Configuration API for PubNub JavaScript SDK

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

You must include the PubNub JavaScript SDK in your code before initializing the client.

<script src="https://cdn.pubnub.com/sdk/javascript/pubnub.8.3.1.js"></script>

Initialization

Use this method to initialize the PubNub Client API context and establish account-level credentials such as publish and subscribe keys. You can create an account and get your keys from the Admin Portal.

Method(s)

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

pubnub.PubNub({
  subscribeKey: string,
  publishKey: string,
  userId: string,
  authKey: string,
  logVerbosity: boolean,
  ssl: boolean,
  origin: string,
  presenceTimeout: number,
  heartbeatInterval: number,
  keepAlive: boolean,
  keepAliveSettings: any,
  suppressLeaveEvents: boolean,
  requestMessageCountThreshold: number,
  enableEventEngine: boolean

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Parameter	Type	Required	Default	Description
Operation Arguments	Hash	Yes		A hash of arguments.
subscribeKey	string	Yes		Specifies the subscribeKey to be used for subscribing to a channel. This key can be specified at initialization or along with a subscribe().
publishKey	string	Optional		Specifies the publishKey to be used for publishing messages to a channel. This key can be specified at initialization or along with a publish().
userId	string	Yes		userId to use. You should set a unique userId to identify 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.
authKey	string	Optional		If Access Manager enabled, this key will be used on all requests.
logVerbosity	boolean	Optional	false	Log HTTP information.
ssl	boolean	Optional	true for v4.20.0 onwards, false before v4.20.0	If set to true, requests will be made over HTTPS.
origin	string	Optional	ps.pndsn.com	If a custom domain is required, SDK accepts it here.
presenceTimeout	number	Optional	300	How long the server will consider the client alive for presence.The value is in seconds.
heartbeatInterval	number	Optional	Not Set	How often the client will announce itself to server.The value is in seconds.
keepAlive	boolean	Optional	false	If set to true, SDK will use the same TCP connection for each HTTP request, instead of opening a new one for each new request.
keepAliveSettings	any	Optional	keepAliveMsecs: 1000 freeSocketKeepAliveTimeout: 15000 timeout: 30000 maxSockets: Infinity maxFreeSockets: 256	Set a custom parameters for setting your connection keepAlive if this is set to true. keepAliveMsecs: (Number) how often to send TCP KeepAlive packets over sockets. freeSocketKeepAliveTimeout: (Number) sets the free socket to timeout after freeSocketKeepAliveTimeout milliseconds of inactivity on the free socket. timeout: (Number) sets the working socket to timeout after timeout milliseconds of inactivity on the working socket. maxSockets: (Number) maximum number of sockets to allow per host. maxFreeSockets: (Number) maximum number of sockets to leave open in a free state.
suppressLeaveEvents	boolean	Optional	false	When true the SDK doesn't send out the leave requests.
requestMessageCountThreshold	number	Optional	100	PNRequestMessageCountExceededCategory is thrown when the number of messages into the payload is above of requestMessageCountThreshold.
enableEventEngine	boolean	Optional	false	Whether to use the standardized workflows for subscribe and presence. Note that the maintainPresenceState parameter is set to true by default, so make sure to disable it if you don't need to maintain presence state. For more information, refer to the param description in this table.
restore	boolean	Optional	false	A flag to allow catch up on the front-end applications. Its main purpose is to manage the state in which the SDK will be set after the network goes down: true — moves the client into the disconnected state without sending any leave events. It keeps the current timetoken and the list of active channels and groups intact. This option also allows for the network restore to try to catch up on messages that were missed when the client was offline. false — the client will reset the current timetoken as well as the list of active channels and groups. This option is available only in the browser environment for both Event Engine and non-Event Engine setups (so with Event Engine enabled or disabled), but requires listenToBrowserNetworkEvents to be set to true.
retryConfiguration	Object	Optional	undefined (no retry policy)	Configuration of failed requests retry attempts before reporting error to the code which made a request. retryConfiguration: policy is the type of policy to be used. Available values: PubNub.LinearRetryPolicy({ delay, maximumRetry }) PubNub.ExponentialRetryPolicy({ minimumDelay, maximumDelay, maximumRetry }) Completion block with error will be called only after all retry attempts are exhausted. retryConfiguration is available both in the browser and Node.js environments. It doesn't matter if enableEventEngine, restore, or listenToBrowserNetworkEvents is enabled.
autoNetworkDetection	boolean	Optional	false	This option is available in the browser and Node.js environments, only when enableEventEngine is set to false. When set to true, this flag tells the SDK whether it should emit statuses with the PNNetworkDownCategory and PNNetworkUpCategory categories on network status change or not. The subscription manager automatically uses the reconnection manager (and there is no way to disable it) to observe a network reachability change, and when it happens, it will try to reconnect (catch up). autoNetworkDetection can't disable reconnection manager, it only disables its ability to emit statuses with the PNNetworkDownCategory and PNNetworkUpCategory categories.
listenToBrowserNetworkEvents	boolean	Optional	true	If the browser fails to detect the network changes from WiFi to LAN and vice versa or you get reconnection issues, set the flag to false. This allows the SDK reconnection logic to take over. When set to true, this flag tells the SDK whether it should emit statuses with the PNNetworkDownCategory and PNNetworkUpCategory categories on a network status change or not. With this option set to true, the SDK will start listening for the browser reachability events in an attempt to restore the subscription loop/Event Engine operation. Event Engine setup is on its own unable to automatically restore after network issues and this is why this handler is of much help in the browser. This option is available only in the browser for both Event Engine and non-Event Engine setups. NOTE: Non-Event Engine setup has a reconnection manager which is based on periodic endpoint calls. When successful, it will ask the SDK client to reconnect (restore subscription). This process is not so fast compared to the reachability events from the browser (so when listenToBrowserNetworkEvents is set to true) and on edge cases may cause duplicated calls to the reconnect logic.
maintainPresenceState	boolean	Optional	true	Whether the state set using setState() should be maintained for the current userId. This option works only when enableEventEngine is set to true.
cryptoModule	PubNub.CryptoModule.legacyCryptoModule({ cipherKey, useRandomIVs }) PubNub.CryptoModule.aesCbcCryptoModule({cipherKey})	Optional	None	The cryptography module used for encryption and decryption of messages and files. Takes the cipherKey and useRandomIVs parameters as arguments. For more information, refer to the cryptoModule section.
subscriptionWorkerUrl	string	Optional	None	The URL for the shared worker on the server or the origin as the page where it's used. For more information, refer to Shared workers.
cipherKey	string	Optional		This way of setting this parameter is deprecated, pass it to cryptoModule instead. If passed, will encrypt the payloads.
useRandomIVs	boolean	Optional	true	This 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.
uuid	string	Yes		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.

