/// <summary>
/// Reads the specified RSS feed
/// </summary>
/// <param name="Request"> The specified way to connect to the web server </param>
/// <param name="oldFeed"> The cached version of the feed </param>
/// <returns> The current contents of the feed </returns>
/// <remarks>
/// Will not download the feed if it has not been modified
/// </remarks>
public static RssFeed Read(HttpWebRequest Request, RssFeed oldFeed)
{
return read(oldFeed.url, Request, oldFeed);
}
private static RssFeed read(string url, HttpWebRequest request, RssFeed oldFeed)
{
// ***** Marked for substantial improvement
RssFeed feed = new RssFeed();
Stream stream = null;
Uri uri = new Uri(url);
feed.url = url;
switch (uri.Scheme)
{
case "file":
feed.lastModified = File.GetLastWriteTime(url);
if ((oldFeed != null) && (feed.LastModified == oldFeed.LastModified))
{
oldFeed.cached = true;
return oldFeed;
}
stream = new FileStream(url, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
break;
case "https":
case "http":
if (request == null)
{
request = (HttpWebRequest) WebRequest.Create(uri);
request.Proxy = WebProxy.GetDefaultProxy();
request.Proxy.Credentials = CredentialCache.DefaultCredentials;
}
if (oldFeed != null)
{
request.IfModifiedSince = oldFeed.LastModified;
request.Headers.Add("If-None-Match", oldFeed.ETag);
}
try
{
HttpWebResponse response = (HttpWebResponse) request.GetResponse();
feed.lastModified = response.LastModified;
feed.etag = response.Headers["ETag"];
try
{
if (response.ContentEncoding != String.Empty)
feed.encoding = Encoding.GetEncoding(response.ContentEncoding);
}
catch
{
}
stream = response.GetResponseStream();
}
catch (WebException we)
{
if (oldFeed != null)
{
oldFeed.cached = true;
return oldFeed;
}
throw we; // bad
}
break;
}
if (stream != null)
{
RssReader reader = null;
try
{
reader = new RssReader(stream);
RssElement element = null;
do
{
element = reader.Read();
if (element is RssChannel.RssChannel)
feed.Channels.Add((RssChannel.RssChannel) element);
} while (element != null);
feed.rssVersion = reader.Version;
}
finally
{
feed.exceptions = reader.Exceptions;
reader.Close();
}
}
else
throw new ApplicationException("Not a valid Url");
return feed;
}
/// <summary>
/// Reads the specified RSS feed
/// </summary>
/// <param name="oldFeed"> The cached version of the feed </param>
/// <returns> The current contents of the feed </returns>
/// <remarks>
/// Will not download the feed if it has not been modified
/// </remarks>
public static RssFeed Read(RssFeed oldFeed)
{
return read(oldFeed.url, null, oldFeed);
}
