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.9.8.4.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.
Clone the PubNub JavaScript SDK repository to a directory of your choice.
In the rollup.config.js
Rollup configuration file, change the value of the enableTreeShaking
constant to true
.
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
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.
Clone the PubNub JavaScript SDK repository to a directory of your choice.
In the repository, create a webpack.config.js
file and base its contents on the Rollup configuration file. This setup allows you to dynamically change which modules are enabled/disabled by setting environment variables in Terminal.
const webpack = require('webpack');
module.exports = {
plugins: [
new webpack.DefinePlugin({
'process.env.CRYPTO_MODULE': JSON.stringify(process.env.CRYPTO_MODULE ?? 'enabled'),
'process.env.SHARED_WORKER': JSON.stringify(process.env.SHARED_WORKER ?? 'enabled'),
'process.env.PUBLISH_MODULE': JSON.stringify(process.env.PUBLISH_MODULE ?? 'enabled'),
'process.env.SUBSCRIBE_MODULE': JSON.stringify(process.env.SUBSCRIBE_MODULE ?? 'enabled'),
'process.env.SUBSCRIBE_EVENT_ENGINE_MODULE': JSON.stringify(process.env.SUBSCRIBE_EVENT_ENGINE_MODULE ?? 'enabled'),
'process.env.SUBSCRIBE_MANAGER_MODULE': JSON.stringify(process.env.SUBSCRIBE_MANAGER_MODULE ?? 'enabled'),
'process.env.PRESENCE_MODULE': JSON.stringify(process.env.PRESENCE_MODULE ?? 'enabled'),
'process.env.PAM_MODULE': JSON.stringify(process.env.PAM_MODULE ?? 'enabled'),
'process.env.CHANNEL_GROUPS_MODULE': JSON.stringify(process.env.CHANNEL_GROUPS_MODULE ?? 'enabled'),
show all 24 lines Webpack configuration
Make sure to add any other necessary configuration to the webpack.config.js
. For more information, refer to Webpack documentation.
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
Run the npx webpack --config webpack.config.js
command to bundle the modules. Once the process is finished, you can find the bundle in the directory you configured in the webpack.config.js
file.
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
Parameter DescriptionsubscribeKey
*
Type: string
Default:
n/a
Specifies thesubscribeKey
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 thepublishKey
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 theuserId
, you won't be able to connect to PubNub. secretKey
Type: string
Default:
n/a
Secret key from Admin Portal. When you initialize PubNub withsecretKey
, 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
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
true
, requests will be made over HTTPS. origin
Type: string or string[]
Default:
ps.pndsn.com
presenceTimeout
Type: number
Default:
300
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
presenceTimeout
.
Configure this property to achieve a shorter presence timeout if needed, with the interval typically recommended to be (presenceTimeout / 2) - 1
. Due to server constraints, don't set the value below 3
.
keepAlive
Type: boolean
Default:
false
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
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
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
This flag affects the following parameters:
autoNetworkDetection
is ignored when enableEventEngine
is true
maintainPresenceState
is automatically enabled when enableEventEngine
is true
restore
Type: boolean
Default:
false
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
:
PubNub.ExponentialRetryPolicy
(subscribe only)
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
enableEventEngine
is false
.
Whether the SDK should emit the PNNetworkDownCategory
and PNNetworkUpCategory
statuses on network status change.
listenToBrowserNetworkEvents
Type: boolean
Default:
true
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
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})
:
None
The cryptography module used for encryption and decryption of messages and files. Takes thecipherKey
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 tocryptoModule
instead.
If passed, will encrypt the payloads.
useRandomIVs
Type: boolean
Default:
true
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, useuserId
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.
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.
For detailed encryption configuration, utility methods for encrypting/decrypting messages and files, and practical examples, see the dedicated Encryption page.
Legacy encryption with 128-bit cipher key entropyYou 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.
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.9.8.4.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.
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.
ConfigurationDownload the shared worker source code from our CDN.
http://cdn.pubnub.com/sdk/javascript/pubnub.worker.9.8.4.js
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.
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 versionThe version of the shared worker must match the version of the PubNub client being used.
Sample code Reference codeThis 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.
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.
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.
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.
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.
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:
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.
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.
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.
PubNub SDKs provide several sources for real-time updates:
Subscription
object can receive updates only for the particular object for which it was created: channel, channel group, channel metadata, or user.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 IDA 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 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.
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
:
* required
Parameter DescriptionuserId
*
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:
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.userId
back to the user upon successful login (authentication process).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.Use this method to get the current userId
set on your application. This method doesn't take any arguments.
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.
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()
.
To Set Authentication Key
you can use the following method(s) in the JavaScript SDK
pubnub.setAuthKey(string)
* required
Parameter Descriptionkey
*
Type: String
Auth key
to set. Sample code Returns
None.
Filter expression Requires Stream Controller add-onThis 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
Parameter DescriptionfilterExpression
*
Type: string
PSV2 feature tosubscribe
with a custom filter expression.
pubnub.getFilterExpression()
This method doesn't take any arguments.
Sample code Set filter expression Get filter expressionRetroSearch is an open source project built by @garambo | Open a GitHub Issue
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