/// <summary>
/// Method used to request the download of a chunk from the network. When it is invoked from
/// a remote peer it gets the chunk from the file and calls back the ReturnChunk method
/// of the requestor.
/// </summary>
/// <param name="chkrq">Message used to pass information about the Chunk requested</param>
public void GetChunk(ChunkRequest chkrq)
{
log.Info("Received request to send chunk!");
servingBuffer++;
TrackModel track = new TrackModel();
RepositoryResponse resp = trackRepository.GetByKey <TrackModel.Track>(chkrq.RID, track);
log.Debug("Searching track " + track + " in repository");
if (resp >= 0)
{
log.Debug("Track found! Extracting chunk.");
byte[] data;
using (FileStream fs = new FileStream(track.Filepath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
int limit = (System.Convert.ToInt32(fs.Length) > (chunkLength * 1024 * (chkrq.CID + 1))) ? chunkLength * 1024 * (chkrq.CID + 1) : (System.Convert.ToInt32(fs.Length));
int begin = chkrq.CID * chunkLength * 1024;
data = new byte[limit - begin];
Console.WriteLine("Reading chunk " + chkrq.CID + " (" + (chkrq.CID * chunkLength * 1024) + " => " + limit + ")");
fs.Seek(begin, SeekOrigin.Begin);
fs.Read(data, 0, (limit - begin));
fs.Close();
}
ChunkResponse chkrs = new ChunkResponse(servingBuffer, chkrq.RID, chkrq.CID, data, myAddress);
if (chkrq.SenderAddress != myAddress)
{
ITransportProtocol svc = ChannelFactory <ITransportProtocol> .CreateChannel(
new NetUdpBinding(), new EndpointAddress(chkrq.SenderAddress)
);
svc.ReturnChunk(chkrs);
}
else
{
this.ReturnChunk(chkrs);
}
log.Debug("Chunk sent to " + chkrq.SenderAddress);
}
servingBuffer--;
}
/// <summary>
/// Method used to return chunk to requestors. When it is invoked from a remote peer
/// it invokes the saveOnBuffer method to store the chunk into the buffer. At the end this
/// method reset the peer status.
/// </summary>
/// <param name="chkrs">Message used to transport the payload of a chunk</param>
public void ReturnChunk(ChunkResponse chkrs)
{
log.Info("Arrived chunk from peer!");
this.saveOnBuffer(chkrs.CID, chkrs.Payload);
this.peerQueue.ResetPeer(chkrs.SenderAddress.AbsoluteUri, chkrs.ServingBuffer);
}
