pubnub

What is pubnub?

PubNub is a real-time communication platform that allows developers to build applications with real-time messaging, presence, and data synchronization capabilities. It is commonly used for chat applications, live updates, IoT device communication, and more.

What are pubnub's main functionalities?

Real-time Messaging

This feature allows you to send real-time messages to a specific channel. The code sample demonstrates how to publish a message to a channel using PubNub.

const PubNub = require('pubnub');
const pubnub = new PubNub({
  publishKey: 'your-publish-key',
  subscribeKey: 'your-subscribe-key'
});

pubnub.publish({
  channel: 'my_channel',
  message: { text: 'Hello, World!' }
}, (status, response) => {
  if (status.error) {
    console.log('Publish failed: ', status);
  } else {
    console.log('Message published with timetoken', response.timetoken);
  }
});

Real-time Subscription

This feature allows you to subscribe to a channel and receive real-time messages. The code sample demonstrates how to listen for new messages on a subscribed channel.

const PubNub = require('pubnub');
const pubnub = new PubNub({
  publishKey: 'your-publish-key',
  subscribeKey: 'your-subscribe-key'
});

pubnub.addListener({
  message: function(event) {
    console.log('New message received: ', event.message);
  }
});

pubnub.subscribe({
  channels: ['my_channel']
});

Presence Detection

This feature allows you to detect the presence of users in a channel. The code sample demonstrates how to listen for presence events such as join, leave, and timeout.

const PubNub = require('pubnub');
const pubnub = new PubNub({
  publishKey: 'your-publish-key',
  subscribeKey: 'your-subscribe-key'
});

pubnub.addListener({
  presence: function(event) {
    console.log('Presence event: ', event);
  }
});

pubnub.subscribe({
  channels: ['my_channel'],
  withPresence: true
});

History

This feature allows you to retrieve the message history of a channel. The code sample demonstrates how to fetch the last 10 messages from a channel's history.

const PubNub = require('pubnub');
const pubnub = new PubNub({
  publishKey: 'your-publish-key',
  subscribeKey: 'your-subscribe-key'
});

pubnub.history({
  channel: 'my_channel',
  count: 10
}, (status, response) => {
  if (status.error) {
    console.log('History retrieval failed: ', status);
  } else {
    console.log('Message history: ', response.messages);
  }
});

Other packages similar to pubnub

socket.io

Socket.IO is a library that enables real-time, bidirectional, and event-based communication between web clients and servers. It is commonly used for chat applications, live updates, and real-time analytics. Compared to PubNub, Socket.IO is more focused on web sockets and may require more server-side setup.

pusher

Pusher is a hosted service that makes it easy to add real-time data and functionality to web and mobile applications. It offers features like real-time messaging, presence, and webhooks. Pusher is similar to PubNub in terms of functionality but is a hosted service with a different pricing model.

ably

Ably is a real-time messaging service that provides pub/sub messaging, presence, and data synchronization. It is designed for high scalability and reliability. Ably offers similar features to PubNub but emphasizes performance and global data distribution.

README

PubNub JavaScript SDK (V4)

This is the official PubNub JavaScript SDK repository.

PubNub takes care of the infrastructure and APIs needed for the realtime communication layer of your application. Work on your app's logic and let PubNub handle sending and receiving data across the world in less than 100ms.

Get keys

You will need the publish and subscribe keys to authenticate your app. Get your keys from the Admin Portal.

Tutorial Video

Watch Getting Started with PubNub JS SDK on Dashcam

Configure PubNub

1. Integrate the JavaScript SDK into your project:

   • use npm:

     npm install pubnub
     

   • or download one of our builds from our CDN:
     • https://cdn.pubnub.com/sdk/javascript/pubnub.8.3.2.js
     • https://cdn.pubnub.com/sdk/javascript/pubnub.8.3.2.min.js

2. Configure your keys:

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

Add event listeners

// create a subscription from a channel entity
const channel = pubnub.channel('my_channel');
const subscription = channel.subscription();
subscription.subscribe();

