Overview

On incoming events such as a new message, or an incoming call, the user often expects to receive a push notification or the app itself. If the app is not active (is in the background), push notifications are the only way to notify app about new events.

This guide explains how to configure your Android app to receive push notifications from the Client SDK.

Set up Firebase project for your Android application

In order to enable push notifications for your Android application, you need to configure your Android application, create a new Firebase project and connect it to your Vonage API application.

Configure Android project

Let's start with setting up Android project.

To add the Client SDK dependency

Add Client SDK to your project.

Add Firebase Cloud Messaging dependency

In your IDE, in your app level build.gradle file (usually app/build.gradle), add the firebase-messaging dependency:

dependencies{
    implementation("com.google.firebase:firebase-messaging:20.3.0")
}
dependencies{
    implementation 'com.google.firebase:firebase-messaging:20.3.0'
}

NOTE: The latest version number can be found on the Firebase website.

Implement a custom service class to receive push notifications

If you do not have one already, create a class (service) that extends FirebaseMessagingService.

In order for Vonage API application to be able to send push notifications to a device, the Vonage server has to know the device token, also known as InstanceID.

In your class that extends FirebaseMessagingService, override onNewToken() method and update the NexmoClient by passing new token:

class MyFirebaseMessagingService: FirebaseMessagingService() {

    // We can retrieve client instance only if it has been already initialized
    // NexmoClient.Builder().build(context)
    private val client = NexmoClient.get()

    override fun onNewToken(token: String) {
        super.onNewToken(token)

        client.enablePushNotifications(token, object: NexmoRequestListener<Void> {
            override fun onSuccess(p0: Void?) { }

            override fun onError(apiError: NexmoApiError) {}
        })
    }
}
public class MyFirebaseMessagingService extends FirebaseMessagingService {

    // We can retrieve client instance only if it has been already initialized
    // new NexmoClient.Builder().build(context)
    private NexmoClient client = NexmoClient.get();

    @Override
    public void onNewToken(@NonNull String token) {
        super.onNewToken(token);

        client.enablePushNotifications(token, new NexmoRequestListener<Void>() {
            @Override
            public void onSuccess(@Nullable Void p0) {}

            @Override
            public void onError(@NonNull NexmoApiError nexmoApiError) {}
        });
    }
}

Make sure your service is declared in your AndroidManifest.xml (typically app/src/main/AndroidManifest.xml) by adding service tag inside application tag:

<service android:name=".MyFirebaseMessagingService">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

Receive push notifications

Push notifications are received in your implementation of MyFirebaseMessagingService, on onMessageReceived() method.

You can use NexmoClient.isNexmoPushNotification(message.data)) to determine if the message is sent from Vonage server.

Use processPushNotification(message.data, listener) to process the data received from Firebase Cloud Messaging (FCM) into an easy to use Nexmo object:

class MyFirebaseMessagingService : FirebaseMessagingService() {

    // We can retrieve client instance only if it has been already initialized
    // NexmoClient.Builder().build(context)
    private val client = NexmoClient.get()

    override fun onNewToken(token: String) {
        super.onNewToken(token)
        //...   
    }

    override fun onMessageReceived(remoteMessage: RemoteMessage) {
        // determine if the message is sent from Nexmo server
        if (NexmoClient.isNexmoPushNotification(remoteMessage.data)) {
            client.processNexmoPush(remoteMessage.data, object : NexmoPushEventListener {
                override fun onIncomingCall(call: NexmoCall?) {
                    Log.d("TAG", "FirebaseMessage:onIncomingCall() with: $call")
                }

                override fun onNewEvent(event: NexmoEvent?) {
                    Log.d("TAG", "FirebaseMessage:onNewEvent() with: $event")
                }

                override fun onError(apiError: NexmoApiError?) {
                    Log.d("TAG", "FirebaseMessage:onError() with: $apiError")
                }
            })
        }
    }
}
public class MyFirebaseMessagingService extends FirebaseMessagingService {

    // We can retrieve client instance only if it has been already initialized
    // new NexmoClient.Builder().build(context)
    private NexmoClient client = NexmoClient.get();

    @Override
    public void onNewToken(@NonNull String token) {
        super.onNewToken(token);

        //...
    }

    @Override
    public void onMessageReceived(@NonNull RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);

