How to send Apple push notification to specific users

I have managed to get push notifications working but I have trouble on how to send notifications to specific users. Perhaps using a customer number or name etc. I don’t know where to even start. I have spent weeks reading hundreds of web sites and I can’t seem to work it out.

These are just a few of the pages I’ve looked at:

• Apple Push Notifications to specific Users
• How to send push notification to specific device
• iOS/Parse – Sending Push Notifications to Specific User
• Send remote push notification to specific user
• Send push notification to specific user?
• https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server?language=objc
• https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/establishing_a_token-based_connection_to_apns?language=objc

Here is my objective-c code in Appdelegate – Sorry if it’s not great I have pieced it together from several posts.

        @implementation AppDelegate
- (void)userNotificationCenter:(UNUserNotificationCenter *)center
willPresentNotification:(UNNotification *)notification  withCompletionHandler:(void (^)(UNNotificationPresentationOptions options))completionHandler{
NSLog( @"for handling push in foreground" );
// Your code
NSLog(@"%@", notification.request.content.userInfo); //for getting response payload data
    completionHandler(UNNotificationPresentationOptionBadge | UNNotificationPresentationOptionBanner);
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    
    UNUserNotificationCenter.currentNotificationCenter.delegate= self;
    [self requestPushNotificationPermissions];
    NSLog(@"need this:01 @");
    return YES;
}

- (void)application:(UIApplication*)app didRegisterForRemoteNotificationsWithDeviceToken:(NSData*)devToken

{
    NSLog(@"need this Token:02 @");
    // parse token bytes to string
    const char *data = [devToken bytes];
    NSMutableString *token = [NSMutableString string];
    for (NSUInteger i = 0; i < [devToken length]; i++)
    {
        [token appendFormat:@"%02.2hhX", data[i]];
    }
    
    // print the token in the console.
    NSLog(@"Push Notification Token: %@", [token copy]);
}

- (void)requestPushNotificationPermissions
{
    // iOS 10+
    UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
    [center getNotificationSettingsWithCompletionHandler:^(UNNotificationSettings * _Nonnull settings) {
        
        switch (settings.authorizationStatus)
        {
            // User hasn't accepted or rejected permissions yet. This block shows the allow/deny dialog
            case UNAuthorizationStatusNotDetermined:
            {
                [[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:(UNAuthorizationOptionBadge | UNAuthorizationOptionSound | UNAuthorizationOptionAlert) completionHandler:^(BOOL granted, NSError * _Nullable error) {
                  if (granted) {
                  dispatch_async(dispatch_get_main_queue(), ^{
                  [[UIApplication sharedApplication] registerForRemoteNotifications];
                  });
                  }
                }];
                
                center.delegate = self;
                [center requestAuthorizationWithOptions:(UNAuthorizationOptionSound | UNAuthorizationOptionAlert | UNAuthorizationOptionBadge) completionHandler:^(BOOL granted, NSError * _Nullable error)
                 {
                     if(granted)
                     {
                         dispatch_async(dispatch_get_main_queue(), ^{
                                 [[UIApplication sharedApplication] registerForRemoteNotifications];
                             });
                       //  [[UIApplication sharedApplication] registerForRemoteNotifications];
                     }
                     else
                     {
                         // notify user to enable push notification permission in settings
                     }
                 }];
                break;
            }
            // the user has denied the permission
            case UNAuthorizationStatusDenied:
            {
                // notify user to enable push notification permission in settings
                break;
            }
            // the user has accepted; Register a PN token
            case UNAuthorizationStatusAuthorized:
            {
                dispatch_async(dispatch_get_main_queue(), ^{
                        [[UIApplication sharedApplication] registerForRemoteNotifications];
                    });
                           
              //  [[UIApplication sharedApplication] registerForRemoteNotifications];
                break;
            }
            default:
                break;
        }
    }];
}

Here is the server side PHP code

         <?php

       $device_token = 
       "AB028BLAH8A2BLAHE0485BLAHEABLAHEDFAKED3EBLAHFF0AFDBBBLAHBLAHBLAH";
       //echo $key;
       $kid      = "6FAKEJFAKE";
       $teamId   = "FAKEZ2FAKE";
       $app_bundle_id = "com.name.appname";
       $base_url = "https://api.development.push.apple.com";

       $header = ["alg" => "ES256", "kid" => $kid];
       $header = base64_encode(json_encode($header));

       $claim = ["iss" => $teamId, "iat" => time()];
       $claim = base64_encode(json_encode($claim));

       $token = $header.".".$claim;
       // key in same folder as the script
       $filename = "AuthKey_6FAKEJFAKE.p8";
       $pkey     = openssl_pkey_get_private("file://{$filename}");
       $signature;
       openssl_sign($token, $signature, $pkey, 'sha256');
       $sign = base64_encode($signature);

       $jws = $token.".".$sign;

       $message = '{"aps":{"alert":"Push Test Message.","sound":"default"}}';

       function sendHTTP2Push($curl, $base_url, $app_bundle_id, $message, $device_token, $jws) {

    $url = "{$base_url}/3/device/{$device_token}";
    // headers
    $headers = array(
        "apns-topic: {$app_bundle_id}",
        'Authorization: bearer ' . $jws
    );
    // other curl options
    curl_setopt_array($curl, array(
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_2_0,
        CURLOPT_URL => $url,
        CURLOPT_PORT => 443,
        CURLOPT_HTTPHEADER => $headers,
        CURLOPT_POST => TRUE,
        CURLOPT_POSTFIELDS => $message,
        CURLOPT_RETURNTRANSFER => TRUE,
        CURLOPT_TIMEOUT => 30,
        CURLOPT_SSL_VERIFYPEER => FALSE,
        CURLOPT_HEADER => 1
    ));
    // go...
    $result = curl_exec($curl);
    if ($result === FALSE) {
        throw new Exception("Curl failed: " .  curl_error($curl));
    }
    print_r($result."n");
    // get response
    $status = curl_getinfo($curl);
    return $status;
    }
    // open connection
    $curl = curl_init();
    sendHTTP2Push($curl, $base_url, $app_bundle_id, $message, $device_token, $jws);

    ?>

This is all working but how to I send it to a specific user?

Answer

You can send push notification to a selected device token.

Before sending follow these steps:

iOS Application side

• On application launch get device token in didRegisterForRemoteNotificationsWithDeviceToken delegate
• Send this token to server using API when user login in the application

Server side

• Store this token in db table corresponding to the user id
• Get device token from db corresponding to the user to whom you want to send notification
• Send notification on that token
• Notification will be received on device