// Event-specific listeners
subscription.onMessage =  (messageEvent) => { console.log("Message event: ", messageEvent); };
subscription.onPresence =  (presenceEvent) => { console.log("Presence event: ", presenceEvent); };
subscription.onMessage = (messageEvent) => { console.log("Message event: ", messageEvent); };
subscription.onPresence = (presenceEvent) => { console.log("Presence event: ", presenceEvent); };
subscription.onSignal = (signalEvent) => { console.log("Signal event: ", signalEvent); };
subscription.onObjects = (objectsEvent) => { console.log("Objects event: ", objectsEvent); };
subscription.onMessageAction = (messageActionEvent) => { console.log("Message Action event: ", messageActionEvent); };
subscription.onFile = (fileEvent) => { console.log("File event: ", fileEvent); };

// Generic listeners
subscription.addListener({
  // Messages
  message: function (m) {
    const channelName = m.channel; // Channel on which the message was published
    const channelGroup = m.subscription; // Channel group or wildcard subscription match (if exists)
    const pubTT = m.timetoken; // Publish timetoken
    const msg = m.message; // Message payload
    const publisher = m.publisher; // Message publisher
  },
  // Presence
  // requires a subscription with presence
  presence: function (p) {
    const action = p.action; // Can be join, leave, state-change, or timeout
    const channelName = p.channel; // Channel to which the message belongs
    const occupancy = p.occupancy; // Number of users subscribed to the channel
    const state = p.state; // User state
    const channelGroup = p.subscription; //  Channel group or wildcard subscription match, if any
    const publishTime = p.timestamp; // Publish timetoken
    const timetoken = p.timetoken; // Current timetoken
    const uuid = p.uuid; // UUIDs of users who are subscribed to the channel
  },
  // Signals
  signal: function (s) {
    const channelName = s.channel; // Channel to which the signal belongs
    const channelGroup = s.subscription; // Channel group or wildcard subscription match, if any
    const pubTT = s.timetoken; // Publish timetoken
    const msg = s.message; // Payload
    const publisher = s.publisher; // Message publisher
  },
  // App Context
  objects: (objectEvent) => {
    const channel = objectEvent.channel; // Channel to which the event belongs
    const channelGroup = objectEvent.subscription; // Channel group
    const timetoken = objectEvent.timetoken; // Event timetoken
    const publisher = objectEvent.publisher; // UUID that made the call
    const event = objectEvent.event; // Name of the event that occurred
    const type = objectEvent.type; // Type of the event that occurred
    const data = objectEvent.data; // Data from the event that occurred
  },
  // Message Reactions
  messageAction: function (ma) {
    const channelName = ma.channel; // Channel to which the message belongs
    const publisher = ma.publisher; // Message publisher
    const event = ma.event; // Message action added or removed
    const type = ma.data.type; // Message action type
    const value = ma.data.value; // Message action value
    const messageTimetoken = ma.data.messageTimetoken; // Timetoken of the original message
    const actionTimetoken = ma.data.actionTimetoken; // Timetoken of the message action
  },
  // File Sharing
  file: function (event) {
    const channelName = event.channel; // Channel to which the file belongs
    const channelGroup = event.subscription; // Channel group or wildcard subscription match (if exists)
    const publisher = event.publisher; // File publisher
    const timetoken = event.timetoken; // Event timetoken

    const message = event.message; // Optional message attached to the file
    const fileId = event.file.id; // File unique id
    const fileName = event.file.name;// File name
    const fileUrl = event.file.url; // File direct URL
  }
});

Publish/subscribe

const channel = pubnub.channel('my_channel');
const subscription = channel.subscription();
subscription.subscribe();

try {
    const result = await pubnub.publish({
        message: {
            such: "object",
        },
        channel: "my_channel",
        sendByPost: false, // true to send via post
        storeInHistory: false, //override default Message Persistence options
        meta: {
            cool: "meta",
        }, // publish extra meta with the request
    });
} catch (status) {
    console.log(status);
}

Documentation

• Build your first realtime JS app with PubNub
• API reference for JavaScript

Support

If you need help or have a general question, contact [e-mail].

Changelog

v8.3.2

December 12 2024

Fixed

• Fix issue with Subscription and SubscriptionSet when one can unsubscribe channel / group which is still in use by another.
• Fix particular TypeError emitted when browser forcefully closes long-poll connection before its timeout and reported as bad request. This type of error will be reported as a network error.
• Fix issue because of which node-fetch used default agent, which after Node.js 19+ has keepAlive enabled by default.