firebase_cloud_messenger

Check out PLM's blog post about our development and use of firebase_cloud_messenger for more information about setting up and getting started.

firebase_cloud_messenger wraps Google's API to make sending push notifications to iOS, android, and web push notifications from your server easy.

NB: Google released the FCM HTTP v1 API in November 2017, giving legacy status to the older but still supported HTTP and XMPP apis. This gem only targets the [FCM HTTP v1 API], which Google recommends using for new projects, because it is the most up-to-date and secure.

Installation

Add this line to your application's Gemfile:

gem 'firebase_cloud_messenger'

And then execute:

$ bundle

Or install it yourself as:

$ gem install firebase_cloud_messenger

Setup

In order for google to authenticate requests to Firebase Cloud Messenger, you must either have your service account credentials file in a place that's accessible, or provide credentials as env vars.

Setup Method 1: Service Account JSON Path Supplied As Env Var

$ export GOOGLE_APPLICATION_CREDENTIALS = "path/to/credentials/file.json"`

Setup Method 2: Service Account JSON Path Supplied To FirebaseCloudMessenger

FirebaseCloudMessenger.credentials_path = "path/to/credentials/file.json"

Setup Method 3: Service Account Credentials Set as Env Vars

$ export GOOGLE_PRIVATE_KEY = "-----BEGIN PRIVATE KEY-----..."
$ export GOOGLE_CLIENT_EMAIL = "firebase-admin-sdk...@iam.gserviceaccount.com"

Also set the project_id, which is otherwise read from the json service account file:

FirebaseCloudMessenger.project_id = "1234567"

Usage

Sending a Message

You can see how your message should be structured here firebase_cloud_messenger provides built-in data classes for each json object type in the FCM API specification, but you can also build up a hash message on your own, or use some combination of the two.

Send messages with built-in data objects, which can be built through a hash argument to the initializer or via writer methods:

android_notification = FirebaseCloudMessenger::Android::Notification.new(title: "title")
android_config = FirebaseCloudMessenger::Android::Config.new(notification: android_notification)
message = FirebaseCloudMessenger::Message.new(android: android_config, token "a_device_token")

FirebaseCloudMessenger.send(message: message) # => { "name" => "name_from_fcm" }

# OR

android_notification = FirebaseCloudMessenger::Android::Notification.new
android_notification.title = "title"

android_config = FirebaseCloudMessenger::Android::Config.new
android_config.notification = android_notification

message = FirebaseCloudMessenger::Message.new
message.android = android_config
message.token = "a_device_token"

FirebaseCloudMessenger.send(message: message) # => { "name" => "name_from_fcm" }

or with just a hash:

message = {
  android: {
    notification: {
      title: "title"
    }
  },
  token: "a_device_token"
}

FirebaseCloudMessenger.send(message: message) # => { "name" => "name_from_fcm" }

or some combination of the two:

message = FirebaseCloudMessenger::Message.new(android: { notification: { title: "title" }, token: "a_device_token" })
FirebaseCloudMessenger.send(message: message) # => { "name" => "name_from_fcm" }

Error Handling

If something goes wrong, ::send will raise an instance of a subclass of FirebaseCloudMessenger::Error with helpful info on what went wrong:

message = FirebaseCloudMessenger::Message.new(android: { bad: "data" }, token: "a_device_token"})
begin
  FirebaseCloudMessenger.send(message: message)
rescue FirebaseCloudMessenger::Error => e
  e.class # => FirebaseCloudMessenger::BadRequest
  e.message # => A message from fcm about what's wrong with the request
  e.status # => 400
  e.details # => An array of error details from fcm
end

Message Validation

Many errors can be caught before sending by validating a message before sending it.

Validate your message either by via the Firebase Cloud Messenger API:

message = FirebaseCloudMessenger::Message.new(android: { bad: "data" })
message.valid?(against_api: true) # => false
message.errors # => [<error_msg>]

or client-side, via json-schema:

message = FirebaseCloudMessenger::Message.new(android: { bad: "data" }, token: "a_device_token")
message.valid? # => false
message.errors # => ["The property '#/android' contains additional properties [\"bad\"] outside of the schema when none are allowed in schema..."]

Validate your hash message (returns only true or false):

message = {
  android: { bad: "data" },
  token: "a_device_token"
}

#api-side
FirebaseCloudMessenger.validate_message(message, against_api: true) # => false

#OR

#client-side
FirebaseCloudMessenger.validate_message(message) # => false

Development

After checking out the repo, run bundle to install dependencies. Then, run bundle exec rake test to run the tests.