create fcm http v1 protocol client

Author: Roy-Mao

lib/fcm/client_v1.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'fcm/connection'
+require 'fcm/response'
+require 'fcm/client_v1/notification_delivery'
+
+module Fcm
+  # Fcm Client class for http v1 protocol API connections
+  #
+  # @see https://firebase.google.com/docs/cloud-messaging/migrate-v1
+  class ClientV1
+    include Fcm::Connection
+    include Fcm::Response
+    include Fcm::ClientV1::NotificationDilivery
+
+    TOKEN_URI = 'https://www.googleapis.com/auth/firebase.messaging'
+
+    # @see https://firebase.google.com/docs/projects/provisioning/configure-oauth#auth
+    # @param json_key_path [String] file path to service_account_key.json
+    # @return [ClientV1] client_v1 instance
+    def initialize(json_key_path)
+      @json_key_path = json_key_path
+    end
+
+    private
+
+    def authorization_headers
+      {
+        'Content-Type' => 'application/json',
+        'Authorization' => "Bearer #{jwt_token}"
+      }
+    end
+
+    def jwt_token
+      @authorizer ||= Google::Auth::ServiceAccountCredentials.make_creds(
+        json_key_io: json_key,
+        scope: TOKEN_URI
+      )
+      token = @authorizer.fetch_access_token!
+      token['access_token']
+    end
+
+    def json_key
+      @json_key ||= if @json_key_path.respond_to?(:read)
+                      @json_key_path
+                    else
+                      File.open(@json_key_path)
+                    end
+    end
+  end
+end