        // determine if the message is sent from Nexmo server
        if (NexmoClient.isNexmoPushNotification(remoteMessage.getData())) {
            client.processNexmoPush(remoteMessage.getData(), new NexmoPushEventListener() {
                @Override
                public void onIncomingCall(NexmoCall call) {
                    Log.d("TAG", "FirebaseMessage:onIncomingCall() with: " + call);
                }

                @Override
                public void onNewEvent(NexmoEvent event) {
                    Log.d("TAG", "FirebaseMessage:onNewEvent() with: " + event);
                }

                @Override
                public void onError(NexmoApiError apiError) {
                    Log.d("TAG", "FirebaseMessage:onError() with: " + apiError);
                }
            });
        }
    }
}

NOTE: In order to apply any methods on Nexmo Client object (for example answer a call, hangup, and so on) Nexmo Client has to be initialized and the user has to be logged in to it.

Connect Vonage API application to Firebase

To connect Vonage API Application with Firebase you will need the following:

  1. Vonage API Application id
  2. Vonage developer JWT
  3. Firebase project id
  4. Firebase token

Get Vonage application Id

Obtain your VONAGE_APP_ID. You can access existing application in the Nexmo Dashboard. If you don't have an application already you can create the new application via Nexmo CLI.

Generate a Vonage developer JWT

JWTs are used to authenticate a user into the Client SDK.

To generate a VONAGE_DEV_JWT run the following command. Remember to replace the VONAGE_APP_ID with id of your Vonage application:

nexmo jwt:generate ./private.key exp=$(($(date +%s)+86400)) acl='{"paths":{"/*/users/**":{},"/*/conversations/**":{},"/*/sessions/**":{},"/*/devices/**":{},"/*/image/**":{},"/*/media/**":{},"/*/applications/**":{},"/*/push/**":{},"/*/knocking/**":{}}}' application_id=VONAGE_APP_ID

NOTE The above commands set the expiry of the JWT to one day from now, which is the maximum.

NOTE A VONAGE_DEV_JWT is a JWT without a sub claim.

NOTE: More details on how to generate a JWT can be found in the setup guide.

Get Firebase project Id

Get your FIREBASE_PROJECT_ID from the Firebase console. Navigate to Firebase console -> Project settings -> General.

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Get Firebase token

Get your FIREBASE_TOKEN from the Firebase console. Navigate to Firebase console -> Project settings -> Service accounts and generate a new private key.

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To link the Nexmo backend push service with the Firebase application you need to make a single request.

Fill VONAGE_APP_ID, VONAGE_DEV_JWT, FIREBASE_PROJECT_ID and FIREBASE_TOKEN with previously obtained values and run the below command:

VONAGE_APP_ID=
VONAGE_DEV_JWT=
FIREBASE_PROJECT_ID=
FIREBASE_TOKEN=

curl -v -X PUT \
   -H "Authorization: Bearer $VONAGE_DEV_JWT" \
   -H "Content-Type: application/json" \
   -d "{\"token\":\"$FIREBASE_TOKEN\", \"projectId\":\"$FIREBASE_PROJECT_ID\"}" \
   https://api.nexmo.com/v1/applications/$VONAGE_APP_ID/push_tokens/android  

Putting it all together

Now you can test your push notification setup by calling any user. Incoming call will trigger onIncomingCall callback presented above.

Conclusion

In this guide you have seen how to set up push notifications.

Overview

On incoming events such as a new message, or an incoming call, the user often expects to receive a push notification, if the app is not active.

There are two types of push notifications that you can use:

  • VoIP push (PushKit) - the better fit for applications that use Nexmo In-App Voice functionality.
  • Regular push (UserNotifications) - the better fit for applications that use Nexmo In-App Chat functionality.

This guide will cover how to VoIP push notifications with the Client SDK.

Create a push certificate

Apple Push Notifications service (APNs) uses certificate-based authentication to secure the connections between APNs and Vonage servers. So you will need to create a certificate and upload it to the Vonage Servers.

Adding a push notification capability

To use push notifications you are required to add the push notification capability to your Xcode project. To do this select your target and select Signing & Capabilities:

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Then select add capability and add the Push Notifications capability:

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If Xcode is automatically managing the signing of your app it will update the provisioning profile linked to your Bundle Identifier to include the capability.

Generating a push certificate

To generate a push certificate you will need to log in to your Apple developer account and head to the Certificates, Identifiers & Profiles page and add a new certificate:

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Choose a VoIP Services Certificate and continue. You will now need to choose the App ID for the app that you want to add VoIP push notifications to and continue. If your app is not listed you will have to create an App ID. Xcode can do this for you if it automatically if it manages your signing for you, otherwise you can create a new App ID on the Certificates, Identifiers & Profiles page under Identifiers. Make sure to select the push notifications capability when doing so.

