在 Xamarin WebView 中将 JWT 令牌作为标头传递

如何解决在 Xamarin WebView 中将 JWT 令牌作为标头传递

我正在使用 Xamarin 表单 WebView 控件来显示使用身份验证 JWT 令牌的页面。我在 Microsoft 站点或任何博客中都找不到执行此操作的任何示例。

我找到的最接近的答案是为每个平台（iOS 和 Droid）中的控件创建一个渲染器。但是我不确定我应该在哪个事件上覆盖请求以及可以传递身份验证标头的格式。感谢您的帮助。

解决方法

您可以尝试以下方法：

安卓：

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);
    }
}

对于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);
        }

    }
}