Configuration API for PubNub Kotlin SDK

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

Calling Kotlin methods

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 choose one of these or the operation will not be performed at all.

For example, the following code is valid and will compile, but the publish won't be performed:

pubnub.publish(
message = "this sdk rules!",
channel = "my_channel"
)

To successfully publish a message, you must follow the actual method invocation with whether to perform it synchronously or asynchronously, for example:

pubnub.publish(
message = "this sdk rules!",
channel = "my_channel"
).async { result, status ->
if (status.error) {
// handle error
} else {
// 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.

Method(s)

val config = PNConfiguration(UserId("myUserId"))

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

PropertiesTypeRequiredDefaultDescription
subscribeKeyStringYessubscribeKey from the Admin Portal.
publishKeyStringOptionalpublishKey from the Admin Portal (only required if publishing).
secretKeyStringOptionalsecretKey (only required for access operations, keep away from Android).
userIdUserIdYesuserId 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 64 alphanumeric characters.

If you don't set the userId, you won't be able to connect to PubNub.
logVerbosityPNLogVerbosityOptionalPNLogVerbosity.NONESet PNLogVerbosity.BODY to enable debug logging. To disable debugging use the option PNLogVerbosity.NONE.
authKeyStringOptionalIf Access Manager is utilized, client will use this authKey in all restricted requests.
cacheBustingBooleanOptionalfalseIf operating behind a misbehaving proxy, allow the client to shuffle the subdomains.
secureBooleanOptionaltrueWhen true, TLS is enabled.
connectTimeoutIntOptional5How long before the client gives up trying to connect with a subscribe call. The unit is seconds.
subscribeTimeoutIntOptional310The subscribe request timeout. The unit is seconds.
nonSubscribeRequestTimeoutIntOptional10For non subscribe operations (publish, herenow, etc), how long to wait to connect to PubNub before giving up with a connection timeout error. The unit is seconds.
filterExpressionStringOptionalFeature to subscribe with a custom filter expression.
heartbeatNotificationOptionsPNHeartbeatNotificationOptionsOptionalPNHeartbeatNotificationOptions.FAILURESHeartbeat 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).
originStringOptionalCustom origin if needed.
presenceTimeoutIntOptional300Sets the custom presence server timeout.
The value is in seconds, and the minimum value is 20 seconds. When set explicitly, also updates the heartbeatInterval.
heartbeatIntervalIntOptional0Sets a custom heartbeat interval at which to ping the server.
Heartbeats are disabled by default, hence the default value is 0 seconds.
proxyProxyOptionalInstructs the SDK to use a proxy configuration when communicating with PubNub servers. For more details refer to Oracle documentation.
proxySelectorProxySelectorOptionalSets Java ProxySelector. For more details, refer to Oracle documentation.
proxyAuthenticatorAuthenticatorOptionalSets Java Authenticator. For more details refer to Oracle documentation
googleAppEngineNetworkingBooleanOptionalEnable Google App Engine networking.
suppressLeaveEventsBooleanOptionalfalseWhen true the SDK doesn't send out the leave requests.
enableEventEngineBooleanOptionaltrueWhether to use the standardized workflows for subscribe and presence. Read Connection status listeners for more information.
retryConfigurationRetryConfigurationOptionalRetryConfiguration.NoneCustom 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 Reconnection Policy.
maintainPresenceStateBooleanOptionaltrueWhether the state set using PubNub.setPresenceState() should be maintained for the current userId. This option works only when enableEventEngine is set to true.
cryptoModuleCryptoModule.createAesCbcCryptoModule(cipherKey)

CryptoModule.createLegacyCryptoModule(cipherKey)
OptionalNoneThe 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.
reconnectionPolicyPNReconnectionPolicyOptionalPNReconnectionPolicy.NONEThis parameter is deprecated, use retryConfiguration instead.

Set to PNReconnectionPolicy.LINEAR for automatic reconnects.
Use PNReconnectionPolicy.NONE to disable automatic reconnects.
Use PNReconnectionPolicy.EXPONENTIAL to set exponential retry interval.
maximumReconnectionRetriesIntOptional-1This parameter is deprecated, use retryConfiguration instead.

