ember-cli-pubnub

An Ember CLI addon to integrate the PubNub low-latency, realtime messaging platform.

PubNub utilises a publish/subscribe model functioning within a quarter of a second to give the user a sense of immediate or current updates to application data making it ideal for chat or any other application requiring transient data.

This addon allows ember to establish and maintain persistent web socket connections to the PubNub service and synchronises messages being sent to and from remote peers.

Compatibility

• Ember.js v2.18 or above
• Ember CLI v2.13 or above

Installation

From within your Ember CLI project directory run:

ember install ember-cli-pubnub

Usage

This addon implements a shim for the PubNub V4 JavaScript library that can be imported as an es6 module. The library is initialised with a pubnub service that should be used to make requests to the PubNub backend.

Configuration

Before the pubnub service can be used it first must be configured through config/environment. Here you must supply both your PubNub subscribe and publish API keys.

Configuration Example

// config/environment.js
module.exports = function(environment) {
  var ENV = {
    pubnub: {
      subscribeKey: 'sub-c-XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX',
      publishKey: 'pub-c-XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX',
      ssl: true
    }
  };

  return ENV;
};

Optionally you may specify whether the PubNub JavaScript library is fetched over HTTPS using the ssl key. Although optional, it is recommended that you set this to true within a production environment.

Injection

This addon makes no assumptions about what ember objects you want to make the pubnub service available. Therefore in order to make the service available you need to implement you own injections.

Injection Initializer Example

// app/initializers/pubnub.js
export function initialize(application) {
  application.inject('controller', 'pubnub', 'service:pubnub');
  application.inject('route', 'pubnub', 'service:pubnub');
};

export default {
  name: 'pubnub',
  initialize: initialize
};

This will make the pubnub service available to all controllers and routes. It is however unlikely that you will require the service to be injected into every controller or route of your applications. Therefore it is recommended that you include the service on a per object basis.

Injection Controller Example

// app/controllers/application.js
import Controller from '@ember/controller';
import { inject } from '@ember/service';

export default Controller.extend({
  pubnub: inject()
});

This will create a dependency on the application controller and inject the pubnub service into this controller only. This can be repeated across all objects that need access to the service.

Subscribe

In order to receive messages published to a channel use the subscribe function passing the required unique channel name. Other optional parameters can be passed into the subscribe function as key/value pairs and are defined within the API reference on the PubNub website.

Subscribe Example

// app/controllers/application.js
import Controller from '@ember/controller';

import { get } from '@ember/object';
import { on } from '@ember/object/evented';
import { inject } from '@ember/service';

export default Controller.extend({
  pubnub: inject(),

  joinChannel: on('init', function() {
    const pubnub = get(this, 'pubnub');

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

This will subscribe the client to the lobby channel and additionally subscribe to the presence channel instance conventionally named lobby-pnpres.

Publish

In order to publish messages to a channel that a client has previously subscribed use the publish function passing both the required channel name and message. Other optional parameters can be passed into the publish function as key/value pairs and are defined within the API reference on the PubNub website.

Publish Example

// app/controllers/application.js
import Controller from '@ember/controller';

import { get } from '@ember/object';
import { inject } from '@ember/service';

export default Controller.extend({
  pubnub: inject(),

  actions: {
    publish(message) {
      const pubnub = get(this, 'pubnub');

      pubnub.publish({
        channel: 'lobby',
        message: 'Hello, World'
      });
    }
  }
});

This will publish the message Hello, World to the lobby channel. All client that have subscribed to this channel will receive this message.

Advanced Setup

Previous examples demonstrate how to subscribe to a channel and subsequently publish a message to the same channel. However there is no guarantee that a client will only publish messages after it has successfully subscribed to a channel. Therefore a client may not receive all of it's own messages.

To ensure the client only publishes messages after it has subscribed to a channel use the addListener function. This allows callbacks for channel status changes that receives events when a client has subscribed to a channel.

Advanced Example

// app/controllers/application.js
import Controller from '@ember/controller';

import { get } from '@ember/object';
import { on } from '@ember/object/evented';
import { inject } from '@ember/service';

export default Controller.extend({
  pubnub: inject(),

  joinChannel: on('init', function() {
    const pubnub = get(this, 'pubnub');
    const channel = 'lobby';

    pubnub.addListener({
      status: function(status) {
        const message = 'Hello, World';

        if (status.category === 'PNConnectedCategory') {
          pubnub.publish({ channel, message }, function(status) {
            // handle publish status.
          });
        }
      }, message: function(message) {
        // handle message.
      }, presence: function(event) {
        // handle presence.
      }
    });

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

By following this pattern on a client that both subscribes and publishes to a channel a client will be able to receive it own published messages. It also sets up a callback to receive message from other clients on the channel and presence events.

License

This project is licensed under the MIT License.