How do you send a Firebase Notification to all devices via CURL?

Solution 1:

Firebase Notifications doesn't have an API to send messages. Luckily it is built on top of Firebase Cloud Messaging, which has precisely such an API.

With Firebase Notifications and Cloud Messaging, you can send so-called downstream messages to devices in three ways:

to specific devices, if you know their device IDs
to groups of devices, if you know the registration IDs of the groups
to topics, which are just keys that devices can subscribe to

You'll note that there is no way to send to all devices explicitly. You can build such functionality with each of these though, for example: by subscribing the app to a topic when it starts (e.g. /topics/all) or by keeping a list of all device IDs, and then sending the message to all of those.

For sending to a topic you have a syntax error in your command. Topics are identified by starting with /topics/. Since you don't have that in your code, the server interprets allDevices as a device id. Since it is an invalid format for a device registration token, it raises an error.

From the documentation on sending messages to topics:

https://fcm.googleapis.com/fcm/send
Content-Type:application/json
Authorization:key=AIzaSyZ-1u...0GBYzPu7Udno5aA

{
  "to": "/topics/foo-bar",
  "data": {
    "message": "This is a Firebase Cloud Messaging Topic Message!",
   }
}

Solution 2:

The most easiest way I came up with to send the push notification to all the devices is to subscribe them to a topic "all" and then send notification to this topic. Copy this in your main activity

FirebaseMessaging.getInstance().subscribeToTopic("all");

Now send the request as

{
   "to":"/topics/all",
   "data":
   {
      "title":"Your title",
      "message":"Your message"
      "image-url":"your_image_url"
   }
}

This might be inefficient or non-standard way, but as I mentioned above it's the easiest. Please do post if you have any better way to send a push notification to all the devices.

_{You can follow this tutorial if you're new to sending push notifications using Firebase Cloud Messaging Tutorial - Push Notifications using FCM}

To send a message to a combination of topics, specify a condition, which is a boolean expression that specifies the target topics. For example, the following condition will send messages to devices that are subscribed to TopicA and either TopicB or TopicC:

{
   "data":
   {
      "title": "Your title",
      "message": "Your message"
      "image-url": "your_image_url"
   },
   "condition": "'TopicA' in topics && ('TopicB' in topics || 'TopicC' in topics)"
}

Read more about conditions and topics here on FCM documentation

Solution 3:

EDIT: It appears that this method is not supported anymore (thx to @FernandoZamperin). Please take a look at the other answers!

Instead of subscribing to a topic you could instead make use of the condition key and send messages to instances, that are not in a group. Your data might look something like this:

{
    "data": {
        "foo": "bar"
    },
    "condition": "!('anytopicyoudontwanttouse' in topics)"
}

See https://firebase.google.com/docs/cloud-messaging/send-message#send_messages_to_topics_2

Solution 4:

One way to do that is to make all your users' devices subscribe to a topic. That way when you target a message to a specific topic, all devices will get it. I think this how the Notifications section in the Firebase console does it.

Solution 5:

I was looking solution for my Ionic Cordova app push notification.

Thanks to Syed Rafay's answer.

in app.component.ts

const options: PushOptions = {
  android: {
    topics: ['all']
  },

in Server file

"to" => "/topics/all",