[SOLVED] Get 403 response with the "new" Firebase Cloud Messaging API

Get 403 response with the "new" Firebase Cloud Messaging API

We are successfully using the Legacy HTTP Server Protocol on our server for FCM. I wanted to update to FCM HTTP v1 API today.

I did it step by step and when the server calls the request, we get this response:

Server returned HTTP response code: 403 for URL: https://fcm.googleapis.com/v1/projects/[projectid]/messages:send

This is the server code:

URL url = new URL("https://fcm.googleapis.com/v1/projects/[projectid]/messages:send");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestProperty("Authorization", "Bearer " + getAccessToken());
conn.setRequestProperty("Content-Type", "application/json");
OutputStream outputStream = conn.getOutputStream();
outputStream.write(req.getBytes("UTF-8"));

// Exception happen here
InputStream inputStream = conn.getInputStream();

The getAccessToken():

private static String getAccessToken() throws IOException {
        GoogleCredential googleCredential = GoogleCredential
            .fromStream(new FileInputStream(ClientApiServlet.context.getRealPath("/WEB-INF/[projectid].json")))         .createScoped(Arrays.asList("https://www.googleapis.com/auth/firebase.messaging"));
        googleCredential.refreshToken();
        return googleCredential.getAccessToken();
}

I have downloaded the json file from the adminsdk page of the firebase cloud.

All with the same projectid...

I updated these 2 libs on the server:

google-http-client-jackson2-1.23.0.jar
google-oauth-client-1.23.0.jar

The getAccessToken() methode returned an accesstoken: "ya29.c.Elr0BAa..."

I think, I miss a small step, maybe you could help? Thanks in advance!

Edit: It is working now with the hint of arterpa! Thanks again!

After that I got a 400 error, so something in the request data was wrong:

The problem was, we didn't converted all data{...}values to strings. With the legacy protocol it was not an issue, but with FCM HTTP v1 API it has to be strings! ;)

Solution

I had this problem, and it seems you need to enable FCM API for your project at Google API console.