Home iOS & Swift Books Push Notifications by Tutorials

7
Expanding the Application Written by Scott Grosch

Now that you’ve got a database up and running, you need to tell your app how to connect to it. As you saw in the previous chapter, “Server Side Pushes,” Vapor will run a local server for you at http://192.168.1.1:8080 (change with your own IP address).

This is the URL that your app will need to talk to if you successfully registered for push notifications. Of course, remember to substitute your IP address in the URL.

Setting the team and bundle identifier

If you take a look at the starter project for this chapter, you’ll see that it’s a standard app that uses push notifications, utilizing the code that you used in previous chapters. Before you can use the project, however, you’ll have to configure the target so that the certificates are created for you. To do so:

  1. Select PushNotifications from the Project navigator ( + 1).
  2. Select the PushNotifications target.
  3. Open the Signing & Capabilities tab.
  4. Choose your Team.
  5. Change the Bundle Identifier.

Follow steps 1–4 as shown below:

Remember, also, to turn on the Push Notifications capability as discussed in Chapter 4, “Xcode Project Setup.”

Updating the server

In your Xcode project, you can now modify AppDelegate.swift to contact the endpoint you just set up to register your device token. Return to your Xcode project. Modify application(_:didRegisterForRemoteNotifications WithDeviceToken:) method.

// 1
let url = URL(string: "http://192.168.1.1:8080/api/token")!
  
// 2
var obj: [String: Any] = [
  "token": token,
  "debug": false
]
    
// 3
#if DEBUG
obj["debug"] = true
#endif

// 4
var request = URLRequest(url: url)
request.addValue("application/json", 
                 forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
request.httpBody = try! JSONSerialization
                          .data(withJSONObject: obj)

// 5
URLSession.shared.dataTask(with: request).resume()

Extending AppDelegate

You can probably already see how the push notification code is going to be almost exactly the same in every project you create. Do a little cleanup by moving this common code to an extension. Create a new file in your Xcode project called ApnsUploads.swift and then move your notification code over.

import UIKit
import UserNotifications

extension AppDelegate {
  func registerForPushNotifications(application: UIApplication) {
    let center = UNUserNotificationCenter.current()
    center.requestAuthorization(
        options: [.badge, .sound, .alert]) { granted, _ in
      guard granted else { return }

      DispatchQueue.main.async {
        application.registerForRemoteNotifications()
      }
    }
  }
  
  func sendPushNotificationDetails(to urlString: String,
                                   using deviceToken: Data) {
    guard let url = URL(string: urlString) else {
      fatalError("Invalid URL string")
    }
    
    let token = deviceToken.reduce("") {
       $0 + String(format: "%02x", $1)
    }

    var obj: [String: Any] = [
      "token": token,
      "debug": false
    ]
    
    #if DEBUG
    obj["debug"] = true
    #endif
          
    var request = URLRequest(url: url)
    request.addValue("application/json",
                     forHTTPHeaderField: "Content-Type")
    request.httpMethod = "POST"
    request.httpBody = try! JSONSerialization.data(
      withJSONObject: obj)
    
    #if DEBUG
    print("Device Token: \(token)")
    
    let pretty = try! JSONSerialization.data(
      withJSONObject: obj,
      options: .prettyPrinted)
    print(String(data: pretty, encoding: .utf8)!)
    #endif
    
    URLSession.shared.dataTask(with: request).resume()
  }
}
extension AppDelegate: UIApplicationDelegate {
  func application(_ application: UIApplication,
                   didFinishLaunchingWithOptions launchOptions:
                   [UIApplication.LaunchOptionsKey: Any]?)
                   -> Bool {
    registerForPushNotifications(application: application)
    return true
  }

  func application(_ application: UIApplication, 
    didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    sendPushNotificationDetails(
      to: "http://192.168.1.1:8080/api/token",
      using: deviceToken
    )
  }
}

Key points

  • Once you have your database established, you need to tell your app how to connect to it. Vapor will allow you to run a server written with Swift.
  • Take the time to add some additional lines at the end of notification registration to display the body of the JSON request in a “pretty,” easy-to-read format, which can help in the future with debugging.

Where to go from here?

And there you have it! You’ve successfully built an API that saves device tokens and an app that consumes that API. This is the basic skeleton you will build upon when using push notifications. In Chapter 8, “Handling Common Scenarios,” you will start handling common push notification scenarios, such as displaying a notification while the app is in the foreground… so keep reading!

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