Kotlin Configuration API Reference for Realtime Apps

Kotlin V4 complete API reference for building Realtime 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

Description

PNConfiguration instance is storage for user-provided information which describe further PubNub client behavior. Configuration instance contain additional set of properties which allow performing precise PubNub client configuration.

Method(s)

val pnConfiguration = PNConfiguration()

To create a pnConfiguration instance you can use the following properties in the Kotlin V4 SDK:

Properties	Type	Required	Default	Description
subscribeKey	String	Yes		subscribeKey from the Admin Portal.
publishKey	String	Optional		publishKey from the Admin Portal (only required if publishing).
secretKey	String	Optional		secretKey (only required for access operations, keep away from Android).
cipherKey	String	Optional		If passed, all communications to and from PubNub will be encrypted.
uuid	String	Yes	SDK generated UUID	UUID to use. You should set a unique UUID to identify the user or the device that connects to PubNub. Allowing the SDK to generate a random UUID can result in significant billing impacts, particularly on an MAU pricing plan.
logVerbosity	PNLogVerbosity	Optional	PNLogVerbosity.NONE	Set PNLogVerbosity.BODY to enable debug logging. To disable debugging use the option PNLogVerbosity.NONE.
authKey	String	Optional		If Access Manager is utilized, client will use this authKey in all restricted requests.
cacheBusting	Boolean	Optional	false	If operating behind a misbehaving proxy, allow the client to shuffle the subdomains.
secure	Boolean	Optional	true	When true, TLS is enabled.
connectTimeout	Int	Optional	5	How long before the client gives up trying to connect with a subscribe call. The unit is seconds.
subscribeTimeout	Int	Optional	310	The subscribe request timeout. The unit is seconds.
nonSubscribeRequestTimeout	Int	Optional	10	For 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.
filterExpression	String	Optional		Feature to subscribe with a custom filter expression.
heartbeatNotificationOptions	PNHeartbeatNotificationOptions	Optional	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	String	Optional		Custom origin if needed.
reconnectionPolicy	PNReconnectionPolicy	Optional	PNReconnectionPolicy.NONE	Set to PNReconnectionPolicy.LINEAR for automatic reconnects. Use PNReconnectionPolicy.NONE to disable automatic reconnects. Use PNReconnectionPolicy.EXPONENTIAL to set exponential retry interval.
maximumReconnectionRetries	Int	Optional	-1	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.
presenceTimeout	Int	Optional	300	Sets the custom presence server timeout. The value is in seconds, and the minimum value is 20 seconds. When set explicitly, also updates the heartbeatInterval.
heartbeatInterval	Int	Optional	0	Sets a custom heartbeat interval at which to ping the server. Heartbeats are disabled by default, hence the default value is 0 seconds.
proxy	Proxy	Optional		Instructs the SDK to use a proxy configuration when communicating with PubNub servers. For more details refer to Oracle documentation.
proxySelector	ProxySelector	Optional		Sets Java ProxySelector. For more details, refer to Oracle documentation.
proxyAuthenticator	Authenticator	Optional		Sets Java Authenticator. For more details refer to Oracle documentation
googleAppEngineNetworking	Boolean	Optional		Enable Google App Engine networking.
suppressLeaveEvents	Boolean	Optional	false	When true the SDK doesn't send out the leave requests.

Basic Usage

Note

Always set the UUID to uniquely identify the user or device that connects to PubNub. This UUID should be persisted, and should remain unchanged for the lifetime of the user or the device. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.

val pnConfiguration = PNConfiguration()

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

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

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

// if cipherKey is passed, all communications to/from pubnub will be encrypted
pnConfiguration.cipherKey = "cipherKey"

// UUID to be used as a device identifier
// A default UUID is generated if not passed
pnConfiguration.uuid = "myUniqueUUID"

// Enable Debugging
pnConfiguration.logVerbosity = PNLogVerbosity.BODY

// if Access Manager is utilized, client will use this authKey in all restricted
// requests
pnConfiguration.authKey = "authKey"

