Firebase Cloud Messaging notification from Java instead of Firebase Console

Question

I am new to Firebase and I am running into errors such as mismatch sender id and Authentication Error with HTTP status 401 when my Java application tries to send a notificat

Answer 1

I wrote an FCMHelper Class, that works fine and is simple to use.

See here https://github.com/MOSDEV82/fcmhelper

Answer 2

I too have recently started using Firebase, with no prior experience in Google Cloud Messaging. AFAIK, there's no server side SDK for Firebase Cloud Messaging, currently.

To send notifications/messages from your App Server to your Mobile Client, you need to implement your own HTTP and/or XMPP methods. See https://firebase.google.com/docs/cloud-messaging/

My testing code, using HTTP:

public CompletableFuture<String> fcmTest1() {
    // https://firebase.google.com/docs/cloud-messaging/http-server-ref
    String host = "fcm.googleapis.com";
    String requestURI = "/fcm/send";
    String CLIENT_TOKEN = "ASK_YOUR_MOBILE_CLIENT_DEV"; // https://developers.google.com/instance-id/

    CompletableFuture<String> fut = new CompletableFuture<>();
    JsonObject body = new JsonObject();
    // JsonArray registration_ids = new JsonArray();
    // body.put("registration_ids", registration_ids);
    body.put("to", CLIENT_TOKEN);
    body.put("priority", "high");
    // body.put("dry_run", true);

    JsonObject notification = new JsonObject();
    notification.put("body", "body string here");
    notification.put("title", "title string here");
    // notification.put("icon", "myicon");

    JsonObject data = new JsonObject();
    data.put("key1", "value1");
    data.put("key2", "value2");

    body.put("notification", notification);
    body.put("data", data);

    HttpClientRequest hcr = httpsClient.post(443, host, requestURI).handler(response -> {
        response.bodyHandler(buffer -> {
            logger.debug("FcmTest1 rcvd: {}, {}", response.statusCode(), buffer.toString());
            if (response.statusCode() == 200) {
                fut.complete(buffer.toString());
            } else {
                fut.completeExceptionally(new RuntimeException(buffer.toString()));
            }
        });
    });
    hcr.putHeader("Authorization", "key=" + Utils.FIREBASE_SERVER_KEY)
        .putHeader("content-type", "application/json").end(body.encode());
    return fut;
}

note: http client and json were provided by vertx (http://vertx.io/), but hopefully the code shows what's going on clear enough so you can use whatever you wish.

Answer 3

I needed to send FCM notification from my java EE application and I found this very helpful. Might save someone some time.

...The github repo is a library interface for Firebase Cloud Messaging (FCM) API (NB// I am not the author). So I followed instructions in the readme: added the jar file as a dependency to my project and could just invoke the library methods with respective parameters.

e.g. Pushraven.setKey(my_key); to set your server key and

Notification raven = new Notification();
raven.title("MyTitle")
     .text("Hello World!")
     .color("#ff0000")
     .to(client_key);

to build a notification. The instructions from the repo are pretty much clear and helpful.

Answer 4

On:

// Obtain serverKey from Project Settings -> Cloud Messaging tab // for "My Notification Server" project in Firebase Console. String serverKey = <get_server_key_from_firebase_console>;

You must obtain the key for your android app.

And thank you, I was struggling to build a service to send/receive notifications for the app. Saw your question, tried to get it right, and used to build mine. Hope this will help you :)

Answer 5

Use this sending push notifications from java.

Spring Framework

Compared to other projects there are just 3 simple classes with minimal dependencies.

https://github.com/AndreiD/testingpushnotifications

Remember to replace the SERVER_API_KEY and the Client_Token.

Answer 6

I was running into the same issue. The problem was in the line:

String serverKey = <get_server_key_from_firebase_console>;

This value should come from the Android app project; in this case it would be "My Notification Client" and not "My Notification Server".