go-fcm-receiver

A library to subscribe to a GCM/FCM (Firebase Cloud Messaging) sender using protobuf.

The library was inspired by push-receiver and by this blog post.

The difference between this library and other libraries

• This library receives FCM notifications the same way an Android device does. This library is an FCM client.
• Other libraries (such as go-fcm) sends notifications via fcm, and does not receive notifications. Those libraries are an FCM server-side.

API Deprecation

[!CAUTION] Breaking changes - Instead of creating an FCMClient object with a SenderId, you now must provide AppId, ApiKey, and a ProjectID. See the updated usage example below.

Google deprecated https://fcm.googleapis.com/fcm/connect/subscribe (/send too), which is slated for full removal on June 21, 2024. (Source: https://firebase.google.com/docs/cloud-messaging/migrate-v1)

Install

import "github.com/morhaviv/go-fcm-receiver"

Requirements

• Firebase sender id to receive notification

Usage

Creating a new device and listening

package main

import (
	go_fcm_receiver "github.com/morhaviv/go-fcm-receiver"
)

func main() {
	newDevice := go_fcm_receiver.FCMClient{
		ApiKey:    "<39_CHARACTERS_API_TOKEN>",
		AppId:     "1:123445679012:android:0123456789abcdef",
		ProjectID: "<PROJECT_ID>",
		OnDataMessage: func(message []byte) {
			fmt.Println("Received a message:", string(message))
		},
	}
	privateKey, authSecret, err := newDevice.CreateNewKeys()
	if err != nil {
		panic(err)
	}
	fcmToken, gcmToken, androidId, securityToken, err := newDevice.Register()
	if err != nil {
		panic(err)
	}
	SaveDeviceDetails(fcmToken, gcmToken, androidId, securityToken, privateKey, authSecret)
	err = newDevice.StartListening()
	if err != nil {
		panic(err)
	}

}

Listening an existing device

package main

import (
	go_fcm_receiver "github.com/morhaviv/go-fcm-receiver"
)

func main() {
	oldDevice := go_fcm_receiver.FCMClient{
		GcmToken:          "<GCM_TOKEN>",
		FcmToken:          "<FCM_TOKEN>",
		AndroidId:         5240887932061714513, // The androidId returned when the device was created
		SecurityToken:     69534515778185919, // The securityToken returned when the device was created
		OnDataMessage: func(message []byte) {
			fmt.Println("Received a message:", string(message))
		},
	}
	
	err := oldDevice.LoadKeys("<PRIVATE_KEY_BASE64>", "<AUTH_SECRET_BASE64>")
	if err != nil {
		panic(err)
	}
	
	err = oldDevice.StartListening()
	if err != nil {
		panic(err)
	}
}