Push notifications to users by using Mobile Services [iOS]

This tutorial walks you through these steps to update push notifications in your app:

1. Create the Devices table
2. Update the app
3. Update server scripts
4. Verify the push notification behavior

Create the new Devices table

1. Log into the Azure Management Portal, click Mobile Services, and then click your app.
   
2. Click the Data tab, and then click Create.
   
   This displays the Create new table dialog.
3. Keeping the default Anybody with the application key setting for all permissions, type Devices in Table name, and then click the check button.
   
   This creates the Devices table, which stores the device tokens used to send push notifications separate from item data.

Next, you will modify the push notifications app to store data in this new table instead of in the TodoItem table.

Update your app

1. In Xcode, open the QSTodoService.h file and add the following method declaration:

   // Declare method to register device token for other users
   - (void)registerDeviceToken:(NSString *)deviceToken;

   This enables the App Delegate to register a deviceToken with the Mobile Service.
2. In QSTodoService.m, add the following instance method:

   // Instance method to register deviceToken in Devices table.
   // Called in AppDelegate.m when APNS registration succeeds.
   - (void)registerDeviceToken:(NSString *)deviceToken
   {
       MSTable *devicesTable = [self.client tableWithName:@"Devices"]; 
       NSDictionary *device = @{ @"deviceToken" : deviceToken };
   
       // Insert the item into the devices table and add to the items array on completion
       [devicesTable insert:device completion:^(NSDictionary *result, NSError *error) {
           if (error) {
               NSLog(@"ERROR %@", error);
           }
       }];
   }

   This allows other callers to register the device token with Mobile Services.
3. In the QSAppDelegate.m file, add the following import statement:

   #import "QSTodoService.h"

   This code makes the AppDelegate aware of the TodoService implementation.
4. In QSAppDelegate.m, replace the didRegisterForRemoteNotificationsWithDeviceToken method with the following code:

   // We have registered, so now store the device token (as a string) on the AppDelegate instance
   // taking care to remove the angle brackets first.
   - (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:
   (NSData *)deviceToken {
   
      // Register the APNS deviceToken with the Mobile Service Devices table.
      NSCharacterSet *angleBrackets = [NSCharacterSet characterSetWithCharactersInString:@"<>"];
      NSString *token = [[deviceToken description] stringByTrimmingCharactersInSet:angleBrackets];
   
      QSTodoService *instance = [QSTodoService defaultService];
      [instance registerDeviceToken:token];
   }

5. In QSTodoListViewController.m, locate the (IBAction)onAdd method and remove the following code:

   // Get a reference to the AppDelegate to easily retrieve the deviceToken
   QSAppDelegate *delegate = [[UIApplication sharedApplication] delegate];
   
   NSDictionary *item = @{
       @"text" : itemText.text,
       @"complete" : @(NO),
       // add the device token property to our todo item payload
       @"deviceToken" : delegate.deviceToken
   };

   Replace this with the following code:

   // We removed the delegate; this application no longer passes the deviceToken here.
   // Remove the device token from the payload
   NSDictionary *item = @{ @"text" : itemText.text, @"complete" : @(NO) };

Your app has now been updated to use the new Devices table to store device tokens that are used to send push notifications back to the device.

Update server scripts

1. In the Management Portal, click the Data tab and then click the Devices table.
   
2. In devices, click the Script tab and select Insert.
   
   This displays the function that is invoked when an insert occurs in the Devices table.
3. Replace the insert function with the following code, and then click Save:

   function insert(item, user, request) {
      var devicesTable = tables.getTable('Devices');
      devicesTable.where({
          token: item.token
      }).read({
          success: insertTokenIfNotFound
      });
   
      function insertTokenIfNotFound(existingTokens) {
          if (existingTokens.length > 0) {
              request.respond(200, existingTokens[0]);
          } else {
              request.execute();
          }
      }
   }

   This script checks the Devices table for an existing device with the same token. The insert only proceeds when no matching device is found. This prevents duplicate device records.
4. Click TodoItem, click Script and select Insert.
   
5. Replace the insert function with the following code, and then click Save:

   function insert(item, user, request) {
     request.execute({
         success: function() {
             request.respond();
             sendNotifications();
         }
     });
   
     function sendNotifications() {
         var devicesTable = tables.getTable('Devices');
         devicesTable.read({
             success: function(devices) {
                 // Set timeout to delay the notifications, 
                 // to provide time for the app to be closed 
                 // on the device to demonstrate toast notifications.
                 setTimeout(function() {
                     devices.forEach(function(device) {
   
                         push.apns.send(device.deviceToken, {
                             alert: "Toast: " + item.text,
                             payload: {
                                 inAppMessage: 
                                 "Hey, a new item arrived: '" + 
                                 item.text + "'"
                             }
                         });
                     });
                 }, 2500);
             }
         });
     }

   }
   This insert script sends a push notification (with the text of the inserted item) to all devices stored in the Devices table.

Test push notifications in your app

1. Press the Run button to build the project and start the app in an iOS capable device, then in the app, type meaningful text, such as A new Mobile Services task and then click the plus (+) icon.
   
2. Verify that a notification is received, then click OK to dismiss the notification.
   
3. Repeat step 2 and immediately close the app, then verify that the following toast is shown.
   

You have successfully completed this tutorial.

Next steps

This concludes the tutorials that demonstrate the basics of working with push notifications. Consider finding out more about the following Mobile Services topics:

• Get started with data
  Learn more about storing and querying data using Mobile Services.
• Get started with authentication
  Learn how to authenticate users of your app with Windows Account.
• Mobile Services server script reference
  Learn more about registering and using server scripts.

Thank: http://azure.microsoft.com/en-us/documentation/articles/mobile-services-ios-push-notifications-app-users/