The property configures how many times to retry to reconnect before giving up.
The default is -1 which means endless retries.

A reconnectionPolicy must be set in order for this property to take effect.
cipherKeyStringOptionalThis way of setting this parameter is deprecated, pass it to cryptoModule instead.

If passed, all communications to and from PubNub will be encrypted.
useRandomInitializationVectorBooleanOptionaltrueThis way of setting this parameter is deprecated, pass it to cryptoModule instead.

When true the initialization vector (IV) is random for all requests (not just for file upload). When false the IV is hard-coded for all requests except for file upload.
uuidStringYesThis parameter is deprecated, use userId instead.

UUID to use. You should set a unique UUID to identify the user or the device that connects to PubNub.If you don't set the UUID, you won't be able to connect to PubNub.
Disabling random initialization vector

Disable random initialization vector (IV) only for backward compatibility (<6.0.0) with existing applications. Never disable random IV on new applications.

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:

// encrypts using 256-bit AES-CBC cipher (recommended)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
config.cryptoModule = CryptoModule.createAesCbcCryptoModule("enigma")

// encrypts with 128-bit cipher key entropy (legacy)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
config.cryptoModule = CryptoModule.createLegacyCryptoModule("enigma")

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

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.

val config = PNConfiguration(UserId("myUserId"))

// subscribeKey from Admin Portal
// required
config.subscribeKey = "SubscribeKey"

// publishKey from Admin Portal (only required if publishing)
config.publishKey = "PublishKey"

// secretKey (only required for access operations, keep away from Android)
config.secretKey = "SecretKey"

// the cryptography module used for encryption and decryption
config.cryptoModule = CryptoModule.createAesCbcCryptoModule("enigma")

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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:

val config = PNConfiguration(UserId("myUserId"))
ParameterTypeRequiredDescription
PNConfigurationPNConfigurationYesRefer 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.

val pnConfiguration = PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
publishKey = "my_pubkey"
secure = true
}
val pubnub = PubNub(pnConfiguration)

Returns

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

Other Examples

Initialize a non-secure client

val PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
publishKey = "my_pubkey"
secure = false
}
val pubnub = PubNub(pnConfiguration)

Initialization for a Read-Only client

val PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
}
val pubnub = PubNub(pnConfiguration)

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.

val PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
publishKey = "my_pubkey"
secure = true
}
val pubnub = PubNub(pnConfiguration)

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:

val PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
publishKey = "my_pubkey"
secretKey = "my_secretkey"
secure = true
}
val pubnub = PubNub(pnConfiguration)

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

val PNConfiguration(UserId("myUserId")).apply {
subscribeKey = "my_subkey"
publishKey = "my_pubkey"
secretKey = "my_secretkey"
proxy = Proxy(
Proxy.Type.HTTP,
InetSocketAddress("http://mydomain.com", 8080)
)
}
val pubnub = PubNub(pnConfiguration)

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.

Methods

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

val PNConfiguration(UserId("myUserId")).apply
ParameterTypeRequiredDefaultDescription
userIdUserIdYesuserId 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.

val PNConfiguration(UserId("myUserId")).apply

// get uuid
pnConfiguration.userId

Authentication Key

Setter and getter for users' authentication key.

Method(s)

val pnConfiguration = PNConfiguration()

pnConfiguration.authKey = String
ParameterTypeRequiredDescription
authKeyStringYesIf Access Manager is utilized, client will use this authKey in all restricted requests.

Basic Usage

val pnConfiguration = PNConfiguration()

// set authKey
pnConfiguration.authKey = "myAuthKey"

// get authKey
pnConfiguration.authKey

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)

val pnConfiguration = PNConfiguration()

pnConfiguration.filterExpression = String
ParameterTypeRequiredDescription
filterExpressionStringYesPSV2 feature to subscribe with a custom filter expression.

Basic Usage

val pnConfiguration = PNConfiguration()

// set filterExpression
pnConfiguration.filterExpression = "such=wow"

// get filterExpression
pnConfiguration.filterExpression
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