Push notifications for SwiftUI

Push notifications are messages that are sent to a user's device from a server. They can be used to notify users of new messages, updates, or other important information. In this guide, we'll show you how to implement push notifications in your client app when using the Sendbird SwiftUI.

Push notification messages for iOS devices will be delivered through Apple Push Notification service (APNs). To notify users of events that take place on a client app, you should register your APNs notification credentials first. The following steps explain how to download your push notification credentials for APNs and register them to the Sendbird server via your dashboard.

• Step 1 Create your certificate signing request

• Step 2 Create your push notification SSL certificate

• Step 3-1 Export a .p12 file and upload to Sendbird Dashboard

• Step 3-2 Export a .p8 file and upload to Sendbird Dashboard

• Step 4 Register a device token to the Sendbird server

• Step 5 Handle a notification payload

To set up push notifications on a client app, have an app ID assigned to your client app. To obtain a signing certificate required to sign apps for installation on iOS devices, you should first create a certificate signing request (CSR) file through Keychain Access on your Mac.

1. Open Keychain Access from the Utilities folder, go to Keychain Access > Certificate Assistant, and then click Request a Certificate From a Certificate Authority.

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2. When the Certificate Information dialog box appears, enter the email address that you use in your Apple Developer account, and enter a common name for your private key. Don't enter CA email address, choose Saved to disk, and then click the Continue button.

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3. Specify the name of your CSR to save and choose the location to save the file on your local disk. Then your CSR file is created, which contains a public/private key pair.

1. Sign in to your account at the Apple Developer Member Center and choose Certificates, Identifiers & Profiles. In the Identifiers > App IDs, select the Push Notifications service, and then click the Configure button.

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2. When prompted by a pop-up window, choose which SSL certificate to create either Development or Production.

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3. In the Certificates, Identifiers & Profiles pane that appears after the selection, under Upload a Certificate Signing Request, upload the CSR file you created through the Choose File button. Then to complete the process, click the Continue button above. When the certificate is ready, choose Download to save it to your Mac.

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4. In order to install the downloaded certificate to the Keychain Access on your Mac, double-click it. You can find the certificate in the Keychain Access > login > Certificates.

The Sendbird server needs to use some of your confidential information in your .p12 file to communicate with and send notification requests to APNs on behalf of your server. A .p12 file is a set of certificates that you generated when building a client app for iOS.

Note: Now you can use a .p8 file to communicate with APNs and register it in the Sendbird Dashboard. See Step 3-2: Export a .p8 file and upload to Sendbird Dashboard for more information.

You can register your .p12 file to the Sendbird server through your dashboard or by using the Chat API's add an APNs push configuration action. The following steps show how to register a .p12 file in the Dashboard.

1. Open Keychain Access and go to login > Certificates. Find the push notification SSL certificate you just added, right-click the certificate, and then select Export "YOUR_PROJECT_NAME" from the context menu to get a .p12 file that contains the certificate.

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2. Type a name for the .p12 file and save it to your Mac. Do not provide an export password when prompted. Then sign in to your dashboard and upload the file under Settings > Chat > Push notifications.

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3. When a dialog opens up, select .p12 for Format. Then click the Choose file and select your .p12 certificate to upload. Once the file is uploaded, a password box appears. If needed, you can also set a password for the file.

4. Then enable Mutable content in the Extensions section. Finally, click Add.

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The Sendbird server needs to use some of your confidential information in your .p8 file to send notification requests to APNs on behalf of your server. A .p8 file is an authentication token that is generated when you build a client app for iOS.

You can register your .p8 file to the Sendbird server through the Sendbird Dashboard or by using the platform API’s add an APNs push configuration action. The following steps show how to register a .p8 file in the dashboard.

Note: To learn more about the authentication token with a .p8 extension, visit Apple Developer's Documentation on a token-based connection to APNs.

1. Log into your Apple Developer account and go to Certificates, Identifiers & Profiles > Keys. Then click Create a key.

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2. Once an authentication key is created, register the key with a key name of your choice and select a service you want to use. In this case, check Apple Push Notifications service (APNs) in the table. Then click Continue.

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3. Make sure the key name and service chosen are correct. Then click Register.

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4. Once the key is registered, you can download the key as a file with a .p8 extension. Download the file so that you can add it to the Sendbird Dashboard.

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Note: The file can be only downloaded once. Make sure to remember the directory where your file is downloaded.

5. Sign in to your Sendbird Dashboard and upload the file under Settings > Chat > Push notifications.

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6. When a dialog opens up, select .p8 for Format. Then click Choose file and select your .p8 key file to upload. Once the file is uploaded, select SSL certificate type between Production and Developer and enable Mutable content in the Extensions section. Then click Add.

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To use remote push notifications in your app's xcode project, you need to enable the push notifications capability.

For more information, follow the steps in the Enable the Push Notifications Capability section of Apple's Registering Your App with APNs article.

When requested to send notifications to a specific client app on an iOS device, APNs requires the app instance's globally-unique and app-specific device token which has been issued by itself. Therefore, to send notification requests to APNs on behalf of your server, the Sendbird server needs every device token of your client app instances. If an app instance is successfully registered to APNs via the registerForRemoteNotifications method, a device token is passed to an app delegate object's application:didRegisterForRemoteNotificationsWithDeviceToken: method which is called by the app. Like the following sample code, you should register this token to the Sendbird server by passing it as an argument to a parameter in the registerDevicePushToken(_:unique:completionHandler:) method.

Note: A user can have up to 20 APNs device tokens. If a user already has 20 device tokens, the oldest token will be deleted before a new token is added. Only the 20 newest tokens will be maintained for users who already have more than 20.

class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {
    // ...
    