// use SSL
pnConfiguration.secure = true

// PSV2 feature to subscribe with a custom filter expression
pnConfiguration.filterExpression = "such=wow"

// heartbeat notifications, by default, the SDK will alert on failed heartbeats.
// other options such as all heartbeats or no heartbeats are supported.
pnConfiguration.heartbeatNotificationOptions = PNHeartbeatNotificationOptions.ALL

pnConfiguration.presenceTimeout = 120

// the number of messages into the payload
pnConfiguration.requestMessageCountThreshold = 100

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 pubnub = PubNub(pnConfiguration)

Parameter	Type	Required	Description
pnConfiguration	PNConfiguration	Yes	Refer to configuration for more details.

Basic Usage

Note

Always set the UUID to uniquely identify the user or device that connects to PubNub. This UUID should be persisted, and should remain unchanged for the lifetime of the user or the device. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.

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

Returns

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

Other Examples

1. Initialize a non-secure client:

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

2. Initialization for a Read-Only client:

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

3. Use a custom UUID

   val pnConfiguration = PNConfiguration().apply {
       subscribeKey = "my_subkey"
       publishKey = "my_pubkey"
       uuid = "myUniqueUuid"
   }
   val pubnub = PubNub(pnConfiguration)
   

4. 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 = PNConfiguration().apply {
       subscribeKey = "my_subkey"
       publishKey = "my_pubkey"
       secure = true
       uuid = "myUniqueUuid"
   }
   val pubnub = PubNub(pnConfiguration)
   

5. Initializing with Access Manager: Requires Access Manager add-onRequires that the Access Manager add-on is enabled for your key. See this page on enabling add-on features on your keys:
   https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-

   Note

   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 PAM permissions, the API is initialized with the secretKey as in the following example:

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

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

6. How to Set Proxy:

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

Event Listeners

Description

You can be notified of connectivity status, message, and presence notifications via the listeners.

Listeners should be added before calling the method.

Adding Listeners

pubnub.addListener(object : SubscribeCallback() {

    override fun status(pubnub: PubNub, status: PNStatus) {
        println("Status category: ${status.category}")
        // PNConnectedCategory, PNReconnectedCategory, PNDisconnectedCategory

        println("Status operation: ${status.operation}")
        // PNSubscribeOperation, PNHeartbeatOperation

        println("Status error: ${status.error}")
        // true or false
    }

    override fun presence(pubnub: PubNub, pnPresenceEventResult: PNPresenceEventResult) {
        println("Presence event: ${pnPresenceEventResult.event}")
        println("Presence channel: ${pnPresenceEventResult.channel}")
        println("Presence uuid: ${pnPresenceEventResult.uuid}")
        println("Presence timetoken: ${pnPresenceEventResult.timetoken}")
        println("Presence occupancy: ${pnPresenceEventResult.occupancy}")
    }

    override fun message(pubnub: PubNub, pnMessageResult: PNMessageResult) {
        println("Message payload: ${pnMessageResult.message}")
        println("Message channel: ${pnMessageResult.channel}")
        println("Message publisher: ${pnMessageResult.publisher}")
        println("Message timetoken: ${pnMessageResult.timetoken}")
    }

    override fun signal(pubnub: PubNub, pnSignalResult: PNSignalResult) {
        println("Signal payload: ${pnSignalResult.message}")
        println("Signal channel: ${pnSignalResult.channel}")
        println("Signal publisher: ${pnSignalResult.publisher}")
        println("Signal timetoken: ${pnSignalResult.timetoken}")
    }

    override fun messageAction(pubnub: PubNub, pnMessageActionResult: PNMessageActionResult) {
        with(pnMessageActionResult.messageAction) {
            println("Message action type: $type")
            println("Message action value: $value")
            println("Message action uuid: $uuid")
            println("Message action actionTimetoken: $actionTimetoken")
            println("Message action messageTimetoken: $messageTimetoken")
        }

        println("Message action subscription: ${pnMessageActionResult.subscription}")
        println("Message action channel: ${pnMessageActionResult.channel}")
        println("Message action timetoken: ${pnMessageActionResult.timetoken}")
    }

    override fun objects(pubnub: PubNub, objectEvent: PNObjectEventResult) {
        println("Object event channel: ${objectEvent.channel}")
        println("Object event publisher: ${objectEvent.publisher}")
        println("Object event subscription: ${objectEvent.subscription}")
        println("Object event timetoken: ${objectEvent.timetoken}")
        println("Object event userMetadata: ${objectEvent.userMetadata}")

        with(objectEvent.extractedMessage) {
            println("Object event event: $event")
            println("Object event source: $source")
            println("Object event type: $type")
            println("Object event version: $version")
        }
    }
})

