Tutorial: Push notifications to iOS apps using Azure Notification Hubs

In this tutorial, you use Azure Notification Hubs to push notifications to an iOS application. You create a blank iOS app that receives push notifications by using the Apple Push Notification service (APNs).

In this tutorial, you take the following steps:

  • Generate the certificate signing request file
  • Request your app for push notifications
  • Create a provisioning profile for the app
  • Configure your notification hub for iOS push notifications
  • Connect your iOS app to notification hubs
  • Send test push notifications
  • Verify that your app receives notifications

The completed code for this tutorial can be found on GitHub.

Prerequisites

  • An active Azure account. If you don't have an account, you can create a free Azure account in just a couple of minutes.

  • Windows Azure Messaging Framework

  • Latest version of Xcode

  • An iOS 10 (or later version)-capable device

  • Apple Developer Program membership.

    Note

    Because of configuration requirements for push notifications, you must deploy and test push notifications on a physical iOS device (iPhone or iPad) instead of the iOS Simulator.

Completing this tutorial is a prerequisite for all other Notification Hubs tutorials for iOS apps.

Generate the certificate-signing request file

The Apple Push Notification Service (APNs) uses certificates to authenticate your push notifications. Follow these instructions to create the necessary push certificate to send and receive notifications. For more information on these concepts, see the official Apple Push Notification Service documentation.

Generate the Certificate Signing Request (CSR) file, which Apple uses to generate a signed push certificate.

  1. On your Mac, run the Keychain Access tool. It can be opened from the Utilities folder or the Other folder on the Launchpad.

  2. Select Keychain Access, expand Certificate Assistant, and then select Request a Certificate from a Certificate Authority.

    Use Keychain Access to request a new certificate

  3. Select your User Email Address, enter your Common Name value, make sure that you specify Saved to disk, and then select Continue. Leave CA Email Address blank as it isn't required.

    Required certificate information

  4. Enter a name for the CSR file in Save As, select the location in Where, and then select Save.

    Choose a file name for the certificate

    This action saves the CSR file in the selected location. The default location is Desktop. Remember the location chosen for the file.

Next, register your app with Apple, enable push notifications, and upload the exported CSR to create a push certificate.

Register your app for push notifications

To push notifications to an iOS app, register your application with Apple and also register for push notifications.

  1. If you haven't already registered your app, browse to the iOS Provisioning Portal at the Apple Developer Center. After that, sign in with your Apple ID, select Identifiers, select App IDs, and finally select + to register a new app.

    iOS Provisioning Portal App IDs page

  2. Update the following three values for your new app, and then select Continue:

    • Name: Type a descriptive name for your app in the Name box in the App ID Description section.

    • Bundle Identifier: In the Explicit App ID section, enter a Bundle Identifier of the form <Organization Identifier>.<Product Name> as mentioned in the App Distribution Guide. The Organization Identifier and Product Name values must match the organization identifier and product name you use when you create your Xcode project. In the following screenshot, the NotificationHubs value is used as an organization identifier and the GetStarted value is used as the product name. Make sure the Bundle Identifier value matches the value in your Xcode project, so that Xcode will use the correct publishing profile.

    • Push Notifications: Check the Push Notifications option in the App Services section.

      Form to register a new App ID

      This action generates your App ID and requests that you confirm the information. Select Register to confirm the new App ID.

      After you select Register, you see the Registration complete screen as shown in the following image. Select Done.

      App ID registration complete showing entitlements

  3. In the Developer Center, under App IDs, locate the app ID that you created and select its row.

    App ID list

    Select the app ID to display the app details, and then select the Edit button at the bottom.

    Edit App ID page

  4. Scroll to the bottom of the screen and select the Create Certificate button under the Development Push SSL Certificate section.

    Create certificate for App ID button

    You now see the Add iOS Certificate assistant.

    Note

    This tutorial uses a development certificate. The same process is used when registering a production certificate. Just make sure that you use the same certificate type when sending notifications.

  5. Select Choose File, browse to the location where you saved the CSR file from the first task, and then select Generate.

    Generated certificate CSR upload page

  6. After the portal creates the certificate, select the Download button and then select Done.

    Generated certificate download page

    The certificate is downloaded and saved to your computer in your Downloads folder.

    Locate certificate file in the Downloads folder

    Note

    By default, the downloaded development certificate is named aps_development.cer.

