Firebase Cloud Messaging（FCM）注册令牌服务器端验证

Question

I'm updating a backend service that sends push notifications to iOS and Android devices through Firebase Cloud Messaging (FCM) HTTP APIs.

I noticed that we were using the legacy "HTTP Server Protocol" and now i'm trying to port our service to "FCM HTTP v1 API" .

Sending a notification, in the previous protocol version responses, there were some error messages (see "Unregistered Device") to identify expired registration tokens. Now I receive a response with a "name" field containing a mysterious "message_id":

{ "name" : "projects/{project_id}/messages/{message_id}" }

I've even tried to send some notifications to very old tokens/devices without receiving any error.

• How can I detect the registration tokens that are not working anymore using the current version of the APIs?
• Is there any documentation about the possible "send" API error responses?
• Bonus: when were released the current "FCM HTTP v1 API"?

I'm also considering to expire tokens on a time or app usage base.

Thanks in advance.

Answer 1

The doc says when the request was successful, the response contains an instance of the message.

https://firebase.google.com/docs/reference/fcm/rest/v1/projects.messages/send

When the token is not available anymore we get a FileNotFoundException (in java) when we want to read the response. You can simple test this by deleting the app.

The "FCM HTTP v1 API" was announced at the last Firebase Dev Summit: https://firebase.googleblog.com/2017/10/whats-new-at-firebase-dev-summit-2017.html

Answer 2

You can validate the FCM token by calling the

(GET) https://iid.googleapis.com/iid/info/YOUR_APP_TOKEN_HERE
[Header] => 'Authorization: key=YOUR_KEY'

Simple and easy.

If token is valid then it will return 200 status code with some more details in JSON format or if it's invalid then status code will be 400 with error detail in JSON format.