/// <summary>
/// Creates the 'feature' XML element which is part of a 'Stream Initiation'
/// request.
/// </summary>
/// <param name="streamOptions">An enumerable collection of accepted stream
/// methods.</param>
/// <returns>An XML 'feature' element.</returns>
/// <exception cref="ArgumentNullException">The streamOptions parameter
/// is null.</exception>
XmlElement CreateFeatureElement(IEnumerable <string> streamOptions)
{
streamOptions.ThrowIfNull("streamOptions");
// Create the data-form for stream-method selection.
DataForm form = new RequestForm();
HashSet <Option> options = new HashSet <Option>();
foreach (string opt in streamOptions)
{
options.Add(new Option(opt));
}
form.Fields.Add(new ListField("stream-method", true, null, null,
options));
// Wrap it in a 'feature' element to create the offer.
return(FeatureNegotiation.Create(form));
}
/// <summary>
/// Invoked whenever a 'Stream Initiation' request for file transfers
/// is received.
/// </summary>
/// <param name="from">The JID of the XMPP entity that wishes to initiate
/// the data-stream.</param>
/// <param name="si">The 'si' element of the request.</param>
/// <returns>The response to the SI request or an error element to include
/// in the IQ response.</returns>
XmlElement OnStreamInitiationRequest(Jid from, XmlElement si)
{
try {
string method = SelectStreamMethod(si["feature"]);
// If the session-id is already in use, we cannot process the request.
string sid = si.GetAttribute("id");
if (String.IsNullOrEmpty(sid) || siSessions.ContainsKey(sid))
{
return(new XmppError(ErrorType.Cancel, ErrorCondition.Conflict).Data);
}
// Extract file information and hand to user.
var file = si["file"];
string desc = file["desc"] != null ? file["desc"].InnerText : null,
name = file.GetAttribute("name");
int size = Int32.Parse(file.GetAttribute("size"));
FileTransfer transfer = new FileTransfer(from, im.Jid, name, size,
sid, desc);
string savePath = TransferRequest.Invoke(transfer);
// User has rejected the request.
if (savePath == null)
{
return(new XmppError(ErrorType.Cancel, ErrorCondition.NotAcceptable).Data);
}
// Create an SI session instance.
SISession session = new SISession(sid, File.OpenWrite(savePath),
size, true, from, im.Jid, im.GetExtension(method) as IDataStream);
siSessions.TryAdd(sid, session);
// Store the file's meta data.
metaData.TryAdd(sid, new FileMetaData(name, desc));
// Construct and return the negotiation result.
return(Xml.Element("si", "http://jabber.org/protocol/si").Child(
FeatureNegotiation.Create(new SubmitForm(
new ListField("stream-method", method)))));
} catch {
return(new XmppError(ErrorType.Cancel, ErrorCondition.BadRequest).Data);
}
}