Disabling random initialization vector

Disable random initialization vector (IV) only for backward compatibility (<4.31.0) with existing applications. Never disable random IV on new applications.

cryptoModule

cryptoModule provides encrypt/decrypt functionality for messages and files. From the 7.3.3 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 useRandomIVs 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 Javascript SDK:

// encrypts using 256-bit AES-CBC cipher (recommended)
// decrypts data encrypted with the legacy and the 256 bit AES-CBC ciphers
const pn = new PubNub({
  cryptoModule: PubNub.CryptoModule.aesCbcCryptoModule({cipherKey: 'pubnubenigma'});
});

// encrypts with 128-bit cipher key entropy (legacy)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
const pn = new PubNub({
  cryptoModule: PubNub.CryptoModule.legacyCryptoModule({cipherKey: 'pubnubenigma', useRandomIVs: true});
});

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 7.3.3 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.

Shared workers

Shared workers manage concurrent connections and maintain presence states across multiple client instances. They're useful in scenarios where you have multiple browser tabs or windows using the PubNub SDK. PubNub's shared worker source code is accessible via our CDN:

http://cdn.pubnub.com/sdk/javascript/pubnub.worker.8.3.1.js

There are two main reasons for implementing shared workers:

• Browser per-origin parallel connections limit

  Browsers limit the number of parallel connections that can be established to the same origin (e.g., ps.pndsn.com). Due to this limitation, having multiple PubNub clients operating independently in the same context may produce connection issues. Shared workers can aggregate subscriptions for matching keysets, allowing them to utilize one long-poll subscribe request rather than one per client.

• Presence maintenance with the "Generate Leave on TCP FIN or RST" feature

  This feature emits a leave presence event immediately when a connection used for a long-poll subscribe request is closed, which can lead to false presence events if multiple tabs or windows are open. The shared worker tracks channels and groups to ensure long-poll requests are only truly terminated when all associated tabs or windows are closed, preventing incorrect presence updates.

Hosting a shared worked

As browsers enforce the Same-origin Policy, you must host the shared worker under the same origin as the client application. Pages loaded from different origins won't be able to share a worker.

Configuration

1. Download the shared worker source code from our CDN.

   http://cdn.pubnub.com/sdk/javascript/pubnub.worker.8.3.1.js

2. Host the shared worker on your server or make it available under the same origin as the page where it's used according to the Same-origin Policy.

