Exclude URLs from Universal Links in Swift: A Comprehensive Guide

Universal Links are a powerful feature in iOS that allow users to open your app directly from a web link, without the need to manually type in the app’s URL or search for it in the App Store. However, there may be instances where you want to exclude certain URLs from being opened in your app. This guide will walk you through the process of excluding URLs from Universal Links in Swift, covering various aspects such as URL schemes, app extensions, and handling URL schemes in your app.

Understanding URL Schemes

URL schemes are a critical component of Universal Links. They are used to identify your app and its specific app extensions. When a user taps on a link, the system checks the URL scheme to determine which app to open. If your app is not the default app for the URL scheme, the system will open the link in the default app instead.

Here’s an example of a URL scheme for an app called “MyApp”:

myapp://

Now, let’s say you want to exclude a specific URL from being opened in your app. You can do this by modifying the URL scheme and adding a query parameter to the URL.

Modifying URL Schemes

To exclude a URL from being opened in your app, you can modify the URL scheme by adding a query parameter. For example, let’s say you want to exclude the URL “https://www.example.com/excluded” from being opened in your app. You can modify the URL scheme as follows:

myapp://?exclude=example.com

In this example, the query parameter “exclude” is used to identify the URL that should be excluded. When the system encounters this URL, it will not open the app and instead open the link in the default app.

Handling URL Schemes in Your App

Now that you’ve modified the URL scheme to exclude a specific URL, you need to handle the URL scheme in your app. This involves creating a URL handler that can process the modified URL scheme and perform the necessary actions.

Here’s an example of how you can handle the modified URL scheme in your app:

import UIKitclass AppDelegate: UIResponder, UIApplicationDelegate {    func application(_ application: UIApplication, continue userActivity: NSUserActivity, restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {        if let activity = userActivity as? NSUserActivity,           let url = activity.webpageURL,           url.scheme == "myapp" {            // Handle the modified URL scheme            if let exclude = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems?.first(where: { $0.name == "exclude" })?.value {                // Exclude the URL                print("Excluded URL: (exclude)")            } else {                // Open the app                openApp(url)            }        }        return true    }    func openApp(_ url: URL) {        // Open the app with the given URL        // ...    }}

In this example, the `application(_:continue:userActivity:restorationHandler:)` method is used to handle the modified URL scheme. The method checks if the URL scheme is “myapp” and if the URL contains the “exclude” query parameter. If the URL contains the “exclude” parameter, it prints the excluded URL; otherwise, it opens the app with the given URL.

Handling App Extensions

Universal Links can also be used with app extensions. If you want to exclude a URL from being opened in an app extension, you need to modify the URL scheme for the extension and handle it in the extension’s code.

Here’s an example of how to exclude a URL from being opened in an app extension:

import UIKitclass ExtensionAppDelegate: UIResponder, UIApplicationDelegate {    func application(_ application: UIApplication, continue userActivity: NSUserActivity, restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {        if let activity = userActivity as? NSUserActivity,           let url = activity.webpageURL,           url.scheme == "myapp-extension" {            // Handle the modified URL scheme for the extension            if let exclude = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems?.first(where: { $0.name == "exclude" })?.value {                // Exclude the URL                print("Excluded URL: (exclude)")            } else {                // Open the extension                openExtension(url)            }        }        return true    }    func openExtension(_ url: