Firebase Device Store (Android SDK)

Automatically store Device and FCM Token information for Firebase Auth Users in Cloud Firestore.

This library is a proof of concept, and very much a work in progress.

Installation

Add the following dependency to your app/build.gradle:

implementation "com.csfrequency.firebase.devicestore:firebase-device-store:0.1.3"

Example usage

import com.csfrequency.firebase.devicestore.FirebaseDeviceStore;

FirebaseDeviceStore deviceStore = new FirebaseDeviceStore(this.getApplicationContext(), FirebaseApp.getInstance(), "user-devices");
deviceStore.subscribe();

Documentation

Firebase Device Store automatically stores device and FCM information for Firebase Auth users in Cloud Firestore.

Data Model

A Document is created in the Cloud Firestore collection for each logged in user:

/user-devices
  - userId1: {},
  - userId2: {},

The structure of this Document is as follows:

{
  devices: {
    deviceId1: Device,
    deviceId2: Device,
    ...
  },
  userId: string,
}

A Device object contains the following:

{
  deviceId: string, // A UUID for the device
  fcmToken: string, // The FCM token
  name: string,     // The name of the device (e.g. 'Bob's Google Pixel')
  os: string,       // The OS of the device
  type: 'Android'
}

API

FirebaseDeviceStore(context: Context, app: FirebaseApp, collectionPath: string)

Create a new DeviceStore.

Parameters:

• context: Context the application context
• app: FirebaseApp (Optional) the Firebase App to use. Defaults to the default Firebase App.
• collectionPath: (Optional) string the Cloud Firestore collection where devices should be stored. Defaults to user-devices.

Returns a FirebaseDeviceStore.

FirebaseDeviceStore.signOut(): Task<Void>

Indicate to the DeviceStore that the user is about to sign out and that the current device token should be removed.

This can't be done automatically with onAuthStateChanged as the user is already signed out at this point. This means the Cloud Firestore security rules will prevent the database deletion as they no longer have the correct user permissions to remove the token.

You should wait for the task to complete before signing the user out of your application. This will ensure that the device is correctly removed.

FirebaseDeviceStore.subscribe(): void

Subscribe a device store to the Firebase App. This will:

1. Subscribe to Firebase Auth and listen to changes in authentication state
2. Subscribe to Firebase Cloud Messaging and listen to changes in the FCM token
3. Automatically store device and FCM token information in the Cloud Firestore collection you specify

FirebaseDeviceStore.unsubscribe(): void

Unsubscribe the device store from the Firebase App.

Security rules

You will need to add the following security rules for your Cloud Firestore collection:

service cloud.firestore {
  match /databases/{database}/documents {
    // Add this rule, replacing `user-devices` with the collection path you would like to use:
    match /user-devices/{userId} {
      allow create, read, update, delete: if request.auth.uid == userId;
    }
  }
}