/// <summary>
/// Initiates a network query for a session
/// </summary>
/// <param name="TimeoutHandler">The Action that is called when the query times out</param>
/// <returns>True if the network query was initiated. Otherwise, false</returns>
protected bool QueryNetwork(System.Threading.WaitCallback TimeoutHandler)
{
ServiceSocket[] peers = service.LivePeers;
if (!service.Settings.StandaloneMode && peers.Length > 0)
{
if (queryTimeout == null)
{
queryTimeout = DateTime.UtcNow + new TimeSpan(0, 0, 0, 0, service.Settings.NetworkQueryTimeout);
}
//Log P2P Querying Network
Diags.LogQueryingNetwork(Resource);
//Create a new guid as the message id
Guid msgID = Guid.NewGuid();
//Add new query to Queries Initiated list (with one minute expiry)
service.QueriesInitiated.Add(DateTime.UtcNow + new TimeSpan(0, 1, 0), msgID, null);
//To get Origin Host: Get the LocalIP of the server IP + Port of peer listening socket
//NOTE: Server IP must be valid within this routine because it is discovered in Server.NewLivePeer() and livePeers > 0
string originEndPoint;
{
string localhost;
int? localport;
ServerSettings.HostEndPoint.Parse(service.ServerIP, out localhost, out localport);
originEndPoint = new ServerSettings.HostEndPoint(localhost, service.Settings.PeerPort).ToString();
}
//Broadcast a GetTransferMessage which will call Process() when the session is returned
//and processes TimeoutHandler delegate when the broadcast times out
GetTransferMessage.Broadcast
(originEndPoint ,new List<ServiceSocket>(peers), service, Resource, msgID, service.Settings.MaxForwards, Guid.Empty, queryTimeout.Value,
delegate(string key) { Process(); }, //Found delegate simply reprocesses the request
delegate (object key) //Timeout delegate calls the time-out handler
{
Diags.LogNetworkQueryTimeout(Resource);
TimeoutHandler(key);
}
);
return true;
}
else
{
return false;
}
}
/// <summary>
/// Called by the SessionDictionary.BeginExport method to complete processing the request,
/// if the requested session was found and read
/// </summary>
/// <param name="Session">The read session</param>
/// <param name="StateObject">The state object passed from the SessionDictionary.BeginExport method</param>
private void CompleteTransferRequest(ISessionObject Session, object StateObject)
{
ISessionResponseInfo response = Session.CreateResponseInfo();
//Get the endpoint for the host to connect to
string remoteHost;
int? remotePort;
ServerSettings.HostEndPoint.Parse(Host,out remoteHost,out remotePort);
if(!remotePort.HasValue) remotePort = service.Settings.PeerPort;
ServerSettings.HostEndPoint endPoint = new ServerSettings.HostEndPoint(remoteHost.Trim(),remotePort.Value);
const int sentTransferExpiryTime = 2; // 2 seconds is sufficient for a broadcast to traverse half a reasonable network
#region Callback Delegate declarations
//SuccessAction
Action<AsyncMessageTracker> successAction =
delegate(AsyncMessageTracker asyncMsg)
{
//Add this transfer to list of recently transferred sessions and have it expire in 15 seconds
service.SentTransfers.Add(DateTime.UtcNow + new TimeSpan(0, 0, sentTransferExpiryTime), Resource, null);
TransferSuccess(asyncMsg);
Diags.LogTransferSuccess(Resource);
};
//FailedAction
Action<AsyncMessageTracker> failureAction =
delegate(AsyncMessageTracker asyncMsg)
{
TransferFailure(asyncMsg);
Diags.LogTransferFailed(Resource, string.Empty);
};
//AlreadyExistsAction
Action<AsyncMessageTracker> alreadyExistsAction =
delegate(AsyncMessageTracker asyncMsg)
{
//Add this transfer to list of recently transferred sessions and have it expire in 15 seconds
service.SentTransfers.Add(DateTime.UtcNow + new TimeSpan(0, 0, sentTransferExpiryTime), Resource, null);
TransferSuccess(asyncMsg);
Diags.LogTransferFailed(Resource, "Resource already exists in remote peer -- deleted local copy");
};
//PeerShuttingDownAction
Action<AsyncMessageTracker> peerShuttingDownAction =
delegate(AsyncMessageTracker asyncMsg)
{
TransferFailure(asyncMsg);
Diags.LogTransferFailed(Resource, "Peer is shutting down");
};
//TimeoutAction
System.Threading.WaitCallback timeoutAction =
delegate(object asyncMsg)
{
//This anonymous method can be called directly from a background thread so make sure it's exception-safe
try
{
TransferFailure((AsyncMessageTracker)asyncMsg);
Diags.LogTransferFailed(Resource, "Timed out");
}
catch (Exception ex)
{
Diags.LogApplicationError( "TimeoutAction delegate error in CompleteTransferRequest", ex);
}
};
//FailedActionForExistingLink
Action<AsyncMessageTracker> failureActionForExistingLink =
delegate(AsyncMessageTracker asyncMsg)
{
Diags.LogTransferFailed(Resource, "Existing link, trying again on new link");
//Try again by reconnecting
service.TransferSession(endPoint, Resource, response, Session.Data,
successAction, failureAction, alreadyExistsAction, peerShuttingDownAction, timeoutAction);
};
#endregion
service.NewActiveExport(Resource); //create an entry in the exports list for this export
//Look for standing link
ServiceSocket linkSocket;
if(service.TryGetLinkTo(endPoint, out linkSocket))
{
//There is a standing link to this peer so send transfer through it
AsyncMessageTracker msg = new AsyncMessageTracker(AsyncMessageOperation.SetTransferOperation, Guid.NewGuid(), linkSocket);
service.TransferSession(msg, Resource, response, Session.Data,
successAction, failureActionForExistingLink, alreadyExistsAction, peerShuttingDownAction, timeoutAction);
}
else
{
//Initiate a brand new connection
service.TransferSession(endPoint, Resource, response, Session.Data,
successAction,failureAction,alreadyExistsAction,peerShuttingDownAction,timeoutAction);
}
}