3. Configure the subscriptionWorkerUrl property when initializing the PubNub client:

const pubnub = new PubNub({
  subscribeKey: "demo",
  publishKey: "demo",
  userId: "unique-user-id",
  // using PubNub JS SDK v8.3.1, make sure the versions match
  subscriptionWorkerUrl: 'https://www.my-domain.com/static/js/pubnub.worker.8.3.1.js'
});

When this URL is specified, the PubNub client downloads the shared worker's source code and uses it to manage subscriptions.

Worker version

The version of the shared worker must match the version of the PubNub client being used.

Basic Usage

Applications can initialize the PubNub object by passing the subscribeKey and publishKey keys from your account. Each client should also pass a userId that represents the user or the device that connects to PubNub.

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.

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    cryptoModule: PubNub.CryptoModule.aesCbcCryptoModule({cipherKey: 'pubnubenigma'}),
    authKey: "myAuthKey",
    logVerbosity: true,
    userId: "myUniqueUserId",
    ssl: true,
    presenceTimeout: 130
});

Server Operations

For servers connecting to PubNub, setting a userId is different than for a client device as there can be multiple instances of the server on the same machine and there is no "authentication" process for a server (at least not like an end-user).

The API can be initialized with the secretKey if the server needs to administer Access Manager permissions for client applications. When you initialize PubNub 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 channels or channel groups. The servers get all access to all channels and channel groups.

Secure your secretKey

Anyone with the secretKey can grant and revoke permissions to your app. Never let your secretKey be discovered, and only exchange and deliver it securely. Only use the secretKey on secure environments such as Node.js applications or other server-side platforms.

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.

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    userId: "myUniqueUserId",
    secretKey: "secretKey",
    heartbeatInterval: 0
});

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.

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 simply omit the publishKey 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.

// Initialize for Read Only Client

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    userId: "myUniqueUserId"
});

Initializing with SSL Enabled

This examples demonstrates how to enable PubNub Transport Layer Encryption with TLS (formerly known as SSL). Just initialize the client with ssl 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.

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.

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    cryptoModule: PubNub.CryptoModule.aesCbcCryptoModule({cipherKey: 'pubnubenigma'}),
    authKey: "myAuthKey",
    logVerbosity: true, // set false for production
    userId: "myUniqueUserId",
    ssl: true
});

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.

User ID

A userId (Universal Unique Identifier) is a required unique alphanumeric identifier used to identify the client to the PubNub platform. Each client must pass a userId that represents the user or the device that connects to PubNub.

Set User ID

Set the userId parameter when you instantiate a PubNub instance (new PubNub()). It's important that your application reuse the userId on each device instead of generating a new userId on each connection.

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.

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    userId: "myUniqueUserId"
});

You can also call the following method to explicitly set the userId:

pubnub.setUserId(string)

Parameter	Type	Required	Description
userId	String	Yes	userId to set.

pubnub.setUserId("myUniqueUserId")

Save User ID

Providing a value for the userId parameter in the PubNub object initialization will result in that value getting saved in the browser's localStorage key (described above) automatically by the PubNub SDK. You may implement a different local caching strategy, as required.

Consider the following when implementing a userId reuse strategy:

1. On your server, generate a userId when a user creates a user profile (user registration process). You can generate this with the SDK, or by another method of your choosing.
2. Pass the userId back to the user upon successful login (authentication process).
3. Persist the userId on the device where it can be retrieved the next time the PubNub instance is instantiated. The PubNub instance might be instantiated multiple times as the app is left and re-entered, and you may not require a login with each new session.

Get User ID

Use this method to get the current userId set on your application. This method doesn't take any arguments.

pubnub.getUserId();

Required UserId recommendation

Remember that whatever user ID you use is visible to other users (if a user peeks behind the scenes using the browser console or other tools), so you should not use a username or email as the userId. The userId should be something that can be easily replaced as required without user interaction or even knowledge that it has happened.

Authentication Key

This function provides the capability to reset a user's auth Key.

Typically auth Key is specified during initialization for Access Manager enabled applications. In the event that auth Key has expired or a new auth Key is issued to the client from a Security Authority, the new auth Key can be sent using setAuthKey().

Property

To Set Authentication Key you can use the following method(s) in the JavaScript SDK

pubnub.setAuthKey(string)

Parameter	Type	Required	Description
key	String	Yes	Auth key to set.

Basic Usage

pubnub.setAuthKey("my_authkey");

Returns

None.

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)

pubnub.setFilterExpression(
  filterExpression: string
)

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

pubnub.getFilterExpression()

This method doesn't take any arguments.

Basic Usage

Set Filter Expression

pubnub.setFilterExpression("such=wow");

Get Filter Expression

pubnub.getFilterExpression();

Generate UUID (deprecated)

Alternative method

This method is deprecated. Use Set User ID instead.

Use this method to generate a UUID.

PubNub.generateUUID();