/// <summary>
/// Callback method called when the "Download" method returns from an HTTPWebRequest.
/// </summary>
/// <param name="result">The result of the asynchronous operation.</param>
private void ResponseCallback(IAsyncResult result)
{
RequestState state = (RequestState)result.AsyncState;
try
{
HttpWebRequest request = state.Request as HttpWebRequest;
if (null != request)
{
// Retrieve response.
using (HttpWebResponse response = request.EndGetResponse(result) as HttpWebResponse)
{
if (null != response && response.StatusCode == HttpStatusCode.OK)
{
using (XmlReader reader = XmlReader.Create(response.GetResponseStream()))
{
Feed parentFeed = state.Argument as Feed;
if (null != parentFeed)
{
// Collection to store all articles
Collection <Article> parsedArticles = _parser.ParseItems(reader, parentFeed);
// Raise event for a single feed downloaded.
if (null != SingleDownloadFinished)
{
SingleDownloadFinished(this, new SingleDownloadFinishedEventArgs(parentFeed, parsedArticles));
}
// Add to all downloads dictionary and raise AllDownloadsFinished if all async requests have finished.
Downloads.Add(parentFeed, parsedArticles);
lock (_lockObject)
{
IsDownloading = ((--_numOfRequests) > 0);
}
if (_numOfRequests <= 0 && null != AllDownloadsFinished)
{
AllDownloadsFinished(this, new AllDownloadsFinishedEventArgs(Downloads));
}
}
}
}
}
}
}
catch (WebException we)
{
if (null != DownloadFailed)
{
DownloadFailed(this, new DownloadFailedEventArgs(we)
{
BadConnectionException = true
});
}
return;
}
catch (XmlException e)
{
if (null != DownloadFailed)
{
DownloadFailed(this, new DownloadFailedEventArgs(e));
}
return;
}
}
/// <summary>
/// Downloads the provided List of Feeds.
/// You cannot call download while downloads are in progress.
/// </summary>
/// <param name="feeds">List of feeds to download.</param>
public void Download(IList <Feed> feeds)
{
if (null != feeds && feeds.Count > 0)
{
_numOfRequests = feeds.Count;
IsDownloading = true;
// Download each separate feed
foreach (Feed feed in feeds)
{
string feedURI = feed.FeedBaseURI;
if (null != feedURI)
{
try
{
HttpWebRequest feedRequest = HttpWebRequest.Create(feedURI) as HttpWebRequest;
// If the user has
if (App.ApplicationSettings.WifionlySetting)
{
try
{
feedRequest.SetNetworkRequirement(NetworkSelectionCharacteristics.NonCellular);
}
catch (NetworkException ne)
{
if (null != DownloadFailed)
{
DownloadFailed(this, new DownloadFailedEventArgs(ne)
{
WifiException = (ne.NetworkErrorCode == NetworkError.NetworkSelectionRequirementFailed)
});
}
return;
}
}
if (null != feedRequest)
{
RequestState feedState = new RequestState()
{
// Change the owner to the parent HTTPWebRequest.
Request = feedRequest,
// Change the argument to be the current feed to be downloaded.
Argument = feed,
};
// Begin download.
feedRequest.BeginGetResponse(ResponseCallback, feedState);
}
}
catch (WebException we)
{
if (null != DownloadFailed)
{
DownloadFailed(this, new DownloadFailedEventArgs(we)
{
BadConnectionException = true
});
}
return;
}
}
}
}
else
{
throw new ArgumentNullException("No feeds");
}
}