SFSafariViewController improvements in iOS 15

Let's look at two new additions to SFSafariViewController. As a reminder this is a class that lets us display a webpage inside our app with familiar look to the Safari browser. It is way easier to use than full-fledged WKWebView.

Pre-loading content

One of the new options lets us start loading pages before the SFSafariViewController is opened. This might be useful in cases when you need it to load resource-intensive webpages and want to provide better experience to the user.

To do this, there is class-level method prewarmConnections which takes as its input an array of URLs to "prewarm". You will get back a token so you can later cancel this operation. Maybe user opens a screen that lets them open the website, but they change their mind, so in the viewDidDisappear you could invalidate this token using its invalidate method.

let urls = [URL(string: "https://apple.com")!]
let token = SFSafariViewController.prewarmConnections(to: urls)

Running custom extension

The second new feature is the ability to run custom extension in the SFSafariViewController. We can use the new configuration options to specify bundle identifier for the extension and image which will be used for the button the controller will display.

let config = SFSafariViewController.Configuration()
config.activityButton = .init(templateImage: UIImage(systemName: "sun.max")!, extensionIdentifier: "com.bundle.extension")

let safariVC = SFSafariViewController(url: URL(string: "https://apple.com")!, configuration: config)

Note that this has to be Share Extension according to the WWDC session. I cannot think of an use case but since Apple added this, I guess there are valid ones.

Let me know if you find this particularly useful - I am curious.