You will be prompted to upload a Certificate Signing Request (CSR). You can follow the instructions on Apple's help website to create a CSR on your Mac. Once the CSR is uploaded you will be able to download the certificate. Double click the .cer file to install it in Keychain Access.

To get the push certificate in the format that is needed by the Vonage servers you will need to export it. Locate your VoIP Services certificate in Keychain Access and right-click to export it. Name the export applecert and select .p12 as the format:

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You can find more details about connecting to APNs in Apple's official documentation.

Upload your certificate

To upload your certificate to the Vonage servers you will also need:

  • A jwt_dev, which is a jwt without a sub claim. More details on how to generate a JWT can be found in the setup guide.

  • Your Nexmo Application ID. It can be obtained from the Nexmo Dashboard.

Then run the following Curl command, replacing jwt_dev, applecert.p12, app_id with your values:

hexdump -ve '1/1 "%.2x"' < applecert.p12 > applecert.pfx.hex
hextoken=`cat applecert.pfx.hex`

curl -v -X PUT \
   -H "Authorization: Bearer $jwt_dev" \
   -H "Content-Type: application/json" \
   -d "{\"token\":\"$hextoken\"}" \
   https://api.nexmo.com/v1/applications/$app_id/push_tokens/ios

Integrate push notifications in your application

VoIP push notifications are suitable for VoIP apps. Among other benefits, it allows you to receive notifications even when the app is terminated.

To integrate VoIP push in your app, follow these steps:

1. Enable VoIP Background Mode for your app

Similar to the process for adding the push notifications capability earlier, in Xcode, under your target, open Capabilities and select Background Modes. Once the capability is added tick the "Voice over IP" option:

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2. Import PushKit, adopt PKPushRegistryDelegate, and sign up to VoIP notifications

Add a voipRegistry property:

let voipRegistry = PKPushRegistry(queue: nil)

and set it up:

func registerForVoIPPushes() {
    self.voipRegistry.delegate = self
    self.voipRegistry.desiredPushTypes = [PKPushType.voIP]
}

Add a voipRegistry property:

@property PKPushRegistry* voipRegistry;

and set it up:

- (void) registerForVoIPPushes {
    self.voipRegistry = [[PKPushRegistry alloc] initWithQueue:nil];
    self.voipRegistry.delegate = self;

    // Initiate registration.
    self.voipRegistry.desiredPushTypes = [NSSet setWithObject:PKPushTypeVoIP];
}

3. Implement the following delegate method and add the code to handle an incoming VoIP push notification

func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith 
        payload: PKPushPayload, for type: PKPushType, completion: @escaping () -> Void) {
    if(NXMClient.shared.isNexmoPush(userInfo: payload.dictionaryPayload)) {
        guard let pushPayload = NXMClient.shared.processNexmoPushPayload(payload.dictionaryPayload) else {
            NSLog("Not a Nexmo push notification")
            return
        }
    }
}
- (void)pushRegistry:(PKPushRegistry *)registry didReceiveIncomingPushWithPayload:(PKPushPayload *)payload 
        forType:(PKPushType)type withCompletionHandler:(void (^)(void))completion {
    if ([NXMClient.shared isNexmoPushWithUserInfo:payload.dictionaryPayload]) {
        NXMPushPayload *pushPayload = [NXMClient.shared processNexmoPushPayload:payload.dictionaryPayload];
        if (!pushPayload){
           NSLog(@"Not a nexmo push");
           return;
        };
    }
}

For the SDK to process the push properly NXMClient should be logged in.

4. Enable Nexmo push notifications through a logged in NXMClient

NXMClient.shared.enablePushNotifications(withPushKitToken: pushKitToken, 
        userNotificationToken: nil, isSandbox: true) { (error) in
    // code
}
[NXMClient.shared enablePushNotificationsWithPushKitToken:pushKitToken 
        userNotificationToken:userNotificationToken isSandbox:YES 
        completionHandler:^(NSError * _Nullable error) {
    // code 
}];
  • 'isSandbox' is YES/true for an app using the Apple sandbox push servers and NO/false for an app using the Apple production push servers.

  • 'pushKitToken' is the token received in pushRegistry(_:didUpdate:for:).

Conclusion

In this guide you have seen how to set up push notifications.