Creating a custom webview from scratch - ios

Question

I am in a situation where I want more flexibility for webview than the offered by UIWebview and not at all by WKWebview. Things like customizing web request before start eg sending headers and redirections. Also as we know UIWebview officially deprecated now in iOS 12.
I'm looking forward to a generic webview now, I know its possible as open source examples say Firefox for iOS.
If you've been using any of your projects or know please tell me. Or if you can give me some information how can this be achieved or any tutorails links would be helpful.

Answer 1

Declare the WebView object
var webView: WKWebView!
//Load the data in webView
func loadUrl() {
var webView : WKWebView!
let script: WKUserScript = WKUserScript(source: source, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
let userContentController: WKUserContentController = WKUserContentController()
let configuration = WKWebViewConfiguration()
configuration.userContentController = userContentController
userContentController.addUserScript(script)
webView = WKWebView(frame: CGRect.zero, configuration: configuration)
webView.uiDelegate = self
webView.navigationDelegate = self
webView.allowsLinkPreview = true
//Load the Data from URL
let url = URL(string: "Your URL")
var urlRequest = URLRequest(url: url! as URL)
urlRequest.setValue("application/json", forHTTPHeaderField: "Accept")
urlRequest.setValue("user-agent", forHTTPHeaderField: "User-Agent")
webView.load(urlRequest)
//Load the Data from local HTML
do {
guard let filePath = Bundle.main.path(forResource: "Your-HTML-File", ofType: "html")
else {
print ("FILE READING ERROR")
return
}
//get the content of HTML File
let contents = try String(contentsOfFile: filePath , encoding: .utf8)
webView.loadHTMLString(contents, baseURL:URL(fileURLWithPath: Bundle.main.bundlePath))
}
catch {
print ("FILE HTML ERROR")
}
}
//Delegate Method that called when webView finish Loading.
//You can apply css or style here
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
///Local CSS File
guard let path = Bundle.main.path(forResource: "Local-CSS-File", ofType: "css") else { return }
let script = "var head = document.getElementsByTagName('head')[0];var link = document.createElement('link');link.rel = 'stylesheet';link.type = 'text/css';link.href = '\(path)';link.media = 'all';head.appendChild(link);"
webView.evaluateJavaScript(script) {(result, error) in
if let error = error {
print(error)
}
}
//External CSS File
let externalCSSLink = "your-css-file-url"
let script2 = "var head = document.getElementsByTagName('head')[0];var link = document.createElement('link');link.rel = 'stylesheet';link.type = 'text/css';link.href = '\(externalCSSLink)';link.media = 'all';head.appendChild(link);"
webView.evaluateJavaScript(jsString1) {(result, error) in
if let error = error {
print(error)
}
}
}