Pass JWT token as header in Xamarin WebView - xamarin.forms

Question

I'm using Xamarin forms WebView control to display a page that uses Authentication JWT token. I could not find any samples that does this either in Microsoft site or any blogs.
Most closest answer I found is to create a renderer for the control in each platform (iOS and Droid). But I'm not sure on which event I should override the request and the format in which the auth header can be passed. Appreciate any help.

Answer 1

You could try the method below:
For Android:
public class FormsWebViewRenderer : ViewRenderer<Xamarin.Forms.WebView, Android.Webkit.WebView>
{
Android.Content.Context _localContext;
public FormsWebViewRenderer(Context context) : base(context)
{
_localContext = context;
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
Dictionary<string, string> headers = new Dictionary<string, string>
{
["A-custom-header"] = "a custom value"
};
Android.Webkit.WebView webView = Control as Android.Webkit.WebView;
if (Control == null) {
webView = new Android.Webkit.WebView(_localContext);
SetNativeControl(webView);
}
webView.Settings.JavaScriptEnabled = true;
webView.Settings.BuiltInZoomControls = true;
webView.Settings.SetSupportZoom(true);
webView.ScrollBarStyle = ScrollbarStyles.OutsideOverlay;
webView.ScrollbarFadingEnabled = false;
webView.SetWebViewClient(new FormsWebViewClient(headers));
UrlWebViewSource source = Element.Source as UrlWebViewSource;
webView.LoadUrl(source.Url, headers);
}
}
public class FormsWebViewClient : Android.Webkit.WebViewClient
{
public Dictionary<string, string> headers { get; set; }
public FormsWebViewClient(Dictionary<string, string> requestHeaders)
{
headers = requestHeaders;
}
public override void OnPageStarted(Android.Webkit.WebView view, string url, Android.Graphics.Bitmap favicon)
{
base.OnPageStarted(view, url, favicon);
System.Diagnostics.Debug.WriteLine("Loading website...");
}
public override void OnPageFinished(Android.Webkit.WebView view, string url)
{
base.OnPageFinished(view, url);
System.Diagnostics.Debug.WriteLine("Load finished.");
}
public override void OnReceivedError(Android.Webkit.WebView view, IWebResourceRequest request, WebResourceError error)
{
base.OnReceivedError(view, request, error);
}
}
For ios:
public class FormsWebViewRenderer : ViewRenderer<WebView, UIWebView>
{
protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
{
base.OnElementChanged(e);
var webView = Control as UIWebView;
if (webView == null) {
webView = new UIWebView();
SetNativeControl(webView);
}
webView.ScalesPageToFit = true;
webView.LoadStarted += (object sender, System.EventArgs evtArgs) => {
System.Diagnostics.Debug.WriteLine("Loading...");
};
webView.LoadFinished += (object sender, System.EventArgs evtArgs) => {
System.Diagnostics.Debug.WriteLine("Load finished.");
};
if (e.NewElement != null) {
UrlWebViewSource source = (Xamarin.Forms.UrlWebViewSource)Element.Source;
var webRequest = new NSMutableUrlRequest(new NSUrl(source.Url));
var headerKey = new NSString("A-custom-header");
var headerValue = new NSString("a custom value");
var dictionary = new NSDictionary(headerKey, headerValue);
webRequest.Headers = dictionary;
this.Control.LoadRequest(webRequest);
}
}
}