Initialize PubNub

Before you start calling PubNub APIs, you must initialize the PubNub object in your app. This initialization uses the publish and subscribe keys you got from the Admin Portal and allows you to work with PubNub functionality. The PubNub object is also where you configure the behavior of the client, such as what to do when a connection is interrupted or whether to encrypt messages.

You only need to provide subscribeKey and userId if you want your app to receive messages. If you plan on sending messages, you must configure publishKey as well. There are other ways of initializing PubNub, depending on the features you want to use.

note

Make userId descriptive

It's up to you to define a userId, which is a UTF-8 encoded string of up to 92 characters used to identify the device that connects to PubNub.

Check out how easy it is:

JavaScript

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

Node.js

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

Swift

import PubNubSDK

var pnconfig = PubNubConfiguration(
  publishKey: "myPublishKey",
  subscribeKey: "mySubscribeKey"
)

pnconfig.userId = "myUniqueUserId"
let pubnub = PubNub(configuration: pnconfig)

Objective-C

PNConfiguration *pnconfig = [PNConfiguration configurationWithPublishKey:@"myPublishKey"
                                             subscribeKey:@"mySubscribeKey"];
pnconfig.uuid = "myUniqueuuid";
PubNub *pubnub = [PubNub clientWithConfiguration:pnconfig];

Java

PNConfiguration.Builder configBuilder = PNConfiguration.builder(new UserId("yourUserId"), "yourSubscribeKey");
configBuilder.publishKey("myPublishKey");
PubNub pubNub = PubNub.create(configBuilder.build());

C#

PNConfiguration pnconfig = new PNConfiguration();
pnconfig.PublishKey = "myPublishKey";
pnconfig.SubscribeKey = "mySubscribeKey";
pnconfig.UserId = "myUniqueUserId";

Pubnub pubnub = new Pubnub(pnconfig);

Python

from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

pnconfig = PNConfiguration()
pnconfig.publish_key = "myPublishKey"
pnconfig.subscribe_key = "mySubscribeKey"
pnconfig.user_id = "myUniqueUserId"

pubnub = PubNub(pnconfig)

Dart

var pubnub = PubNub(
      defaultKeyset:
          Keyset(subscribeKey: 'mySubscribeKey', publishKey: 'myPublishKey', userId: UserId('myUniqueUserId')));

Kotlin

val builder = PNConfiguration.builder(UserId("myUniquesUserID"), "subscribeKey") {
    publishKey = "publishKey"
}
val pubnub = PubNub.create(builder.build())

User ID / UUID

User ID is also referred to as UUID/uuid in some APIs and server responses but holds the value of the userId parameter you set during initialization.

You don't have to create a separate PubNub object every time you want to send or receive a message. After the initialization, subscribeKey, publishKey, and userId are reused for all operations.

Let's look into the userId parameter a bit more.