  7. Select the downloaded push certificate aps_development.cer.

    This action installs the new certificate in the Keychain, as shown in the following image:

    Keychain access certificates list showing new certificate

    Note

    Although the name in your certificate might be different, the name will be prefixed with Apple Development iOS Push Services.

  8. In Keychain Access, right-click the new push certificate that you created in the Certificates category. Select Export, name the file, select the .p12 format, and then select Save.

    Export certificate as p12 format

    Make a note of the file name and location of the exported .p12 certificate. They are used to enable authentication with APNs.

    Note

    This tutorial creates a file named QuickStart.p12. Your file name and location might be different.

Create a provisioning profile for the app

  1. In the iOS Provisioning Portal, select Provisioning Profiles, select All, and then select + to create a new profile. You see the Add iOS Provisioning Profile wizard.

    Provisioning profile list

  2. Select iOS App Development under Development as the provisioning profile type, and select Continue.

  3. Next, select the app ID you created from the App ID drop-down list, and select Continue.

    Select the App ID

  4. In the Select certificates window, select your usual development certificate that you used for code signing, and select Continue. This certificate isn't the push certificate you created.

    Select the certificate

  5. Next, select the devices to use for testing, and select Continue.

    Select the devices

  6. Finally, pick a name for the profile in Profile Name, and select Generate.

    Choose a provisioning profile name

  7. When the new provisioning profile is created, choose to download and install it on your Xcode development machine. Then select Done.

    Download the provisioning profile

Create a notification hub

In this section, you create a notification hub and configure authentication with APNs by using the .p12 push certificate that you previously created. If you want to use a notification hub that you've already created, you can skip to step 5.

  1. Sign in to the Azure portal.

  2. Select All services on the left menu, and select Notification Hubs in the Mobile section. Select the star icon next to the service name to add the service to the FAVORITES section on the left menu. After you add Notification Hubs to FAVORITES, select it on the left menu.

    Azure portal - select Notification Hubs

  3. On the Notification Hubs page, select Add on the toolbar.

    Notification Hubs - Add toolbar button

  4. On the Notification Hub page, do the following steps:

    1. Enter a name in Notification Hub.

    2. Enter a name in Create a new namespace. A namespace contains one or more hubs.

    3. Select a value from the Location drop-down list box. This value specifies the location in which you want to create the notification hub.

    4. Select an existing resource group in Resource Group, or create a name for a new resource group.

    5. Select Create.

      Azure portal - set notification hub properties

  5. Select Notifications (the bell icon), and select Go to resource. You can also refresh the list on the Notification Hubs page and select your notification hub.

    Azure portal - notifications -> Go to resource

  6. Select Access Policies from the list. Note the two connection strings that are available to you. You'll later need them to handle push notifications.

    Important

    Do not use the DefaultFullSharedAccessSignature policy in your application. This is meant to be used in your back end only.

    Azure portal - notification hub connection strings

Configure your notification hub with APNs information

  1. Under Notification Services, select Apple (APNS).

  2. Select Certificate.

  3. Select the file icon.

  4. Select the .p12 file that you exported earlier.

  5. Specify the correct password.

  6. Select Sandbox mode. Use the Production mode only if you want to send push notifications to users who purchased your app from the store.

    Configure APNs certification in Azure portal

You've now configured your notification hub with APNs. You also have the connection strings to register your app and send push notifications.

Connect your iOS app to Notification Hubs

  1. In Xcode, create a new iOS project and select the Single View Application template.

    Xcode - Single View Application

  2. When setting the options for your new project, make sure to use the same Product Name and Organization Identifier that you used when you set the bundle identifier in the Apple Developer portal.

    Xcode - project options

  3. Under Project Navigator, click your project name, click the General tab, and find Signing. Make sure you select the appropriate Team for your Apple Developer account. XCode should automatically pull down the Provisioning Profile you created previously based on your bundle identifier.

    If you don't see the new provisioning profile that you created in Xcode, try refreshing the profiles for your signing identity. Click Xcode on the menu bar, click Preferences, click the Account tab, click the View Details button, click your signing identity, and then click the refresh button in the bottom-right corner.

    Xcode - provisioning profile

  4. Select the Capabilities tab and make sure to enable Push Notifications

    Xcode - push capabilities

  5. Add the Azure Notification Hubs SDK modules.

    You can integrate the Azure Notification Hubs SDK in your app by using Cocoapods or by manually adding the binaries to your project.

    • Integration via Cocoapods

      Add the following dependencies to your podfile to include Azure Notification Hubs SDK into your app.

      pod 'AzureNotificationHubs-iOS'
      

      Run pod install to install your newly defined pod and open your .xcworkspace.