    // unique: The default is `false`. If `true`, register device token after
    // removing all existing device tokens of the current user. If `false`, just add the device token
    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        SendbirdUI.registerPush(deviceToken: deviceToken, unique: true) { (success) in
          // Handle success or failure
        }
    }
    
    // ...
}

Make sure you call the following code in the appropriate place to receive permissions from your users.

let center = UNUserNotificationCenter.current()
center.delegate = self
center.requestAuthorization(options: [.sound, .alert, .badge]) { granted, error in
    DispatchQueue.main.async {
        UIApplication.shared.registerForRemoteNotifications()
    }
}

Sendbird Chat SwiftUI includes a PushPayloadManager that handles secondary events on behalf of the user when a push notification is received. The PushPayloadManager processes the logic for navigating to the channel with the received message in the channel list after receiving a push notification or emits the push event through its Combine publisher, pushNotificationPublisher.

To deliver a push event to the PushPayloadManager, use the save method in the UNUserNotificationCenterDelegate to pass the userInfo information.

extension AppDelegate: UNUserNotificationCenterDelegate {
  func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Swift.Void) {
      let userInfo = response.notification.request.content.userInfo
      
     // Update information
      SendbirdUI.PushPayloadManager.save(userInfo: userInfo)
  }
}

Users can subscribe to Sendbird's push events through the pushNotificationPublisher provided by the PushPayloadManager. In a SwiftUI view, it can be used as follows:

@State var showChannelList = false

var body: some View {
  NavigationView {
      NavigationLink(isActive: $showChannelList, destination: {
          GroupChannelListView()
      }) {
          EmptyView()
      }
      .navigationTitle("Sample List")
      .onReceive(SendbirdUI.PushPayloadManager.pushNotificationPublisher) { _ in 
          showChannelList = true
      }
  }

  // If iOS 16 is available 
  NavigationStack {
      EmptyView()
      .navigationTitle("Sample List")
      .onReceive(SendbirdUI.PushPayloadManager.pushNotificationPublisher) { _ in 
          showChannelList = true
      }
      .navigationDestination(isPresented: $showChannelList) {
          GroupChannelListView()
      }
  }
}

Note : If a view that subscribes to a publisher using onReceive is not present in the SwiftUI view hierarchy, it will not receive events. To continuously observe events, it is recommended to subscribe to events from the app’s root view.

The following is a complete payload format of the sendbird object, which contains a set of provided key-value items. As for channel_unread_count, the attribute can be added into or removed from the payload in Settings > Chat > Push notifications on the Sendbird Dashboard.

{
    "category": "messaging:offline_notification",
    "type": string,                 // Message type can be MESG, FILE, or ADMM.
    "message": string,              // User input message.
    "custom_type": string,          // Custom message type.
    "message_id": long,             // Message ID.
    "created_at": long,             // The time that the message was created in a 13-digit Unix milliseconds format.
    "app_id": string,               // Application's unique ID.
    "unread_message_count": int,    // Total number of new messages unread by the user.
    "channel": {
        "channel_url": string,      // Group channel URL.
        "name": string,             // Group channel name.
        "custom_type": string,       // Custom Group channel type.
        "channel_unread_count": int // Total number of unread new messages from the specific channel.
    },
    "channel_type": string,         // The value of channel_type is set by the system.
                                    // messaging indicates a distinct group channel,
                                    // while group_messaging indicates a private group channel.
                                    // chat indicates all other cases.
    "sender": {
        "id": string,               // Sender's unique ID.
        "name": string,             // Sender's nickname.
        "profile_url": string,       // Sender's profile image URL.
        "require_auth_for_profile_image": false,
        "metadata": {}
    },
    "recipient": {
        "id": string,               // Recipient's unique ID.
        "name": string              // Recipient's nickname.
    },
    "files": [],                    // An array of data regarding the file message, such as filename.
    "translations": {},             // The items of locale:translation.
    "push_title": string,           // Title of a notification message that can be customized on the Sendbird Dashboard with or without variables.
    "push_alert": string,           // Body text of a notification message that can be customized on the Sendbird Dashboard with or without variables.
    "push_sound": string,           // The location of a sound file for notifications.
    "audience_type": string,        // The type of audiences for notifications.
    "mentioned_users": {
        "user_id": string,          // The ID of a mentioned user.
        "nickname": string,         // The nickname of a mentioned user.
        "profile_url": string,      // Mentioned user's profile image URL.
        "require_auth_for_profile_image": false
    },
}

Sendbird’s push notifications with multi-device support provide the same features as our general push notifications, but with additional support for multi-device users. If implemented, notifications are delivered to all online and offline devices of a multi-device user. However, through our Sendbird SwiftUI, push notifications are displayed only on offline devices, while ignored by online devices. As a result, client apps are able to display push notifications on all offline devices, regardless of whether one or more are online.

For example, let’s say a multi-device user who has six devices installed with your client app is online on one device and offline on the remaining five. If push notifications are implemented, notifications aren’t delivered to any devices. If push notifications with multi-device support are implemented, notifications are delivered to all six devices, but displayed only on the five devices that are offline.

After the above implementation is completed, determine whether multi-device push notification is required for your client app. To set it up, go to Settings > Chat > Push notifications > Push notifications for multi-device users on our dashboard.

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The following table explains when a notification message is sent and whether it is displayed on the device depending on your notification support settings and the device' online status. Refer to the table to find out which notification support best suits the client app use cases.

You should unregister a user's device token from Sendbird server if you don’t want to send push notifications to the user.

// If you want to unregister the current device only, call this method.
SendbirdUI.unregisterPushToken { (success) in

}

// If you want to unregister all devices of the user, call this method.
SendbirdUI.unregisterAllPushToken { (success) in

}

Note : You can use these methods when the SBUGlobals.currentUser is set and connected to Sendbird server.