Firebase Subscriber

FirebaseSubscriber is an abstract layer on top of Firebase official SDK. The main purpose of FirebaseSubscriber is to:

• Abstract logic token expiring/re-auth from application logic
• Abstract event unsubscribing by an additional Channel layer

Installation

This lib does not include firebase, so you'll need to install it as well

$ yarn add firebase-subscriber firebase

Usage

const FirebaseSubscriber = require('firebase-subscriber');

const getAuthToken = function() {
  // request application api here to get fresh firebase auth token
  // return a promise
  // this function would be invoked whenever the firebase auth token is expired
}

const subscribe = FirebaseSubscriber.subscriber({
  appName: "default",
  apiKey: "AIza....",                             // Auth / General Use
  authDomain: "YOUR_APP.firebaseapp.com",         // Auth with popup/redirect
  databaseURL: "https://YOUR_APP.firebaseio.com", // Realtime Database
  storageBucket: "YOUR_APP.appspot.com",          // Storage
  messagingSenderId: "123456789"                  // Cloud Messaging
}, {
  getAuthToken
});

subscribe('/my-test-path').then((channel) => {
  channel.on('child_added', function(val) {
    // `val` here is the result of snapshot.val()
    console.log('on child added', val);
  })
  channel.on('value', function(val) {
    console.log('on value', val);
  })

  channel.off(); //=> unsubscribe ALL event handlers bound on the channel
});

API

.subscriber()

The .subscriber() method takes two arguments, firebaseConfig and options for Connection, and returns a Promise for subscribing certain path of a database.

Please refer to the Connection section for the details of options.

Channel

A Channel instance is returned by subscribe function.

channel.on(eventName, handler):

Wrap Firebase.on(), invoke handler with snapshot.val()

channel.off():

Unregister ALL event handlers on the channel

channel.onDisconnect(callback):

Invoke callback with disconnected ref, for example:

channel.onDisconnect(function(presenceRef) {
  presenceRef.set('offline')
})

Setter Methods

Channel instances are equipped with some setter methods simply delegate to its underlying firebase ref:

• channel.set()
• channel.push()
• channel.remove()
• channel.update()

Connection

Connection is a configurable factory, which

• takes two arguments: firebaseConfig and options
• returns singleton connection, which would auto re-auth when expired

options:

Option	Description
getAuthToken	A function which fetches firebase auth token from your application server and returns a promise
needAuth	A flag to determine if user need to auth or not, default: true
isAnonymous	A flag to determine if auth anonymously, default: false

Usage

import { Connection } from 'firebase-subscriber';

const getConnection = Connection(firebaseConfig, { getAuthToken });
const connection1 = getConnection();
const connection2 = getConnection();

expect(connection1).to.equal(connection2);

Auth Anonymously

// specify `isAnonymous: true` in the options to create an anonymous connection
// returns singleton connection with auto re-auth as well
const getConnection = Connection(firebaseConfig, { isAnonymous: true });
const connection = getConnection()

Testing

$ npm test

LICENCE

MIT