Why can't I collapse my push notifications when I use Firebase FCM?

Question

const options = {
    priority: 'high',
    collapseKey: user_id
};
const deviceTokensPromise = db.ref('/users-fcm-tokens/' + user_id).once('value');
deviceTokensPromise.then(tokensSnapshot => {
    if (!tokensSnapshot.hasChildren()) {
        return console.log('There are no device tokens to send to.');
    }
    const tokens = Object.keys(tokensSnapshot.val());
    console.log(tokens);
    console.log(payload);
     return admin.messaging().sendToDevice(tokens, payload, options).then(response => {
         console.log(response);
         return removeInvalidFCMTokens(tokensSnapshot, response);
     });
});

I have a collapse-Key field in my options.

When this code is ran, the iPhone receives multiple notifications, all on top of each other. I'd like to have most recent notification replace the previous ones.

Answer 1

@Timex you can pass same notification id for all notifications with the same collapse_id. For this you need to implement your own SendNotification method.

Answer 2

Check out the "Delivery Options" section in Firebase's FCM Messages documentation.

"collapsible" message behavior is supported on Android via FCM's collapse_key, on iOS via apns-collapse-id, and on JavaScript/Web via Topic.

Intuitively you might expect that the apns-collapse-id setting might go into the options parameter passed into the sendToMessage method you are using. However, this is not the case. Instead try patching it into the payload object, like this:

const patchedPayload = Object.assign({}, payload, {
    apns: {
        headers: {
            'apns-collapse-id': user_id
        }
    }
});

This follows the payload format presented in the documentation linked above.

Once you've constructed this patched payload don't forget to update sendToDevice(tokens, payload, options) to sendToDevice(tokens, patchedPayload, options).

Hope this works out for you!

Answer 3

For iOS:

Use apns-collapse-id see the docs.

if you use collapsible messages, remember that FCM only allows a maximum of four different collapse keys to be used by the FCM connection server per registration token at any given time. You must not exceed this number, or it could cause unpredictable consequences.

Collapsible:

Use scenario

When there is a newer message that renders an older, related message irrelevant to the client app, FCM replaces the older message. For example: messages used to initiate a data sync from the server, or outdated notification messages.

How to send

Set the appropriate parameter in your message request:

• collapseKey on Android
• apns-collapse-id on iOS
• Topic on Web
• collapse_key in legacy protocols (all platforms)

See the implementation of apns-collapse-id in the article:

# Script to send push notifications for each song in a Phish Setlist via an updateable Push Notification.
# Place a config.yml in the same directory as the script and your push notification PEM file.  
#
# Config Format:

# push_token: XXXXXXXXXXXXXX
# phish_api_key: XXXXXXXXXXXXXX
# push_mode: XXXXXXXXXXXXXX # development or production

require 'apnotic'
require 'phish_dot_net_client'
require 'awesome_print'
require 'yaml'

show_date = ARGV[0]

if show_date 

    script_config = YAML.load(File.read(File.expand_path('../config.yml', __FILE__)))

    PhishDotNetClient.apikey = script_config["phish_api_key"]

    the_show = PhishDotNetClient.shows_setlists_get :showdate => show_date

    push_body = ""

    if script_config["push_mode"] == "development"
        connection = Apnotic::Connection.new(cert_path: "pushcert.pem", url: "https://api.development.push.apple.com:443")
    else
        connection = Apnotic::Connection.new(cert_path: "pushcert.pem")
    end

    token = script_config["push_token"] 

    notification       = Apnotic::Notification.new(token)

    notification.apns_id = SecureRandom.uuid

    notification.apns_collapse_id = "Phish " + the_show[0]["showdate"] + ": "

    notification.mutable_content = true

    the_show[0]["setlistdata"].sets.each do |set_data|
        set_name = set_data.name + ": "
        set_data.songs.each do |song|
            song_str = set_name + song.title
            push_body = push_body + set_name + song.title + "\n"
            set_name = ""
            push_content = {'title' => song_str, 'body' => push_body} 
            puts push_content

            notification.alert = push_content

            response = connection.push(notification)

            # read the response
            puts ""
            puts response.ok?      # => true
            puts response.status   # => '200'
            puts response.headers  # => {":status"=>"200", "apns-id"=>"XXXX"}
            puts response.body     # => ""
            puts ""

            sleep(5)

        end

    end

    connection.close
else
    puts "Usage ruby send_push.rb SHOWDATE(Format:YYYY-MM-DD)"
end

For Android:

Use a tag variable in your notification payload.

"notification":{
  "title":"Huawei",
  "body":"21 Notification received", 
  "sound":"default",
  "badge":4,
  "tag":"1",
  "click_action":"Your_Activity"
   "icon":"Push_Icon" 
}