      Note

      If you see an error like [!] Unable to find a specification for `AzureNotificationHubs-iOS` while running pod install, please run pod repo update to get the latest pods from the Cocoapods repository and then run pod install.

    • Integration via Carthage

      Add the following dependencies to your Cartfile to include Azure Notification Hubs SDK into your app.

      github "Azure/azure-notificationhubs-ios"
      

      Next, update, and build dependencies:

      $ carthage update
      

      For more information about using Carthage, see the Carthage GitHub repository.

    • Integration by copying the binaries into your project

      1. Download the Azure Notification Hubs SDK framework provided as a zip file and unzip it.

      2. In Xcode, right-click your project and click the Add Files to option to add the WindowsAzureMessaging.framework folder to your Xcode project. Select Options and make sure Copy items if needed is selected, and then click Add.

        Unzip Azure SDK

  6. Add a new header file to your project named HubInfo.h. This file holds the constants for your notification hub. Add the following definitions and replace the string literal placeholders with your hub name and the DefaultListenSharedAccessSignature noted earlier.

    #ifndef HubInfo_h
    #define HubInfo_h
    
        #define HUBNAME @"<Enter the name of your hub>"
        #define HUBLISTENACCESS @"<Enter your DefaultListenSharedAccess connection string"
    
    #endif /* HubInfo_h */
    
  7. Open your AppDelegate.h file add the following import directives:

    #import <WindowsAzureMessaging/WindowsAzureMessaging.h>
    #import <UserNotifications/UserNotifications.h>
    #import "HubInfo.h"
    
  8. In your AppDelegate.m file, add the following code in the didFinishLaunchingWithOptions method based on your version of iOS. This code registers your device handle with APNs:

    UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeSound |
        UIUserNotificationTypeAlert | UIUserNotificationTypeBadge categories:nil];
    
    [[UIApplication sharedApplication] registerUserNotificationSettings:settings];
    [[UIApplication sharedApplication] registerForRemoteNotifications];
    
  9. In the same file, add the following methods:

        - (void) application:(UIApplication *) application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *) deviceToken {
        SBNotificationHub* hub = [[SBNotificationHub alloc] initWithConnectionString:HUBLISTENACCESS
                                    notificationHubPath:HUBNAME];
    
        [hub registerNativeWithDeviceToken:deviceToken tags:nil completion:^(NSError* error) {
            if (error != nil) {
                NSLog(@"Error registering for notifications: %@", error);
            }
            else {
                [self MessageBox:@"Registration Status" message:@"Registered"];
            }
        }];
        }
    
    -(void)MessageBox:(NSString *) title message:(NSString *)messageText
    {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:messageText preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
        [alert addAction:okAction];
        [[[[UIApplication sharedApplication] keyWindow] rootViewController] presentViewController:alert animated:YES completion:nil];
    }
    

    This code connects to the notification hub using the connection information you specified in HubInfo.h. It then gives the device token to the notification hub so that the notification hub can send notifications.

  10. In the same file, add the following method to display a UIAlert if the notification is received while the app is active:

    - (void)application:(UIApplication *)application didReceiveRemoteNotification: (NSDictionary *)userInfo {
        NSLog(@"%@", userInfo);
        [self MessageBox:@"Notification" message:[[userInfo objectForKey:@"aps"] valueForKey:@"alert"]];
    }
    
  11. To verify there are no failures, build and run the app on your device.

Send test push notifications

You can test receiving notifications in your app with the Test Send option in the Azure portal. It sends a test push notification to your device.

Azure portal - Test Send

Push notifications are normally sent in a back-end service like Mobile Apps or ASP.NET using a compatible library. If a library is not available for your back-end you can also use the REST API directly to send notification messages.

Here is a list of some other tutorials you may want to review for sending notifications:

Verify that your app receives push notifications

To test push notifications on iOS, you must deploy the app to a physical iOS device. You cannot send Apple push notifications by using the iOS Simulator.

  1. Run the app and verify that registration succeeds, and then press OK.

    iOS App Push Notification Registration Test

  2. Next you send a test push notification from the Azure portal, as described in the previous section.

  3. The push notification is sent to all devices that are registered to receive the notifications from the particular Notification Hub.

    iOS App Push Notification Receive Test

Next steps

In this simple example, you broadcasted push notifications to all your registered iOS devices. To learn how to push notifications to specific iOS devices, advance to the following tutorial: