Configuration API for Swift Native SDK

A configuration object that defines behavior and policies for a PubNub instance.

Initializer(s)

Creates a configuration using the specified PubNub Publish and Subscribe Keys.

Privacy

MAU billing tracks users (Device and MAU) for analytics and billing. PubNub does not track customers using transactions with random UUIDs/UserIDs.

Method(s)

To Initialize PubNub, you can use the following method(s) in the Swift SDK:

PubNubConfiguration(
  publishKey: String?,
  subscribeKey: String,
  userId: String,
  cryptoModule: CryptoModule? = nil,
  authKey: String? = nil,
  authToken: String? = nil,
  useSecureConnections: Bool = true,
  origin: String = "ps.pndsn.com",
  useInstanceId: Bool = false,
  useRequestId: Bool = false,
  automaticRetry: AutomaticRetry? = .default,
  durationUntilTimeout: UInt = 300,
  heartbeatInterval: UInt = 0,
  supressLeaveEvents: Bool = false,

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* required

Parameter	Description
publishKey Type: String? Default: nil	Specifies the PubNub Publish Key to be used when publishing messages to a channel.
subscribeKey * Type: String Default: nil	Specifies the PubNub Subscribe Key to be used when subscribing to a channel.
userId * Type: String Default: n/a	userId to use. 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.
cryptoModule Type: CryptoModule? Default: nil	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.
authKey Type: String? Default: nil	If Access Manager is enabled, client will use authKey on all requests.
authToken Type: String? Default: nil	If Access Manager is enabled, client will use authToken instead of authKey on all requests.
useSecureConnections Type: Bool Default: true	If true, requests will be made over HTTPS; otherwise they will use HTTP (for cases when HTTPS might not be necessary or feasible, like development or testing purposes). You will still need to disable ATS for the system to allow insecure network traffic. See Apple's documentation for further details.
origin Type: String Default: "ps.pndsn.com"	Domain name used for requests. To request a custom domain, contact support and follow the request process.
useInstanceId Type: Bool Default: false	Whether a PubNub object instanceId should be included on outgoing requests.
useRequestId Type: Bool Default: false	Whether a request identifier should be included on outgoing requests.
automaticRetry Type: AutomaticRetry? Default: ReconnectionPolicy.exponential (subscribe only)	Custom reconnection configuration parameters. For more information, refer to the automaticRetry section.
durationUntilTimeout 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. Minimum value is 20.
heartbeatInterval Type: UInt 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 durationUntilTimeout. Configure this property to achieve a shorter presence timeout if needed, with the interval typically recommended to be (durationUntilTimeout / 2) - 1. The default value is 0 and it means that the SDK doesn't send explicit heartbeat messages to the server. Due to server constraints, don't set the value below 3 when configuring this parameter.
suppressLeaveEvents Type: Bool Default: false	Whether to send out the leave requests.
requestMessageCountThreshold Type: UInt Default: 100	The number of messages into the payload before emitting RequestMessageCountExceeded.
filterExpression Type: String? Default: nil	PSV2 feature to subscribe with a custom filter expression.
enableEventEngine Type: Bool Default: true	Whether to use the recommended standardized workflows for subscribe and presence, optimizing how the SDK internally handles these operations and which statuses it emits.
maintainPresenceState Type: Bool Default: true	This option works only when enableEventEngine is set to true. Whether the custom presence state information set using pubnub.setPresence() should be sent every time the SDK sends a subscribe call.
cipherKey Type: Crypto? Default: nil	This way of setting this parameter is deprecated, pass it to cryptoModule instead. If set, all communication will be encrypted with this key.
uuid * Type: String Default: n/a	This 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.

cryptoModule

cryptoModule provides encrypt/decrypt functionality for messages and files. From the 6.1.0 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 param 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 Swift 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 6.1.0 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.

automaticRetry

automaticRetry provides automatic reconnection options. The AutomaticRetry object has the following parameters:

Parameter	Description
retryLimit Type: UInt	Maximum number of times a request can be retried before failing.
policy Type: ReconnectionPolicy	The policy to be used. Available values include: ReconnectionPolicy.linear(delay) ReconnectionPolicy.exponential(minDelay, maxDelay) ReconnectionPolicy.exponential is the default value for subscribe connections.
retryableHTTPStatusCodes Type: Set<Int>	One or more HTTP status codes for which the retry policy will be applied.
retryableURLErrorCode Type: Set<URLError.Code>	One or more URL error codes for which the retry policy will be applied.
excluded Type: [AutomaticRetry.Endpoint]	One or more endpoints for which the retry policy won't be applied.

