/// <summary>
/// Create and Add Parse error to the current feed result.
/// </summary>
/// <param name="errorType">Type of parse error.</param>
/// <param name="nodeInformation">Current node base information.</param>
/// <param name="feed">Current feed result.</param>
/// <param name="content">Current node content data. (Optonal)</param>
/// <param name="message">Parse error message. (Optional)</param>
protected void SetParseError(ParseErrorType errorType, NodeInformation nodeInformation, Feed feed, string?content = null, string?message = null)
{
//Create and Add Parse error to the current feed result
var error = ParseError.Create(nodeInformation, ToString(), errorType, feed.CurrentParseType, content, message);
(feed.ParseError ??= new List <ParseError>()).Add(error);
Debug.WriteLine(error);
}
/// <summary>
/// Main parse feed stream method.
/// </summary>
/// <param name="source">Feed source name/url.</param>
/// <param name="stream">Feed stream.</param>
/// <param name="cancellationToken">Parse task cancellation token.</param>
/// <returns>The parsed feed result Feed object.</returns>
public static async Task <Feed> ParseFeedAsync(string source, Stream stream, CancellationToken cancellationToken)
{
//Init
bool parseNode;
var feed = new Feed();
var defaultParser = RSS_2_0_Parser.Instance;
var settings = new XmlReaderSettings()
{
CloseInput = true, ConformanceLevel = ConformanceLevel.Document, IgnoreWhitespace = true, IgnoreComments = true, Async = true, DtdProcessing = DtdProcessing.Ignore
};
using var reader = XmlReader.Create(stream, settings);
try
{
//Start Reading and move to root node
if (parseNode = await reader.MoveToContentAsync().ConfigureAwait(false) != XmlNodeType.None)
{
//Save Parent Node
var parent = new Stack <NodeInformation>(new List <NodeInformation>()
{
reader.NodeInformation()
});
//Attempt to identify feed type
defaultParser = ParseFeedType(reader, feed) ?? defaultParser;
//Read first feed node
parseNode = await reader.ReadAsync().ConfigureAwait(false);
//Identify and parse nodes until EOF or Cancellation
while (parseNode && !reader.EOF && !cancellationToken.IsCancellationRequested)
{
//Feed node or Extended Namespace node?
if (string.IsNullOrWhiteSpace(reader.NamespaceURI))
{
//Parse node with default feed parser
await defaultParser.Value.Parse(parent, reader, feed).ConfigureAwait(false);
}
else if (parseNode = parsers.TryGetValue(reader.NamespaceURI, out var parser))
{
//Parse node with current Namespace parser
await parser.Value.Parse(parent, reader, feed).ConfigureAwait(false);
}
else
{
//Unknown Namespace
var error = ParseError.Create(reader.NodeInformation(), "FeedParser", ParseErrorType.UnknownNamespace, feed.CurrentParseType);
(feed.ParseError ??= new List <ParseError>()).Add(error);
Debug.WriteLine(error);
}
//Save Parent Node
if (reader.NodeType != XmlNodeType.EndElement && reader.Depth > (parent.Count > 0 ? parent.Peek().Depth : -1))
{
parent.Push(reader.NodeInformation());
}
//Read next node
parseNode = await reader.ReadAsync().ConfigureAwait(false);
//Verify Parent
while (parent.Count > 0 && reader.Depth <= parent.Peek().Depth)
{
parent.Pop();
}
}
}
}
//Rethrow Feed Parser Exception
catch (FeedParseException ex) { throw ex; }
catch (Exception ex)
{
//Rethrow all other exceptions as FeedParseException
throw new FeedParseException(source, reader, ex);
}
finally
{
//Close Reader and Stream
reader?.Close();
}
//Return Parsed Feed
return(feed);
}