set the cryptoModule in your app and have the cipherKey and useRandomInitializationVector params set in PubNub config, the client defaults to using the legacy 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.

cryptoModule configuration​

To configure the cryptoModule to encrypt all messages/files, you can use the following methods in the Kotlin SDK:


Your client can decrypt content encrypted using either of the modules. This way, you can interact with historical messages or messages sent from older clients while encoding new messages using the more secure 256-bit AES-CBC cipher.

Older SDK versions

Apps built using the SDK versions lower than 7.6.0 will not be able to decrypt data encrypted using the 256-bit AES-CBC cipher. Make sure to update your clients or encrypt data using the legacy algorithm.

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.

Required UserId

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.


Value override​

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


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 defined in Getting Started.

Description​

This function is used for initializing the PubNub Client API context. You must call this function before attempting to utilize any API functionality to establish account level credentials such as publishKey and subscribeKey.

Methods​

To initialize PubNub, you can use the following constructor in the Kotlin SDK:


* required
ParameterDescription
builder *
Type: PNConfiguration
Refer to configuration for more details.

Basic Usage​

Required UserId

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.


Returns​

It returns the PubNub instance for invoking PubNub APIs like publish(), subscribe(), history(), hereNow(), etc.

Other Examples​

Initialize a non-secure client​


Initialization for a Read-Only client​


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.


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:


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​


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 facilitate working with those real-time update sources, PubNub SDKs use local representations of server entities that allow you to subscribe and add handlers on a per-entity basis. For more information, refer to 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:

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

* required
ParameterDescription
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.

Basic Usage​

Required UserId

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​


Get UserId​


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)​


* required
ParameterDescription
filterExpression *
Type: String
PSV2 feature to subscribe with a custom filter expression.

Basic Usage​


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