/// <summary>
/// Handles messages received from other machines on the network and dispatches them locally.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void OnMessageReceived(object sender, XDMessageEventArgs e)
{
// network message is of format machine:channel:message
if (e.DataGram.IsValid)
{
using (DataGram machineInfo = DataGram.ExpandFromRaw(e.DataGram.Message))
{
if (machineInfo.IsValid)
{
// don't relay if the message was broadcast on this machine
if (machineInfo.Channel != Environment.MachineName)
{
using (DataGram dataGram = DataGram.ExpandFromRaw(machineInfo.Message))
{
if (dataGram.IsValid)
{
// propagate the message on this machine using the same mode as the sender
nativeBroadcast.SendToChannel(dataGram.Channel, dataGram.Message);
}
}
}
}
}
}
}
private void ProcessMessage(object state)
{
string filepath = state as string;
try
{
// check if file exists
if (File.Exists(filepath))
{
string rawmessage = null;
// try to load the file in shared access mode
using (FileStream stream = File.Open(filepath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
using (StreamReader reader = new StreamReader(stream))
{
rawmessage = reader.ReadToEnd();
}
}
using (DataGram dataGram = DataGram.ExpandFromRaw(rawmessage))
{
if (dataGram.IsValid)
{
// dispatch the message received event
MessageReceived(this, new XDMessageEventArgs(dataGram));
}
}
try
{
File.Delete(filepath);
}
catch { }
}
}
catch (FileNotFoundException)
{
// if for any reason the file was deleted before the message could be read from the file,
// then can safely ignore this message
}
catch (UnauthorizedAccessException ue)
{
throw new UnauthorizedAccessException(string.Format("Unable to bind to channel as access is denied." +
" Ensure the process has read/write access to the directory '{0}'.", filepath), ue);
}
catch (IOException ie)
{
throw new IOException(string.Format("There was an unexpected IO error binding to a channel." +
" Ensure the process is unable to read/write to directory '{0}'.", filepath), ie);
}
}
/// <summary>
/// Extracts the message for the buffer and raises the MessageReceived event.
/// </summary>
/// <param name="buffer"></param>
/// <param name="bytesRead"></param>
private void ProcessMessage(byte[] buffer, uint bytesRead)
{
BinaryFormatter b = new BinaryFormatter();
string rawMessage = string.Empty;
try
{
rawMessage = Encoding.UTF8.GetString(buffer, 0, (int)bytesRead);
}
catch
{
// if something goes wrong such as handle is closed,
// we will not process this message
}
/*
* using (MemoryStream stream = new MemoryStream())
* {
* stream.Write(buffer, 0, (int)bytesRead);
* stream.Flush();
* // reset the stream cursor back to the beginning
* stream.Seek(0, SeekOrigin.Begin);
* try
* {
* rawMessage = (string)b.Deserialize(stream);
* }
* catch (SerializationException) { } // if something goes wrong such as handle is closed,
* // we will not process this message
* }*/
// mailslot message format is id:channel:message
using (DataGram dataGramId = DataGram.ExpandFromRaw(rawMessage))
{
// only dispatch event if this is a new message
// this filters out mailslot duplicates which are sent once per protocol
if (dataGramId.IsValid && dataGramId.Channel != lastMessageId)
{
// remember we have seen this message
lastMessageId = dataGramId.Channel;
using (DataGram dataGram = DataGram.ExpandFromRaw(dataGramId.Message))
{
if (dataGram.IsValid)
{
OnMessageReceived(dataGram);
}
}
}
}
}