private IBlogProviderButtonNotification GetButtonNotification()
{
string notificationUrl = String.Format(
CultureInfo.InvariantCulture,
"{0}?blog_id={1}&button_id={2}&image_url={3}",
NotificationUrl,
HttpUtility.UrlEncode(_hostBlogId),
HttpUtility.UrlEncode(_buttonId),
HttpUtility.UrlEncode(ImageUrl));
// get the content
HttpWebResponse response = null;
XmlDocument xmlDocument = new XmlDocument();
try
{
using (Blog blog = new Blog(_blogId))
response = blog.SendAuthenticatedHttpRequest(notificationUrl, 10000);
// parse the results
xmlDocument.Load(response.GetResponseStream());
}
catch (Exception)
{
throw;
}
finally
{
if (response != null)
response.Close();
}
// create namespace manager
XmlNamespaceManager nsmgr = new XmlNamespaceManager(xmlDocument.NameTable);
nsmgr.AddNamespace("n", "http://schemas.microsoft.com/wlw/buttons/notification");
// throw if the root element is not manifest
if (xmlDocument.DocumentElement.LocalName.ToLower(CultureInfo.InvariantCulture) != "notification")
throw new ArgumentException("Not a valid writer button notification");
// polling interval
int checkAgainMinutes = XmlHelper.NodeInt(xmlDocument.SelectSingleNode("//n:checkAgainMinutes", nsmgr), 0);
if (checkAgainMinutes == 0)
{
throw new ArgumentException("You must specify a value for checkAgainMinutes");
}
TimeSpan pollingInterval = TimeSpan.FromMinutes(checkAgainMinutes);
// notification text
string notificationText = XmlHelper.NodeText(xmlDocument.SelectSingleNode("//n:text", nsmgr));
// notification image
Bitmap notificationImage = null;
string notificationImageUrl = XmlHelper.NodeText(xmlDocument.SelectSingleNode("//n:imageUrl", nsmgr));
if (notificationImageUrl != String.Empty)
{
// compute the absolute url then allow parameter substitution
notificationImageUrl = BlogClientHelper.GetAbsoluteUrl(notificationImageUrl, NotificationUrl);
notificationImageUrl = BlogClientHelper.FormatUrl(notificationImageUrl, _homepageUrl, _postApiUrl, _hostBlogId);
// try to download it (will use the cache if available)
// note that failing to download it is a recoverable error, we simply won't show a notification image
try
{
// try to get a credentials context for the download
WinInetCredentialsContext credentialsContext = null;
try
{
credentialsContext = BlogClientHelper.GetCredentialsContext(_blogId, notificationImageUrl);
}
catch (BlogClientOperationCancelledException)
{
}
// execute the download
notificationImage = ImageHelper.DownloadBitmap(notificationImageUrl, credentialsContext);
}
catch (Exception ex)
{
Trace.WriteLine("Error downloading notification image: " + ex.ToString());
}
}
// clear notification on click
bool clearNotificationOnClick = XmlHelper.NodeBool(xmlDocument.SelectSingleNode("//n:resetOnClick", nsmgr), true);
// return the notification
return new BlogProviderButtonNotification(pollingInterval, notificationText, notificationImage, clearNotificationOnClick);
}
