private void browser_Navigating(object sender, Microsoft.Phone.Controls.NavigatingEventArgs e)
{
// show the overlay
//
overlay.Visibility = System.Windows.Visibility.Visible;
browser.Visibility = System.Windows.Visibility.Collapsed;
// if we somehow got to the home page, redirect to the login page.
// this will kick off our login process and result in us getting an access token.
//
if (FacebookUrls.IsFacebookHome(e.Uri))
{
GotoLoginPage();
e.Cancel = true;
return;
}
// if we see the redirect URL that we passed as part of the login process,
// we know that we need to start looking for parameters.
//
if (FacebookUrls.IsRedirectUrl(e.Uri))
{
Status = "Processing Login...";
string query = e.Uri.Query;
if (!ProcessParams(query))
{
e.Cancel = true;
}
}
}
/// <summary>
/// This function walks parameters looking for tokens, etc.
/// </summary>
/// <param name="query"></param>
/// <returns></returns>
private bool ProcessParams(string query)
{
// pick out all of the params.
Match queryParams = Regex.Match(query, "(?<name>[^?=&]+)(=(?<value>[^&]*)?)");
string access_token = null;
string code = null;
int expires_in_seconds = -1;
bool? fail = null;
string error = null;
// walk through the matches looking for code, access_token, and expiration.
//
while (queryParams.Success)
{
string value = queryParams.Groups["value"].Value;
switch (queryParams.Groups["name"].Value)
{
// Due to the URL # problem in the WebBrowser control, we need to do this process in two steps,
// which is to first get a code that we can then exchange for a token. This code parameter is
// what we need.
//
case "code":
code = value;
string tokenAccessUrl = FacebookUrls.GetTokenUrl(code);
// now just use a web request rather than the browser to load up the
// actual page that will have the access token..
HttpWebRequest hwr = HttpWebRequest.CreateHttp(tokenAccessUrl);
hwr.BeginGetResponse(
(asyncObject) =>
{
try {
HttpWebResponse resp = (HttpWebResponse)hwr.EndGetResponse(asyncObject);
var c = resp.StatusCode;
if (c == HttpStatusCode.OK)
{
string html = new StreamReader(resp.GetResponseStream()).ReadLine();
Dispatcher.BeginInvoke(
() =>
{
// recurse with the content of the page.
ProcessParams(html);
});
}
}
catch (WebException ex) {
Debug.WriteLine(ex.ToString());
}
}
, null);
return(false);
case "access_token":
access_token = value;
fail = false;
break;
case "state":
fail = (value != FacebookUrls.VerificationState);
break;
case "error":
fail = true;
break;
case "error_description":
fail = true;
error = value;
break;
case "expires":
expires_in_seconds = int.Parse(value);
break;
}
queryParams = queryParams.NextMatch();
}
// if we don't hae a failure and we do have an access token,
// fire the completion event.
//
if (!fail.GetValueOrDefault() && access_token != null)
{
FacebookLoginEventArgs args = new FacebookLoginEventArgs {
AccessToken = access_token,
Error = error,
Expiration = DateTime.Now.AddSeconds(expires_in_seconds)
};
OnComplete(args);
}
return(true);
}