For more information, refer to SDK connection lifecycle.

Request configuration

The PubNub.RequestConfiguration object allows for per-request customization of PubNub behavior without modifying the global configuration.

* required

Parameter	Description
customSession Type: SessionReplaceable? Default: nil	A custom network session that implements the SessionReplaceable protocol, which provides session management capabilities including request routing, task execution, and session lifecycle control.
customConfiguration Type: RouterConfiguration? Default: nil	The endpoint configuration used by the request.
responseQueue Type: DispatchQueue Default: n/a	The queue that will be used for dispatching a response.

SessionReplaceable

SessionReplaceable is a protocol that defines an interface for objects capable of replacing the default network session implementation. It provides session management capabilities including request routing, task execution, and session lifecycle control.

Property	Description
sessionID Type: UUID	The unique identifier for the session object
session Type: URLSessionReplaceable	The underlying URLSession used to execute network tasks
sessionQueue Type: DispatchQueue	The dispatch queue used to execute session operations
defaultRequestOperator Type: RequestOperator?	The default request operator attached to every request (settable)
sessionStream Type: SessionStream?	Optional session stream for real-time communication (settable)

RouterConfiguration

RouterConfiguration is a protocol that defines the base configuration interface for PubNub endpoints. It encapsulates all the essential settings required for PubNub API communication, including authentication keys, connection security, encryption, and various behavioral options. This protocol serves as the foundation for configuring how HTTP requests are constructed and executed within the PubNub SDK.

* required

Property	Description
publishKey Type: String?	Refer to the publishKey section.
subscribeKey Type: String	Refer to the subscribeKey section.
uuid Type: String	Unique device identifier for the client (equivalent to userId in Configuration)
useSecureConnections Type: Bool	Refer to the useSecureConnections section.
origin Type: String	Refer to the origin section. To request a custom domain, contact support and follow the request process.
authKey Type: String?	Refer to the authKey section.
authToken Type: String?	Refer to the authToken section.
cryptoModule Type: CryptoModule?	Refer to the cryptoModule section.
useRequestId Type: Bool	Refer to the useRequestId section.
consumerIdentifiers Type: [String: String]	Key-value pairs identifying various consumers for request tracking
enableEventEngine Type: Bool	Refer to the enableEventEngine section.
maintainPresenceState Type: Bool	Refer to the maintainPresenceState section.
urlScheme Type: String	URL scheme derived from useSecureConnections ("https" or "http").
subscribeKeyExists Type: Bool	Whether subscribeKey is valid and not empty.
publishKeyExists Type: Bool	Whether publishKey is valid and not empty.

DispatchQueue

DispatchQueue is Apple's Foundation framework type used to specify which queue should handle response callbacks in PubNub SDK.

Method	Description
currentLabel Type: String	Returns the label of the current DispatchQueue or "Unknown Queue" if no label was set

Official Apple Documentation

For standard DispatchQueue properties and methods, refer to Apple's DispatchQueue documentation.

Sample code

Initialize the PubNub client API

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.

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.

Other examples

Initialization for a Read-Only client

In the case where a client will only read messages and never publish to a channel, you can set the publishKey to nil when initializing the client:

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.

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.
• 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.

Overriding PubNub configuration

All PubNubConfiguration properties are mutable, and can be changed after the object has been initialized. However, once the configuration is set on a PubNub instance those configurations are locked and can't be changed. Any changes would require a creating new PubNub instance.

Filter

You can override the filter expression without creating a new PubNub instance by using this approach: