Configuration API for 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.9.8.0.js"></script>

Bundling​

PubNub JavaScript SDK allows you to opt out of modules you don't want to use in your application. You can use either Rollup or Webpack to bundle modules.

We provide a configuration file you can use to create your bundle configuration for both systems.

  1. Clone the PubNub JavaScript SDK repository to a directory of your choice.

  2. In the rollup.config.js Rollup configuration file, change the value of the enableTreeShaking constant to true.

  3. Inspect the rollup.config.js file and decide which modules you want to bundle. Disable the unnecessary modules by setting the environment variables with their labels to disabled, for example, in Terminal:

    export PRESENCE_MODULE=disabled PUBLISH_MODULE=disabled

  4. Run the rollup -c rollup.config.js --bundleConfigAsCjs command to bundle the modules. Once the process is finished, you can find the bundle in the your_js_sdk_repo_dir/upload directory.

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 | string[],
  presenceTimeout: number,
  heartbeatInterval: number,
  keepAlive: boolean,
  keepAliveSettings: any,
  suppressLeaveEvents: boolean,
  requestMessageCountThreshold: number,
  enableEventEngine: boolean
show all 25 lines
* required
ParameterDescription
subscribeKey *
Type: string
Default:
n/a
Specifies the subscribeKey to be used for subscribing to a channel. This key can be specified at initialization or along with a subscribe().
publishKey
Type: string
Default:
n/a
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 *
Type: string
Default:
n/a
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.
secretKey
Type: string
Default:
n/a
Secret key from Admin Portal. When you initialize PubNub with secretKey, you get root permissions for Access Manager. For more information, refer to Server Operations.
authKey
Type: string
Default:
n/a
The token returned from Access Manager that provides access to resources. For more information, refer to Access Manager.
logVerbosity
Type: boolean
Default:
false
Log HTTP information.

For information on enabling logging and collecting logs for troubleshooting, see Logging.
ssl
Type: boolean
Default:
true for v4.20.0 onwards,
false before v4.20.0
If set to true, requests will be made over HTTPS.
origin
Type: string or string[]
Default:
ps.pndsn.com
If a custom domain is required, SDK accepts it here.
presenceTimeout
Type: number
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.
heartbeatInterval
Type: number
Default:
Not Set
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.
keepAlive
Type: boolean
Default:
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
Type: any
Default:
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
Type: boolean
Default:
false
When true the SDK doesn't send out the leave requests.
requestMessageCountThreshold
Type: number
Default:
100
PNRequestMessageCountExceededCategory is thrown when the number of messages into the payload is above of requestMessageCountThreshold.
enableEventEngine
Type: boolean
Default:
false
Whether to use the recommended standardized workflows for subscribe and presence, optimizing how the SDK internally handles these operations and which statuses it emits. Refer to SDK connection lifecycle for more information.

This flag affects the following parameters:

restore
Type: boolean
Default:
false
This option is available only in the browser environment and requires listenToBrowserNetworkEvents to be set to true.

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.
retryConfiguration
Type: RequestRetryPolicy
Default:
PubNub.ExponentialRetryPolicy (subscribe only)
This option is available in the browser and Node.js environments.

Custom reconnection configuration parameters. You can specify one or more endpoint groups for which the retry policy won't be applied.

retryConfiguration: policy is the type of policy to be used.

Available values:
  • PubNub.NoneRetryPolicy()
  • PubNub.LinearRetryPolicy({ delay, maximumRetry, excluded })
  • PubNub.ExponentialRetryPolicy({ minimumDelay, maximumDelay, maximumRetry, excluded })
excluded takes an array of Endpoint enum values, for example, excluded: [PubNub.Endpoint.MessageSend].

For more information, refer to SDK connection lifecycle.
autoNetworkDetection
Type: boolean
Default:
false
This option is available in the browser and Node.js environments, only when enableEventEngine is false.

Whether the SDK should emit the PNNetworkDownCategory and PNNetworkUpCategory statuses on network status change.
listenToBrowserNetworkEvents
Type: boolean
Default:
true
This option is available only in the browser environment.

Whether the SDK should emit the PNNetworkDownCategory and PNNetworkUpCategory statuses, listen for the browser reachability events, and try to reconnect on network status change.

If the browser fails to detect the network changes from WiFi to LAN or you get reconnection issues, set the flag to false. This allows the SDK reconnection logic to take over.
maintainPresenceState
Type: boolean
Default:
true
Works only when enableEventEngine is true.

Whether the custom presence state information set using pubnub.setState() should be sent every time the SDK sends a subscribe call.
cryptoModule
Type: PubNub.CryptoModule.legacyCryptoModule({ cipherKey, useRandomIVs })

PubNub.CryptoModule.aesCbcCryptoModule({cipherKey})
Default:
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
Type: string
Default:
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
Type: string
Default:
n/a
This way of setting this parameter is deprecated, pass it to cryptoModule instead.

If passed, will encrypt the payloads.
useRandomIVs
Type: boolean
Default:
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 *
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.
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:


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.9.8.0.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.9.8.0.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:


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​

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.

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.


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.


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.


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)
* required
ParameterDescription
userId *
Type: String
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)
* required
ParameterDescription
key *
Type: String
Auth key to set.

Basic Usage​


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
)
* required
ParameterDescription
filterExpression *
Type: string
PSV2 feature to subscribe with a custom filter expression.
pubnub.getFilterExpression()

This method doesn't take any arguments.

Basic Usage​

Set Filter Expression​


Get Filter Expression​


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