Disable the loading of Stylesheets in UIWebView and/or WKWebView - swift

Question

I have absolutely tried everything with this one. I've read every apple article and no where can I find how to disable the loading of CSS (Styling) in the legacy UIWebView or the new WKWebView. I don't mind what web view I use just as long as it can accomplish this.
I've tried WKPreferences() and WKWebViewConfiguration and both have no member userStyleSheetEnabled.
I've referred myself to this apple article https://developer.apple.com/documentation/webkit/webpreferences/1536396-userstylesheetenabled?
Does anyone know the answer and how to achieve this on Swift 4?

Answer 1

The WebView class you referenced is very old and has been deprecated. If you need to add a webview to your app, use WKWebView instead. This answer works with iOS >= 11 and macOS >= 10.13.
What you need is adding WKContentRuleList to your WKWebView's configuration. They are similar to Safari content blockers (i.e. ad-blockers) that you may already have installed on your phone:
// This should ideally be in a file but we're using string for convenience
let jsonRuleList = """
[{
"trigger": {
"url-filter": ".*",
"resource-type": ["style-sheet"]
},
"action": {
"type": "block"
}
}]
"""
// Compile the content-blocking list
WKContentRuleListStore.default().compileContentRuleList(forIdentifier: "blockStyleSheet", encodedContentRuleList: jsonRuleList) { list, error in
guard error == nil else { print(error!.localizedDescription); return }
guard let list = list else { return }
// Add the stylesheet-blocker to your webview's configuration
let configuration = WKWebViewConfiguration()
configuration.userContentController.add(list)
// Adding the webview to the view. Nothing to see here
self.webView = WKWebView(frame: self.view.bounds, configuration: configuration)
self.view.addSubview(self.webView)
// Let's try Apple's website without CSS
let request = URLRequest(url: URL(string: "https://www.apple.com")!)
self.webView.load(request)
}
Result:
References
Customized Loading in WKWebView (WWDC video)
Creating Safari Content-Blocking Rules