FcmJava

Description

FcmJava is a library for working with the Firebase Cloud Messaging (FCM) API.

Maven Dependencies

You can add the following dependencies to your pom.xml to include FcmJava in your project.

<dependency>
  <groupId>de.bytefish.fcmjava</groupId>
  <artifactId>fcmjava-core</artifactId>
  <version>0.4</version>
</dependency>

<dependency>
  <groupId>de.bytefish.fcmjava</groupId>
  <artifactId>fcmjava-client</artifactId>
  <version>0.4</version>
</dependency>

Quickstart

The Quickstart shows you how to work with FcmJava.

API Key Settings

The FCM API Key is read from an external .properties file to ensure the API Key secret does not reside in code or leaks into the public.

The file contains the API Endpoint to send to and the API Key:

fcm.api.url=https://fcm.googleapis.com/fcm/send
fcm.api.key=<YOUR_API_KEY_HERE>

You can use the PropertiesBasedSettings class to read the Properties:

1. PropertiesBasedSettings.createFromDefault()
   • Uses the default file location of System.getProperty("user.home") + "/.fcmjava/fcmjava.properties" to read the properties. This is the recommended way of reading your API Key.
2. PropertiesBasedSettings.createFromFile(Path path, Charset charset)
   • Uses a custom file location to read the Client Settings from.
3. PropertiesBasedSettings.createFromSystemProperties()
   • Uses the System Properties to initialize the Client Settings.

FcmClient

// Copyright (c) Philipp Wagner. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

package de.bytefish.fcmjava.integration;

import com.fasterxml.jackson.annotation.JsonProperty;
import de.bytefish.fcmjava.client.FcmClient;
import de.bytefish.fcmjava.constants.Constants;
import de.bytefish.fcmjava.http.options.IFcmClientSettings;
import de.bytefish.fcmjava.model.options.FcmMessageOptions;
import de.bytefish.fcmjava.model.topics.Topic;
import de.bytefish.fcmjava.requests.topic.TopicUnicastMessage;
import org.junit.Ignore;
import org.junit.Test;

import java.nio.charset.Charset;
import java.time.Duration;

public class FcmClientIntegrationTest {

    private class PersonData {

        private final String firstName;
        private final String lastName;

        public PersonData(String firstName, String lastName) {
            this.firstName = firstName;
            this.lastName = lastName;
        }

        @JsonProperty("firstName")
        public String getFirstName() {
            return firstName;
        }

        @JsonProperty("lastName")
        public String getLastName() {
            return lastName;
        }
    }

    @Test
    @Ignore("This is an Integration Test using system properties to contact the FCM Server")
    public void SendTopicMessageTest() throws Exception {

        // Create the Client using system-properties-based settings:
        FcmClient client = new FcmClient(PropertiesBasedSettings.createFromDefault());

        // Message Options:
        FcmMessageOptions options = FcmMessageOptions.builder()
                .setTimeToLive(Duration.ofHours(1))
                .build();

        // Send a Message:
        client.send(new TopicUnicastMessage(options, new Topic("news"), new PersonData("Philipp", "Wagner")));
    }
}

Android Client

I have decided to clone the messaging quickstart sample of Google, which is available at:

• https://github.com/firebase/quickstart-android/tree/master/messaging

Now first subscribe to the news topic, then execute the above FcmJava application.

The Android app will now receive a message with the sent data included:

09-17 21:10:45.250 10882-11300/com.google.firebase.quickstart.fcm D/MyFirebaseMsgService: From: /topics/news
09-17 21:10:45.251 10882-11300/com.google.firebase.quickstart.fcm D/MyFirebaseMsgService: Message data payload: {lastName=Wagner, firstName=Philipp}