/// <summary>
/// Helper method to read from a web service asynchronously.
/// </summary>
public static void OpenReadAsync(Uri uri, object userState, EventHandler <OpenReadEventArgs> callback,
bool forceBrowserAuth = false, string proxyUrl = null)
{
System.Diagnostics.Debug.WriteLine(uri.ToString());
if (m_browserAuthInProgress)
{
m_openReadRequests.Enqueue(new RequestInfo(uri, userState, callback, forceBrowserAuth));
}
else
{
string id = "hiddenSLViewerAuthFrame";
bool iframeExists = HtmlPage.Document.GetElementById(id) != null;
if (!iframeExists || forceBrowserAuth)
{
m_browserAuthInProgress = true;
// The portal may be PKI-secured. Try injecting an iframe into the HTML DOM to hit the portal endpoint.
// In IE, this will force the browser to perform client certificate authentication. If the initial request
// to the portal endpoint fails, the client cert auth will not occur, so we must try this first.
// Insert the iframe
var iframe = WebUtil.insertHiddenIFrame("hiddenSLViewerAuthFrame");
var loadErrorTimer = new DispatcherTimer()
{
Interval = TimeSpan.FromSeconds(10)
};
// Create a handler for the iframe's onload event
EventHandler onloadHandler = null;
onloadHandler = (o, e) =>
{
loadErrorTimer.Stop();
loadErrorTimer.Tick -= onloadHandler;
iframe.DetachEvent("onload", onloadHandler);
doOpenRead(uri, userState, callback);
};
// Register the handler with the iframe's onload event and the load error timer's tick event
iframe.AttachEvent("onload", onloadHandler);
loadErrorTimer.Tick += onloadHandler;
// Set the source of the iframe to make it hit the portal. Append ticks to circumvent caching.
var tempUrl = uri.ToString() + "&r=" + DateTime.Now.Ticks;
iframe.SetAttribute("src", tempUrl);
// Start the load error timer. If the timer ticks, the onload handler will be called. This is needed
// in scenarios where the iframe's onload event never fires.
loadErrorTimer.Tick += onloadHandler;
loadErrorTimer.Start();
}
else
{
doOpenRead(uri, userState, callback);
}
}
}