I keep getting :bad_device_token for APN

[edisonywh]

Environment

• Elixir & Erlang/OTP versions (elixir --version): Elixir 1.9.1 (compiled with Erlang/OTP 20), Erlang/OTP 22
• Operating system: Mac OS

Current behavior

I've been trying to just send a notification to my iOS device and it hasn't been working. Android worked fine, but for iOS it just never worked. I use runtime config, like so:

# config.exs
config :pigeon,
  workers: [
    {Slick.Pigeon, :apns_jwt}
  ]

defmodule Slick.Pigeon do
  def apns_jwt do
    APNS.JWTConfig.new(
      name: :apns_default,
      key: System.get_env("APN_AUTH_KEY"),
      key_identifier: System.get_env("APN_KEY_IDENTIFIER"),
      team_id: System.get_env("APN_TEAM_ID"),
      mode: :prod
    )
  end
end

My frontend is Flutter, I'm using Google's firebase_messasing package to get the device token.

Here's how I am sending the notification:

Pigeon.APNS.Notification.new("coconut", token)
|> Pigeon.APNS.Notification.put_alert(%{
  "title" => "coconut",
  "body" =>"coconut", 
})
|> Pigeon.APNS.push()

and the response:

%Pigeon.APNS.Notification{
  collapse_id: nil,
  device_token: "eL_kWlLwRfE:APA91bHedOstPi9tMF6YZet1pebmRPwt2h3tVcKX4Uxgp96USfGrE2tj3ok5CCvlCwCMZFmpipboh47L_IvkVTG20M47QsaDiNaWPQrCV9MmtdbEdLsiT2ets8LnYX4U2J1PFa9sJAXE",
  expiration: nil,
  id: nil,
  payload: %{
    "aps" => %{"alert" => %{"body" => "coconut", "title" => "coconut"}}
  },
  priority: nil,
  push_type: "alert",
  response: :bad_device_token,
  topic: nil
}

Expected behavior

I expect it to send notification to my iOS device

[edisonywh]

Slightly unrelated, but depending on how I pass in the token my key for APNs will also result in:

argument error: [[], {:jose_jws, {:jose_jws_alg_ecdsa, :ES256}, :undefined, %{"kid" => "...", "typ" => "JWT"}}, %{"aud" => "Joken", "exp" => ..., "iat" => ..., "iss" => "...", "jti" => "...", "nbf" => ...}]

[hpopp]

If you're using firebase, use FCM notifications for all push notifications, even iOS devices. APNS workers talk to Apple servers, which would reject the device token you've sent.

[edisonywh]

@hpopp does that mean I only have to set-up FCM then?

I don't think I see it in the docs, do you have an example perhaps? Thanks!

Also, why would the Apple servers reject the token I sent? What's wrong with that token?

[hpopp]

Think about it this way... if Firebase on Google servers was the one issuing device tokens, Apple servers wouldn't know anything about it.

Using FCM for iOS is not something I personally use in production, but I have verified that it does indeed work. You'll notice that some of the helper functions in FCM.Notification are iOS-specific. I don't have an actual guide for this, but perhaps I should write one.

[edisonywh]

Ah, I thought the the device tokens were Apple's tokens. I thought it didn't matter how the token was retrieved, because ultimately it's a "device token" that belongs to the device. Looks like I'm wrong?

Yeah a guide would be immensely helpful, I'm going to try it out and see how to get it to work, thanks for the pointers! Hopefully this works

[edisonywh]

I just gave it a go and I got it under 30 minutes. It was incredibly easy, I spent so much time figuring out why the token was bad turns out this whole time I had a FCM token instead of an iOS token.. Thanks for the help @hpopp!

Anyway, here's a code snippet for people who stumble upon this and want to send notification to APN via FCM:

body = %{"title" => title, "body" => message}

Pigeon.FCM.Notification.new(token)
|> Pigeon.FCM.Notification.put_notification(body)
|> Pigeon.FCM.Notification.put_content_available(true)
|> Pigeon.FCM.push()

That's literally all you need to do to send notifications to iOS. No need to fuss around with APN settings!