Removing Listeners

val listener = object : SubscribeCallback() {
    override fun status(pubnub: PubNub, pnStatus: PNStatus) {}
    override fun message(pubnub: PubNub, pnMessageResult: PNMessageResult) {}
    // and other callbacks
}

pubnub.addListener(listener)

// some time later
pubnub.removeListener(listener)

Handling Disconnects

The client may disconnect due to unpredictable network conditions.

You can configure automatic reconnection as follows:

pubnub.configuration.reconnectionPolicy = PNReconnectionPolicy.LINEAR
// choose between LINEAR and EXPONENTIAL
// default is NONE

pubnub.configuration.maximumReconnectionRetries = 10
// how many times the client will try to reconnect
// until giving up
// default is infinite

Or manually:

pubnub.addListener(object : SubscribeCallback() {

    override fun status(pubnub: PubNub, status: PNStatus) {
        if (status.category == PNStatusCategory.PNUnexpectedDisconnectCategory ||
            status.category == PNStatusCategory.PNTimeoutCategory
        ) {
            pubnub.reconnect()
        }
    }

})

Listeners status events

Category	Description
PNAcknowledgmentCategory	Used API report success with this status category.
PNAccessDeniedCategory	Request failed because of access error (active PAM)
PNTimeoutCategory	Used API didn't received response from server in time.
PNConnectedCategory	SDK subscribed with a new mix of channels (fired every time the channel / channel group mix changed).
PNReconnectedCategory	Subscription loop has been reconnected due some reasons.
PNUnexpectedDisconnectCategory	Previously started subscribe loop did fail and at this moment client disconnected from real-time data channels.
PNCancelledCategory	Request was cancelled by user.
PNBadRequestCategory	The server responded with 400 because the request is malformed.
PNMalformedResponseCategory	Request received in response non-JSON data. It can be because of publish WiFi hotspot which require authorization or proxy server message.
PNRequestMessageCountExceededCategory	If requestMessageCountThreshold is set, this status event will arrive each time when the client receives more messages than specified.
PNReconnectionAttemptsExhausted	The SDK loop has been stopped due maximum reconnection exhausted.
PNNotFoundCategory	The subscriber gets a 404 from the server.
PNUnknownCategory	The subscriber gets a 4xx code from the server, other than 400, 403 and 404

UUID

Description

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

Methods

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

val pnConfiguration = PNConfiguration()

pnConfiguration.uuid = String

Parameter	Type	Required	Default	Description
uuid	String	Yes	SDK generated UUID	UUID to be used as a device identifier, a default UUID is generated if not passed.

Basic Usage

Note

Always set the UUID to uniquely identify the user or device that connects to PubNub. This UUID should be persisted, and should remain unchanged for the lifetime of the user or the device. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.

val pnConfiguration = PNConfiguration()

// set uuid
pnConfiguration.uuid = "myUniqueUUID"

// get uuid
pnConfiguration.uuid

Authentication Key

Description

Setter and getter for users' authentication key.

Method(s)

val pnConfiguration = PNConfiguration()

pnConfiguration.authKey = String

Parameter	Type	Required	Description
authKey	String	Yes	If 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-onRequires that the Stream Controller add-on is enabled for your key. See this page on enabling add-on features on your keys:
https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-

Description

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/get 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

Parameter	Type	Required	Description
filterExpression	String	Yes	PSV2 feature to subscribe with a custom filter expression.

Basic Usage

val pnConfiguration = PNConfiguration()

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

// get filterExpression
pnConfiguration.filterExpression