Firebase Cloud Messaging wrapper for Scala

This small Scala Library makes it easy to send a notification through the FCM HTTP API. It allows you to:

• Send a message to single/multiple devices
• Handle updated tokens
• Handle deleted/invalid tokens

This library makes use of the STTP HTTP Client and the Circe JSON library.

Requirements8

• Scala 2.12.x

Usage

Configuration

Either construct an instance of DefaultFcmSender and supply the necessary parameters or use your favorite DI framework.

DI configuration (using Google Guice)

Bind the DefaultFcmSender to use it in your application:

bind(classOf[FcmSender]).to(classOf[DefaultFcmSender])

Bind the DefaultFirebaseAuthenticator:

bind(classOf[FirebaseAuthenticator]).to(classOf[DefaultFirebaseAuthenticator])

FCM configuration

The FcmSender needs configuration, easiest is to use a Typesafe Config file to configure FCM. In your application.conf add the following configuration:

fcm {
  endpoint = "<Google endpoint e.g.: https://fcm.googleapis.com/v1/{parent=projects/*}/messages:send"
  key-file = "Path to the JSON key file"
  validate-only = true # If true FCM will only validate your notifications but not send them!
  token-endpoint = "<Google token endpoint, optional, defaults to: https://www.googleapis.com/oauth2/v4/token>"
}

Bind the DefaultFcmConfigProvider dependency to read the configuration from the application.conf, in case of Google Guice:

bind(classOf[FcmConfigProvider]).to(classOf[DefaultFcmConfigProvider])

You can also provide your own implementation of the FcmConfigProvider trait to get needed configuration.

By default the FcmConfigProvider defaults to an async based STTP client; this can be overriden in your own FcmConfigProvider implementation.

Token repository

Implement the trait io.ceratech.fcm.TokenRepository in your codebase to handle updated/deleted tokens from the FCM server. The library expects an instance of the trait to be injectable. E.g. add the binding in code:

bind(classOf[TokenRepository]).to(classOf[MyTokenRepository])

Sending notifications

Inject an instance of io.ceratech.fcm.FcmSender into your desired class and call sendMessage(FcmNotification, token). The FcmMessage case class contains the fields you can supply to FCM.